feat: support filtering apps by label in CLI (#368)

5 files changed, 101 insertions, 4 deletions

diff --git a/cmd/main.go b/cmd/main.go
index 74009cb..3a4019d 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -40,6 +40,7 @@ type ImageUpdaterConfig struct {
 	MetricsPort         int
 	RegistriesConf      string
 	AppNamePatterns     []string
+	AppLabel            string
 	GitCommitUser       string
 	GitCommitMail       string
 	GitCommitMessage    *template.Template
diff --git a/cmd/run.go b/cmd/run.go
index 8016c8f..581bc4b 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -218,6 +218,7 @@ func newRunCommand() *cobra.Command {
 	runCmd.Flags().IntVar(&cfg.MaxConcurrency, "max-concurrency", 10, "maximum number of update threads to run concurrently")
 	runCmd.Flags().StringVar(&cfg.ArgocdNamespace, "argocd-namespace", "", "namespace where ArgoCD runs in (current namespace by default)")
 	runCmd.Flags().StringSliceVar(&cfg.AppNamePatterns, "match-application-name", nil, "patterns to match application name against")
+	runCmd.Flags().StringVar(&cfg.AppLabel, "match-application-label", "", "label to match application labels against")
 	runCmd.Flags().BoolVar(&warmUpCache, "warmup-cache", true, "whether to perform a cache warm-up on startup")
 	runCmd.Flags().StringVar(&cfg.GitCommitUser, "git-commit-user", env.GetStringVal("GIT_COMMIT_USER", "argocd-image-updater"), "Username to use for Git commits")
 	runCmd.Flags().StringVar(&cfg.GitCommitMail, "git-commit-email", env.GetStringVal("GIT_COMMIT_EMAIL", "noreply@argoproj.io"), "E-Mail address to use for Git commits")
@@ -259,7 +260,7 @@ func runImageUpdater(cfg *ImageUpdaterConfig, warmUp bool) (argocd.ImageUpdaterR
 
 	// Get the list of applications that are allowed for updates, that is, those
 	// applications which have correct annotation.
-	appList, err := argocd.FilterApplicationsForUpdate(apps, cfg.AppNamePatterns)
+	appList, err := argocd.FilterApplicationsForUpdate(apps, cfg.AppNamePatterns, cfg.AppLabel)
 	if err != nil {
 		return result, err
 	}
diff --git a/docs/install/running.md b/docs/install/running.md
index 6f05e5c..e5556c1 100644
--- a/docs/install/running.md
+++ b/docs/install/running.md
@@ -116,6 +116,16 @@ style wildcards, i.e. `*-staging` would match any application name with a
 suffix of `-staging`. Can be specified multiple times to define more than
 one pattern, from which at least one has to match.
 
+**--match-application-label *label* **
+
+Only process applications that have a valid annotation and match the given
+*label*. The *label* is a string that matches the standard kubernetes label 
+syntax of `key=value`. For e.g, `custom.label/name=xyz` would be a valid label
+that can be supplied through this parameter. Any applications carrying this 
+exact label will be considered as candidates for image updates. This parameter
+currently does not support patten matching on label values (e.g `customer.label/name=*-staging`)
+and only accepts a single label to match applications against. 
+
 **--max-concurrency *number* **
 
 Process a maximum of *number* applications concurrently. To disable concurrent
diff --git a/pkg/argocd/argocd.go b/pkg/argocd/argocd.go
index 10ed390..66e3f0c 100644
--- a/pkg/argocd/argocd.go
+++ b/pkg/argocd/argocd.go
@@ -145,10 +145,34 @@ func nameMatchesPattern(name string, patterns []string) bool {
 	return false
 }
 
+// Match app labels against provided filter label
+func matchAppLabels(appName string, appLabels map[string]string, filterLabel string) bool {
+
+	if filterLabel == "" {
+		return true
+	}
+
+	filterLabelMap, err := parseLabel(filterLabel)
+	if err != nil {
+		log.Errorf("Unable match app labels against %s: %s", filterLabel, err)
+		return false
+	}
+
+	for filterLabelKey, filterLabelValue := range filterLabelMap {
+		log.Tracef("Matching application name %s against label %s", appName, filterLabel)
+		if appLabelValue, ok := appLabels[filterLabelKey]; ok {
+			if appLabelValue == filterLabelValue {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // Retrieve a list of applications from ArgoCD that qualify for image updates
 // Application needs either to be of type Kustomize or Helm and must have the
 // correct annotation in order to be considered.
-func FilterApplicationsForUpdate(apps []v1alpha1.Application, patterns []string) (map[string]ApplicationImages, error) {
+func FilterApplicationsForUpdate(apps []v1alpha1.Application, patterns []string, appLabel string) (map[string]ApplicationImages, error) {
 	var appsForUpdate = make(map[string]ApplicationImages)
 
 	for _, app := range apps {
@@ -172,6 +196,12 @@ func FilterApplicationsForUpdate(apps []v1alpha1.Application, patterns []string)
 			continue
 		}
 
+		// Check if application carries requested label
+		if !matchAppLabels(app.GetName(), app.GetLabels(), appLabel) {
+			logCtx.Debugf("Skipping app '%s' because it does not carry requested label", app.GetName())
+			continue
+		}
+
 		logCtx.Tracef("processing app '%s' of type '%v'", app.GetName(), app.Status.SourceType)
 		imageList := parseImageList(annotations)
 		appImages := ApplicationImages{}
@@ -198,6 +228,20 @@ func parseImageList(annotations map[string]string) *image.ContainerImageList {
 	return &results
 }
 
+func parseLabel(inputLabel string) (map[string]string, error) {
+	var selectedLabels map[string]string
+	const labelFieldDelimiter = "="
+	if inputLabel != "" {
+		selectedLabels = map[string]string{}
+		fields := strings.Split(inputLabel, labelFieldDelimiter)
+		if len(fields) != 2 {
+			return nil, fmt.Errorf("labels should have key%svalue, but instead got: %s", labelFieldDelimiter, inputLabel)
+		}
+		selectedLabels[fields[0]] = fields[1]
+	}
+	return selectedLabels, nil
+}
+
 // GetApplication gets the application named appName from Argo CD API
 func (client *argoCD) GetApplication(ctx context.Context, appName string) (*v1alpha1.Application, error) {
 	conn, appClient, err := client.Client.NewApplicationClient()
diff --git a/pkg/argocd/argocd_test.go b/pkg/argocd/argocd_test.go
index 4fc61bf..c6b4be4 100644
--- a/pkg/argocd/argocd_test.go
+++ b/pkg/argocd/argocd_test.go
@@ -203,7 +203,7 @@ func Test_FilterApplicationsForUpdate(t *testing.T) {
 				},
 			},
 		}
-		filtered, err := FilterApplicationsForUpdate(applicationList, []string{})
+		filtered, err := FilterApplicationsForUpdate(applicationList, []string{}, "")
 		require.NoError(t, err)
 		require.Len(t, filtered, 1)
 		require.Contains(t, filtered, "app1")
@@ -255,7 +255,7 @@ func Test_FilterApplicationsForUpdate(t *testing.T) {
 				},
 			},
 		}
-		filtered, err := FilterApplicationsForUpdate(applicationList, []string{"app*"})
+		filtered, err := FilterApplicationsForUpdate(applicationList, []string{"app*"}, "")
 		require.NoError(t, err)
 		require.Len(t, filtered, 2)
 		require.Contains(t, filtered, "app1")
@@ -263,6 +263,47 @@ func Test_FilterApplicationsForUpdate(t *testing.T) {
 		assert.Len(t, filtered["app1"].Images, 2)
 	})
 
+	t.Run("Filter for applications with label", func(t *testing.T) {
+		applicationList := []v1alpha1.Application{
+			// Annotated and carries required label
+			{
+				ObjectMeta: v1.ObjectMeta{
+					Name:      "app1",
+					Namespace: "argocd",
+					Annotations: map[string]string{
+						common.ImageUpdaterAnnotation: "nginx, quay.io/dexidp/dex:v1.23.0",
+					},
+					Labels: map[string]string{
+						"custom.label/name": "xyz",
+					},
+				},
+				Spec: v1alpha1.ApplicationSpec{},
+				Status: v1alpha1.ApplicationStatus{
+					SourceType: v1alpha1.ApplicationSourceTypeKustomize,
+				},
+			},
+			// Annotated but does not carry required label
+			{
+				ObjectMeta: v1.ObjectMeta{
+					Name:      "app2",
+					Namespace: "argocd",
+					Annotations: map[string]string{
+						common.ImageUpdaterAnnotation: "nginx, quay.io/dexidp/dex:v1.23.0",
+					},
+				},
+				Spec: v1alpha1.ApplicationSpec{},
+				Status: v1alpha1.ApplicationStatus{
+					SourceType: v1alpha1.ApplicationSourceTypeHelm,
+				},
+			},
+		}
+		filtered, err := FilterApplicationsForUpdate(applicationList, []string{}, "custom.label/name=xyz")
+		require.NoError(t, err)
+		require.Len(t, filtered, 1)
+		require.Contains(t, filtered, "app1")
+		assert.Len(t, filtered["app1"].Images, 2)
+	})
+
 }
 
 func Test_GetHelmParamAnnotations(t *testing.T) {