fix: avoid panic in the RetryUntil (#15501)

1. Use jpillora/backoff to get the backoff to avoid the panic in RetryUntil.
2. Return with last err when retry timeout.

Signed-off-by: He Weiwei <hweiwei@vmware.com>
This commit is contained in:
He Weiwei 2021-08-27 17:28:33 +08:00 committed by GitHub
parent b58158c30f
commit d482a0c323
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
34 changed files with 328 additions and 1693 deletions

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@ -27,6 +27,7 @@ import (
"github.com/goharbor/harbor/src/lib/log"
"github.com/goharbor/harbor/src/lib/orm"
"github.com/goharbor/harbor/src/lib/q"
"github.com/goharbor/harbor/src/lib/retry"
"github.com/goharbor/harbor/src/pkg/reg"
"github.com/goharbor/harbor/src/pkg/reg/model"
"github.com/goharbor/harbor/src/pkg/replication"
@ -129,7 +130,7 @@ func (c *controller) Start(ctx context.Context, policy *replicationmodel.Policy,
// as we start a new transaction in the goroutine, the execution record may not
// be inserted yet, wait until it is ready before continue
if err := lib.RetryUntil(func() error {
if err := retry.Retry(func() error {
_, err := c.execMgr.Get(ctx, id)
return err
}); err != nil {

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@ -28,12 +28,12 @@ import (
sc "github.com/goharbor/harbor/src/controller/scanner"
"github.com/goharbor/harbor/src/controller/tag"
"github.com/goharbor/harbor/src/jobservice/job"
"github.com/goharbor/harbor/src/lib"
"github.com/goharbor/harbor/src/lib/config"
"github.com/goharbor/harbor/src/lib/errors"
"github.com/goharbor/harbor/src/lib/log"
"github.com/goharbor/harbor/src/lib/orm"
"github.com/goharbor/harbor/src/lib/q"
"github.com/goharbor/harbor/src/lib/retry"
allowlist "github.com/goharbor/harbor/src/pkg/allowlist/models"
"github.com/goharbor/harbor/src/pkg/permission/types"
"github.com/goharbor/harbor/src/pkg/robot/model"
@ -322,7 +322,7 @@ func (bc *basicController) ScanAll(ctx context.Context, trigger string, async bo
if async {
go func(ctx context.Context) {
// if async, this is running in another goroutine ensure the execution exists in db
err := lib.RetryUntil(func() error {
err := retry.Retry(func() error {
_, err := bc.execMgr.Get(ctx, executionID)
return err
})

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@ -49,6 +49,7 @@ require (
github.com/gorilla/mux v1.7.4
github.com/graph-gophers/dataloader v5.0.0+incompatible
github.com/jinzhu/gorm v1.9.8 // indirect
github.com/jpillora/backoff v1.0.0
github.com/lib/pq v1.10.0
github.com/miekg/pkcs11 v0.0.0-20170220202408-7283ca79f35e // indirect
github.com/ncw/swift v1.0.49 // indirect

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@ -245,7 +245,6 @@ github.com/denverdino/aliyungo v0.0.0-20191227032621-df38c6fa730c/go.mod h1:dV8l
github.com/dghubble/sling v1.1.0 h1:DLu20Bq2qsB9cI5Hldaxj+TMPEaPpPE8IR2kvD22Atg=
github.com/dghubble/sling v1.1.0/go.mod h1:ZcPRuLm0qrcULW2gOrjXrAWgf76sahqSyxXyVOvkunE=
github.com/dgrijalva/jwt-go v0.0.0-20170104182250-a601269ab70c/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
github.com/dhui/dktest v0.3.2 h1:nZSDcnkpbotzT/nEHNsO+JCKY8i1Qoki1AYOpeLRb6M=
@ -638,6 +637,8 @@ github.com/jmoiron/sqlx v1.2.0/go.mod h1:1FEQNm3xlJgrMD+FBdI9+xvCksHtbpVBBw5dYhB
github.com/jmoiron/sqlx v1.3.1/go.mod h1:2BljVx/86SuTyjE+aPYlHCTNvZrnJXghYGpNiXLBMCQ=
github.com/joho/godotenv v1.3.0/go.mod h1:7hK45KPybAkOC6peb+G5yklZfMxEjkZhHbwpqxOKXbg=
github.com/jonboulle/clockwork v0.1.0/go.mod h1:Ii8DK3G1RaLaWxj9trq07+26W01tbo22gdxWY5EU2bo=
github.com/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
github.com/json-iterator/go v1.1.5/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
github.com/json-iterator/go v1.1.7/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
@ -1400,6 +1401,7 @@ gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C
gopkg.in/yaml.v3 v3.0.0-20200605160147-a5ece683394c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 h1:tQIYjPdBoyREyB9XMu+nnTclpTYkz2zFM+lzLJFO4gQ=
gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gotest.tools v2.2.0+incompatible h1:VsBPFP1AI068pPrMxtb/S8Zkgf9xEmTLJjfM+P5UIEo=
gotest.tools v2.2.0+incompatible/go.mod h1:DsYFclhRJ6vuDpmuTbkuFWG+y2sxOXAzmJt81HFBacw=
gotest.tools/v3 v3.0.2/go.mod h1:3SzNCllyD9/Y+b5r9JIKQ474KzkZyqLqEfYqMsX94Bk=
gotest.tools/v3 v3.0.3 h1:4AuOwCGf4lLR9u3YOe2awrHygurzhO/HeQ6laiA6Sx0=

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@ -15,7 +15,6 @@
package gc
import (
"github.com/goharbor/harbor/src/lib"
"os"
"time"
@ -27,6 +26,7 @@ import (
"github.com/goharbor/harbor/src/lib/errors"
"github.com/goharbor/harbor/src/lib/q"
redislib "github.com/goharbor/harbor/src/lib/redis"
"github.com/goharbor/harbor/src/lib/retry"
"github.com/goharbor/harbor/src/pkg/artifactrash"
"github.com/goharbor/harbor/src/pkg/artifactrash/model"
"github.com/goharbor/harbor/src/pkg/blob"
@ -271,11 +271,11 @@ func (gc *GarbageCollector) sweep(ctx job.Context) error {
}
// for manifest, it has to delete the revisions folder of each repository
gc.logger.Infof("delete manifest from storage: %s", blob.Digest)
if err := lib.RetryUntil(func() error {
if err := retry.Retry(func() error {
return ignoreNotFound(func() error {
return gc.registryCtlClient.DeleteManifest(art.RepositoryName, blob.Digest)
})
}, lib.RetryCallback(func(err error, sleep time.Duration) {
}, retry.Callback(func(err error, sleep time.Duration) {
gc.logger.Infof("failed to exec DeleteManifest retry after %s : %v", sleep, err)
})); err != nil {
if err := ignoreNotFound(func() error {
@ -299,11 +299,11 @@ func (gc *GarbageCollector) sweep(ctx job.Context) error {
// for the foreign layer, as it's not stored in the storage, no need to call the delete api and count size, but still have to delete the DB record.
if !blob.IsForeignLayer() {
gc.logger.Infof("delete blob from storage: %s", blob.Digest)
if err := lib.RetryUntil(func() error {
if err := retry.Retry(func() error {
return ignoreNotFound(func() error {
return gc.registryCtlClient.DeleteBlob(blob.Digest)
})
}, lib.RetryCallback(func(err error, sleep time.Duration) {
}, retry.Callback(func(err error, sleep time.Duration) {
gc.logger.Infof("failed to exec DeleteBlob retry after %s : %v", sleep, err)
})); err != nil {
if err := ignoreNotFound(func() error {

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@ -2,11 +2,12 @@ package gc
import (
"fmt"
"github.com/goharbor/harbor/src/lib"
"time"
"github.com/goharbor/harbor/src/lib/errors"
"github.com/goharbor/harbor/src/lib/retry"
"github.com/goharbor/harbor/src/pkg/registry"
"github.com/gomodule/redigo/redis"
"time"
)
// delKeys ...
@ -52,9 +53,9 @@ func v2DeleteManifest(repository, digest string) error {
if !exist {
return nil
}
return lib.RetryUntil(func() error {
return retry.Retry(func() error {
return registry.Cli.DeleteManifest(repository, digest)
}, lib.RetryCallback(func(err error, sleep time.Duration) {
}, retry.Callback(func(err error, sleep time.Duration) {
fmt.Printf("failed to exec DeleteManifest retry after %s : %v\n", sleep, err)
}))
}

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@ -21,8 +21,8 @@ import (
"sync"
"time"
"github.com/goharbor/harbor/src/lib"
"github.com/goharbor/harbor/src/lib/log"
"github.com/goharbor/harbor/src/lib/retry"
)
const (
@ -102,16 +102,16 @@ func Initialize(typ, addr string) error {
redactedAddr = redacted(u)
}
options := []lib.RetryOption{
lib.RetryInitialInterval(time.Millisecond * 500),
lib.RetryMaxInterval(time.Second * 10),
lib.RetryTimeout(time.Minute),
lib.RetryCallback(func(err error, sleep time.Duration) {
options := []retry.Option{
retry.InitialInterval(time.Millisecond * 500),
retry.MaxInterval(time.Second * 10),
retry.Timeout(time.Minute),
retry.Callback(func(err error, sleep time.Duration) {
log.Errorf("failed to ping %s, retry after %s : %v", redactedAddr, sleep, err)
}),
}
if err := lib.RetryUntil(c.Ping, options...); err != nil {
if err := retry.Retry(c.Ping, options...); err != nil {
return err
}

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@ -12,13 +12,14 @@
// See the License for the specific language governing permissions and
// limitations under the License.
package lib
package retry
import (
"errors"
"math"
"math/rand"
"time"
"github.com/goharbor/harbor/src/lib/errors"
"github.com/jpillora/backoff"
)
func init() {
@ -30,51 +31,51 @@ var (
ErrRetryTimeout = errors.New("retry timeout")
)
// RetryOptions options for the retry functions
type RetryOptions struct {
// Options options for the retry functions
type Options struct {
InitialInterval time.Duration // the initial interval for retring after failure, default 100 milliseconds
MaxInterval time.Duration // the max interval for retring after failure, default 1 second
Timeout time.Duration // the total time before returning if something is wrong, default 1 minute
Callback func(err error, sleep time.Duration) // the callback function for Retry when the f called failed
}
// RetryOption ...
type RetryOption func(*RetryOptions)
// Option ...
type Option func(*Options)
// RetryInitialInterval set initial interval
func RetryInitialInterval(initial time.Duration) RetryOption {
return func(opts *RetryOptions) {
// InitialInterval set initial interval
func InitialInterval(initial time.Duration) Option {
return func(opts *Options) {
opts.InitialInterval = initial
}
}
// RetryMaxInterval set max interval
func RetryMaxInterval(max time.Duration) RetryOption {
return func(opts *RetryOptions) {
// MaxInterval set max interval
func MaxInterval(max time.Duration) Option {
return func(opts *Options) {
opts.MaxInterval = max
}
}
// RetryTimeout set timeout interval
func RetryTimeout(timeout time.Duration) RetryOption {
return func(opts *RetryOptions) {
// Timeout set timeout interval
func Timeout(timeout time.Duration) Option {
return func(opts *Options) {
opts.Timeout = timeout
}
}
// RetryCallback set callback
func RetryCallback(callback func(err error, sleep time.Duration)) RetryOption {
return func(opts *RetryOptions) {
// Callback set callback
func Callback(callback func(err error, sleep time.Duration)) Option {
return func(opts *Options) {
opts.Callback = callback
}
}
// RetryUntil retry until f run successfully or timeout
// Retry retry until f run successfully or timeout
//
// NOTE: This function will use exponential backoff and jitter for retrying, see
// https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/ for more information
func RetryUntil(f func() error, options ...RetryOption) error {
opts := &RetryOptions{}
func Retry(f func() error, options ...Option) error {
opts := &Options{}
for _, o := range options {
o(opts)
@ -92,42 +93,32 @@ func RetryUntil(f func() error, options ...RetryOption) error {
opts.Timeout = time.Minute
}
b := &backoff.Backoff{
Min: opts.InitialInterval,
Max: opts.MaxInterval,
Factor: 2,
Jitter: true,
}
var err error
timeout := time.After(opts.Timeout)
for attempt := 1; ; attempt++ {
for {
select {
case <-timeout:
return ErrRetryTimeout
return errors.New(ErrRetryTimeout).WithCause(err)
default:
if err := f(); err != nil {
sleep := getBackoff(attempt, opts.InitialInterval, opts.MaxInterval, true)
if opts.Callback != nil {
opts.Callback(err, sleep)
}
time.Sleep(sleep)
} else {
err = f()
if err == nil {
return nil
}
sleep := b.Duration()
if opts.Callback != nil {
opts.Callback(err, sleep)
}
time.Sleep(sleep)
}
}
}
func getBackoff(attempt int, initialInterval, maxInterval time.Duration, equalJitter bool) time.Duration {
max := float64(maxInterval)
base := float64(initialInterval)
dur := base * math.Pow(2, float64(attempt))
if equalJitter {
dur = dur/2 + float64(rand.Int63n(int64(dur))/2)
}
if dur < base {
dur = base
}
if dur > max {
dur = max
}
return time.Duration(dur)
}

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@ -12,7 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.
package lib
package retry
import (
"fmt"
@ -30,7 +30,7 @@ func TestRetryUntil(t *testing.T) {
i++
return fmt.Errorf("failed")
}
assert.Error(RetryUntil(f1, RetryInitialInterval(time.Second), RetryMaxInterval(time.Second), RetryTimeout(time.Second*5)))
assert.Error(Retry(f1, InitialInterval(time.Second), MaxInterval(time.Second), Timeout(time.Second*5)))
// f1 called time 0s - sleep - 1s - sleep - 2s - sleep - 3s - sleep - 4s - sleep - 5s
// i after f1 called 1 2 3 4 5 6
// the i may be 5 or 6 depend on timeout or default which is seleted by the select statement
@ -39,7 +39,7 @@ func TestRetryUntil(t *testing.T) {
f2 := func() error {
return nil
}
assert.Nil(RetryUntil(f2))
assert.Nil(Retry(f2))
i = 0
f3 := func() error {
@ -52,13 +52,20 @@ func TestRetryUntil(t *testing.T) {
}
return nil
}
assert.Nil(RetryUntil(f3))
assert.Nil(Retry(f3))
RetryUntil(
Retry(
f1,
RetryTimeout(time.Second*5),
RetryCallback(func(err error, sleep time.Duration) {
Timeout(time.Second*5),
Callback(func(err error, sleep time.Duration) {
fmt.Printf("failed to exec f1 retry after %s : %v\n", sleep, err)
}),
)
err := Retry(func() error {
return fmt.Errorf("always failed")
})
assert.Error(err)
assert.Equal("retry timeout: always failed", err.Error())
}

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@ -1,4 +0,0 @@
.DS_Store
bin

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@ -1,13 +0,0 @@
language: go
script:
- go vet ./...
- go test -v ./...
go:
- 1.3
- 1.4
- 1.5
- 1.6
- 1.7
- tip

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@ -1,8 +0,0 @@
Copyright (c) 2012 Dave Grijalva
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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@ -1,97 +0,0 @@
## Migration Guide from v2 -> v3
Version 3 adds several new, frequently requested features. To do so, it introduces a few breaking changes. We've worked to keep these as minimal as possible. This guide explains the breaking changes and how you can quickly update your code.
### `Token.Claims` is now an interface type
The most requested feature from the 2.0 verison of this library was the ability to provide a custom type to the JSON parser for claims. This was implemented by introducing a new interface, `Claims`, to replace `map[string]interface{}`. We also included two concrete implementations of `Claims`: `MapClaims` and `StandardClaims`.
`MapClaims` is an alias for `map[string]interface{}` with built in validation behavior. It is the default claims type when using `Parse`. The usage is unchanged except you must type cast the claims property.
The old example for parsing a token looked like this..
```go
if token, err := jwt.Parse(tokenString, keyLookupFunc); err == nil {
fmt.Printf("Token for user %v expires %v", token.Claims["user"], token.Claims["exp"])
}
```
is now directly mapped to...
```go
if token, err := jwt.Parse(tokenString, keyLookupFunc); err == nil {
claims := token.Claims.(jwt.MapClaims)
fmt.Printf("Token for user %v expires %v", claims["user"], claims["exp"])
}
```
`StandardClaims` is designed to be embedded in your custom type. You can supply a custom claims type with the new `ParseWithClaims` function. Here's an example of using a custom claims type.
```go
type MyCustomClaims struct {
User string
*StandardClaims
}
if token, err := jwt.ParseWithClaims(tokenString, &MyCustomClaims{}, keyLookupFunc); err == nil {
claims := token.Claims.(*MyCustomClaims)
fmt.Printf("Token for user %v expires %v", claims.User, claims.StandardClaims.ExpiresAt)
}
```
### `ParseFromRequest` has been moved
To keep this library focused on the tokens without becoming overburdened with complex request processing logic, `ParseFromRequest` and its new companion `ParseFromRequestWithClaims` have been moved to a subpackage, `request`. The method signatues have also been augmented to receive a new argument: `Extractor`.
`Extractors` do the work of picking the token string out of a request. The interface is simple and composable.
This simple parsing example:
```go
if token, err := jwt.ParseFromRequest(tokenString, req, keyLookupFunc); err == nil {
fmt.Printf("Token for user %v expires %v", token.Claims["user"], token.Claims["exp"])
}
```
is directly mapped to:
```go
if token, err := request.ParseFromRequest(req, request.OAuth2Extractor, keyLookupFunc); err == nil {
claims := token.Claims.(jwt.MapClaims)
fmt.Printf("Token for user %v expires %v", claims["user"], claims["exp"])
}
```
There are several concrete `Extractor` types provided for your convenience:
* `HeaderExtractor` will search a list of headers until one contains content.
* `ArgumentExtractor` will search a list of keys in request query and form arguments until one contains content.
* `MultiExtractor` will try a list of `Extractors` in order until one returns content.
* `AuthorizationHeaderExtractor` will look in the `Authorization` header for a `Bearer` token.
* `OAuth2Extractor` searches the places an OAuth2 token would be specified (per the spec): `Authorization` header and `access_token` argument
* `PostExtractionFilter` wraps an `Extractor`, allowing you to process the content before it's parsed. A simple example is stripping the `Bearer ` text from a header
### RSA signing methods no longer accept `[]byte` keys
Due to a [critical vulnerability](https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries/), we've decided the convenience of accepting `[]byte` instead of `rsa.PublicKey` or `rsa.PrivateKey` isn't worth the risk of misuse.
To replace this behavior, we've added two helper methods: `ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error)` and `ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error)`. These are just simple helpers for unpacking PEM encoded PKCS1 and PKCS8 keys. If your keys are encoded any other way, all you need to do is convert them to the `crypto/rsa` package's types.
```go
func keyLookupFunc(*Token) (interface{}, error) {
// Don't forget to validate the alg is what you expect:
if _, ok := token.Method.(*jwt.SigningMethodRSA); !ok {
return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
}
// Look up key
key, err := lookupPublicKey(token.Header["kid"])
if err != nil {
return nil, err
}
// Unpack key from PEM encoded PKCS8
return jwt.ParseRSAPublicKeyFromPEM(key)
}
```

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@ -1,100 +0,0 @@
# jwt-go
[![Build Status](https://travis-ci.org/dgrijalva/jwt-go.svg?branch=master)](https://travis-ci.org/dgrijalva/jwt-go)
[![GoDoc](https://godoc.org/github.com/dgrijalva/jwt-go?status.svg)](https://godoc.org/github.com/dgrijalva/jwt-go)
A [go](http://www.golang.org) (or 'golang' for search engine friendliness) implementation of [JSON Web Tokens](http://self-issued.info/docs/draft-ietf-oauth-json-web-token.html)
**NEW VERSION COMING:** There have been a lot of improvements suggested since the version 3.0.0 released in 2016. I'm working now on cutting two different releases: 3.2.0 will contain any non-breaking changes or enhancements. 4.0.0 will follow shortly which will include breaking changes. See the 4.0.0 milestone to get an idea of what's coming. If you have other ideas, or would like to participate in 4.0.0, now's the time. If you depend on this library and don't want to be interrupted, I recommend you use your dependency mangement tool to pin to version 3.
**SECURITY NOTICE:** Some older versions of Go have a security issue in the cryotp/elliptic. Recommendation is to upgrade to at least 1.8.3. See issue #216 for more detail.
**SECURITY NOTICE:** It's important that you [validate the `alg` presented is what you expect](https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries/). This library attempts to make it easy to do the right thing by requiring key types match the expected alg, but you should take the extra step to verify it in your usage. See the examples provided.
## What the heck is a JWT?
JWT.io has [a great introduction](https://jwt.io/introduction) to JSON Web Tokens.
In short, it's a signed JSON object that does something useful (for example, authentication). It's commonly used for `Bearer` tokens in Oauth 2. A token is made of three parts, separated by `.`'s. The first two parts are JSON objects, that have been [base64url](http://tools.ietf.org/html/rfc4648) encoded. The last part is the signature, encoded the same way.
The first part is called the header. It contains the necessary information for verifying the last part, the signature. For example, which encryption method was used for signing and what key was used.
The part in the middle is the interesting bit. It's called the Claims and contains the actual stuff you care about. Refer to [the RFC](http://self-issued.info/docs/draft-jones-json-web-token.html) for information about reserved keys and the proper way to add your own.
## What's in the box?
This library supports the parsing and verification as well as the generation and signing of JWTs. Current supported signing algorithms are HMAC SHA, RSA, RSA-PSS, and ECDSA, though hooks are present for adding your own.
## Examples
See [the project documentation](https://godoc.org/github.com/dgrijalva/jwt-go) for examples of usage:
* [Simple example of parsing and validating a token](https://godoc.org/github.com/dgrijalva/jwt-go#example-Parse--Hmac)
* [Simple example of building and signing a token](https://godoc.org/github.com/dgrijalva/jwt-go#example-New--Hmac)
* [Directory of Examples](https://godoc.org/github.com/dgrijalva/jwt-go#pkg-examples)
## Extensions
This library publishes all the necessary components for adding your own signing methods. Simply implement the `SigningMethod` interface and register a factory method using `RegisterSigningMethod`.
Here's an example of an extension that integrates with the Google App Engine signing tools: https://github.com/someone1/gcp-jwt-go
## Compliance
This library was last reviewed to comply with [RTF 7519](http://www.rfc-editor.org/info/rfc7519) dated May 2015 with a few notable differences:
* In order to protect against accidental use of [Unsecured JWTs](http://self-issued.info/docs/draft-ietf-oauth-json-web-token.html#UnsecuredJWT), tokens using `alg=none` will only be accepted if the constant `jwt.UnsafeAllowNoneSignatureType` is provided as the key.
## Project Status & Versioning
This library is considered production ready. Feedback and feature requests are appreciated. The API should be considered stable. There should be very few backwards-incompatible changes outside of major version updates (and only with good reason).
This project uses [Semantic Versioning 2.0.0](http://semver.org). Accepted pull requests will land on `master`. Periodically, versions will be tagged from `master`. You can find all the releases on [the project releases page](https://github.com/dgrijalva/jwt-go/releases).
While we try to make it obvious when we make breaking changes, there isn't a great mechanism for pushing announcements out to users. You may want to use this alternative package include: `gopkg.in/dgrijalva/jwt-go.v3`. It will do the right thing WRT semantic versioning.
**BREAKING CHANGES:***
* Version 3.0.0 includes _a lot_ of changes from the 2.x line, including a few that break the API. We've tried to break as few things as possible, so there should just be a few type signature changes. A full list of breaking changes is available in `VERSION_HISTORY.md`. See `MIGRATION_GUIDE.md` for more information on updating your code.
## Usage Tips
### Signing vs Encryption
A token is simply a JSON object that is signed by its author. this tells you exactly two things about the data:
* The author of the token was in the possession of the signing secret
* The data has not been modified since it was signed
It's important to know that JWT does not provide encryption, which means anyone who has access to the token can read its contents. If you need to protect (encrypt) the data, there is a companion spec, `JWE`, that provides this functionality. JWE is currently outside the scope of this library.
### Choosing a Signing Method
There are several signing methods available, and you should probably take the time to learn about the various options before choosing one. The principal design decision is most likely going to be symmetric vs asymmetric.
Symmetric signing methods, such as HSA, use only a single secret. This is probably the simplest signing method to use since any `[]byte` can be used as a valid secret. They are also slightly computationally faster to use, though this rarely is enough to matter. Symmetric signing methods work the best when both producers and consumers of tokens are trusted, or even the same system. Since the same secret is used to both sign and validate tokens, you can't easily distribute the key for validation.
Asymmetric signing methods, such as RSA, use different keys for signing and verifying tokens. This makes it possible to produce tokens with a private key, and allow any consumer to access the public key for verification.
### Signing Methods and Key Types
Each signing method expects a different object type for its signing keys. See the package documentation for details. Here are the most common ones:
* The [HMAC signing method](https://godoc.org/github.com/dgrijalva/jwt-go#SigningMethodHMAC) (`HS256`,`HS384`,`HS512`) expect `[]byte` values for signing and validation
* The [RSA signing method](https://godoc.org/github.com/dgrijalva/jwt-go#SigningMethodRSA) (`RS256`,`RS384`,`RS512`) expect `*rsa.PrivateKey` for signing and `*rsa.PublicKey` for validation
* The [ECDSA signing method](https://godoc.org/github.com/dgrijalva/jwt-go#SigningMethodECDSA) (`ES256`,`ES384`,`ES512`) expect `*ecdsa.PrivateKey` for signing and `*ecdsa.PublicKey` for validation
### JWT and OAuth
It's worth mentioning that OAuth and JWT are not the same thing. A JWT token is simply a signed JSON object. It can be used anywhere such a thing is useful. There is some confusion, though, as JWT is the most common type of bearer token used in OAuth2 authentication.
Without going too far down the rabbit hole, here's a description of the interaction of these technologies:
* OAuth is a protocol for allowing an identity provider to be separate from the service a user is logging in to. For example, whenever you use Facebook to log into a different service (Yelp, Spotify, etc), you are using OAuth.
* OAuth defines several options for passing around authentication data. One popular method is called a "bearer token". A bearer token is simply a string that _should_ only be held by an authenticated user. Thus, simply presenting this token proves your identity. You can probably derive from here why a JWT might make a good bearer token.
* Because bearer tokens are used for authentication, it's important they're kept secret. This is why transactions that use bearer tokens typically happen over SSL.
## More
Documentation can be found [on godoc.org](http://godoc.org/github.com/dgrijalva/jwt-go).
The command line utility included in this project (cmd/jwt) provides a straightforward example of token creation and parsing as well as a useful tool for debugging your own integration. You'll also find several implementation examples in the documentation.

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## `jwt-go` Version History
#### 3.2.0
* Added method `ParseUnverified` to allow users to split up the tasks of parsing and validation
* HMAC signing method returns `ErrInvalidKeyType` instead of `ErrInvalidKey` where appropriate
* Added options to `request.ParseFromRequest`, which allows for an arbitrary list of modifiers to parsing behavior. Initial set include `WithClaims` and `WithParser`. Existing usage of this function will continue to work as before.
* Deprecated `ParseFromRequestWithClaims` to simplify API in the future.
#### 3.1.0
* Improvements to `jwt` command line tool
* Added `SkipClaimsValidation` option to `Parser`
* Documentation updates
#### 3.0.0
* **Compatibility Breaking Changes**: See MIGRATION_GUIDE.md for tips on updating your code
* Dropped support for `[]byte` keys when using RSA signing methods. This convenience feature could contribute to security vulnerabilities involving mismatched key types with signing methods.
* `ParseFromRequest` has been moved to `request` subpackage and usage has changed
* The `Claims` property on `Token` is now type `Claims` instead of `map[string]interface{}`. The default value is type `MapClaims`, which is an alias to `map[string]interface{}`. This makes it possible to use a custom type when decoding claims.
* Other Additions and Changes
* Added `Claims` interface type to allow users to decode the claims into a custom type
* Added `ParseWithClaims`, which takes a third argument of type `Claims`. Use this function instead of `Parse` if you have a custom type you'd like to decode into.
* Dramatically improved the functionality and flexibility of `ParseFromRequest`, which is now in the `request` subpackage
* Added `ParseFromRequestWithClaims` which is the `FromRequest` equivalent of `ParseWithClaims`
* Added new interface type `Extractor`, which is used for extracting JWT strings from http requests. Used with `ParseFromRequest` and `ParseFromRequestWithClaims`.
* Added several new, more specific, validation errors to error type bitmask
* Moved examples from README to executable example files
* Signing method registry is now thread safe
* Added new property to `ValidationError`, which contains the raw error returned by calls made by parse/verify (such as those returned by keyfunc or json parser)
#### 2.7.0
This will likely be the last backwards compatible release before 3.0.0, excluding essential bug fixes.
* Added new option `-show` to the `jwt` command that will just output the decoded token without verifying
* Error text for expired tokens includes how long it's been expired
* Fixed incorrect error returned from `ParseRSAPublicKeyFromPEM`
* Documentation updates
#### 2.6.0
* Exposed inner error within ValidationError
* Fixed validation errors when using UseJSONNumber flag
* Added several unit tests
#### 2.5.0
* Added support for signing method none. You shouldn't use this. The API tries to make this clear.
* Updated/fixed some documentation
* Added more helpful error message when trying to parse tokens that begin with `BEARER `
#### 2.4.0
* Added new type, Parser, to allow for configuration of various parsing parameters
* You can now specify a list of valid signing methods. Anything outside this set will be rejected.
* You can now opt to use the `json.Number` type instead of `float64` when parsing token JSON
* Added support for [Travis CI](https://travis-ci.org/dgrijalva/jwt-go)
* Fixed some bugs with ECDSA parsing
#### 2.3.0
* Added support for ECDSA signing methods
* Added support for RSA PSS signing methods (requires go v1.4)
#### 2.2.0
* Gracefully handle a `nil` `Keyfunc` being passed to `Parse`. Result will now be the parsed token and an error, instead of a panic.
#### 2.1.0
Backwards compatible API change that was missed in 2.0.0.
* The `SignedString` method on `Token` now takes `interface{}` instead of `[]byte`
#### 2.0.0
There were two major reasons for breaking backwards compatibility with this update. The first was a refactor required to expand the width of the RSA and HMAC-SHA signing implementations. There will likely be no required code changes to support this change.
The second update, while unfortunately requiring a small change in integration, is required to open up this library to other signing methods. Not all keys used for all signing methods have a single standard on-disk representation. Requiring `[]byte` as the type for all keys proved too limiting. Additionally, this implementation allows for pre-parsed tokens to be reused, which might matter in an application that parses a high volume of tokens with a small set of keys. Backwards compatibilty has been maintained for passing `[]byte` to the RSA signing methods, but they will also accept `*rsa.PublicKey` and `*rsa.PrivateKey`.
It is likely the only integration change required here will be to change `func(t *jwt.Token) ([]byte, error)` to `func(t *jwt.Token) (interface{}, error)` when calling `Parse`.
* **Compatibility Breaking Changes**
* `SigningMethodHS256` is now `*SigningMethodHMAC` instead of `type struct`
* `SigningMethodRS256` is now `*SigningMethodRSA` instead of `type struct`
* `KeyFunc` now returns `interface{}` instead of `[]byte`
* `SigningMethod.Sign` now takes `interface{}` instead of `[]byte` for the key
* `SigningMethod.Verify` now takes `interface{}` instead of `[]byte` for the key
* Renamed type `SigningMethodHS256` to `SigningMethodHMAC`. Specific sizes are now just instances of this type.
* Added public package global `SigningMethodHS256`
* Added public package global `SigningMethodHS384`
* Added public package global `SigningMethodHS512`
* Renamed type `SigningMethodRS256` to `SigningMethodRSA`. Specific sizes are now just instances of this type.
* Added public package global `SigningMethodRS256`
* Added public package global `SigningMethodRS384`
* Added public package global `SigningMethodRS512`
* Moved sample private key for HMAC tests from an inline value to a file on disk. Value is unchanged.
* Refactored the RSA implementation to be easier to read
* Exposed helper methods `ParseRSAPrivateKeyFromPEM` and `ParseRSAPublicKeyFromPEM`
#### 1.0.2
* Fixed bug in parsing public keys from certificates
* Added more tests around the parsing of keys for RS256
* Code refactoring in RS256 implementation. No functional changes
#### 1.0.1
* Fixed panic if RS256 signing method was passed an invalid key
#### 1.0.0
* First versioned release
* API stabilized
* Supports creating, signing, parsing, and validating JWT tokens
* Supports RS256 and HS256 signing methods

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package jwt
import (
"crypto/subtle"
"fmt"
"time"
)
// For a type to be a Claims object, it must just have a Valid method that determines
// if the token is invalid for any supported reason
type Claims interface {
Valid() error
}
// Structured version of Claims Section, as referenced at
// https://tools.ietf.org/html/rfc7519#section-4.1
// See examples for how to use this with your own claim types
type StandardClaims struct {
Audience string `json:"aud,omitempty"`
ExpiresAt int64 `json:"exp,omitempty"`
Id string `json:"jti,omitempty"`
IssuedAt int64 `json:"iat,omitempty"`
Issuer string `json:"iss,omitempty"`
NotBefore int64 `json:"nbf,omitempty"`
Subject string `json:"sub,omitempty"`
}
// Validates time based claims "exp, iat, nbf".
// There is no accounting for clock skew.
// As well, if any of the above claims are not in the token, it will still
// be considered a valid claim.
func (c StandardClaims) Valid() error {
vErr := new(ValidationError)
now := TimeFunc().Unix()
// The claims below are optional, by default, so if they are set to the
// default value in Go, let's not fail the verification for them.
if c.VerifyExpiresAt(now, false) == false {
delta := time.Unix(now, 0).Sub(time.Unix(c.ExpiresAt, 0))
vErr.Inner = fmt.Errorf("token is expired by %v", delta)
vErr.Errors |= ValidationErrorExpired
}
if c.VerifyIssuedAt(now, false) == false {
vErr.Inner = fmt.Errorf("Token used before issued")
vErr.Errors |= ValidationErrorIssuedAt
}
if c.VerifyNotBefore(now, false) == false {
vErr.Inner = fmt.Errorf("token is not valid yet")
vErr.Errors |= ValidationErrorNotValidYet
}
if vErr.valid() {
return nil
}
return vErr
}
// Compares the aud claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (c *StandardClaims) VerifyAudience(cmp string, req bool) bool {
return verifyAud(c.Audience, cmp, req)
}
// Compares the exp claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (c *StandardClaims) VerifyExpiresAt(cmp int64, req bool) bool {
return verifyExp(c.ExpiresAt, cmp, req)
}
// Compares the iat claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (c *StandardClaims) VerifyIssuedAt(cmp int64, req bool) bool {
return verifyIat(c.IssuedAt, cmp, req)
}
// Compares the iss claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (c *StandardClaims) VerifyIssuer(cmp string, req bool) bool {
return verifyIss(c.Issuer, cmp, req)
}
// Compares the nbf claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (c *StandardClaims) VerifyNotBefore(cmp int64, req bool) bool {
return verifyNbf(c.NotBefore, cmp, req)
}
// ----- helpers
func verifyAud(aud string, cmp string, required bool) bool {
if aud == "" {
return !required
}
if subtle.ConstantTimeCompare([]byte(aud), []byte(cmp)) != 0 {
return true
} else {
return false
}
}
func verifyExp(exp int64, now int64, required bool) bool {
if exp == 0 {
return !required
}
return now <= exp
}
func verifyIat(iat int64, now int64, required bool) bool {
if iat == 0 {
return !required
}
return now >= iat
}
func verifyIss(iss string, cmp string, required bool) bool {
if iss == "" {
return !required
}
if subtle.ConstantTimeCompare([]byte(iss), []byte(cmp)) != 0 {
return true
} else {
return false
}
}
func verifyNbf(nbf int64, now int64, required bool) bool {
if nbf == 0 {
return !required
}
return now >= nbf
}

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// Package jwt is a Go implementation of JSON Web Tokens: http://self-issued.info/docs/draft-jones-json-web-token.html
//
// See README.md for more info.
package jwt

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package jwt
import (
"crypto"
"crypto/ecdsa"
"crypto/rand"
"errors"
"math/big"
)
var (
// Sadly this is missing from crypto/ecdsa compared to crypto/rsa
ErrECDSAVerification = errors.New("crypto/ecdsa: verification error")
)
// Implements the ECDSA family of signing methods signing methods
// Expects *ecdsa.PrivateKey for signing and *ecdsa.PublicKey for verification
type SigningMethodECDSA struct {
Name string
Hash crypto.Hash
KeySize int
CurveBits int
}
// Specific instances for EC256 and company
var (
SigningMethodES256 *SigningMethodECDSA
SigningMethodES384 *SigningMethodECDSA
SigningMethodES512 *SigningMethodECDSA
)
func init() {
// ES256
SigningMethodES256 = &SigningMethodECDSA{"ES256", crypto.SHA256, 32, 256}
RegisterSigningMethod(SigningMethodES256.Alg(), func() SigningMethod {
return SigningMethodES256
})
// ES384
SigningMethodES384 = &SigningMethodECDSA{"ES384", crypto.SHA384, 48, 384}
RegisterSigningMethod(SigningMethodES384.Alg(), func() SigningMethod {
return SigningMethodES384
})
// ES512
SigningMethodES512 = &SigningMethodECDSA{"ES512", crypto.SHA512, 66, 521}
RegisterSigningMethod(SigningMethodES512.Alg(), func() SigningMethod {
return SigningMethodES512
})
}
func (m *SigningMethodECDSA) Alg() string {
return m.Name
}
// Implements the Verify method from SigningMethod
// For this verify method, key must be an ecdsa.PublicKey struct
func (m *SigningMethodECDSA) Verify(signingString, signature string, key interface{}) error {
var err error
// Decode the signature
var sig []byte
if sig, err = DecodeSegment(signature); err != nil {
return err
}
// Get the key
var ecdsaKey *ecdsa.PublicKey
switch k := key.(type) {
case *ecdsa.PublicKey:
ecdsaKey = k
default:
return ErrInvalidKeyType
}
if len(sig) != 2*m.KeySize {
return ErrECDSAVerification
}
r := big.NewInt(0).SetBytes(sig[:m.KeySize])
s := big.NewInt(0).SetBytes(sig[m.KeySize:])
// Create hasher
if !m.Hash.Available() {
return ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Verify the signature
if verifystatus := ecdsa.Verify(ecdsaKey, hasher.Sum(nil), r, s); verifystatus == true {
return nil
} else {
return ErrECDSAVerification
}
}
// Implements the Sign method from SigningMethod
// For this signing method, key must be an ecdsa.PrivateKey struct
func (m *SigningMethodECDSA) Sign(signingString string, key interface{}) (string, error) {
// Get the key
var ecdsaKey *ecdsa.PrivateKey
switch k := key.(type) {
case *ecdsa.PrivateKey:
ecdsaKey = k
default:
return "", ErrInvalidKeyType
}
// Create the hasher
if !m.Hash.Available() {
return "", ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Sign the string and return r, s
if r, s, err := ecdsa.Sign(rand.Reader, ecdsaKey, hasher.Sum(nil)); err == nil {
curveBits := ecdsaKey.Curve.Params().BitSize
if m.CurveBits != curveBits {
return "", ErrInvalidKey
}
keyBytes := curveBits / 8
if curveBits%8 > 0 {
keyBytes += 1
}
// We serialize the outpus (r and s) into big-endian byte arrays and pad
// them with zeros on the left to make sure the sizes work out. Both arrays
// must be keyBytes long, and the output must be 2*keyBytes long.
rBytes := r.Bytes()
rBytesPadded := make([]byte, keyBytes)
copy(rBytesPadded[keyBytes-len(rBytes):], rBytes)
sBytes := s.Bytes()
sBytesPadded := make([]byte, keyBytes)
copy(sBytesPadded[keyBytes-len(sBytes):], sBytes)
out := append(rBytesPadded, sBytesPadded...)
return EncodeSegment(out), nil
} else {
return "", err
}
}

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package jwt
import (
"crypto/ecdsa"
"crypto/x509"
"encoding/pem"
"errors"
)
var (
ErrNotECPublicKey = errors.New("Key is not a valid ECDSA public key")
ErrNotECPrivateKey = errors.New("Key is not a valid ECDSA private key")
)
// Parse PEM encoded Elliptic Curve Private Key Structure
func ParseECPrivateKeyFromPEM(key []byte) (*ecdsa.PrivateKey, error) {
var err error
// Parse PEM block
var block *pem.Block
if block, _ = pem.Decode(key); block == nil {
return nil, ErrKeyMustBePEMEncoded
}
// Parse the key
var parsedKey interface{}
if parsedKey, err = x509.ParseECPrivateKey(block.Bytes); err != nil {
return nil, err
}
var pkey *ecdsa.PrivateKey
var ok bool
if pkey, ok = parsedKey.(*ecdsa.PrivateKey); !ok {
return nil, ErrNotECPrivateKey
}
return pkey, nil
}
// Parse PEM encoded PKCS1 or PKCS8 public key
func ParseECPublicKeyFromPEM(key []byte) (*ecdsa.PublicKey, error) {
var err error
// Parse PEM block
var block *pem.Block
if block, _ = pem.Decode(key); block == nil {
return nil, ErrKeyMustBePEMEncoded
}
// Parse the key
var parsedKey interface{}
if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
if cert, err := x509.ParseCertificate(block.Bytes); err == nil {
parsedKey = cert.PublicKey
} else {
return nil, err
}
}
var pkey *ecdsa.PublicKey
var ok bool
if pkey, ok = parsedKey.(*ecdsa.PublicKey); !ok {
return nil, ErrNotECPublicKey
}
return pkey, nil
}

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@ -1,59 +0,0 @@
package jwt
import (
"errors"
)
// Error constants
var (
ErrInvalidKey = errors.New("key is invalid")
ErrInvalidKeyType = errors.New("key is of invalid type")
ErrHashUnavailable = errors.New("the requested hash function is unavailable")
)
// The errors that might occur when parsing and validating a token
const (
ValidationErrorMalformed uint32 = 1 << iota // Token is malformed
ValidationErrorUnverifiable // Token could not be verified because of signing problems
ValidationErrorSignatureInvalid // Signature validation failed
// Standard Claim validation errors
ValidationErrorAudience // AUD validation failed
ValidationErrorExpired // EXP validation failed
ValidationErrorIssuedAt // IAT validation failed
ValidationErrorIssuer // ISS validation failed
ValidationErrorNotValidYet // NBF validation failed
ValidationErrorId // JTI validation failed
ValidationErrorClaimsInvalid // Generic claims validation error
)
// Helper for constructing a ValidationError with a string error message
func NewValidationError(errorText string, errorFlags uint32) *ValidationError {
return &ValidationError{
text: errorText,
Errors: errorFlags,
}
}
// The error from Parse if token is not valid
type ValidationError struct {
Inner error // stores the error returned by external dependencies, i.e.: KeyFunc
Errors uint32 // bitfield. see ValidationError... constants
text string // errors that do not have a valid error just have text
}
// Validation error is an error type
func (e ValidationError) Error() string {
if e.Inner != nil {
return e.Inner.Error()
} else if e.text != "" {
return e.text
} else {
return "token is invalid"
}
}
// No errors
func (e *ValidationError) valid() bool {
return e.Errors == 0
}

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package jwt
import (
"crypto"
"crypto/hmac"
"errors"
)
// Implements the HMAC-SHA family of signing methods signing methods
// Expects key type of []byte for both signing and validation
type SigningMethodHMAC struct {
Name string
Hash crypto.Hash
}
// Specific instances for HS256 and company
var (
SigningMethodHS256 *SigningMethodHMAC
SigningMethodHS384 *SigningMethodHMAC
SigningMethodHS512 *SigningMethodHMAC
ErrSignatureInvalid = errors.New("signature is invalid")
)
func init() {
// HS256
SigningMethodHS256 = &SigningMethodHMAC{"HS256", crypto.SHA256}
RegisterSigningMethod(SigningMethodHS256.Alg(), func() SigningMethod {
return SigningMethodHS256
})
// HS384
SigningMethodHS384 = &SigningMethodHMAC{"HS384", crypto.SHA384}
RegisterSigningMethod(SigningMethodHS384.Alg(), func() SigningMethod {
return SigningMethodHS384
})
// HS512
SigningMethodHS512 = &SigningMethodHMAC{"HS512", crypto.SHA512}
RegisterSigningMethod(SigningMethodHS512.Alg(), func() SigningMethod {
return SigningMethodHS512
})
}
func (m *SigningMethodHMAC) Alg() string {
return m.Name
}
// Verify the signature of HSXXX tokens. Returns nil if the signature is valid.
func (m *SigningMethodHMAC) Verify(signingString, signature string, key interface{}) error {
// Verify the key is the right type
keyBytes, ok := key.([]byte)
if !ok {
return ErrInvalidKeyType
}
// Decode signature, for comparison
sig, err := DecodeSegment(signature)
if err != nil {
return err
}
// Can we use the specified hashing method?
if !m.Hash.Available() {
return ErrHashUnavailable
}
// This signing method is symmetric, so we validate the signature
// by reproducing the signature from the signing string and key, then
// comparing that against the provided signature.
hasher := hmac.New(m.Hash.New, keyBytes)
hasher.Write([]byte(signingString))
if !hmac.Equal(sig, hasher.Sum(nil)) {
return ErrSignatureInvalid
}
// No validation errors. Signature is good.
return nil
}
// Implements the Sign method from SigningMethod for this signing method.
// Key must be []byte
func (m *SigningMethodHMAC) Sign(signingString string, key interface{}) (string, error) {
if keyBytes, ok := key.([]byte); ok {
if !m.Hash.Available() {
return "", ErrHashUnavailable
}
hasher := hmac.New(m.Hash.New, keyBytes)
hasher.Write([]byte(signingString))
return EncodeSegment(hasher.Sum(nil)), nil
}
return "", ErrInvalidKeyType
}

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package jwt
import (
"encoding/json"
"errors"
// "fmt"
)
// Claims type that uses the map[string]interface{} for JSON decoding
// This is the default claims type if you don't supply one
type MapClaims map[string]interface{}
// Compares the aud claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (m MapClaims) VerifyAudience(cmp string, req bool) bool {
aud, _ := m["aud"].(string)
return verifyAud(aud, cmp, req)
}
// Compares the exp claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (m MapClaims) VerifyExpiresAt(cmp int64, req bool) bool {
switch exp := m["exp"].(type) {
case float64:
return verifyExp(int64(exp), cmp, req)
case json.Number:
v, _ := exp.Int64()
return verifyExp(v, cmp, req)
}
return req == false
}
// Compares the iat claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (m MapClaims) VerifyIssuedAt(cmp int64, req bool) bool {
switch iat := m["iat"].(type) {
case float64:
return verifyIat(int64(iat), cmp, req)
case json.Number:
v, _ := iat.Int64()
return verifyIat(v, cmp, req)
}
return req == false
}
// Compares the iss claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (m MapClaims) VerifyIssuer(cmp string, req bool) bool {
iss, _ := m["iss"].(string)
return verifyIss(iss, cmp, req)
}
// Compares the nbf claim against cmp.
// If required is false, this method will return true if the value matches or is unset
func (m MapClaims) VerifyNotBefore(cmp int64, req bool) bool {
switch nbf := m["nbf"].(type) {
case float64:
return verifyNbf(int64(nbf), cmp, req)
case json.Number:
v, _ := nbf.Int64()
return verifyNbf(v, cmp, req)
}
return req == false
}
// Validates time based claims "exp, iat, nbf".
// There is no accounting for clock skew.
// As well, if any of the above claims are not in the token, it will still
// be considered a valid claim.
func (m MapClaims) Valid() error {
vErr := new(ValidationError)
now := TimeFunc().Unix()
if m.VerifyExpiresAt(now, false) == false {
vErr.Inner = errors.New("Token is expired")
vErr.Errors |= ValidationErrorExpired
}
if m.VerifyIssuedAt(now, false) == false {
vErr.Inner = errors.New("Token used before issued")
vErr.Errors |= ValidationErrorIssuedAt
}
if m.VerifyNotBefore(now, false) == false {
vErr.Inner = errors.New("Token is not valid yet")
vErr.Errors |= ValidationErrorNotValidYet
}
if vErr.valid() {
return nil
}
return vErr
}

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@ -1,52 +0,0 @@
package jwt
// Implements the none signing method. This is required by the spec
// but you probably should never use it.
var SigningMethodNone *signingMethodNone
const UnsafeAllowNoneSignatureType unsafeNoneMagicConstant = "none signing method allowed"
var NoneSignatureTypeDisallowedError error
type signingMethodNone struct{}
type unsafeNoneMagicConstant string
func init() {
SigningMethodNone = &signingMethodNone{}
NoneSignatureTypeDisallowedError = NewValidationError("'none' signature type is not allowed", ValidationErrorSignatureInvalid)
RegisterSigningMethod(SigningMethodNone.Alg(), func() SigningMethod {
return SigningMethodNone
})
}
func (m *signingMethodNone) Alg() string {
return "none"
}
// Only allow 'none' alg type if UnsafeAllowNoneSignatureType is specified as the key
func (m *signingMethodNone) Verify(signingString, signature string, key interface{}) (err error) {
// Key must be UnsafeAllowNoneSignatureType to prevent accidentally
// accepting 'none' signing method
if _, ok := key.(unsafeNoneMagicConstant); !ok {
return NoneSignatureTypeDisallowedError
}
// If signing method is none, signature must be an empty string
if signature != "" {
return NewValidationError(
"'none' signing method with non-empty signature",
ValidationErrorSignatureInvalid,
)
}
// Accept 'none' signing method.
return nil
}
// Only allow 'none' signing if UnsafeAllowNoneSignatureType is specified as the key
func (m *signingMethodNone) Sign(signingString string, key interface{}) (string, error) {
if _, ok := key.(unsafeNoneMagicConstant); ok {
return "", nil
}
return "", NoneSignatureTypeDisallowedError
}

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@ -1,148 +0,0 @@
package jwt
import (
"bytes"
"encoding/json"
"fmt"
"strings"
)
type Parser struct {
ValidMethods []string // If populated, only these methods will be considered valid
UseJSONNumber bool // Use JSON Number format in JSON decoder
SkipClaimsValidation bool // Skip claims validation during token parsing
}
// Parse, validate, and return a token.
// keyFunc will receive the parsed token and should return the key for validating.
// If everything is kosher, err will be nil
func (p *Parser) Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
return p.ParseWithClaims(tokenString, MapClaims{}, keyFunc)
}
func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
token, parts, err := p.ParseUnverified(tokenString, claims)
if err != nil {
return token, err
}
// Verify signing method is in the required set
if p.ValidMethods != nil {
var signingMethodValid = false
var alg = token.Method.Alg()
for _, m := range p.ValidMethods {
if m == alg {
signingMethodValid = true
break
}
}
if !signingMethodValid {
// signing method is not in the listed set
return token, NewValidationError(fmt.Sprintf("signing method %v is invalid", alg), ValidationErrorSignatureInvalid)
}
}
// Lookup key
var key interface{}
if keyFunc == nil {
// keyFunc was not provided. short circuiting validation
return token, NewValidationError("no Keyfunc was provided.", ValidationErrorUnverifiable)
}
if key, err = keyFunc(token); err != nil {
// keyFunc returned an error
if ve, ok := err.(*ValidationError); ok {
return token, ve
}
return token, &ValidationError{Inner: err, Errors: ValidationErrorUnverifiable}
}
vErr := &ValidationError{}
// Validate Claims
if !p.SkipClaimsValidation {
if err := token.Claims.Valid(); err != nil {
// If the Claims Valid returned an error, check if it is a validation error,
// If it was another error type, create a ValidationError with a generic ClaimsInvalid flag set
if e, ok := err.(*ValidationError); !ok {
vErr = &ValidationError{Inner: err, Errors: ValidationErrorClaimsInvalid}
} else {
vErr = e
}
}
}
// Perform validation
token.Signature = parts[2]
if err = token.Method.Verify(strings.Join(parts[0:2], "."), token.Signature, key); err != nil {
vErr.Inner = err
vErr.Errors |= ValidationErrorSignatureInvalid
}
if vErr.valid() {
token.Valid = true
return token, nil
}
return token, vErr
}
// WARNING: Don't use this method unless you know what you're doing
//
// This method parses the token but doesn't validate the signature. It's only
// ever useful in cases where you know the signature is valid (because it has
// been checked previously in the stack) and you want to extract values from
// it.
func (p *Parser) ParseUnverified(tokenString string, claims Claims) (token *Token, parts []string, err error) {
parts = strings.Split(tokenString, ".")
if len(parts) != 3 {
return nil, parts, NewValidationError("token contains an invalid number of segments", ValidationErrorMalformed)
}
token = &Token{Raw: tokenString}
// parse Header
var headerBytes []byte
if headerBytes, err = DecodeSegment(parts[0]); err != nil {
if strings.HasPrefix(strings.ToLower(tokenString), "bearer ") {
return token, parts, NewValidationError("tokenstring should not contain 'bearer '", ValidationErrorMalformed)
}
return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
// parse Claims
var claimBytes []byte
token.Claims = claims
if claimBytes, err = DecodeSegment(parts[1]); err != nil {
return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
dec := json.NewDecoder(bytes.NewBuffer(claimBytes))
if p.UseJSONNumber {
dec.UseNumber()
}
// JSON Decode. Special case for map type to avoid weird pointer behavior
if c, ok := token.Claims.(MapClaims); ok {
err = dec.Decode(&c)
} else {
err = dec.Decode(&claims)
}
// Handle decode error
if err != nil {
return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
// Lookup signature method
if method, ok := token.Header["alg"].(string); ok {
if token.Method = GetSigningMethod(method); token.Method == nil {
return token, parts, NewValidationError("signing method (alg) is unavailable.", ValidationErrorUnverifiable)
}
} else {
return token, parts, NewValidationError("signing method (alg) is unspecified.", ValidationErrorUnverifiable)
}
return token, parts, nil
}

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@ -1,101 +0,0 @@
package jwt
import (
"crypto"
"crypto/rand"
"crypto/rsa"
)
// Implements the RSA family of signing methods signing methods
// Expects *rsa.PrivateKey for signing and *rsa.PublicKey for validation
type SigningMethodRSA struct {
Name string
Hash crypto.Hash
}
// Specific instances for RS256 and company
var (
SigningMethodRS256 *SigningMethodRSA
SigningMethodRS384 *SigningMethodRSA
SigningMethodRS512 *SigningMethodRSA
)
func init() {
// RS256
SigningMethodRS256 = &SigningMethodRSA{"RS256", crypto.SHA256}
RegisterSigningMethod(SigningMethodRS256.Alg(), func() SigningMethod {
return SigningMethodRS256
})
// RS384
SigningMethodRS384 = &SigningMethodRSA{"RS384", crypto.SHA384}
RegisterSigningMethod(SigningMethodRS384.Alg(), func() SigningMethod {
return SigningMethodRS384
})
// RS512
SigningMethodRS512 = &SigningMethodRSA{"RS512", crypto.SHA512}
RegisterSigningMethod(SigningMethodRS512.Alg(), func() SigningMethod {
return SigningMethodRS512
})
}
func (m *SigningMethodRSA) Alg() string {
return m.Name
}
// Implements the Verify method from SigningMethod
// For this signing method, must be an *rsa.PublicKey structure.
func (m *SigningMethodRSA) Verify(signingString, signature string, key interface{}) error {
var err error
// Decode the signature
var sig []byte
if sig, err = DecodeSegment(signature); err != nil {
return err
}
var rsaKey *rsa.PublicKey
var ok bool
if rsaKey, ok = key.(*rsa.PublicKey); !ok {
return ErrInvalidKeyType
}
// Create hasher
if !m.Hash.Available() {
return ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Verify the signature
return rsa.VerifyPKCS1v15(rsaKey, m.Hash, hasher.Sum(nil), sig)
}
// Implements the Sign method from SigningMethod
// For this signing method, must be an *rsa.PrivateKey structure.
func (m *SigningMethodRSA) Sign(signingString string, key interface{}) (string, error) {
var rsaKey *rsa.PrivateKey
var ok bool
// Validate type of key
if rsaKey, ok = key.(*rsa.PrivateKey); !ok {
return "", ErrInvalidKey
}
// Create the hasher
if !m.Hash.Available() {
return "", ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Sign the string and return the encoded bytes
if sigBytes, err := rsa.SignPKCS1v15(rand.Reader, rsaKey, m.Hash, hasher.Sum(nil)); err == nil {
return EncodeSegment(sigBytes), nil
} else {
return "", err
}
}

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@ -1,126 +0,0 @@
// +build go1.4
package jwt
import (
"crypto"
"crypto/rand"
"crypto/rsa"
)
// Implements the RSAPSS family of signing methods signing methods
type SigningMethodRSAPSS struct {
*SigningMethodRSA
Options *rsa.PSSOptions
}
// Specific instances for RS/PS and company
var (
SigningMethodPS256 *SigningMethodRSAPSS
SigningMethodPS384 *SigningMethodRSAPSS
SigningMethodPS512 *SigningMethodRSAPSS
)
func init() {
// PS256
SigningMethodPS256 = &SigningMethodRSAPSS{
&SigningMethodRSA{
Name: "PS256",
Hash: crypto.SHA256,
},
&rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthAuto,
Hash: crypto.SHA256,
},
}
RegisterSigningMethod(SigningMethodPS256.Alg(), func() SigningMethod {
return SigningMethodPS256
})
// PS384
SigningMethodPS384 = &SigningMethodRSAPSS{
&SigningMethodRSA{
Name: "PS384",
Hash: crypto.SHA384,
},
&rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthAuto,
Hash: crypto.SHA384,
},
}
RegisterSigningMethod(SigningMethodPS384.Alg(), func() SigningMethod {
return SigningMethodPS384
})
// PS512
SigningMethodPS512 = &SigningMethodRSAPSS{
&SigningMethodRSA{
Name: "PS512",
Hash: crypto.SHA512,
},
&rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthAuto,
Hash: crypto.SHA512,
},
}
RegisterSigningMethod(SigningMethodPS512.Alg(), func() SigningMethod {
return SigningMethodPS512
})
}
// Implements the Verify method from SigningMethod
// For this verify method, key must be an rsa.PublicKey struct
func (m *SigningMethodRSAPSS) Verify(signingString, signature string, key interface{}) error {
var err error
// Decode the signature
var sig []byte
if sig, err = DecodeSegment(signature); err != nil {
return err
}
var rsaKey *rsa.PublicKey
switch k := key.(type) {
case *rsa.PublicKey:
rsaKey = k
default:
return ErrInvalidKey
}
// Create hasher
if !m.Hash.Available() {
return ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
return rsa.VerifyPSS(rsaKey, m.Hash, hasher.Sum(nil), sig, m.Options)
}
// Implements the Sign method from SigningMethod
// For this signing method, key must be an rsa.PrivateKey struct
func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (string, error) {
var rsaKey *rsa.PrivateKey
switch k := key.(type) {
case *rsa.PrivateKey:
rsaKey = k
default:
return "", ErrInvalidKeyType
}
// Create the hasher
if !m.Hash.Available() {
return "", ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Sign the string and return the encoded bytes
if sigBytes, err := rsa.SignPSS(rand.Reader, rsaKey, m.Hash, hasher.Sum(nil), m.Options); err == nil {
return EncodeSegment(sigBytes), nil
} else {
return "", err
}
}

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@ -1,101 +0,0 @@
package jwt
import (
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"errors"
)
var (
ErrKeyMustBePEMEncoded = errors.New("Invalid Key: Key must be PEM encoded PKCS1 or PKCS8 private key")
ErrNotRSAPrivateKey = errors.New("Key is not a valid RSA private key")
ErrNotRSAPublicKey = errors.New("Key is not a valid RSA public key")
)
// Parse PEM encoded PKCS1 or PKCS8 private key
func ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error) {
var err error
// Parse PEM block
var block *pem.Block
if block, _ = pem.Decode(key); block == nil {
return nil, ErrKeyMustBePEMEncoded
}
var parsedKey interface{}
if parsedKey, err = x509.ParsePKCS1PrivateKey(block.Bytes); err != nil {
if parsedKey, err = x509.ParsePKCS8PrivateKey(block.Bytes); err != nil {
return nil, err
}
}
var pkey *rsa.PrivateKey
var ok bool
if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
return nil, ErrNotRSAPrivateKey
}
return pkey, nil
}
// Parse PEM encoded PKCS1 or PKCS8 private key protected with password
func ParseRSAPrivateKeyFromPEMWithPassword(key []byte, password string) (*rsa.PrivateKey, error) {
var err error
// Parse PEM block
var block *pem.Block
if block, _ = pem.Decode(key); block == nil {
return nil, ErrKeyMustBePEMEncoded
}
var parsedKey interface{}
var blockDecrypted []byte
if blockDecrypted, err = x509.DecryptPEMBlock(block, []byte(password)); err != nil {
return nil, err
}
if parsedKey, err = x509.ParsePKCS1PrivateKey(blockDecrypted); err != nil {
if parsedKey, err = x509.ParsePKCS8PrivateKey(blockDecrypted); err != nil {
return nil, err
}
}
var pkey *rsa.PrivateKey
var ok bool
if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
return nil, ErrNotRSAPrivateKey
}
return pkey, nil
}
// Parse PEM encoded PKCS1 or PKCS8 public key
func ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error) {
var err error
// Parse PEM block
var block *pem.Block
if block, _ = pem.Decode(key); block == nil {
return nil, ErrKeyMustBePEMEncoded
}
// Parse the key
var parsedKey interface{}
if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
if cert, err := x509.ParseCertificate(block.Bytes); err == nil {
parsedKey = cert.PublicKey
} else {
return nil, err
}
}
var pkey *rsa.PublicKey
var ok bool
if pkey, ok = parsedKey.(*rsa.PublicKey); !ok {
return nil, ErrNotRSAPublicKey
}
return pkey, nil
}

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@ -1,35 +0,0 @@
package jwt
import (
"sync"
)
var signingMethods = map[string]func() SigningMethod{}
var signingMethodLock = new(sync.RWMutex)
// Implement SigningMethod to add new methods for signing or verifying tokens.
type SigningMethod interface {
Verify(signingString, signature string, key interface{}) error // Returns nil if signature is valid
Sign(signingString string, key interface{}) (string, error) // Returns encoded signature or error
Alg() string // returns the alg identifier for this method (example: 'HS256')
}
// Register the "alg" name and a factory function for signing method.
// This is typically done during init() in the method's implementation
func RegisterSigningMethod(alg string, f func() SigningMethod) {
signingMethodLock.Lock()
defer signingMethodLock.Unlock()
signingMethods[alg] = f
}
// Get a signing method from an "alg" string
func GetSigningMethod(alg string) (method SigningMethod) {
signingMethodLock.RLock()
defer signingMethodLock.RUnlock()
if methodF, ok := signingMethods[alg]; ok {
method = methodF()
}
return
}

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package jwt
import (
"encoding/base64"
"encoding/json"
"strings"
"time"
)
// TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time).
// You can override it to use another time value. This is useful for testing or if your
// server uses a different time zone than your tokens.
var TimeFunc = time.Now
// Parse methods use this callback function to supply
// the key for verification. The function receives the parsed,
// but unverified Token. This allows you to use properties in the
// Header of the token (such as `kid`) to identify which key to use.
type Keyfunc func(*Token) (interface{}, error)
// A JWT Token. Different fields will be used depending on whether you're
// creating or parsing/verifying a token.
type Token struct {
Raw string // The raw token. Populated when you Parse a token
Method SigningMethod // The signing method used or to be used
Header map[string]interface{} // The first segment of the token
Claims Claims // The second segment of the token
Signature string // The third segment of the token. Populated when you Parse a token
Valid bool // Is the token valid? Populated when you Parse/Verify a token
}
// Create a new Token. Takes a signing method
func New(method SigningMethod) *Token {
return NewWithClaims(method, MapClaims{})
}
func NewWithClaims(method SigningMethod, claims Claims) *Token {
return &Token{
Header: map[string]interface{}{
"typ": "JWT",
"alg": method.Alg(),
},
Claims: claims,
Method: method,
}
}
// Get the complete, signed token
func (t *Token) SignedString(key interface{}) (string, error) {
var sig, sstr string
var err error
if sstr, err = t.SigningString(); err != nil {
return "", err
}
if sig, err = t.Method.Sign(sstr, key); err != nil {
return "", err
}
return strings.Join([]string{sstr, sig}, "."), nil
}
// Generate the signing string. This is the
// most expensive part of the whole deal. Unless you
// need this for something special, just go straight for
// the SignedString.
func (t *Token) SigningString() (string, error) {
var err error
parts := make([]string, 2)
for i, _ := range parts {
var jsonValue []byte
if i == 0 {
if jsonValue, err = json.Marshal(t.Header); err != nil {
return "", err
}
} else {
if jsonValue, err = json.Marshal(t.Claims); err != nil {
return "", err
}
}
parts[i] = EncodeSegment(jsonValue)
}
return strings.Join(parts, "."), nil
}
// Parse, validate, and return a token.
// keyFunc will receive the parsed token and should return the key for validating.
// If everything is kosher, err will be nil
func Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
return new(Parser).Parse(tokenString, keyFunc)
}
func ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
return new(Parser).ParseWithClaims(tokenString, claims, keyFunc)
}
// Encode JWT specific base64url encoding with padding stripped
func EncodeSegment(seg []byte) string {
return strings.TrimRight(base64.URLEncoding.EncodeToString(seg), "=")
}
// Decode JWT specific base64url encoding with padding stripped
func DecodeSegment(seg string) ([]byte, error) {
if l := len(seg) % 4; l > 0 {
seg += strings.Repeat("=", 4-l)
}
return base64.URLEncoding.DecodeString(seg)
}

21
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@ -0,0 +1,21 @@
The MIT License (MIT)
Copyright (c) 2017 Jaime Pillora
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

119
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# Backoff
A simple exponential backoff counter in Go (Golang)
[![GoDoc](https://godoc.org/github.com/jpillora/backoff?status.svg)](https://godoc.org/github.com/jpillora/backoff) [![Circle CI](https://circleci.com/gh/jpillora/backoff.svg?style=shield)](https://circleci.com/gh/jpillora/backoff)
### Install
```
$ go get -v github.com/jpillora/backoff
```
### Usage
Backoff is a `time.Duration` counter. It starts at `Min`. After every call to `Duration()` it is multiplied by `Factor`. It is capped at `Max`. It returns to `Min` on every call to `Reset()`. `Jitter` adds randomness ([see below](#example-using-jitter)). Used in conjunction with the `time` package.
---
#### Simple example
``` go
b := &backoff.Backoff{
//These are the defaults
Min: 100 * time.Millisecond,
Max: 10 * time.Second,
Factor: 2,
Jitter: false,
}
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("Reset!\n")
b.Reset()
fmt.Printf("%s\n", b.Duration())
```
```
100ms
200ms
400ms
Reset!
100ms
```
---
#### Example using `net` package
``` go
b := &backoff.Backoff{
Max: 5 * time.Minute,
}
for {
conn, err := net.Dial("tcp", "example.com:5309")
if err != nil {
d := b.Duration()
fmt.Printf("%s, reconnecting in %s", err, d)
time.Sleep(d)
continue
}
//connected
b.Reset()
conn.Write([]byte("hello world!"))
// ... Read ... Write ... etc
conn.Close()
//disconnected
}
```
---
#### Example using `Jitter`
Enabling `Jitter` adds some randomization to the backoff durations. [See Amazon's writeup of performance gains using jitter](http://www.awsarchitectureblog.com/2015/03/backoff.html). Seeding is not necessary but doing so gives repeatable results.
```go
import "math/rand"
b := &backoff.Backoff{
Jitter: true,
}
rand.Seed(42)
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("Reset!\n")
b.Reset()
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
```
```
100ms
106.600049ms
281.228155ms
Reset!
100ms
104.381845ms
214.957989ms
```
#### Documentation
https://godoc.org/github.com/jpillora/backoff
#### Credits
Forked from [some JavaScript](https://github.com/segmentio/backo) written by [@tj](https://github.com/tj)

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// Package backoff provides an exponential-backoff implementation.
package backoff
import (
"math"
"math/rand"
"sync/atomic"
"time"
)
// Backoff is a time.Duration counter, starting at Min. After every call to
// the Duration method the current timing is multiplied by Factor, but it
// never exceeds Max.
//
// Backoff is not generally concurrent-safe, but the ForAttempt method can
// be used concurrently.
type Backoff struct {
attempt uint64
// Factor is the multiplying factor for each increment step
Factor float64
// Jitter eases contention by randomizing backoff steps
Jitter bool
// Min and Max are the minimum and maximum values of the counter
Min, Max time.Duration
}
// Duration returns the duration for the current attempt before incrementing
// the attempt counter. See ForAttempt.
func (b *Backoff) Duration() time.Duration {
d := b.ForAttempt(float64(atomic.AddUint64(&b.attempt, 1) - 1))
return d
}
const maxInt64 = float64(math.MaxInt64 - 512)
// ForAttempt returns the duration for a specific attempt. This is useful if
// you have a large number of independent Backoffs, but don't want use
// unnecessary memory storing the Backoff parameters per Backoff. The first
// attempt should be 0.
//
// ForAttempt is concurrent-safe.
func (b *Backoff) ForAttempt(attempt float64) time.Duration {
// Zero-values are nonsensical, so we use
// them to apply defaults
min := b.Min
if min <= 0 {
min = 100 * time.Millisecond
}
max := b.Max
if max <= 0 {
max = 10 * time.Second
}
if min >= max {
// short-circuit
return max
}
factor := b.Factor
if factor <= 0 {
factor = 2
}
//calculate this duration
minf := float64(min)
durf := minf * math.Pow(factor, attempt)
if b.Jitter {
durf = rand.Float64()*(durf-minf) + minf
}
//ensure float64 wont overflow int64
if durf > maxInt64 {
return max
}
dur := time.Duration(durf)
//keep within bounds
if dur < min {
return min
}
if dur > max {
return max
}
return dur
}
// Reset restarts the current attempt counter at zero.
func (b *Backoff) Reset() {
atomic.StoreUint64(&b.attempt, 0)
}
// Attempt returns the current attempt counter value.
func (b *Backoff) Attempt() float64 {
return float64(atomic.LoadUint64(&b.attempt))
}
// Copy returns a backoff with equals constraints as the original
func (b *Backoff) Copy() *Backoff {
return &Backoff{
Factor: b.Factor,
Jitter: b.Jitter,
Min: b.Min,
Max: b.Max,
}
}

3
src/vendor/github.com/jpillora/backoff/go.mod generated vendored Normal file
View File

@ -0,0 +1,3 @@
module github.com/jpillora/backoff
go 1.13

View File

@ -226,8 +226,6 @@ github.com/denverdino/aliyungo/util
# github.com/dghubble/sling v1.1.0
## explicit
github.com/dghubble/sling
# github.com/dgrijalva/jwt-go v3.2.0+incompatible
github.com/dgrijalva/jwt-go
# github.com/docker/cli v20.10.5+incompatible
github.com/docker/cli/cli/config
github.com/docker/cli/cli/config/configfile
@ -491,6 +489,9 @@ github.com/inconshreveable/mousetrap
## explicit
# github.com/jmespath/go-jmespath v0.3.0
github.com/jmespath/go-jmespath
# github.com/jpillora/backoff v1.0.0
## explicit
github.com/jpillora/backoff
# github.com/json-iterator/go v1.1.10
github.com/json-iterator/go
# github.com/lib/pq v1.10.0