improve mechanism inside invocation rule

This improves the mechanism inside the invocation rule to check if all tasks are
completed.

Some temp variables are removed away, and it should check the task status in each loop,
to return the result when it is the right condition.

This enhance readability and the performance a little.

pkg/controller/invocation/rules.go

@@ -3,6 +3,8 @@ package invocation
 import (
 	"errors"
 
+	"github.com/sirupsen/logrus"
+
 	"github.com/fission/fission-workflows/pkg/api"
 	"github.com/fission/fission-workflows/pkg/controller"
 	"github.com/fission/fission-workflows/pkg/controller/expr"
@@ -119,41 +121,54 @@ type RuleCheckIfCompleted struct {
 }
 
 func (cc *RuleCheckIfCompleted) Eval(cec controller.EvalContext) controller.Action {
-	ec := EnsureInvocationContext(cec)
-	wf := ec.Workflow()
-	wfi := ec.Invocation()
+	var (
+		err   error
+		ec    = EnsureInvocationContext(cec)
+		wf    = ec.Workflow()
+		wfi   = ec.Invocation()
+		tasks = types.GetTasks(wf, wfi)
+	)
+
+	log.WithFields(logrus.Fields{
+		"wfi-id": wfi.ID(),
+		"wf-id":  wf.ID(),
+	}).Debugf("check if all tasks are finished.")
+
 	// Check if the workflow invocation is complete
-	tasks := types.GetTasks(wf, wfi)
-	var err error
-	finished := true
-	success := true
 	for id := range tasks {
 		t, ok := wfi.Status.Tasks[id]
 		if !ok || !t.Status.Finished() {
-			finished = false
-			break
-		} else {
-			success = success && t.Status.Status == types.TaskInvocationStatus_SUCCEEDED
+			return nil
 		}
-	}
-	if finished {
-		var finalOutput *types.TypedValue
-		if len(wf.Spec.OutputTask) != 0 {
-			finalOutput = typedvalues.ResolveTaskOutput(wf.Spec.OutputTask, wfi)
-		}
-
-		// TODO extract to action
-		if success {
-			err = cc.InvocationAPI.Complete(wfi.ID(), finalOutput)
-		} else {
+		if t.Status.Status != types.TaskInvocationStatus_SUCCEEDED {
 			err = cc.InvocationAPI.Fail(wfi.ID(), errors.New("not all tasks succeeded"))
-		}
-		if err != nil {
-			return &controller.ActionError{
-				Err: err,
+			if err != nil {
+				return &controller.ActionError{
+					Err: err,
+				}
 			}
 		}
 	}
+
+	var finalOutput *types.TypedValue
+	if len(wf.Spec.OutputTask) != 0 {
+		finalOutput = typedvalues.ResolveTaskOutput(wf.Spec.OutputTask, wfi)
+	}
+
+	log.WithFields(logrus.Fields{
+		"wfi-id":       wfi.ID(),
+		"wf-id":        wf.ID(),
+		"final-output": finalOutput,
+	}).Debugf("all tasks finished.")
+
+	// TODO extract to action
+	err = cc.InvocationAPI.Complete(wfi.ID(), finalOutput)
+	if err != nil {
+		return &controller.ActionError{
+			Err: err,
+		}
+	}
+
 	return nil
 }