waveterm/pkg/waveai/anthropicbackend.go
2024-11-20 18:05:13 -08:00

293 lines
8.0 KiB
Go

// Copyright 2024, Command Line Inc.
// SPDX-License-Identifier: Apache-2.0
package waveai
import (
"bufio"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"strings"
"github.com/wavetermdev/waveterm/pkg/panichandler"
"github.com/wavetermdev/waveterm/pkg/wshrpc"
)
type AnthropicBackend struct{}
var _ AIBackend = AnthropicBackend{}
// Claude API request types
type anthropicMessage struct {
Role string `json:"role"`
Content string `json:"content"`
}
type anthropicRequest struct {
Model string `json:"model"`
Messages []anthropicMessage `json:"messages"`
System string `json:"system,omitempty"`
MaxTokens int `json:"max_tokens,omitempty"`
Stream bool `json:"stream"`
Temperature float32 `json:"temperature,omitempty"`
}
// Claude API response types for SSE events
type anthropicContentBlock struct {
Type string `json:"type"` // "text" or other content types
Text string `json:"text,omitempty"`
}
type anthropicUsage struct {
InputTokens int `json:"input_tokens"`
OutputTokens int `json:"output_tokens"`
}
type anthropicResponseMessage struct {
ID string `json:"id"`
Type string `json:"type"`
Role string `json:"role"`
Content []anthropicContentBlock `json:"content"`
Model string `json:"model"`
StopReason string `json:"stop_reason,omitempty"`
StopSequence string `json:"stop_sequence,omitempty"`
Usage *anthropicUsage `json:"usage,omitempty"`
}
type anthropicStreamEventError struct {
Type string `json:"type"`
Message string `json:"message"`
}
type anthropicStreamEventDelta struct {
Text string `json:"text"`
}
type anthropicStreamEvent struct {
Type string `json:"type"`
Message *anthropicResponseMessage `json:"message,omitempty"`
ContentBlock *anthropicContentBlock `json:"content_block,omitempty"`
Delta *anthropicStreamEventDelta `json:"delta,omitempty"`
Error *anthropicStreamEventError `json:"error,omitempty"`
Usage *anthropicUsage `json:"usage,omitempty"`
}
// SSE event represents a parsed Server-Sent Event
type sseEvent struct {
Event string // The event type field
Data string // The data field
}
// parseSSE reads and parses SSE format from a bufio.Reader
func parseSSE(reader *bufio.Reader) (*sseEvent, error) {
var event sseEvent
for {
line, err := reader.ReadString('\n')
if err != nil {
return nil, err
}
line = strings.TrimSpace(line)
if line == "" {
// Empty line signals end of event
if event.Event != "" || event.Data != "" {
return &event, nil
}
continue
}
if strings.HasPrefix(line, "event:") {
event.Event = strings.TrimSpace(strings.TrimPrefix(line, "event:"))
} else if strings.HasPrefix(line, "data:") {
event.Data = strings.TrimSpace(strings.TrimPrefix(line, "data:"))
}
}
}
func (AnthropicBackend) StreamCompletion(ctx context.Context, request wshrpc.OpenAiStreamRequest) chan wshrpc.RespOrErrorUnion[wshrpc.OpenAIPacketType] {
rtn := make(chan wshrpc.RespOrErrorUnion[wshrpc.OpenAIPacketType])
go func() {
defer func() {
panicErr := panichandler.PanicHandler("AnthropicBackend.StreamCompletion")
if panicErr != nil {
rtn <- makeAIError(panicErr)
}
close(rtn)
}()
if request.Opts == nil {
rtn <- makeAIError(errors.New("no anthropic opts found"))
return
}
model := request.Opts.Model
if model == "" {
model = "claude-3-sonnet-20240229" // default model
}
// Convert messages format
var messages []anthropicMessage
var systemPrompt string
for _, msg := range request.Prompt {
if msg.Role == "system" {
if systemPrompt != "" {
systemPrompt += "\n"
}
systemPrompt += msg.Content
continue
}
role := "user"
if msg.Role == "assistant" {
role = "assistant"
}
messages = append(messages, anthropicMessage{
Role: role,
Content: msg.Content,
})
}
anthropicReq := anthropicRequest{
Model: model,
Messages: messages,
System: systemPrompt,
Stream: true,
MaxTokens: request.Opts.MaxTokens,
}
reqBody, err := json.Marshal(anthropicReq)
if err != nil {
rtn <- makeAIError(fmt.Errorf("failed to marshal anthropic request: %v", err))
return
}
req, err := http.NewRequestWithContext(ctx, "POST", "https://api.anthropic.com/v1/messages", strings.NewReader(string(reqBody)))
if err != nil {
rtn <- makeAIError(fmt.Errorf("failed to create anthropic request: %v", err))
return
}
req.Header.Set("Content-Type", "application/json")
req.Header.Set("Accept", "text/event-stream")
req.Header.Set("x-api-key", request.Opts.APIToken)
req.Header.Set("anthropic-version", "2023-06-01")
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
rtn <- makeAIError(fmt.Errorf("failed to send anthropic request: %v", err))
return
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
bodyBytes, _ := io.ReadAll(resp.Body)
rtn <- makeAIError(fmt.Errorf("Anthropic API error: %s - %s", resp.Status, string(bodyBytes)))
return
}
reader := bufio.NewReader(resp.Body)
for {
// Check for context cancellation
select {
case <-ctx.Done():
rtn <- makeAIError(fmt.Errorf("request cancelled: %v", ctx.Err()))
return
default:
}
sse, err := parseSSE(reader)
if err == io.EOF {
break
}
if err != nil {
rtn <- makeAIError(fmt.Errorf("error reading SSE stream: %v", err))
break
}
if sse.Event == "ping" {
continue // Ignore ping events
}
var event anthropicStreamEvent
if err := json.Unmarshal([]byte(sse.Data), &event); err != nil {
rtn <- makeAIError(fmt.Errorf("error unmarshaling event data: %v", err))
break
}
if event.Error != nil {
rtn <- makeAIError(fmt.Errorf("Anthropic API error: %s - %s", event.Error.Type, event.Error.Message))
break
}
switch sse.Event {
case "message_start":
if event.Message != nil {
pk := MakeOpenAIPacket()
pk.Model = event.Message.Model
rtn <- wshrpc.RespOrErrorUnion[wshrpc.OpenAIPacketType]{Response: *pk}
}
case "content_block_start":
if event.ContentBlock != nil && event.ContentBlock.Text != "" {
pk := MakeOpenAIPacket()
pk.Text = event.ContentBlock.Text
rtn <- wshrpc.RespOrErrorUnion[wshrpc.OpenAIPacketType]{Response: *pk}
}
case "content_block_delta":
if event.Delta != nil && event.Delta.Text != "" {
pk := MakeOpenAIPacket()
pk.Text = event.Delta.Text
rtn <- wshrpc.RespOrErrorUnion[wshrpc.OpenAIPacketType]{Response: *pk}
}
case "content_block_stop":
// Note: According to the docs, this just signals the end of a content block
// We might want to use this for tracking block boundaries, but for now
// we don't need to send anything special to match OpenAI's format
case "message_delta":
// Update message metadata, usage stats
if event.Usage != nil {
pk := MakeOpenAIPacket()
pk.Usage = &wshrpc.OpenAIUsageType{
PromptTokens: event.Usage.InputTokens,
CompletionTokens: event.Usage.OutputTokens,
TotalTokens: event.Usage.InputTokens + event.Usage.OutputTokens,
}
rtn <- wshrpc.RespOrErrorUnion[wshrpc.OpenAIPacketType]{Response: *pk}
}
case "message_stop":
if event.Message != nil {
pk := MakeOpenAIPacket()
pk.FinishReason = event.Message.StopReason
if event.Message.Usage != nil {
pk.Usage = &wshrpc.OpenAIUsageType{
PromptTokens: event.Message.Usage.InputTokens,
CompletionTokens: event.Message.Usage.OutputTokens,
TotalTokens: event.Message.Usage.InputTokens + event.Message.Usage.OutputTokens,
}
}
rtn <- wshrpc.RespOrErrorUnion[wshrpc.OpenAIPacketType]{Response: *pk}
}
default:
rtn <- makeAIError(fmt.Errorf("unknown Anthropic event type: %s", sse.Event))
return
}
}
}()
return rtn
}