cli: Add option to whitelist hooks (#302)

README.md

@@ -110,6 +110,8 @@ Usage of tusd:
     	Use Google Cloud Storage with this bucket as storage backend (requires the GCS_SERVICE_ACCOUNT_FILE environment variable to be set)
   -hooks-dir string
     	Directory to search for available hooks scripts
+  -hooks-enabled-events string
+    	Comma separated list of enabled hook events (e.g. post-create,post-finish). Leave empty to enable all events
   -hooks-http string
     	An HTTP endpoint to which hook events will be sent to
   -hooks-http-backoff int

cmd/tusd/cli/flags.go

@@ -4,6 +4,8 @@ import (
 	"flag"
 	"path/filepath"
 	"strings"
+
+	"github.com/tus/tusd/cmd/tusd/cli/hooks"
 )
 
 var Flags struct {
@@ -20,12 +22,14 @@ var Flags struct {
 	S3Endpoint          string
 	GCSBucket           string
 	GCSObjectPrefix     string
+	EnabledHooksString  string
 	FileHooksDir        string
 	HttpHooksEndpoint   string
 	HttpHooksRetry      int
 	HttpHooksBackoff    int
 	HooksStopUploadCode int
 	PluginHookPath      string
+	EnabledHooks        []hooks.HookType
 	ShowVersion         bool
 	ExposeMetrics       bool
 	MetricsPath         string
@@ -50,6 +54,7 @@ func ParseFlags() {
 	flag.StringVar(&Flags.S3Endpoint, "s3-endpoint", "", "Endpoint to use S3 compatible implementations like minio (requires s3-bucket to be pass)")
 	flag.StringVar(&Flags.GCSBucket, "gcs-bucket", "", "Use Google Cloud Storage with this bucket as storage backend (requires the GCS_SERVICE_ACCOUNT_FILE environment variable to be set)")
 	flag.StringVar(&Flags.GCSObjectPrefix, "gcs-object-prefix", "", "Prefix for GCS object names (can't contain underscore character)")
+	flag.StringVar(&Flags.EnabledHooksString, "hooks-enabled-events", "", "Comma separated list of enabled hook events (e.g. post-create,post-finish). Leave empty to enable all events")
 	flag.StringVar(&Flags.FileHooksDir, "hooks-dir", "", "Directory to search for available hooks scripts")
 	flag.StringVar(&Flags.HttpHooksEndpoint, "hooks-http", "", "An HTTP endpoint to which hook events will be sent to")
 	flag.IntVar(&Flags.HttpHooksRetry, "hooks-http-retry", 3, "Number of times to retry on a 500 or network timeout")
@@ -61,9 +66,10 @@ func ParseFlags() {
 	flag.StringVar(&Flags.MetricsPath, "metrics-path", "/metrics", "Path under which the metrics endpoint will be accessible")
 	flag.BoolVar(&Flags.BehindProxy, "behind-proxy", false, "Respect X-Forwarded-* and similar headers which may be set by proxies")
 	flag.BoolVar(&Flags.VerboseOutput, "verbose", true, "Enable verbose logging output")
-
 	flag.Parse()
 
+	SetEnabledHooks()
+
 	if Flags.FileHooksDir != "" {
 		Flags.FileHooksDir, _ = filepath.Abs(Flags.FileHooksDir)
 		Flags.FileHooksInstalled = true
@@ -89,3 +95,30 @@ func ParseFlags() {
 			"Please remove underscore from the value", Flags.GCSObjectPrefix)
 	}
 }
+
+func SetEnabledHooks() {
+	if Flags.EnabledHooksString != "" {
+		slc := strings.Split(Flags.EnabledHooksString, ",")
+
+		for i, h := range slc {
+			slc[i] = strings.TrimSpace(h)
+
+			if !hookTypeInSlice(hooks.HookType(h), hooks.AvailableHooks) {
+				stderr.Fatalf("Unknown hook event type in -hooks-enabled-events flag: %s", h)
+			}
+
+			Flags.EnabledHooks = append(Flags.EnabledHooks, hooks.HookType(h))
+		}
+	}
+
+	if len(Flags.EnabledHooks) == 0 {
+		Flags.EnabledHooks = hooks.AvailableHooks
+	}
+
+	var enabledHooksString []string
+	for _, h := range Flags.EnabledHooks {
+		enabledHooksString = append(enabledHooksString, string(h))
+	}
+
+	stdout.Printf("Enabled hook events: %s", strings.Join(enabledHooksString, ", "))
+}

cmd/tusd/cli/hooks.go

@@ -10,6 +10,15 @@ import (
 
 var hookHandler hooks.HookHandler = nil
 
+func hookTypeInSlice(a hooks.HookType, list []hooks.HookType) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}
+
 type hookDataStore struct {
 	tusd.DataStore
 }
@@ -62,7 +71,6 @@ func SetupPreHooks(composer *tusd.StoreComposer) error {
 	composer.UseCore(hookDataStore{
 		DataStore: composer.Core,
 	})
-
 	return nil
 }
 
@@ -91,6 +99,10 @@ func invokeHookAsync(typ hooks.HookType, info tusd.FileInfo) {
 }
 
 func invokeHookSync(typ hooks.HookType, info tusd.FileInfo, captureOutput bool) ([]byte, error) {
+	if !hookTypeInSlice(typ, Flags.EnabledHooks) {
+		return nil, nil
+	}
+
 	switch typ {
 	case hooks.HookPostFinish:
 		logEv(stdout, "UploadFinished", "id", info.ID, "size", strconv.FormatInt(info.Size, 10))

cmd/tusd/cli/hooks/hooks.go

@@ -19,6 +19,8 @@ const (
 	HookPreCreate     HookType = "pre-create"
 )
 
+var AvailableHooks []HookType = []HookType{HookPreCreate, HookPostCreate, HookPostReceive, HookPostTerminate, HookPostFinish}
+
 type hookDataStore struct {
 	tusd.DataStore
 }

docs/hooks.md

@@ -45,6 +45,9 @@ This event will be triggered after an upload has been terminated, meaning that t
 
 This event will be triggered for every running upload to indicate its current progress. It will be emitted whenever the server has received more data from the client but at most every second. The offset property will be set to the number of bytes which have been transfered to the server, at the time in total. Please be aware that this number may be higher than the number of bytes which have been stored by the data store!
 
+## Whitelisting Hook Events
+
+The `--hooks-enabled-events` option for the tusd binary works as a whitelist for hook events and takes a comma separated list of hook events (for instance: `pre-create,post-create`). This can be useful to limit the number of hook executions and save resources if you are only interested in some events. If the `--hooks-enabled-events` option is omitted, all hook events are enabled.
 
 ## File Hooks
 ### The Hook Directory