support multiple ACK resource tag formats (#88)

Issue #, if available: aws-controllers-k8s/community#1261

Description of changes:
* support '%CONTROLLER_SERVICE%' , '%CONTROLLER_VERSION%', '%K8S_NAMESPACE%' and '%K8S_RESOURCE_NAME%' as the resource tag format
* support tag format as substring, and not just complete tag value
* As per the [comment](#87 (review)) , I did not add 'OWNER_ACCOUNT_ID' because any AWS related information will be known to customer when describing tags or viewing the resource in AWS console.  
* I also did not add 'K8S_CRD_VERSION' right now and waiting for multi version support , to find out the best place to find the k8s resource crd version.



By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: vijtrip2

pkg/runtime/tags.go

@@ -14,7 +14,6 @@
 package runtime
 
 import (
-	"fmt"
 	"strings"
 
 	rtclient "sigs.k8s.io/controller-runtime/pkg/client"
@@ -23,19 +22,71 @@ import (
 	acktypes "github.com/aws-controllers-k8s/runtime/pkg/types"
 )
 
+// resolveTagFormat is a function which returns the resolved value for an
+// ACK resource tag format. Ex: %CONTROLLER_SERVICE% -> s3
+type resolveTagFormat func(rtclient.Object, acktypes.ServiceControllerMetadata) string
+
 const (
 	// MissingImageTagValue is the placeholder value when ACK controller
 	// image tag(release semver) cannot be determined.
-	MissingImageTagValue = "unknown"
+	MissingImageTagValue       = "unknown"
+	ServiceAliasTagFormat      = "%CONTROLLER_SERVICE%"
+	ControllerVersionTagFormat = "%CONTROLLER_VERSION%"
+	NamespaceTagFormat         = "%K8S_NAMESPACE%"
+	ResourceNameTagFormat      = "%K8S_RESOURCE_NAME%"
 )
 
+// ACKResourceTagFormats is map of ACK resource tag formats to it's
+// resolveTagFormat function.
+//
+// To add a new ACKResourceTag format, include it in this map, along with the
+// resolveTagFormat function and expandTagValue() method will start
+// expanding the new resource tag format.
+var ACKResourceTagFormats = map[string]resolveTagFormat{
+	ServiceAliasTagFormat: func(
+		obj rtclient.Object,
+		md acktypes.ServiceControllerMetadata,
+	) string {
+		return md.ServiceAlias
+	},
+
+	ControllerVersionTagFormat: func(
+		obj rtclient.Object,
+		md acktypes.ServiceControllerMetadata,
+	) string {
+		controllerImageTag := md.GitVersion
+		// ACK controller released from the ACK CD pipeline will have the correct
+		// GitVersion. But this value can be empty when manually building ACK
+		// controller image locally and not passing the go ldflags.
+		// Add a placeholder value when git tag is found missing.
+		if controllerImageTag == "" {
+			controllerImageTag = MissingImageTagValue
+		}
+		return controllerImageTag
+	},
+
+	NamespaceTagFormat: func(
+		obj rtclient.Object,
+		md acktypes.ServiceControllerMetadata,
+	) string {
+		return obj.GetNamespace()
+	},
+
+	ResourceNameTagFormat: func(
+		obj rtclient.Object,
+		md acktypes.ServiceControllerMetadata,
+	) string {
+		return obj.GetName()
+	},
+}
+
 // GetDefaultTags provides Default tags (key value pairs) for given resource
 func GetDefaultTags(
 	config *ackconfig.Config,
-	object rtclient.Object,
+	obj rtclient.Object,
 	md acktypes.ServiceControllerMetadata,
 ) map[string]string {
-	if object == nil || config == nil || len(config.ResourceTags) == 0 {
+	if obj == nil || config == nil || len(config.ResourceTags) == 0 {
 		return nil
 	}
 	var populatedTags = make(map[string]string)
@@ -49,46 +100,20 @@ func GetDefaultTags(
 		if key == "" || val == "" {
 			continue
 		}
-		populatedValue := expandTagValue(&val, object, md)
-		populatedTags[key] = *populatedValue
-	}
-	if len(populatedTags) == 0 {
-		return nil
+		populatedTags[key] = expandTagValue(val, obj, md)
 	}
 	return populatedTags
 }
 
+// expandTagValue returns the tag value after expanding all the ACKResourceTag
+// formats.
 func expandTagValue(
-	value *string,
+	value string,
 	obj rtclient.Object,
 	md acktypes.ServiceControllerMetadata,
-) *string {
-	if value == nil || obj == nil {
-		return nil
-	}
-	var expandedValue string = ""
-	switch *value {
-	case "%CONTROLLER_VERSION%":
-		expandedValue = generateControllerVersion(md)
-	case "%K8S_NAMESPACE%":
-		expandedValue = obj.GetNamespace()
-	default:
-		expandedValue = *value
-	}
-	return &expandedValue
-}
-
-// generateControllerVersion creates the tag value for key
-// "services.k8s.aws/controller-version". The value for this tag is in the
-// format "<service-name>-<controller-image-tag>". Ex: s3-v0.0.10
-func generateControllerVersion(md acktypes.ServiceControllerMetadata) string {
-	controllerImageTag := md.GitVersion
-	// ACK controller released from the ACK CD pipeline will have the correct
-	// GitVersion. But this value can be empty when manually building ACK
-	// controller image locally and not passing the go ldflags.
-	// Add a placeholder value when git tag is found missing.
-	if controllerImageTag == "" {
-		controllerImageTag = MissingImageTagValue
+) string {
+	for tagFormat, resolveTagFormat := range ACKResourceTagFormats {
+		value = strings.ReplaceAll(value, tagFormat, resolveTagFormat(obj, md))
 	}
-	return fmt.Sprintf("%s-%s", md.ServiceAlias, controllerImageTag)
+	return value
 }

pkg/runtime/tags_test.go

@@ -0,0 +1,75 @@
+package runtime_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/aws-controllers-k8s/runtime/pkg/config"
+
+	mocks "github.com/aws-controllers-k8s/runtime/mocks/controller-runtime/pkg/client"
+	"github.com/aws-controllers-k8s/runtime/pkg/runtime"
+	"github.com/aws-controllers-k8s/runtime/pkg/types"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetDefaultTags(t *testing.T) {
+	assert := assert.New(t)
+	obj := mocks.Object{}
+	obj.On("GetNamespace").Return("ns")
+	obj.On("GetName").Return("res")
+
+	cfg := config.Config{}
+
+	md := types.ServiceControllerMetadata{
+		ServiceAlias: "s3",
+		VersionInfo: types.VersionInfo{
+			GitVersion: "v0.0.10",
+		},
+	}
+
+	// nil config
+	assert.Nil(runtime.GetDefaultTags(nil, &obj, md))
+
+	// nil object
+	assert.Nil(runtime.GetDefaultTags(&cfg, nil, md))
+
+	// no resource tags
+	assert.Nil(runtime.GetDefaultTags(&cfg, &obj, md))
+
+	// ill formed tags
+	cfg.ResourceTags = []string{"foobar"}
+	expandedTags := runtime.GetDefaultTags(&cfg, &obj, md)
+	assert.Empty(expandedTags)
+
+	// ill formed tags
+	cfg.ResourceTags = []string{"foo=bar=baz"}
+	expandedTags = runtime.GetDefaultTags(&cfg, &obj, md)
+	assert.Empty(expandedTags)
+
+	// tags without any ack resource tag format
+	cfg.ResourceTags = []string{"foo=bar"}
+	expandedTags = runtime.GetDefaultTags(&cfg, &obj, md)
+	assert.Equal(1, len(expandedTags))
+	assert.Equal("bar", expandedTags["foo"])
+
+	// expand ack resource tag formats
+	cfg.ResourceTags = []string{
+		"foo=bar",
+		fmt.Sprintf("services.k8s.aws/controller-version=%s-%s",
+			runtime.ServiceAliasTagFormat,
+			runtime.ControllerVersionTagFormat,
+		),
+		fmt.Sprintf("services.k8s.aws/namespace=%s",
+			runtime.NamespaceTagFormat,
+		),
+		fmt.Sprintf("services.k8s.aws/name=%s",
+			runtime.ResourceNameTagFormat,
+		),
+	}
+	expandedTags = runtime.GetDefaultTags(&cfg, &obj, md)
+	assert.Equal(4, len(expandedTags))
+	assert.Equal("bar", expandedTags["foo"])
+	assert.Equal("s3-v0.0.10", expandedTags["services.k8s.aws/controller-version"])
+	assert.Equal("ns", expandedTags["services.k8s.aws/namespace"])
+	assert.Equal("res", expandedTags["services.k8s.aws/name"])
+}