Reduce to a single webhook call

cmd/git-sync/main.go

@@ -21,7 +21,6 @@ package main // import "k8s.io/git-sync/cmd/git-sync"
 import (
 	"bytes"
 	"context"
-	"encoding/json"
 	"flag"
 	"fmt"
 	"io"
@@ -63,8 +62,14 @@ var flMaxSyncFailures = flag.Int("max-sync-failures", envInt("GIT_SYNC_MAX_SYNC_
 var flChmod = flag.Int("change-permissions", envInt("GIT_SYNC_PERMISSIONS", 0),
 	"the file permissions to apply to the checked-out files")
 
-var flWebhooks = flag.String("webhook", envString("GIT_SYNC_WEBHOOK", ""),
-	"the JSON formatted array of webhooks to be sent when git is synced")
+var flWebhookURL = flag.String("webhook-url", envString("GIT_SYNC_WEBHOOK_URL", ""),
+	"the URL for the webook to send to. Default is \"\" which disables the webook.")
+var flWebhookMethod = flag.String("webhook-method", envString("GIT_SYNC_WEBHOOK_METHOD", "POST"),
+	"the method for the webook to send with")
+var flWebhookStatusSuccess = flag.Int("webhook-success-status", envInt("GIT_SYNC_WEBHOOK_SUCCESS_STATUS", 200),
+	"the status code which indicates a successful webhook call")
+var flWebhookTimeout = flag.Duration("webhook-timeout-duration", envDuration("GIT_SYNC_WEBHOOK_TIMEOUT_DURATION", time.Second),
+	"the timeout used when communicating with the webhook target")
 
 var flUsername = flag.String("username", envString("GIT_SYNC_USERNAME", ""),
 	"the username to use")
@@ -140,6 +145,18 @@ func envFloat(key string, def float64) float64 {
 	return def
 }
 
+func envDuration(key string, def time.Duration) time.Duration {
+	if env := os.Getenv(key); env != "" {
+		val, err := time.ParseDuration(env)
+		if err != nil {
+			log.Errorf("invalid value for %q: using default: %v", key, def)
+			return def
+		}
+		return val
+	}
+	return def
+}
+
 func main() {
 	setFlagDefaults()
 
@@ -175,13 +192,6 @@ func main() {
 		}
 	}
 
-	if *flWebhooks != "" {
-		if err := json.Unmarshal([]byte(*flWebhooks), &WebhookArray); err != nil {
-			fmt.Fprintf(os.Stderr, "Error parsing webhooks JSON: %v\n", err)
-			os.Exit(1)
-		}
-	}
-
 	if *flSSH {
 		if err := setupGitSSH(*flSSHKnownHosts); err != nil {
 			fmt.Fprintf(os.Stderr, "ERROR: can't configure SSH: %v\n", err)
@@ -200,8 +210,16 @@ func main() {
 	log.V(0).Infof("starting up: %q", os.Args)
 
 	// Startup webhooks goroutine
-	webhookTriggerChan := make(chan struct{})
-	go ServeWebhooks(webhookTriggerChan)
+	webhookTriggerChan := make(chan struct{}, 1)
+	if *flWebhookURL != "" {
+		webhook := Webhook{
+			URL:     *flWebhookURL,
+			Method:  *flWebhookMethod,
+			Success: flWebhookStatusSuccess,
+			Timeout: *flWebhookTimeout,
+		}
+		go webhook.run(webhookTriggerChan)
+	}
 
 	initialSync := true
 	failCount := 0
@@ -220,8 +238,14 @@ func main() {
 			time.Sleep(waitTime(*flWait))
 			continue
 		} else if changed {
-			// Trigger webhooks to be called
-			webhookTriggerChan <- struct{}{}
+			// Trigger webhooks to be called. We do a non-blocking write to the channel as we
+			// don't want to backup the syncing locally because we can't complete a webhook call.
+			// Since the channel has a buffer of 1 we ensure that it is called for a change, but
+			// this allows us to de-dupe calls if they happen before the webhook call completes.
+			select {
+			case webhookTriggerChan <- struct{}{}:
+			default:
+			}
 		}
 		if initialSync {
 			if *flOneTime {

cmd/git-sync/webhook.go

@@ -2,38 +2,22 @@ package main
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"net/http"
 	"time"
 )
 
-// Webhook collection
-var WebhookArray = []Webhook{}
-
 // WebHook structure
 type Webhook struct {
 	// URL for the http/s request
-	URL string `json:"url"`
+	URL string
 	// Method for the http/s request
-	Method string `json:"method"`
+	Method string
 	// Code to look for when determining if the request was successful.
 	//   If this is not specified, request is sent and forgotten about.
-	Success *int `json:"success"`
+	Success *int
 	// Timeout for the http/s request
-	Timeout time.Duration `json:"timeout"`
-}
-
-func (w *Webhook) UnmarshalJSON(data []byte) error {
-	type testAlias Webhook
-	test := &testAlias{
-		Timeout: time.Second * 5,
-	}
-
-	_ = json.Unmarshal(data, test)
-
-	*w = Webhook(*test)
-	return nil
+	Timeout time.Duration
 }
 
 func (w *Webhook) Do() error {
@@ -62,20 +46,18 @@ func (w *Webhook) Do() error {
 }
 
 // Wait for trigger events from the channel, and send webhooks when triggered
-func ServeWebhooks(ch chan struct{}) {
+func (w *Webhook) run(ch chan struct{}) {
 	for {
 		// Wait for trigger
 		<-ch
 
-		// Calling webhook - one after another
-		for _, v := range WebhookArray {
-			log.V(0).Infof("calling webhook %v\n", v.URL)
-			if err := v.Do(); err != nil {
-				log.Errorf("error calling webhook %v: %v", v.URL, err)
+		for {
+			if err := w.Do(); err != nil {
+				log.Errorf("error calling webhook %v: %v", w.URL, err)
 			} else {
-				log.V(0).Infof("calling webhook %v was: OK\n", v.URL)
+				log.V(0).Infof("calling webhook %v was: OK\n", w.URL)
+				break
 			}
 		}
 	}
-
 }