Initial boilerplate for tag retention policies

src/common/retention/filter.go

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+// Copyright 2019 Project Harbor Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package retention
+
+import (
+	"time"
+
+	"github.com/goharbor/harbor/src/common/models"
+)
+
+// FilterAction denotes the action a filter has taken for a given tag record
+type FilterAction uint
+
+const (
+	// FilterActionKeep explicitly marks the tag as kept
+	FilterActionKeep FilterAction = iota
+
+	// FilterActionDelete explicitly marks the tag as deleted
+	FilterActionDelete
+
+	// FilterActionNoDecision passes the tag onto the next filter in the chain
+	FilterActionNoDecision
+)
+
+// FilterMetadata defines the metadata needed to construct various Filter instances
+type FilterMetadata struct {
+	ID int64
+	// The type of the filter to construct
+	Type string
+	// Parameters used to construct the filter
+	Options map[string]interface{}
+}
+
+// TagRecord represents all pertinent metadata about a tag
+type TagRecord struct {
+	Project    *models.Project
+	Repository *models.RepoRecord
+
+	Name       string
+	CreatedAt  time.Time
+	LastPullAt time.Time
+	Labels     []*models.Label
+}
+
+// Filter is a tag filter in a Retention Policy Filter Chain
+type Filter interface {
+	// Process determines what to do for a given tag record
+	Process(tag *TagRecord) (FilterAction, error)
+
+	// InitializeFor re-initializes the filter for tags from the specified project and repository
+	//
+	// Filters that maintain per-project or per-repository tracking metadata should reset it when
+	// this method is called. Every call to `Process` will be for the same project and repo until
+	// `InitializeFor` is called again.
+	InitializeFor(project *models.Project, repo *models.RepoRecord)
+}

src/common/retention/policy.go

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+// Copyright 2019 Project Harbor Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package retention
+
+import "time"
+
+// Scope identifies the scope of a specific retention policy
+type Scope int
+
+const (
+	// ScopeServer identifies a retention policy defined server-wide
+	ScopeServer Scope = iota
+
+	// ScopeProject identifies a retention policy defined for a specific project
+	ScopeProject
+
+	// ScopeRepository identifies a retention policy defined for a specific repository
+	ScopeRepository
+)
+
+// FallThroughAction determines what action the policy should take when a tag has not
+// been explicitly kept nor explicitly deleted by all filters in the filter chain
+type FallThroughAction int
+
+const (
+	// KeepExtraTags indicates that tags which are not explicitly kept or deleted are implicitly kept
+	KeepExtraTags FallThroughAction = iota
+	// DeleteExtraTags indicates that tags which are not explicitly kept or deleted are implicitly deleted
+	DeleteExtraTags
+)
+
+// Policy contains an ordered slice of FilterMetadata used to construct filter chains
+// during tag retention procession
+type Policy struct {
+	ID      int64
+	Name    string
+	Enabled bool
+
+	Scope             Scope
+	FallThroughAction FallThroughAction
+
+	ProjectID    int64
+	RepositoryID int64
+
+	// When a filter chain is constructed for this policy, these filters will
+	// be chained together in the order they appear in the slice
+	Filters []*FilterMetadata
+
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}