feat: improve the Listener interface

- pass in a context for easier cancellation of tasks and sharing of data (such as loggers)

Author: denopink

chrysom/listenerClient.go

@@ -118,7 +118,7 @@ func (c *ListenerClient) Start(ctx context.Context) error {
 				outcome := SuccessOutcome
 				items, err := c.reader.GetItems(ctx, "")
 				if err == nil {
-					c.observer.listener.Update(items)
+					c.observer.listener.Update(ctx, items)
 				} else {
 					outcome = FailureOutcome
 					logger.Error("Failed to get items for listeners", zap.Error(err))

chrysom/listenerClient_test.go

@@ -19,7 +19,7 @@ import (
 )
 
 var (
-	mockListener = ListenerFunc((func(_ Items) {
+	mockListener = ListenerFunc((func(context.Context, Items) {
 		fmt.Println("Doing amazing work for 100ms")
 		time.Sleep(time.Millisecond * 100)
 	}))

chrysom/store.go

@@ -27,13 +27,13 @@ type Listener interface {
 	// additions, or updates.
 	//
 	// The list of hooks must contain only the current items.
-	Update(items Items)
+	Update(ctx context.Context, items Items)
 }
 
-type ListenerFunc func(items Items)
+type ListenerFunc func(ctx context.Context, items Items)
 
-func (l ListenerFunc) Update(items Items) {
-	l(items)
+func (l ListenerFunc) Update(ctx context.Context, items Items) {
+	l(ctx, items)
 }
 
 type Reader interface {

service.go

@@ -11,7 +11,9 @@ import (
 	"time"
 
 	"github.com/xmidt-org/ancla/chrysom"
+	"github.com/xmidt-org/sallust"
 	"go.uber.org/fx"
+	"go.uber.org/zap"
 )
 
 const errFmt = "%w: %v"
@@ -143,9 +145,11 @@ func prepArgusBasicClientConfig(cfg *Config) error {
 
 func prepArgusListenerConfig(cfg *chrysom.ListenerConfig, metrics chrysom.Measures, watches ...Watch) {
 	watches = append(watches, webhookListSizeWatch(metrics.WebhookListSizeGauge))
-	cfg.Listener = chrysom.ListenerFunc(func(items chrysom.Items) {
+	cfg.Listener = chrysom.ListenerFunc(func(ctx context.Context, items chrysom.Items) {
+		logger := sallust.Get(ctx)
 		iws, err := ItemsToInternalWebhooks(items)
 		if err != nil {
+			logger.Error("Failed to convert items to webhooks", zap.Error(err))
 			return
 		}
 		for _, watch := range watches {