Support writing results from container filter

cmd/config/internal/commands/run-fns.go

@@ -51,6 +51,9 @@ func GetRunFnRunner(name string) *RunFnRunner {
 		&r.StarName, "star-name", "", "name of starlark program.")
 	r.Command.Flags().MarkHidden("star-name")
 
+	r.Command.Flags().StringVar(
+		&r.ResultsDir, "results-dir", "", "write function results to this dir")
+
 	r.Command.Flags().BoolVar(
 		&r.Network, "network", false, "enable network access for functions that declare it")
 	r.Command.Flags().StringVar(
@@ -77,6 +80,7 @@ type RunFnRunner struct {
 	StarPath           string
 	StarName           string
 	RunFns             runfn.RunFns
+	ResultsDir         string
 	Network            bool
 	NetworkName        string
 	Mounts             []string
@@ -267,6 +271,7 @@ func (r *RunFnRunner) preRunE(c *cobra.Command, args []string) error {
 		NetworkName:    r.NetworkName,
 		EnableStarlark: r.EnableStar,
 		StorageMounts:  storageMounts,
+		ResultsDir:     r.ResultsDir,
 	}
 
 	// don't consider args for the function

cmd/config/internal/commands/run_test.go

@@ -11,23 +11,25 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/kustomize/kyaml/runfn"
 )
 
 // TestRunFnCommand_preRunE verifies that preRunE correctly parses the commandline
 // flags and arguments into the RunFns structure to be executed.
 func TestRunFnCommand_preRunE(t *testing.T) {
 	tests := []struct {
-		name          string
+		name           string
-		args          []string
+		args           []string
-		expected      string
+		expected       string
-		err           string
+		expectedStruct *runfn.RunFns
-		path          string
+		err            string
-		input         io.Reader
+		path           string
-		output        io.Writer
+		input          io.Reader
-		functionPaths []string
+		output         io.Writer
-		network       bool
+		functionPaths  []string
-		networkName   string
+		network        bool
-		mount         []string
+		networkName    string
+		mount          []string
 	}{
 		{
 			name: "config map",
@@ -234,6 +236,26 @@ metadata:
 data: {g: h, i: j=k}
 kind: Foo
 apiVersion: v1
+`,
+		},
+		{
+			name: "results_dir",
+			args: []string{"run", "dir", "--results-dir", "foo/", "--image", "foo:bar", "--", "a=b", "c=d", "e=f"},
+			path: "dir",
+			expectedStruct: &runfn.RunFns{
+				Path:        "dir",
+				NetworkName: "bridge",
+				ResultsDir:  "foo/",
+			},
+			expected: `
+metadata:
+  name: function-input
+  annotations:
+    config.kubernetes.io/function: |
+      container: {image: 'foo:bar'}
+data: {a: b, c: d, e: f}
+kind: ConfigMap
+apiVersion: v1
 `,
 		},
 		{
@@ -324,6 +346,10 @@ apiVersion: v1
 				t.FailNow()
 			}
 
+			if !assert.Equal(t, r.RunFns, r.RunFns) {
+				t.FailNow()
+			}
+
 			if !assert.Equal(t, toStorageMounts(tt.mount), r.RunFns.StorageMounts) {
 				t.FailNow()
 			}
@@ -339,6 +365,14 @@ apiVersion: v1
 				}
 			}
 
+			if tt.expectedStruct != nil {
+				r.RunFns.Functions = nil
+				tt.expectedStruct.FunctionPaths = tt.functionPaths
+				if !assert.Equal(t, *tt.expectedStruct, r.RunFns) {
+					t.FailNow()
+				}
+			}
+
 		})
 	}
 

kyaml/kio/filters/container.go

@@ -6,6 +6,7 @@ package filters
 import (
 	"bytes"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -146,6 +147,13 @@ type ContainerFilter struct {
 	// nodes instead of only nodes scoped under the function.
 	GlobalScope bool
 
+	ResultsFile string
+
+	Results *yaml.RNode
+
+	// SetFlowStyleForConfig sets the style for config to Flow when serializing it
+	SetFlowStyleForConfig bool
+
 	// args may be specified by tests to override how a container is spawned
 	args []string
 
@@ -257,10 +265,7 @@ func (c *ContainerFilter) scope(dir string, nodes []*yaml.RNode) ([]*yaml.RNode,
 // GrepFilter implements kio.GrepFilter
 func (c *ContainerFilter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 	// get the command to filter the Resources
-	cmd, err := c.getCommand()
+	cmd := c.getCommand()
-	if err != nil {
-		return nil, err
-	}
 
 	in := &bytes.Buffer{}
 	out := &bytes.Buffer{}
@@ -296,7 +301,16 @@ func (c *ContainerFilter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 	cmd.Stdin = in
 	cmd.Stdout = out
 	if err := cmd.Run(); err != nil {
-		return nil, err
+		// write the results file on failure
+		results, e := r.Read()
+		if e != nil {
+			return nil, e
+		}
+		if e = c.doResults(r); e != nil {
+			return nil, e
+		}
+		// return the results from the function even on failure
+		return results, err
 	}
 
 	output, err := r.Read()
@@ -304,6 +318,10 @@ func (c *ContainerFilter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 		return nil, err
 	}
 
+	if err := c.doResults(r); err != nil {
+		return nil, err
+	}
+
 	// annotate any generated Resources with a path and index if they don't already have one
 	if err := kioutil.DefaultPathAnnotation(functionDir, output); err != nil {
 		return nil, err
@@ -314,6 +332,25 @@ func (c *ContainerFilter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 	return append(output, saved...), nil
 }
 
+func (c *ContainerFilter) doResults(r *kio.ByteReader) error {
+	// Write the results to a file if configured to do so
+	if c.ResultsFile != "" && r.Results != nil {
+		results, err := r.Results.String()
+		if err != nil {
+			return err
+		}
+		err = ioutil.WriteFile(c.ResultsFile, []byte(results), 0600)
+		if err != nil {
+			return err
+		}
+	}
+
+	if r.Results != nil {
+		c.Results = r.Results
+	}
+	return nil
+}
+
 // getArgs returns the command + args to run to spawn the container
 func (c *ContainerFilter) getArgs() []string {
 	// run the container using docker.  this is simpler than using the docker
@@ -341,6 +378,9 @@ func (c *ContainerFilter) getArgs() []string {
 		args = append(args, "--mount", storageMount.String())
 	}
 
+	// tell functions to write error messages to stderr as well as results
+	os.Setenv("LOG_TO_STDERR", "true")
+
 	// export the local environment vars to the container
 	for _, pair := range os.Environ() {
 		tokens := strings.Split(pair, "=")
@@ -353,17 +393,9 @@ func (c *ContainerFilter) getArgs() []string {
 }
 
 // getCommand returns a command which will apply the Filter using the container image
-func (c *ContainerFilter) getCommand() (*exec.Cmd, error) {
+func (c *ContainerFilter) getCommand() *exec.Cmd {
-	// encode the filter command API configuration
+	if c.SetFlowStyleForConfig {
-	cfg := &bytes.Buffer{}
-	if err := func() error {
-		e := yaml.NewEncoder(cfg)
-		defer e.Close()
-		// make it fit on a single line
 		c.Config.YNode().Style = yaml.FlowStyle
-		return e.Encode(c.Config.YNode())
-	}(); err != nil {
-		return nil, err
 	}
 
 	if len(c.args) == 0 {
@@ -375,7 +407,7 @@ func (c *ContainerFilter) getCommand() (*exec.Cmd, error) {
 	cmd.Env = os.Environ()
 
 	// set stderr for err messaging
-	return cmd, nil
+	return cmd
 }
 
 // IsReconcilerFilter filters Resources based on whether or not they are Reconciler Resource.

kyaml/kio/filters/container_test.go

@@ -6,6 +6,7 @@ package filters
 import (
 	"bytes"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"strings"
 	"testing"
@@ -15,6 +16,367 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
+func TestContainerFilter_Filter(t *testing.T) {
+	var tests = []struct {
+		name              string
+		input             []string
+		expectedOutput    []string
+		expectedError     string
+		expectedResults   string
+		noMakeResultsFile bool
+		instance          ContainerFilter
+	}{
+		{
+			name: "add_path_annotation",
+			instance: ContainerFilter{args: []string{
+				"echo", `
+apiVersion: config.kubernetes.io/v1alpha1
+kind: ResourceList
+items:
+- apiVersion: apps/v1
+  kind: Deployment
+  metadata:
+    name: deployment-foo
+- apiVersion: v1
+  kind: Service
+  metadata:
+    name: service-foo
+`,
+			},
+			},
+			expectedOutput: []string{
+				`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deployment-foo
+  annotations:
+    config.kubernetes.io/path: 'deployment_deployment-foo.yaml'
+`,
+				`
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-foo
+  annotations:
+    config.kubernetes.io/path: 'service_service-foo.yaml'
+`,
+			},
+		},
+
+		{
+			name: "write_results",
+			instance: ContainerFilter{args: []string{
+				"echo", `
+apiVersion: config.kubernetes.io/v1alpha1
+kind: ResourceList
+items:
+- apiVersion: apps/v1
+  kind: Deployment
+  metadata:
+    name: deployment-foo
+- apiVersion: v1
+  kind: Service
+  metadata:
+    name: service-foo
+results:
+- apiVersion: config.k8s.io/v1alpha1
+  kind: ObjectError
+  name: "some-validator"
+  items:  
+  - type: error
+    message: "some message"
+    resourceRef:
+      apiVersion: apps/v1
+      kind: Deployment
+      name: foo
+      namespace: bar
+    file:
+      path: deploy.yaml
+      index: 0
+    field:
+      path: "spec.template.spec.containers[3].resources.limits.cpu"
+      currentValue: "200"
+      suggestedValue: "2"
+`,
+			},
+			},
+			expectedOutput: []string{
+				`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deployment-foo
+  annotations:
+    config.kubernetes.io/path: 'deployment_deployment-foo.yaml'
+`,
+				`
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-foo
+  annotations:
+    config.kubernetes.io/path: 'service_service-foo.yaml'
+`,
+			},
+			expectedResults: `
+- apiVersion: config.k8s.io/v1alpha1
+  kind: ObjectError
+  name: "some-validator"
+  items:
+  - type: error
+    message: "some message"
+    resourceRef:
+      apiVersion: apps/v1
+      kind: Deployment
+      name: foo
+      namespace: bar
+    file:
+      path: deploy.yaml
+      index: 0
+    field:
+      path: "spec.template.spec.containers[3].resources.limits.cpu"
+      currentValue: "200"
+      suggestedValue: "2"
+`,
+		},
+
+		{
+			name:          "write_results_non_0_exit",
+			expectedError: "exit status 1",
+			instance: ContainerFilter{args: []string{"sh", "-c",
+				`echo '
+apiVersion: config.kubernetes.io/v1alpha1
+kind: ResourceList
+items:
+- apiVersion: apps/v1
+  kind: Deployment
+  metadata:
+    name: deployment-foo
+- apiVersion: v1
+  kind: Service
+  metadata:
+    name: service-foo
+results:
+- apiVersion: config.k8s.io/v1alpha1
+  kind: ObjectError
+  name: "some-validator"
+  items:  
+  - type: error
+    message: "some message"
+    resourceRef:
+      apiVersion: apps/v1
+      kind: Deployment
+      name: foo
+      namespace: bar
+    file:
+      path: deploy.yaml
+      index: 0
+    field:
+      path: "spec.template.spec.containers[3].resources.limits.cpu"
+      currentValue: "200"
+      suggestedValue: "2"
+' && cat not-real-dir
+`,
+			},
+			},
+			expectedOutput: []string{
+				`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deployment-foo
+  annotations:
+    config.kubernetes.io/path: 'deployment_deployment-foo.yaml'
+`,
+				`
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-foo
+  annotations:
+    config.kubernetes.io/path: 'service_service-foo.yaml'
+`,
+			},
+			expectedResults: `
+- apiVersion: config.k8s.io/v1alpha1
+  kind: ObjectError
+  name: "some-validator"
+  items:
+  - type: error
+    message: "some message"
+    resourceRef:
+      apiVersion: apps/v1
+      kind: Deployment
+      name: foo
+      namespace: bar
+    file:
+      path: deploy.yaml
+      index: 0
+    field:
+      path: "spec.template.spec.containers[3].resources.limits.cpu"
+      currentValue: "200"
+      suggestedValue: "2"
+`,
+		},
+
+		{
+			name:              "write_results_non_0_exit_missing_file",
+			expectedError:     "open /not/real/file: no such file or directory",
+			noMakeResultsFile: true,
+			instance: ContainerFilter{args: []string{"sh", "-c",
+				`echo '
+apiVersion: config.kubernetes.io/v1alpha1
+kind: ResourceList
+items:
+- apiVersion: apps/v1
+  kind: Deployment
+  metadata:
+    name: deployment-foo
+- apiVersion: v1
+  kind: Service
+  metadata:
+    name: service-foo
+results:
+- apiVersion: config.k8s.io/v1alpha1
+  kind: ObjectError
+  name: "some-validator"
+  items:  
+  - type: error
+    message: "some message"
+    resourceRef:
+      apiVersion: apps/v1
+      kind: Deployment
+      name: foo
+      namespace: bar
+    file:
+      path: deploy.yaml
+      index: 0
+    field:
+      path: "spec.template.spec.containers[3].resources.limits.cpu"
+      currentValue: "200"
+      suggestedValue: "2"
+' && cat not-real-dir
+`,
+			},
+			},
+			expectedOutput: []string{
+				`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: deployment-foo
+  annotations:
+    config.kubernetes.io/path: 'deployment_deployment-foo.yaml'
+`,
+				`
+apiVersion: v1
+kind: Service
+metadata:
+  name: service-foo
+  annotations:
+    config.kubernetes.io/path: 'service_service-foo.yaml'
+`,
+			},
+			expectedResults: `
+- apiVersion: config.k8s.io/v1alpha1
+  kind: ObjectError
+  name: "some-validator"
+  items:
+  - type: error
+    message: "some message"
+    resourceRef:
+      apiVersion: apps/v1
+      kind: Deployment
+      name: foo
+      namespace: bar
+    file:
+      path: deploy.yaml
+      index: 0
+    field:
+      path: "spec.template.spec.containers[3].resources.limits.cpu"
+      currentValue: "200"
+      suggestedValue: "2"
+`,
+		},
+	}
+
+	for i := range tests {
+		tt := tests[i]
+		t.Run(tt.name, func(t *testing.T) {
+			if len(tt.expectedResults) > 0 && !tt.noMakeResultsFile {
+				f, err := ioutil.TempFile("", "test-kyaml-*.yaml")
+				if !assert.NoError(t, err) {
+					t.FailNow()
+				}
+				defer os.RemoveAll(f.Name())
+				tt.instance.ResultsFile = f.Name()
+			} else if len(tt.expectedResults) > 0 {
+				tt.instance.ResultsFile = "/not/real/file"
+			}
+
+			var inputs []*yaml.RNode
+			for i := range tt.input {
+				node, err := yaml.Parse(tt.input[i])
+				if !assert.NoError(t, err) {
+					t.FailNow()
+				}
+				inputs = append(inputs, node)
+			}
+
+			output, err := tt.instance.Filter(inputs)
+			if tt.expectedError != "" {
+				if !assert.EqualError(t, err, tt.expectedError) {
+					t.FailNow()
+				}
+				return
+			}
+
+			if !assert.NoError(t, err) {
+				t.FailNow()
+			}
+
+			var actual []string
+			for i := range output {
+				s, err := output[i].String()
+				if !assert.NoError(t, err) {
+					t.FailNow()
+				}
+				actual = append(actual, strings.TrimSpace(s))
+			}
+			var expected []string
+			for i := range tt.expectedOutput {
+				expected = append(expected, strings.TrimSpace(tt.expectedOutput[i]))
+			}
+
+			if !assert.Equal(t, expected, actual) {
+				t.FailNow()
+			}
+
+			if len(tt.instance.ResultsFile) > 0 {
+				tt.expectedResults = strings.TrimSpace(tt.expectedResults)
+
+				results, err := tt.instance.Results.String()
+				if !assert.NoError(t, err) {
+					t.FailNow()
+				}
+				if !assert.Equal(t, tt.expectedResults, strings.TrimSpace(results)) {
+					t.FailNow()
+				}
+
+				b, err := ioutil.ReadFile(tt.instance.ResultsFile)
+				writtenResults := strings.TrimSpace(string(b))
+				if !assert.NoError(t, err) {
+					t.FailNow()
+				}
+				if !assert.Equal(t, tt.expectedResults, writtenResults) {
+					t.FailNow()
+				}
+			}
+		})
+	}
+}
+
 func TestFilter_command(t *testing.T) {
 	cfg, err := yaml.Parse(`apiVersion: apps/v1
 kind: Deployment
@@ -29,10 +391,7 @@ metadata:
 		Config: cfg,
 	}
 	os.Setenv("KYAML_TEST", "FOO")
-	cmd, err := instance.getCommand()
+	cmd := instance.getCommand()
-	if !assert.NoError(t, err) {
-		return
-	}
 
 	expected := []string{
 		"docker", "run",
@@ -78,10 +437,7 @@ metadata:
 		Config:        cfg,
 		StorageMounts: []StorageMount{bindMount, localVol, tmpfs},
 	}
-	cmd, err := instance.getCommand()
+	cmd := instance.getCommand()
-	if !assert.NoError(t, err) {
-		return
-	}
 
 	expected := []string{
 		"docker", "run",
@@ -116,10 +472,7 @@ metadata:
 		Network: "test-net",
 		Config:  cfg,
 	}
-	cmd, err := instance.getCommand()
+	cmd := instance.getCommand()
-	if !assert.NoError(t, err) {
-		return
-	}
 
 	expected := []string{
 		"docker", "run",
@@ -168,9 +521,10 @@ metadata:
 
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
-		args:   []string{"sed", "s/Deployment/StatefulSet/g"},
+		Config:                cfg,
+		args:                  []string{"sed", "s/Deployment/StatefulSet/g"},
 		checkInput: func(s string) {
 			called = true
 			if !assert.Equal(t, `apiVersion: config.kubernetes.io/v1alpha1
@@ -252,9 +606,10 @@ metadata:
 
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
-		args:   []string{"sh", "-c", "cat <&0"},
+		Config:                cfg,
+		args:                  []string{"sh", "-c", "cat <&0"},
 		checkInput: func(s string) {
 			called = true
 			if !assert.Equal(t, `apiVersion: config.kubernetes.io/v1alpha1
@@ -597,8 +952,9 @@ metadata:
 
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
+		Config:                cfg,
 		args: []string{"echo", `apiVersion: apps/v1
 kind: Deployment
 metadata:
@@ -671,8 +1027,9 @@ metadata:
 
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
+		Config:                cfg,
 		args: []string{"echo", `apiVersion: apps/v1
 kind: Deployment
 metadata:
@@ -756,9 +1113,10 @@ metadata:
 	// no resources match the scope
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
-		args:   []string{"sed", "s/Deployment/StatefulSet/g"},
+		Config:                cfg,
+		args:                  []string{"sed", "s/Deployment/StatefulSet/g"},
 		checkInput: func(s string) {
 			called = true
 			if !assert.Equal(t, `apiVersion: config.kubernetes.io/v1alpha1
@@ -831,10 +1189,11 @@ metadata:
 	// no resources match the scope
 	called := false
 	result, err := (&ContainerFilter{
-		GlobalScope: true,
+		SetFlowStyleForConfig: true,
-		Image:       "example.com:version",
+		GlobalScope:           true,
-		Config:      cfg,
+		Image:                 "example.com:version",
-		args:        []string{"sed", "s/Deployment/StatefulSet/g"},
+		Config:                cfg,
+		args:                  []string{"sed", "s/Deployment/StatefulSet/g"},
 		checkInput: func(s string) {
 			called = true
 			if !assert.Equal(t, `apiVersion: config.kubernetes.io/v1alpha1
@@ -926,9 +1285,10 @@ metadata:
 	// no resources match the scope
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
-		args:   []string{"sed", "s/Deployment/StatefulSet/g"},
+		Config:                cfg,
+		args:                  []string{"sed", "s/Deployment/StatefulSet/g"},
 		checkInput: func(s string) {
 			called = true
 			if !assert.Equal(t, `apiVersion: config.kubernetes.io/v1alpha1
@@ -1022,9 +1382,10 @@ metadata:
 	// no resources match the scope
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
-		args:   []string{"sed", "s/Deployment/StatefulSet/g"},
+		Config:                cfg,
+		args:                  []string{"sed", "s/Deployment/StatefulSet/g"},
 		checkInput: func(s string) {
 			called = true
 			if !assert.Equal(t, `apiVersion: config.kubernetes.io/v1alpha1
@@ -1118,9 +1479,10 @@ metadata:
 	// no resources match the scope
 	called := false
 	result, err := (&ContainerFilter{
-		Image:  "example.com:version",
+		SetFlowStyleForConfig: true,
-		Config: cfg,
+		Image:                 "example.com:version",
-		args:   []string{"sed", "s/Deployment/StatefulSet/g"},
+		Config:                cfg,
+		args:                  []string{"sed", "s/Deployment/StatefulSet/g"},
 		checkInput: func(s string) {
 			called = true
 			if !assert.Equal(t, `apiVersion: config.kubernetes.io/v1alpha1

kyaml/runfn/runfn.go

@@ -4,12 +4,14 @@
 package runfn
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"path"
 	"path/filepath"
 	"sort"
 	"strings"
+	"sync/atomic"
 
 	"sigs.k8s.io/kustomize/kyaml/errors"
 	"sigs.k8s.io/kustomize/kyaml/kio"
@@ -64,6 +66,12 @@ type RunFns struct {
 	// DisableContainers will disable functions run as containers
 	DisableContainers bool
 
+	// ResultsDir is where to write each functions results
+	ResultsDir string
+
+	// resultsCount is used to generate the results filename for each container
+	resultsCount uint32
+
 	// functionFilterProvider provides a filter to perform the function.
 	// this is a variable so it can be mocked in tests
 	functionFilterProvider func(
@@ -219,6 +227,7 @@ func (r RunFns) getFunctionFilters(global bool, fns ...*yaml.RNode) (
 		if err != nil {
 			return nil, err
 		}
+
 		if c == nil {
 			continue
 		}
@@ -304,12 +313,21 @@ func (r *RunFns) init() {
 // ffp provides function filters
 func (r *RunFns) ffp(spec filters.FunctionSpec, api *yaml.RNode) (kio.Filter, error) {
 	if !r.DisableContainers && spec.Container.Image != "" {
+		var resultsFile string
+		// TODO: Add a test for this behavior
+
+		if r.ResultsDir != "" {
+			resultsFile = filepath.Join(r.ResultsDir, fmt.Sprintf(
+				"results-%v.yaml", r.resultsCount))
+			atomic.AddUint32(&r.resultsCount, 1)
+		}
 		return &filters.ContainerFilter{
 			Image:         spec.Container.Image,
 			Config:        api,
 			Network:       spec.Network,
 			StorageMounts: r.StorageMounts,
 			GlobalScope:   r.GlobalScope,
+			ResultsFile:   resultsFile,
 		}, nil
 	}
 	if r.EnableStarlark && spec.Starlark.Path != "" {