fix: shorten git traffic tags

Author: seo-rii

main.go

@@ -29,6 +29,8 @@ type config struct {
 }
 
 const gitTrafficTagPrefix = "git-"
+const cloudRunServiceAndTagMaxLength = 46
+const minGitTrafficTagSHALength = 7
 
 func main() {
 	cfg, err := parseConfig()
@@ -255,6 +257,26 @@ func resolveGitSHA(dir string) (string, error) {
 	return sha, nil
 }
 
+func buildGitTrafficTag(service, gitSHA string) (string, bool) {
+	serviceName := strings.TrimSpace(service)
+	sha := strings.TrimSpace(strings.ToLower(gitSHA))
+	if serviceName == "" || sha == "" {
+		return "", false
+	}
+
+	maxTagLength := cloudRunServiceAndTagMaxLength - len(serviceName)
+	minTagLength := len(gitTrafficTagPrefix) + minGitTrafficTagSHALength
+	if maxTagLength < minTagLength {
+		return "", false
+	}
+
+	maxSHALength := maxTagLength - len(gitTrafficTagPrefix)
+	if maxSHALength > len(sha) {
+		maxSHALength = len(sha)
+	}
+	return gitTrafficTagPrefix + sha[:maxSHALength], true
+}
+
 func deployServices(cfg *config, image string) error {
 	var wg sync.WaitGroup
 	errs := make(chan error, len(cfg.services))
@@ -311,15 +333,24 @@ func deployService(cfg *config, service, image string) error {
 		"--project=" + cfg.project,
 	}
 	if cfg.gitSHA != "" {
-		gitTrafficTag := gitTrafficTagPrefix + cfg.gitSHA
-		oldGitTags, err := listServiceGitTags(cfg, service)
-		if err != nil {
-			return fmt.Errorf("list git tags for %s: %w", service, err)
-		}
-		if len(oldGitTags) > 0 {
-			updateTrafficArgs = append(updateTrafficArgs, "--remove-tags="+strings.Join(oldGitTags, ","))
+		gitTrafficTag, ok := buildGitTrafficTag(service, cfg.gitSHA)
+		if !ok {
+			fmt.Fprintf(
+				os.Stderr,
+				"warn: service %q is too long to fit a git traffic tag within %d characters, skipping git tag\n",
+				service,
+				cloudRunServiceAndTagMaxLength,
+			)
+		} else {
+			oldGitTags, err := listServiceGitTags(cfg, service)
+			if err != nil {
+				return fmt.Errorf("list git tags for %s: %w", service, err)
+			}
+			if len(oldGitTags) > 0 {
+				updateTrafficArgs = append(updateTrafficArgs, "--remove-tags="+strings.Join(oldGitTags, ","))
+			}
+			updateTrafficArgs = append(updateTrafficArgs, "--update-tags="+gitTrafficTag+"=LATEST")
 		}
-		updateTrafficArgs = append(updateTrafficArgs, "--update-tags="+gitTrafficTag+"=LATEST")
 	}
 	if err := runCommandStreaming(cfg.workdir, "gcloud", updateTrafficArgs...); err != nil {
 		return fmt.Errorf("update traffic for %s: %w", service, err)