implement --hooks-async

main.go

@@ -207,7 +207,8 @@ func main() {
 	flGroupWrite := pflag.Bool("group-write",
 		envBool(false, "GITSYNC_GROUP_WRITE", "GIT_SYNC_GROUP_WRITE"),
 		"ensure that all data (repo, worktrees, etc.) is group writable")
-	flStaleWorktreeTimeout := pflag.Duration("stale-worktree-timeout", envDuration(0, "GITSYNC_STALE_WORKTREE_TIMEOUT"),
+	flStaleWorktreeTimeout := pflag.Duration("stale-worktree-timeout",
+		envDuration(0, "GITSYNC_STALE_WORKTREE_TIMEOUT"),
 		"how long to retain non-current worktrees")
 
 	flExechookCommand := pflag.String("exechook-command",
@@ -236,6 +237,10 @@ func main() {
 		envDuration(3*time.Second, "GITSYNC_WEBHOOK_BACKOFF", "GIT_SYNC_WEBHOOK_BACKOFF"),
 		"the time to wait before retrying a failed webhook")
 
+	flHooksAsync := pflag.Bool("hooks-async",
+		envBool(true, "GITSYNC_HOOKS_ASYNC", "GIT_SYNC_HOOKS_ASYNC"),
+		"run hooks asynchronously")
+
 	flUsername := pflag.String("username",
 		envString("", "GITSYNC_USERNAME", "GIT_SYNC_USERNAME"),
 		"the username to use for git auth")
@@ -844,6 +849,7 @@ func main() {
 			hook.NewHookData(),
 			log,
 			*flOneTime,
+			*flHooksAsync,
 		)
 		go webhookRunner.Run(context.Background())
 	}
@@ -868,6 +874,7 @@ func main() {
 			hook.NewHookData(),
 			log,
 			*flOneTime,
+			*flHooksAsync,
 		)
 		go exechookRunner.Run(context.Background())
 	}

pkg/hook/hook.go

@@ -89,10 +89,10 @@ func (d *hookData) send(newHash string) {
 }
 
 // NewHookRunner returns a new HookRunner.
-func NewHookRunner(hook Hook, backoff time.Duration, data *hookData, log logintf, oneTime bool) *HookRunner {
-	hr := &HookRunner{hook: hook, backoff: backoff, data: data, log: log}
-	if oneTime {
-		hr.oneTimeResult = make(chan bool, 1)
+func NewHookRunner(hook Hook, backoff time.Duration, data *hookData, log logintf, oneTime bool, async bool) *HookRunner {
+	hr := &HookRunner{hook: hook, backoff: backoff, data: data, log: log, oneTime: oneTime, async: async}
+	if oneTime || !async {
+		hr.result = make(chan bool, 1)
 	}
 	return hr
 }
@@ -107,9 +107,13 @@ type HookRunner struct {
 	data *hookData
 	// Logger
 	log logintf
-	// Used to send a status result when running in one-time mode.
+	// Used to send a status result when running in one-time or non-async mode.
 	// Should be initialised to a buffered channel of size 1.
-	oneTimeResult chan bool
+	result chan bool
+	// Bool for whether this is a one-time hook or not.
+	oneTime bool
+	// Bool for whether this is an async hook or not.
+	async bool
 }
 
 // Just the logr methods we need in this package.
@@ -120,8 +124,17 @@ type logintf interface {
 }
 
 // Send sends hash to hookdata.
-func (r *HookRunner) Send(hash string) {
+func (r *HookRunner) Send(hash string) error {
 	r.data.send(hash)
+	if !r.async {
+		r.log.V(1).Info("waiting for completion", "hash", hash, "name", r.hook.Name())
+		err := r.WaitForCompletion()
+		r.log.V(1).Info("hook completed", "hash", hash, "err", err, "name", r.hook.Name())
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 // Run waits for trigger events from the channel, and run hook when triggered.
@@ -144,45 +157,49 @@ func (r *HookRunner) Run(ctx context.Context) {
 				r.log.Error(err, "hook failed", "hash", hash, "retry", r.backoff)
 				updateHookRunCountMetric(r.hook.Name(), "error")
 				// don't want to sleep unnecessarily terminating anyways
-				r.sendOneTimeResultAndTerminate(false)
+				r.sendResult(false)
 				time.Sleep(r.backoff)
 			} else {
 				updateHookRunCountMetric(r.hook.Name(), "success")
 				lastHash = hash
-				r.sendOneTimeResultAndTerminate(true)
+				r.sendResult(true)
 				break
 			}
 		}
 	}
 }
 
-// If oneTimeResult is nil, does nothing. Otherwise, forwards the caller
-// provided success status (as a boolean) of HookRunner to receivers of
-// oneTimeResult, closes said chanel, and terminates this goroutine.
-// Using this function to write to oneTimeResult ensures it is only ever
-// written to once.
-func (r *HookRunner) sendOneTimeResultAndTerminate(completedSuccessfully bool) {
-	if r.oneTimeResult != nil {
-		r.oneTimeResult <- completedSuccessfully
-		close(r.oneTimeResult)
+func (r *HookRunner) sendResult(completedSuccessfully bool) {
+	// if onetime is true, we send the result then exit
+	if r.oneTime {
+		r.result <- completedSuccessfully
+		close(r.result)
 		runtime.Goexit()
+	} else if !r.async {
+		// if onetime is false, and we've set non-async we send but don't exit.
+		r.result <- completedSuccessfully
 	}
+	// if neither oneTime nor !async, we do nothing here.
 }
 
 // WaitForCompletion waits for HookRunner to send completion message to
 // calling thread and returns either true if HookRunner executed successfully
 // and some error otherwise.
-// Assumes that r.oneTimeResult is not nil, but if it is, returns an error.
+// Assumes that either r.oneTime or !r.async, otherwise returns an error.
 func (r *HookRunner) WaitForCompletion() error {
 	// Make sure function should be called
-	if r.oneTimeResult == nil {
+	if r.result == nil {
 		return fmt.Errorf("HookRunner.WaitForCompletion called on async runner")
 	}
 
-	// Perform wait on HookRunner
-	hookRunnerFinishedSuccessfully := <-r.oneTimeResult
-	if !hookRunnerFinishedSuccessfully {
-		return fmt.Errorf("hook completed with error")
+	// If oneTimeResult is not nil, we wait for its result.
+	if r.result != nil {
+		hookRunnerFinishedSuccessfully := <-r.result
+		r.log.V(1).Info("hook completed", "success", hookRunnerFinishedSuccessfully,
+			"oneTime", r.oneTime, "async", r.async, "name", r.hook.Name())
+		if !hookRunnerFinishedSuccessfully {
+			return fmt.Errorf("hook completed with error")
+		}
 	}
 
 	return nil

test_e2e.sh

@@ -2406,7 +2406,7 @@ function e2e::exechook_fail_retry() {
         --exechook-command="/$EXECHOOK_COMMAND_FAIL" \
         --exechook-backoff=1s \
         &
-    sleep 3 # give it time to retry
+    sleep 4 # give it time to retry
 
     # Check that exechook was called
     assert_file_lines_ge "$RUNLOG" 2
@@ -2486,6 +2486,29 @@ function e2e::exechook_startup_after_crash() {
     assert_file_lines_eq "$RUNLOG" 1
 }
 
+##############################################
+# Test exechook-success with --hooks-async=false
+##############################################
+function e2e::exechook_success_hooks_non_async() {
+    cat /dev/null > "$RUNLOG"
+
+    GIT_SYNC \
+        --hooks-async=false \
+        --period=100ms \
+        --repo="file://$REPO" \
+        --root="$ROOT" \
+        --link="link" \
+        --exechook-command="/$EXECHOOK_COMMAND_SLEEPY" \
+        &
+    sleep 5 # give it time to run
+    assert_link_exists "$ROOT/link"
+    assert_file_exists "$ROOT/link/file"
+    assert_file_exists "$ROOT/link/exechook"
+    assert_file_eq "$ROOT/link/file" "${FUNCNAME[0]}"
+    assert_file_eq "$ROOT/link/exechook" "${FUNCNAME[0]}"
+    assert_file_eq "$ROOT/link/exechook-env" "$EXECHOOK_ENVKEY=$EXECHOOK_ENVVAL"
+}
+
 ##############################################
 # Test webhook success
 ##############################################
@@ -3797,8 +3820,7 @@ for t; do
         fi
         remove_containers || true
         run=$((run+1))
-    done
-    if [[ "$test_ret" != 0 ]]; then
+    done    if [[ "$test_ret" != 0 ]]; then
         final_ret=1
         failures+=("$t  (log: ${log}.*)")
     fi