Fix #233 - Add support to 'switch' task

Signed-off-by: Ricardo Zanini <[email protected]>

Author: ricardozanini

README.md

@@ -132,7 +132,7 @@ The table below lists the current state of this implementation. This table is a
 | Task Raise | ✅ |
 | Task Run | ❌ |
 | Task Set | ✅ | 
-| Task Switch | ❌ | 
+| Task Switch | ✅ | 
 | Task Try | ❌ | 
 | Task Wait | ❌ |
 | Lifecycle Events | 🟡 |
@@ -157,7 +157,7 @@ The table below lists the current state of this implementation. This table is a
 | AsyncAPI Server | ❌ |
 | AsyncAPI Outbound Message | ❌ |
 | AsyncAPI Subscription | ❌ |
-| Workflow Definition Reference | ❌ |
+| Workflow Definition Reference | ✅ |
 | Subscription Iterator | ❌ |
 
 We love contributions! Our aim is to have a complete implementation to serve as a reference or to become a project on its own to favor the CNCF Ecosystem.

impl/runner_test.go

@@ -407,3 +407,51 @@ func TestForTaskRunner_Run(t *testing.T) {
 	})
 
 }
+
+func TestSwitchTaskRunner_Run(t *testing.T) {
+	t.Run("Color is red", func(t *testing.T) {
+		workflowPath := "./testdata/switch_match.yaml"
+		input := map[string]interface{}{
+			"color": "red",
+		}
+		expectedOutput := map[string]interface{}{
+			"colors": []interface{}{"red"},
+		}
+		runWorkflowTest(t, workflowPath, input, expectedOutput)
+	})
+
+	t.Run("Color is green", func(t *testing.T) {
+		workflowPath := "./testdata/switch_match.yaml"
+		input := map[string]interface{}{
+			"color": "green",
+		}
+		expectedOutput := map[string]interface{}{
+			"colors": []interface{}{"green"},
+		}
+		runWorkflowTest(t, workflowPath, input, expectedOutput)
+	})
+
+	t.Run("Color is blue", func(t *testing.T) {
+		workflowPath := "./testdata/switch_match.yaml"
+		input := map[string]interface{}{
+			"color": "blue",
+		}
+		expectedOutput := map[string]interface{}{
+			"colors": []interface{}{"blue"},
+		}
+		runWorkflowTest(t, workflowPath, input, expectedOutput)
+	})
+}
+
+func TestSwitchTaskRunner_DefaultCase(t *testing.T) {
+	t.Run("Color is unknown, should match default", func(t *testing.T) {
+		workflowPath := "./testdata/switch_with_default.yaml"
+		input := map[string]interface{}{
+			"color": "yellow",
+		}
+		expectedOutput := map[string]interface{}{
+			"colors": []interface{}{"default"},
+		}
+		runWorkflowTest(t, workflowPath, input, expectedOutput)
+	})
+}

impl/task_runner_do.go

@@ -86,6 +86,24 @@ func (d *DoTaskRunner) runTasks(input interface{}, tasks *model.TaskList) (outpu
 		}
 
 		d.TaskSupport.SetTaskStatus(currentTask.Key, ctx.PendingStatus)
+
+		// Check if this task is a SwitchTask and handle it
+		if switchTask, ok := currentTask.Task.(*model.SwitchTask); ok {
+			flowDirective, err := d.evaluateSwitchTask(input, currentTask.Key, switchTask)
+			if err != nil {
+				d.TaskSupport.SetTaskStatus(currentTask.Key, ctx.FaultedStatus)
+				return output, err
+			}
+			d.TaskSupport.SetTaskStatus(currentTask.Key, ctx.CompletedStatus)
+
+			// Process FlowDirective: update idx/currentTask accordingly
+			idx, currentTask = tasks.KeyAndIndex(flowDirective.Value)
+			if currentTask == nil {
+				return nil, fmt.Errorf("flow directive target '%s' not found", flowDirective.Value)
+			}
+			continue
+		}
+
 		runner, err := NewTaskRunner(currentTask.Key, currentTask.Task, d.TaskSupport)
 		if err != nil {
 			return output, err
@@ -116,6 +134,32 @@ func (d *DoTaskRunner) shouldRunTask(input interface{}, task *model.TaskItem) (b
 	return true, nil
 }
 
+func (d *DoTaskRunner) evaluateSwitchTask(input interface{}, taskKey string, switchTask *model.SwitchTask) (*model.FlowDirective, error) {
+	var defaultThen *model.FlowDirective
+	for _, switchItem := range switchTask.Switch {
+		for _, switchCase := range switchItem {
+			if switchCase.When == nil {
+				defaultThen = switchCase.Then
+				continue
+			}
+			result, err := traverseAndEvaluateBool(model.NormalizeExpr(switchCase.When.String()), input, d.TaskSupport.GetContext())
+			if err != nil {
+				return nil, model.NewErrExpression(err, taskKey)
+			}
+			if result {
+				if switchCase.Then == nil {
+					return nil, model.NewErrExpression(fmt.Errorf("missing 'then' directive in matched switch case"), taskKey)
+				}
+				return switchCase.Then, nil
+			}
+		}
+	}
+	if defaultThen != nil {
+		return defaultThen, nil
+	}
+	return nil, model.NewErrExpression(fmt.Errorf("no matching switch case"), taskKey)
+}
+
 // runTask executes an individual task.
 func (d *DoTaskRunner) runTask(input interface{}, runner TaskRunner, task *model.TaskBase) (output interface{}, err error) {
 	taskName := runner.GetTaskName()

impl/testdata/switch_match.yaml

@@ -0,0 +1,29 @@
+document:
+  dsl: '1.0.0'
+  namespace: default
+  name: switch-match
+  version: '1.0.0'
+do:
+  - switchColor:
+      switch:
+        - red:
+            when: '.color == "red"'
+            then: setRed
+        - green:
+            when: '.color == "green"'
+            then: setGreen
+        - blue:
+            when: '.color == "blue"'
+            then: setBlue
+  - setRed:
+      set:
+        colors: '${ .colors + [ "red" ] }'
+      then: end
+  - setGreen:
+      set:
+        colors: '${ .colors + [ "green" ] }'
+      then: end
+  - setBlue:
+      set:
+        colors: '${ .colors + [ "blue" ] }'
+      then: end

impl/testdata/switch_with_default.yaml

@@ -0,0 +1,29 @@
+document:
+  dsl: '1.0.0'
+  namespace: default
+  name: switch-with-default
+  version: '1.0.0'
+
+do:
+  - switchColor:
+      switch:
+        - red:
+            when: '.color == "red"'
+            then: setRed
+        - green:
+            when: '.color == "green"'
+            then: setGreen
+        - fallback:
+            then: setDefault
+  - setRed:
+      set:
+        colors: '${ .colors + [ "red" ] }'
+      then: end
+  - setGreen:
+      set:
+        colors: '${ .colors + [ "green" ] }'
+      then: end
+  - setDefault:
+      set:
+        colors: '${ .colors + [ "default" ] }'
+      then: end

model/runtime_expression.go

@@ -59,6 +59,14 @@ func IsValidExpr(expression string) bool {
 	return err == nil
 }
 
+// NormalizeExpr adds ${} to the given string
+func NormalizeExpr(expr string) string {
+	if strings.HasPrefix(expr, "${") {
+		return expr
+	}
+	return fmt.Sprintf("${%s}", expr)
+}
+
 // IsValid checks if the RuntimeExpression value is valid, handling both with and without `${}`.
 func (r *RuntimeExpression) IsValid() bool {
 	return IsValidExpr(r.Value)