First draft of modifying RunnerListener to CallListener to get it closer to the action (and named better).

api/agent/listeners.go

@@ -0,0 +1,32 @@
+package agent
+
+import (
+	"context"
+
+	"github.com/fnproject/fn/api/extenders"
+	"github.com/fnproject/fn/api/models"
+)
+
+func (a *agent) AddCallListener(listener extenders.CallListener) {
+	a.callListeners = append(a.callListeners, listener)
+}
+
+func (a *agent) fireBeforeCall(ctx context.Context, call *models.Call) error {
+	for _, l := range a.callListeners {
+		err := l.BeforeCall(ctx, call)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (a *agent) fireAfterCall(ctx context.Context, call *models.Call) error {
+	for _, l := range a.callListeners {
+		err := l.AfterCall(ctx, call)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}