Remove duplicate tags (#3740)

* Removee duplicate tags

* Adding changelog entry

changelog/fragments/1697662209-duplicate-tags.yaml

@@ -0,0 +1,32 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user’s deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: enhancement
+
+# Change summary; a 80ish characters long description of the change.
+summary: Remove duplicated tags when specified during the Agent enrollment. 
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+description: ""
+
+# Affected component; a word indicating the component this changeset affects.
+component: agent
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+pr: https://github.com/elastic/elastic-agent/pull/3740
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+issue: https://github.com/elastic/elastic-agent/issues/858

internal/pkg/agent/cmd/enroll_cmd.go

@@ -1066,10 +1066,15 @@ func expBackoffWithContext(ctx context.Context, init, max time.Duration) backoff
 
 func cleanTags(tags []string) []string {
 	var r []string
+	// Create a map to store unique elements
+	seen := make(map[string]bool)
 	for _, str := range tags {
 		tag := strings.TrimSpace(str)
 		if tag != "" {
-			r = append(r, tag)
+			if _, ok := seen[tag]; !ok {
+				seen[tag] = true
+				r = append(r, tag)
+			}
 		}
 	}
 	return r

internal/pkg/agent/cmd/enroll_cmd_test.go

@@ -351,9 +351,9 @@ func TestValidateArgs(t *testing.T) {
 		require.Contains(t, cleanedTags, "production")
 	})
 
-	t.Run("comma separated tags are cleaned", func(t *testing.T) {
+	t.Run("comma separated tags and duplicated tags are cleaned", func(t *testing.T) {
 		cmd := newEnrollCommandWithArgs([]string{}, streams)
-		err := cmd.Flags().Set("tag", "windows, production")
+		err := cmd.Flags().Set("tag", "windows, production, windows")
 		require.NoError(t, err)
 		args := buildEnrollmentFlags(cmd, url, enrolmentToken)
 		require.Contains(t, args, "--tag")
@@ -362,6 +362,9 @@ func TestValidateArgs(t *testing.T) {
 		cleanedTags := cleanTags(args)
 		require.Contains(t, cleanedTags, "windows")
 		require.Contains(t, cleanedTags, "production")
+		// Validate that we remove the duplicates
+		require.Equal(t, len(args), 10)
+		require.Equal(t, len(cleanedTags), 7)
 	})
 
 	t.Run("valid tag and empty tag", func(t *testing.T) {