feat: Add default field in parameters.valueFrom (#2500)

api/openapi-spec/swagger.json

@@ -10,6 +10,7 @@
  ],
  "swagger": "2.0",
  "info": {
+ "description": "Workflow Service API performs CRUD actions against application resources",
  "title": "Argo",
  "version": "latest"
  },
@@ -2722,6 +2723,10 @@
  "type": "object",
  "title": "ValueFrom describes a location in which to obtain the value to a parameter",
  "properties": {
+ "default": {
+ "type": "string",
+ "title": "Default specifies a value to be used if retrieving the value from the specified source fails"
+ },
  "jqFilter": {
  "type": "string",
  "title": "JQFilter expression against the resource object in resource templates"
@@ -5874,5 +5879,31 @@
  "description": "HTTP Basic authentication",
  "type": "basic"
  }
+ },
+ "x-stream-definitions": {
+ "io.argoproj.workflow.v1alpha1.LogEntry": {
+ "properties": {
+ "error": {
+ "$ref": "#/definitions/grpc.gateway.runtime.StreamError"
+ },
+ "result": {
+ "$ref": "#/definitions/io.argoproj.workflow.v1alpha1.LogEntry"
+ }
+ },
+ "title": "Stream result of io.argoproj.workflow.v1alpha1.LogEntry",
+ "type": "object"
+ },
+ "io.argoproj.workflow.v1alpha1.WorkflowWatchEvent": {
+ "properties": {
+ "error": {
+ "$ref": "#/definitions/grpc.gateway.runtime.StreamError"
+ },
+ "result": {
+ "$ref": "#/definitions/io.argoproj.workflow.v1alpha1.WorkflowWatchEvent"
+ }
+ },
+ "title": "Stream result of io.argoproj.workflow.v1alpha1.WorkflowWatchEvent",
+ "type": "object"
+ }
  }
 }

examples/output-parameter.yaml

@@ -37,6 +37,7 @@ spec:
  parameters:
  - name: hello-param
  valueFrom:
+ default: "Foobar" # Default value to use if retrieving valueFrom fails. If not provided workflow will fail instead
  path: /tmp/hello_world.txt
 
  - name: print-message

pkg/apiclient/cronworkflow/cron-workflow.swagger.json

@@ -1552,6 +1552,10 @@
  "parameter": {
  "type": "string",
  "title": "Parameter reference to a step or dag task in which to retrieve an output parameter value from\n(e.g. '{{steps.mystep.outputs.myparam}}')"
+ },
+ "default": {
+ "type": "string",
+ "title": "Default specifies a value to be used if retrieving the value from the specified source fails"
  }
  },
  "title": "ValueFrom describes a location in which to obtain the value to a parameter"

pkg/apiclient/workflow/workflow.swagger.json

@@ -1929,6 +1929,10 @@
  "parameter": {
  "type": "string",
  "title": "Parameter reference to a step or dag task in which to retrieve an output parameter value from\n(e.g. '{{steps.mystep.outputs.myparam}}')"
+ },
+ "default": {
+ "type": "string",
+ "title": "Default specifies a value to be used if retrieving the value from the specified source fails"
  }
  },
  "title": "ValueFrom describes a location in which to obtain the value to a parameter"

pkg/apiclient/workflowarchive/workflow-archive.swagger.json

@@ -1360,6 +1360,10 @@
  "parameter": {
  "type": "string",
  "title": "Parameter reference to a step or dag task in which to retrieve an output parameter value from\n(e.g. '{{steps.mystep.outputs.myparam}}')"
+ },
+ "default": {
+ "type": "string",
+ "title": "Default specifies a value to be used if retrieving the value from the specified source fails"
  }
  },
  "title": "ValueFrom describes a location in which to obtain the value to a parameter"

pkg/apiclient/workflowtemplate/workflow-template.swagger.json

@@ -1420,6 +1420,10 @@
  "parameter": {
  "type": "string",
  "title": "Parameter reference to a step or dag task in which to retrieve an output parameter value from\n(e.g. '{{steps.mystep.outputs.myparam}}')"
+ },
+ "default": {
+ "type": "string",
+ "title": "Default specifies a value to be used if retrieving the value from the specified source fails"
  }
  },
  "title": "ValueFrom describes a location in which to obtain the value to a parameter"

pkg/apis/workflow/v1alpha1/workflow_types.go

@@ -620,6 +620,9 @@ type ValueFrom struct {
  // Parameter reference to a step or dag task in which to retrieve an output parameter value from
  // (e.g. '{{steps.mystep.outputs.myparam}}')
  Parameter string `json:"parameter,omitempty" protobuf:"bytes,4,opt,name=parameter"`
+
+ // Default specifies a value to be used if retrieving the value from the specified source fails
+ Default string `json:"default,omitempty" protobuf:"bytes,5,opt,name=default"`
 }
 
 // Artifact indicates an artifact to place at a specified path

test/e2e/functional_test.go

@@ -342,6 +342,64 @@ func (s *FunctionalSuite) TestTerminateBehavior() {
  })
 }
 
+func (s *FunctionalSuite) TestDefaultParameterOutputs() {
+ s.Given().
+ Workflow(`
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+ name: default-params
+ labels:
+ argo-e2e: true
+spec:
+ entrypoint: start
+ templates:
+ - name: start
+ steps:
+ - - name: generate-1
+ template: generate
+ - - name: generate-2
+ when: "True == False"
+ template: generate
+ outputs:
+ parameters:
+ - name: nested-out-parameter
+ valueFrom:
+ default: "Default value"
+ parameter: "{{steps.generate-2.outputs.parameters.out-parameter}}"
+
+ - name: generate
+ container:
+ image: docker/whalesay:latest
+ command: [sh, -c]
+ args: ["
+ echo 'my-output-parameter' > /tmp/my-output-parameter.txt
+ "]
+ outputs:
+ parameters:
+ - name: out-parameter
+ valueFrom:
+ path: /tmp/my-output-parameter.txt
+`).
+ When().
+ SubmitWorkflow().
+ WaitForWorkflow(30 * time.Second).
+ Then().
+ ExpectWorkflow(func(t *testing.T, _ *metav1.ObjectMeta, status *wfv1.WorkflowStatus) {
+ assert.Equal(t, wfv1.NodeSucceeded, status.Phase)
+ assert.True(t, status.Nodes.Any(func(node wfv1.NodeStatus) bool {
+ if node.Outputs != nil {
+ for _, param := range node.Outputs.Parameters {
+ if param.Value != nil && *param.Value == "Default value" {
+ return true
+ }
+ }
+ }
+ return false
+ }))
+ })
+}
+
 func TestFunctionalSuite(t *testing.T) {
  suite.Run(t, new(FunctionalSuite))
 }

workflow/controller/operator.go

@@ -1801,7 +1801,12 @@ func getTemplateOutputsFromScope(tmpl *wfv1.Template, scope *wfScope) (*wfv1.Out
  }
  val, err := scope.resolveParameter(param.ValueFrom.Parameter)
  if err != nil {
- return nil, err
+ // We have a default value to use instead of returning an error
+ if param.ValueFrom.Default != "" {
+ val = param.ValueFrom.Default
+ } else {
+ return nil, err
+ }
  }
  param.Value = &val
  param.ValueFrom = nil

workflow/executor/executor.go

@@ -425,14 +425,24 @@ func (we *WorkflowExecutor) SaveParameters() error {
  log.Infof("Copying %s from base image layer", param.ValueFrom.Path)
  output, err = we.RuntimeExecutor.GetFileContents(mainCtrID, param.ValueFrom.Path)
  if err != nil {
- return err
+ // We have a default value to use instead of returning an error
+ if param.ValueFrom.Default != "" {
+ output = param.ValueFrom.Default
+ } else {
+ return err
+ }
  }
  } else {
  log.Infof("Copying %s from from volume mount", param.ValueFrom.Path)
  mountedPath := filepath.Join(common.ExecutorMainFilesystemDir, param.ValueFrom.Path)
  out, err := ioutil.ReadFile(mountedPath)
  if err != nil {
- return err
+ // We have a default value to use instead of returning an error
+ if param.ValueFrom.Default != "" {
+ output = param.ValueFrom.Default
+ } else {
+ return err
+ }
  }
  output = string(out)
  }

workflow/executor/executor_test.go

@@ -1,6 +1,7 @@
 package executor
 
 import (
+ "fmt"
  "testing"
 
  "github.com/stretchr/testify/assert"
@@ -104,3 +105,35 @@ func TestIsBaseImagePath(t *testing.T) {
  assert.False(t, we.isBaseImagePath("/user-mount/some-path/foo"))
  assert.True(t, we.isBaseImagePath("/user-mount-coincidence"))
 }
+
+func TestDefaultParameters(t *testing.T) {
+ fakeClientset := fake.NewSimpleClientset()
+ mockRuntimeExecutor := mocks.ContainerRuntimeExecutor{}
+ templateWithOutParam := wfv1.Template{
+ Outputs: wfv1.Outputs{
+ Parameters: []wfv1.Parameter{
+ {
+ Name: "my-out",
+ ValueFrom: &wfv1.ValueFrom{
+ Default: "Default Value",
+ Path: "/path",
+ },
+ },
+ },
+ },
+ }
+ we := WorkflowExecutor{
+ PodName: fakePodName,
+ Template: templateWithOutParam,
+ ClientSet: fakeClientset,
+ Namespace: fakeNamespace,
+ PodAnnotationsPath: fakeAnnotations,
+ ExecutionControl: nil,
+ RuntimeExecutor: &mockRuntimeExecutor,
+ mainContainerID: fakeContainerID,
+ }
+ mockRuntimeExecutor.On("GetFileContents", fakeContainerID, "/path").Return("", fmt.Errorf("file not found"))
+ err := we.SaveParameters()
+ assert.NoError(t, err)
+ assert.Equal(t, "Default Value", *we.Template.Outputs.Parameters[0].Value)
+}

workflow/executor/resource.go

@@ -308,10 +308,15 @@ func (we *WorkflowExecutor) SaveResourceParameters(resourceNamespace string, res
  log.Info(cmd.Args)
  out, err := cmd.Output()
  if err != nil {
- if exErr, ok := err.(*exec.ExitError); ok {
- log.Errorf("`%s` stderr:\n%s", cmd.Args, string(exErr.Stderr))
+ // We have a default value to use instead of returning an error
+ if param.ValueFrom.Default != "" {
+ out = []byte(param.ValueFrom.Default)
+ } else {
+ if exErr, ok := err.(*exec.ExitError); ok {
+ log.Errorf("`%s` stderr:\n%s", cmd.Args, string(exErr.Stderr))
+ }
+ return errors.InternalWrapError(err)
  }
- return errors.InternalWrapError(err)
  }
  output := string(out)
  we.Template.Outputs.Parameters[i].Value = &output