retain nothing rule

Change-Id: I4e7a4ecb40fe39b80e41a6d9bf8b5fb3968a41af
Signed-off-by: Ziming Zhang <zziming@vmware.com>

src/core/api/retention.go

@@ -88,6 +88,13 @@ func (r *RetentionAPI) GetMetadatas() {
                     "required": true
                 }
             ]
+	},
+	{
+            "rule_template": "nothing",
+            "display_text": "none",
+            "action": "retain",
+            "params": [
+            ]
         }
     ],
     "scope_selectors": [

src/pkg/retention/policy/rule/index/index.go

@@ -15,6 +15,7 @@
 package index
 
 import (
+	"github.com/goharbor/harbor/src/pkg/retention/policy/rule/nothing"
 	"sync"
 
 	"github.com/goharbor/harbor/src/pkg/retention/policy/rule"
@@ -125,6 +126,13 @@ func init() {
 		},
 	}, lastx.New)
 
+	// Register nothing
+	Register(&Metadata{
+		TemplateID: nothing.TemplateID,
+		Action:     action.Retain,
+		Parameters: []*IndexedParam{},
+	}, nothing.New)
+
 	// Register always
 	Register(&Metadata{
 		TemplateID: always.TemplateID,

src/pkg/retention/policy/rule/index/index_test.go

@@ -84,7 +84,7 @@ func (suite *IndexTestSuite) TestGet() {
 // TestIndex tests Index
 func (suite *IndexTestSuite) TestIndex() {
 	metas := Index()
-	require.Equal(suite.T(), 6, len(metas))
+	require.Equal(suite.T(), 7, len(metas))
 	assert.Condition(suite.T(), func() bool {
 		for _, m := range metas {
 			if m.TemplateID == "fakeEvaluator" &&

src/pkg/retention/policy/rule/nothing/evaluator.go

@@ -0,0 +1,42 @@
+// Copyright 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 nothing
+
+import (
+	"github.com/goharbor/harbor/src/pkg/retention/policy/action"
+	"github.com/goharbor/harbor/src/pkg/retention/policy/rule"
+	"github.com/goharbor/harbor/src/pkg/retention/res"
+)
+
+const (
+	// TemplateID of the always retain rule
+	TemplateID = "nothing"
+)
+
+type evaluator struct{}
+
+// Process for the "nothing" Evaluator simply returns the input with no error
+func (e *evaluator) Process(artifacts []*res.Candidate) (processed []*res.Candidate, err error) {
+	return processed, err
+}
+
+func (e *evaluator) Action() string {
+	return action.Retain
+}
+
+// New returns an "always" Evaluator. It requires no parameters.
+func New(_ rule.Parameters) rule.Evaluator {
+	return &evaluator{}
+}

src/pkg/retention/policy/rule/nothing/evaluator_test.go

@@ -0,0 +1,49 @@
+// Copyright 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 nothing
+
+import (
+	"testing"
+
+	"github.com/goharbor/harbor/src/pkg/retention/policy/rule"
+	"github.com/goharbor/harbor/src/pkg/retention/res"
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+)
+
+type EvaluatorTestSuite struct {
+	suite.Suite
+}
+
+func (e *EvaluatorTestSuite) TestNew() {
+	sut := New(rule.Parameters{})
+
+	require.NotNil(e.T(), sut)
+	require.IsType(e.T(), &evaluator{}, sut)
+}
+
+func (e *EvaluatorTestSuite) TestProcess() {
+	sut := New(rule.Parameters{})
+	input := []*res.Candidate{{PushedTime: 0}, {PushedTime: 1}, {PushedTime: 2}, {PushedTime: 3}}
+
+	result, err := sut.Process(input)
+
+	require.NoError(e.T(), err)
+	require.Len(e.T(), result, 0)
+}
+
+func TestEvaluatorSuite(t *testing.T) {
+	suite.Run(t, &EvaluatorTestSuite{})
+}