Enable functions to defer failures

so multiple validators can be run sequentially without shortcircuiting the pipeline

kyaml/runfn/runfn.go

@@ -164,7 +164,27 @@ func (r RunFns) runFunctions(
 		// the output is nil (reading from Input)
 		outputs = append(outputs, kio.ByteWriter{Writer: r.Output})
 	}
-	return kio.Pipeline{Inputs: []kio.Reader{input}, Filters: fltrs, Outputs: outputs}.Execute()
+	err := kio.Pipeline{
+		Inputs: []kio.Reader{input}, Filters: fltrs, Outputs: outputs}.Execute()
+	if err != nil {
+		return err
+	}
+
+	// check for deferred function errors
+	var errs []string
+	for i := range fltrs {
+		cf, ok := fltrs[i].(filters.DeferFailureFunction)
+		if !ok {
+			continue
+		}
+		if cf.GetExit() != nil {
+			errs = append(errs, cf.GetExit().Error())
+		}
+	}
+	if len(errs) > 0 {
+		return fmt.Errorf(strings.Join(errs, "\n---\n"))
+	}
+	return nil
 }
 
 // getFunctionsFromInput scans the input for functions and runs them
@@ -328,6 +348,7 @@ func (r *RunFns) ffp(spec filters.FunctionSpec, api *yaml.RNode) (kio.Filter, er
 			StorageMounts: r.StorageMounts,
 			GlobalScope:   r.GlobalScope,
 			ResultsFile:   resultsFile,
+			DeferFailure:  spec.DeferFailure,
 		}, nil
 	}
 	if r.EnableStarlark && spec.Starlark.Path != "" {

kyaml/runfn/runfn_test.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"sigs.k8s.io/kustomize/kyaml/copyutil"
+	"sigs.k8s.io/kustomize/kyaml/errors"
 	"sigs.k8s.io/kustomize/kyaml/kio"
 	"sigs.k8s.io/kustomize/kyaml/kio/filters"
 	"sigs.k8s.io/kustomize/kyaml/yaml"
@@ -234,6 +235,29 @@ metadata:
 			out: []string{"gcr.io/example.com/image:v1.0.0"},
 		},
 
+		// Test
+		//
+		//
+		{name: "defer_failure",
+			in: []f{
+				{
+					path: filepath.Join("foo", "bar.yaml"),
+					value: `
+apiVersion: example.com/v1alpha1
+kind: ExampleFunction
+metadata:
+  annotations:
+    config.kubernetes.io/function: |
+      deferFailure: true
+      container:
+        image: gcr.io/example.com/image:v1.0.0
+    config.kubernetes.io/local-config: "true"
+`,
+				},
+			},
+			out: []string{"gcr.io/example.com/image:v1.0.0 deferFailure: true"},
+		},
+
 		{name: "disable containers",
 			in: []f{
 				{
@@ -674,6 +698,93 @@ func TestCmd_Execute(t *testing.T) {
 	assert.Contains(t, string(b), "kind: StatefulSet")
 }
 
+type TestFilter struct {
+	invoked bool
+	Exit    error
+}
+
+func (f *TestFilter) Filter(input []*yaml.RNode) ([]*yaml.RNode, error) {
+	f.invoked = true
+	return input, nil
+}
+
+func (f *TestFilter) GetExit() error {
+	return f.Exit
+}
+
+func TestCmd_Execute_deferFailure(t *testing.T) {
+	dir := setupTest(t)
+	defer os.RemoveAll(dir)
+
+	// write a test filter to the directory of configuration
+	if !assert.NoError(t, ioutil.WriteFile(
+		filepath.Join(dir, "filter1.yaml"), []byte(`apiVersion: v1
+kind: ValueReplacer
+metadata:
+  annotations:
+    config.kubernetes.io/function: |
+      container:
+        image: 1
+    config.kubernetes.io/local-config: "true"
+stringMatch: Deployment
+replace: StatefulSet
+`), 0600)) {
+		t.FailNow()
+	}
+
+	// write a test filter to the directory of configuration
+	if !assert.NoError(t, ioutil.WriteFile(
+		filepath.Join(dir, "filter2.yaml"), []byte(`apiVersion: v1
+kind: ValueReplacer
+metadata:
+  annotations:
+    config.kubernetes.io/function: |
+      container:
+        image: 2
+    config.kubernetes.io/local-config: "true"
+stringMatch: Deployment
+replace: StatefulSet
+`), 0600)) {
+		t.FailNow()
+	}
+
+	var fltrs []*TestFilter
+	instance := RunFns{
+		Path: dir,
+		functionFilterProvider: func(f filters.FunctionSpec, node *yaml.RNode) (kio.Filter, error) {
+			tf := &TestFilter{
+				Exit: errors.Errorf("message: %s", f.Container.Image),
+			}
+			fltrs = append(fltrs, tf)
+			return tf, nil
+		},
+	}
+	instance.init()
+
+	err := instance.Execute()
+
+	// make sure all filters were run
+	if !assert.Equal(t, 2, len(fltrs)) {
+		t.FailNow()
+	}
+	for i := range fltrs {
+		if !assert.True(t, fltrs[i].invoked) {
+			t.FailNow()
+		}
+	}
+
+	if !assert.EqualError(t, err, "message: 1\n---\nmessage: 2") {
+		t.FailNow()
+	}
+	b, err := ioutil.ReadFile(
+		filepath.Join(dir, "java", "java-deployment.resource.yaml"))
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+	// files weren't changed because there was an error
+	assert.Contains(t, string(b), "kind: Deployment")
+}
+
 // TestCmd_Execute_setOutput tests the execution of a filter reading and writing to a dir
 func TestCmd_Execute_setFunctionPaths(t *testing.T) {
 	dir := setupTest(t)