fix: enable when expressions to use expr; add new json variables to avoid expr conflicts

examples/conditionals.yaml

@@ -1,35 +1,41 @@
 # Conditionals provide a way to affect the control flow of a
 # workflow at runtime, depending on parameters. In this example
-# the 'print-hello' template may or may not be executed depending
-# on the input parameter, 'should-print'. When submitted with:
+# the 'printHello' template may or may not be executed depending
+# on the input parameter, 'shouldPrint'. When submitted with:
 #   argo submit examples/conditionals.yaml
-# the step will be skipped since 'should-print' will evaluate false.
+# the step will be skipped since 'shouldPrint' will evaluate false.
 # When submitted with:
-#   argo submit examples/conditionals.yaml -p should-print=true
-# the step will be executed since 'should-print' will evaluate true.
+#   argo submit examples/conditionals.yaml -p shouldPrint=true
+# the step will be executed since 'shouldPrint' will evaluate true.
 apiVersion: argoproj.io/v1alpha1
 kind: Workflow
 metadata:
   generateName: conditional-
 spec:
-  entrypoint: conditional-example
+  entrypoint: conditionalExample
   arguments:
     parameters:
-    - name: should-print
-      value: "false"
+    - name: shouldPrint
+      value: "true"
 
   templates:
-  - name: conditional-example
+  - name: conditionalExample
     inputs:
       parameters:
-      - name: should-print
+      - name: shouldPrint
     steps:
-    - - name: print-hello
-        template: whalesay
-        when: "{{inputs.parameters.should-print}} == true"
+    - - name: printHello-govaluate
+        template: argosay
+        when: "{{inputs.parameters.shouldPrint}} == true" # govaluate form
+      - name: printHello-expr
+        template: argosay
+        when: "{{= inputs.parameters.shouldPrint == 'true'}}" # expr form
+      - name: printHello-expr-json
+        template: argosay
+        when: "{{=jsonpath(workflow.parameters.json, '$[0].value') == 'true'}}" # expr form
 
-  - name: whalesay
+  - name: argosay
     container:
-      image: docker/whalesay:latest
+      image: argoproj/argosay:v1
       command: [sh, -c]
       args: ["cowsay hello"]

test/e2e/functional_test.go

@@ -89,6 +89,44 @@ spec:
 		})
 }
 
+func (s *FunctionalSuite) TestWhenExpressions() {
+	s.Given().
+		Workflow("@functional/conditionals.yaml").
+		When().
+		SubmitWorkflow().
+		WaitForWorkflow(fixtures.ToBeSucceeded, 2*time.Minute).
+		Then().
+		ExpectWorkflowNode(wfv1.NodeWithDisplayName("printHello-govaluate"), func(t *testing.T, n *wfv1.NodeStatus, p *apiv1.Pod) {
+			assert.NotEqual(t, wfv1.NodeTypeSkipped, n.Type)
+		}).
+		ExpectWorkflowNode(wfv1.NodeWithDisplayName("printHello-expr"), func(t *testing.T, n *wfv1.NodeStatus, p *apiv1.Pod) {
+			assert.NotEqual(t, wfv1.NodeTypeSkipped, n.Type)
+		}).
+		ExpectWorkflowNode(wfv1.NodeWithDisplayName("printHello-expr-json"), func(t *testing.T, n *wfv1.NodeStatus, p *apiv1.Pod) {
+			assert.NotEqual(t, wfv1.NodeTypeSkipped, n.Type)
+		})
+}
+
+func (s *FunctionalSuite) TestJSONVariables() {
+
+	s.Given().
+		Workflow("@testdata/json-variables.yaml").
+		When().
+		SubmitWorkflow().
+		WaitForWorkflow().
+		Then().
+		ExpectWorkflowNode(wfv1.SucceededPodNode, func(t *testing.T, n *wfv1.NodeStatus, p *apiv1.Pod) {
+			for _, c := range p.Spec.Containers {
+				if c.Name == "main" {
+					assert.Equal(t, 3, len(c.Args))
+					assert.Equal(t, "myLabelValue", c.Args[0])
+					assert.Equal(t, "myAnnotationValue", c.Args[1])
+					assert.Equal(t, "myParamValue", c.Args[2])
+				}
+			}
+		})
+}
+
 func (s *FunctionalSuite) TestWorkflowTTL() {
 	s.Given().
 		Workflow(`

test/e2e/testdata/json-variables.yaml

@@ -0,0 +1,26 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+
+metadata:
+  generateName: json-variables-
+
+  labels:
+    myLabel: myLabelValue
+  annotations:
+    myAnnotation: myAnnotationValue
+spec:
+  entrypoint: argosay1
+  arguments:
+    parameters:
+    - name: myParam
+      value: myParamValue
+
+  templates:
+  - name: argosay1
+    container:
+      image: argoproj/argosay:v1
+      command: [echo]
+      args: 
+        - "{{=jsonpath(workflow.labels.json, '$.myLabel')}}"
+        - "{{=jsonpath(workflow.annotations.json, '$.myAnnotation')}}"
+        - "{{=jsonpath(workflow.parameters.json, '$[0].value')}}"

workflow/common/common.go

@@ -175,12 +175,18 @@ const (
 	GlobalVarWorkflowFailures = "workflow.failures"
 	// GlobalVarWorkflowDuration is the current duration of this workflow
 	GlobalVarWorkflowDuration = "workflow.duration"
-	// GlobalVarWorkflowAnnotations is a JSON string containing all workflow annotations
+	// GlobalVarWorkflowAnnotations is a JSON string containing all workflow annotations - which will be deprecated in favor of GlobalVarWorkflowAnnotationsJSON
 	GlobalVarWorkflowAnnotations = "workflow.annotations"
-	// GlobalVarWorkflowLabels is a JSON string containing all workflow labels
+	// GlobalVarWorkflowAnnotationsJSON is a JSON string containing all workflow annotations
+	GlobalVarWorkflowAnnotationsJSON = "workflow.annotations.json"
+	// GlobalVarWorkflowLabels is a JSON string containing all workflow labels - which will be deprecated in favor of GlobalVarWorkflowLabelsJSON
 	GlobalVarWorkflowLabels = "workflow.labels"
-	// GlobalVarWorkflowParameters is a JSON string containing all workflow parameters
+	// GlobalVarWorkflowLabelsJSON is a JSON string containing all workflow labels
+	GlobalVarWorkflowLabelsJSON = "workflow.labels.json"
+	// GlobalVarWorkflowParameters is a JSON string containing all workflow parameters - which will be deprecated in favor of GlobalVarWorkflowParametersJSON
 	GlobalVarWorkflowParameters = "workflow.parameters"
+	// GlobalVarWorkflowParametersJSON is a JSON string containing all workflow parameters
+	GlobalVarWorkflowParametersJSON = "workflow.parameters.json"
 	// GlobalVarWorkflowCronScheduleTime is the scheduled timestamp of a Workflow started by a CronWorkflow
 	GlobalVarWorkflowCronScheduleTime = "workflow.scheduledTime"
 

workflow/controller/operator.go

@@ -570,6 +570,7 @@ func (woc *wfOperationCtx) setGlobalParameters(executionParameters wfv1.Argument
 
 	if workflowParameters, err := json.Marshal(woc.execWf.Spec.Arguments.Parameters); err == nil {
 		woc.globalParams[common.GlobalVarWorkflowParameters] = string(workflowParameters)
+		woc.globalParams[common.GlobalVarWorkflowParametersJSON] = string(workflowParameters)
 	}
 	for _, param := range executionParameters.Parameters {
 		if param.Value == nil && param.ValueFrom == nil {
@@ -605,12 +606,14 @@ func (woc *wfOperationCtx) setGlobalParameters(executionParameters wfv1.Argument
 
 	if workflowAnnotations, err := json.Marshal(woc.wf.ObjectMeta.Annotations); err == nil {
 		woc.globalParams[common.GlobalVarWorkflowAnnotations] = string(workflowAnnotations)
+		woc.globalParams[common.GlobalVarWorkflowAnnotationsJSON] = string(workflowAnnotations)
 	}
 	for k, v := range woc.wf.ObjectMeta.Annotations {
 		woc.globalParams["workflow.annotations."+k] = v
 	}
 	if workflowLabels, err := json.Marshal(woc.wf.ObjectMeta.Labels); err == nil {
 		woc.globalParams[common.GlobalVarWorkflowLabels] = string(workflowLabels)
+		woc.globalParams[common.GlobalVarWorkflowLabelsJSON] = string(workflowLabels)
 	}
 	for k, v := range woc.wf.ObjectMeta.Labels {
 		// if the Label will get overridden by a LabelsFrom expression later, don't set it now

workflow/validate/validate.go

@@ -161,6 +161,7 @@ func ValidateWorkflow(wftmplGetter templateresolution.WorkflowTemplateNamespaced
 	}
 	if len(wfArgs.Parameters) > 0 {
 		ctx.globalParams[common.GlobalVarWorkflowParameters] = placeholderGenerator.NextPlaceholder()
+		ctx.globalParams[common.GlobalVarWorkflowParametersJSON] = placeholderGenerator.NextPlaceholder()
 	}
 
 	for _, param := range wfArgs.Parameters {
@@ -190,11 +191,13 @@ func ValidateWorkflow(wftmplGetter templateresolution.WorkflowTemplateNamespaced
 		ctx.globalParams["workflow.annotations."+k] = placeholderGenerator.NextPlaceholder()
 	}
 	ctx.globalParams[common.GlobalVarWorkflowAnnotations] = placeholderGenerator.NextPlaceholder()
+	ctx.globalParams[common.GlobalVarWorkflowAnnotationsJSON] = placeholderGenerator.NextPlaceholder()
 
 	for k := range mergedLabels {
 		ctx.globalParams["workflow.labels."+k] = placeholderGenerator.NextPlaceholder()
 	}
 	ctx.globalParams[common.GlobalVarWorkflowLabels] = placeholderGenerator.NextPlaceholder()
+	ctx.globalParams[common.GlobalVarWorkflowLabelsJSON] = placeholderGenerator.NextPlaceholder()
 
 	if wf.Spec.Priority != nil {
 		ctx.globalParams[common.GlobalVarWorkflowPriority] = strconv.Itoa(int(*wf.Spec.Priority))
@@ -825,10 +828,6 @@ func (ctx *templateValidationCtx) validateSteps(scope map[string]interface{}, tm
 				return errors.Errorf(errors.CodeBadRequest, "templates.%s.steps[%d].%s %s", tmpl.Name, i, step.Name, err.Error())
 			}
 
-			if !validateWhenExpression(step.When) {
-				return errors.Errorf(errors.CodeBadRequest, "templates.%s when expression doesn't support 'expr' format '{{='. 'When' expression is only support govaluate format {{", tmpl.Name)
-			}
-
 			if step.HasExitHook() {
 				ctx.addOutputsToScope(resolvedTmpl, fmt.Sprintf("steps.%s", step.Name), scope, false, false)
 			}
@@ -1150,10 +1149,6 @@ func (d *dagValidationContext) GetTaskFinishedAtTime(taskName string) time.Time
 	return time.Now()
 }
 
-func validateWhenExpression(when string) bool {
-	return !strings.HasPrefix(when, "{{=")
-}
-
 func (ctx *templateValidationCtx) validateDAG(scope map[string]interface{}, tmplCtx *templateresolution.Context, tmpl *wfv1.Template) error {
 	err := validateNonLeaf(tmpl)
 	if err != nil {
@@ -1202,10 +1197,6 @@ func (ctx *templateValidationCtx) validateDAG(scope map[string]interface{}, tmpl
 			return errors.Errorf(errors.CodeBadRequest, "templates.%s cannot use 'continueOn' when using 'depends'. Instead use 'dep-task.Failed'/'dep-task.Errored'", tmpl.Name)
 		}
 
-		if !validateWhenExpression(task.When) {
-			return errors.Errorf(errors.CodeBadRequest, "templates.%s when doesn't support 'expr' expression '{{='. 'When' expression is only support govaluate format {{", tmpl.Name)
-		}
-
 		resolvedTmpl, err := ctx.validateTemplateHolder(&task, tmplCtx, &FakeArguments{})
 		if err != nil {
 			return errors.Errorf(errors.CodeBadRequest, "templates.%s.tasks.%s %s", tmpl.Name, task.Name, err.Error())