define filter interfaces for replication service including:interface Filter,Converter and FilterChain and other supporting models

src/replication/consts.go

@@ -0,0 +1,10 @@
+package replication
+
+const (
+	//Kind of filter item is 'project'
+	filterItemKindProject = "project"
+	//Kind of filter item is 'repository'
+	filterItemKindRepository = "repository"
+	//Kind of filter item is 'tag'
+	filterItemKindTag = "tag"
+)

src/replication/models/filter_config.go

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+package models
+
+//FilterConfig is data model to provide configurations to the filters.
+type FilterConfig struct {
+	//The pattern for fuzzy matching
+	pattern string
+}

src/replication/models/filter_item.go

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+package models
+
+//FilterItem is the general data model represents the filtering resources which are used as input and output for the filters.
+type FilterItem struct {
+
+	//The kind of the filtering resources. Support 'project','repository' and 'tag' etc.
+	kind string
+
+	//The key value of resource which can be used to filter out the resource matched with specified pattern.
+	//E.g:
+	//kind == 'project', value will be project name;
+	//kind == 'repository', value will be repository name
+	//kind == 'tag', value will be tag name.
+	value string
+
+	//Extension placeholder.
+	//To append more additional information if required by the filter.
+	metadata map[string]interface{}
+}

src/replication/source/convertor.go

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+package source
+
+import (
+	"github.com/vmware/harbor/src/replication/models"
+)
+
+//Convertor is designed to covert the format of output from upstream filter to the input format
+//required by the downstream filter if needed.
+//Each convertor covers only one specified conversion process between the two filters.
+//E.g:
+//If project filter connects to repository filter, then one convertor should be defined for this connection;
+//If project filter connects to tag filter, then another one should be defined. The above one can not be reused.
+type Convertor interface {
+	//Accept the items from upstream filter as input and then covert them to the required format and returned.
+	Convert(itemsOfUpstream []models.FilterItem) (itemsOfDownstream []models.FilterItem)
+}

src/replication/source/filter.go

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+package source
+
+import (
+	"github.com/vmware/harbor/src/replication/models"
+)
+
+//Filter define the operations of selecting the matched resources from the candidates
+//according to the specified pattern.
+type Filter interface {
+	//Initialize the filter with specified configurations like pattern definition
+	Init(config models.FilterConfig)
+
+	//Set Convertor if necessary
+	SetConvertor(convertor Convertor)
+
+	//Return the convertor if existing or nil if never set
+	GetConvertor() Convertor
+
+	//Filter the items
+	DoFilter(filterItems []models.FilterItem) []models.FilterItem
+}

src/replication/source/filter_chain.go

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+package source
+
+import (
+	"github.com/vmware/harbor/src/replication/models"
+)
+
+//FilterChain is the interface to define the operations of coordinating multiple filters
+//to work together as a whole pipeline.
+//E.g:
+//(original resources)---->[project filter]---->[repository filter]---->[tag filter]---->[......]---->(filter resources)
+type FilterChain interface {
+	//Build the filter chain with the filters provided;
+	//if failed, an error will be returned.
+	Build(filter []Filter) error
+
+	//Return all the filters in the chain.
+	Filters() []Filter
+
+	//Filter the items and returned the filtered items via the appended filters in the chain.
+	DoFilter(filterItems []models.FilterItem) []models.FilterItem
+}