test without system call

kyaml/fn/runtime/container/container.go

@@ -5,7 +5,6 @@ package container
 
 import (
 	"fmt"
-	"os/user"
 
 	runtimeexec "sigs.k8s.io/kustomize/kyaml/fn/runtime/exec"
 	"sigs.k8s.io/kustomize/kyaml/fn/runtime/runtimeutil"
@@ -185,28 +184,9 @@ func (c *Filter) getCommand() (string, []string) {
 	return "docker", a
 }
 
-// getUIDGID will return "nobody" if asCurrentUser is false. Otherwise
-// return "uid:gid" according to current user who runs the command.
-func getUIDGID(asCurrentUser bool) (string, error) {
-	if !asCurrentUser {
-		return "nobody", nil
-	}
-
-	u, err := user.Current()
-	if err != nil {
-		return "", err
-	}
-	return fmt.Sprintf("%s:%s", u.Uid, u.Gid), nil
-}
-
 // NewContainer returns a new container filter
-func NewContainer(spec runtimeutil.ContainerSpec, asCurrentUser bool) (Filter, error) {
-	f := Filter{ContainerSpec: spec}
-	u, err := getUIDGID(asCurrentUser)
-	if err != nil {
-		return f, err
-	}
-	f.UIDGID = u
+func NewContainer(spec runtimeutil.ContainerSpec, uidgid string) (Filter, error) {
+	f := Filter{ContainerSpec: spec, UIDGID: uidgid}
 
 	return f, nil
 }

kyaml/fn/runtime/container/container_test.go

@@ -6,7 +6,6 @@ package container
 import (
 	"bytes"
 	"fmt"
-	"os/user"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -16,16 +15,12 @@ import (
 )
 
 func TestFilter_setupExec(t *testing.T) {
-	u, err := user.Current()
-	if err != nil {
-		t.Fatal(err)
-	}
 	var tests = []struct {
 		name           string
 		functionConfig string
 		expectedArgs   []string
 		containerSpec  runtimeutil.ContainerSpec
-		asCurrentUser  bool
+		UIDGID         string
 	}{
 		{
 			name: "command",
@@ -45,6 +40,7 @@ metadata:
 			containerSpec: runtimeutil.ContainerSpec{
 				Image: "example.com:version",
 			},
+			UIDGID: "nobody",
 		},
 
 		{
@@ -62,12 +58,11 @@ metadata:
 				"--user", "nobody",
 				"--security-opt=no-new-privileges",
 			},
-			instance: NewContainer(
-				runtimeutil.ContainerSpec{
-					Image:   "example.com:version",
-					Network: true,
-				},
+			containerSpec: runtimeutil.ContainerSpec{
+				Image:   "example.com:version",
+				Network: true,
 			},
+			UIDGID: "nobody",
 		},
 
 		{
@@ -98,6 +93,7 @@ metadata:
 					{MountType: "tmpfs", Src: "", DstPath: "/local/"},
 				},
 			},
+			UIDGID: "nobody",
 		},
 		{
 			name: "as current user",
@@ -111,13 +107,13 @@ metadata:
 				"--rm",
 				"-i", "-a", "STDIN", "-a", "STDOUT", "-a", "STDERR",
 				"--network", "none",
-				"--user", fmt.Sprintf("%s:%s", u.Uid, u.Gid),
+				"--user", "1:2",
 				"--security-opt=no-new-privileges",
 			},
 			containerSpec: runtimeutil.ContainerSpec{
 				Image: "example.com:version",
 			},
-			asCurrentUser: true,
+			UIDGID: "1:2",
 		},
 	}
 
@@ -129,7 +125,7 @@ metadata:
 				t.FailNow()
 			}
 
-			instance, err := NewContainer(tt.containerSpec, tt.asCurrentUser)
+			instance, err := NewContainer(tt.containerSpec, tt.UIDGID)
 			if err != nil {
 				t.Fatal(err)
 			}

kyaml/runfn/runfn.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/user"
 	"path"
 	"path/filepath"
 	"sort"
@@ -83,7 +84,7 @@ type RunFns struct {
 	// functionFilterProvider provides a filter to perform the function.
 	// this is a variable so it can be mocked in tests
 	functionFilterProvider func(
-		filter runtimeutil.FunctionSpec, api *yaml.RNode) (kio.Filter, error)
+		filter runtimeutil.FunctionSpec, api *yaml.RNode, currentUser currentUserFunc) (kio.Filter, error)
 
 	// AsCurrentUser is a boolean to indicate whether docker container should use
 	// the uid and gid that run the command
@@ -303,7 +304,7 @@ func (r RunFns) getFunctionFilters(global bool, fns ...*yaml.RNode) (
 		// merge envs from imperative and declarative
 		spec.Container.Env = r.mergeContainerEnv(spec.Container.Env)
 
-		c, err := r.functionFilterProvider(*spec, api)
+		c, err := r.functionFilterProvider(*spec, api, user.Current)
 		if err != nil {
 			return nil, err
 		}
@@ -395,8 +396,24 @@ func (r *RunFns) init() {
 	}
 }
 
+type currentUserFunc func() (*user.User, error)
+
+// getUIDGID will return "nobody" if asCurrentUser is false. Otherwise
+// return "uid:gid" according to the return from currentUser function.
+func getUIDGID(asCurrentUser bool, currentUser currentUserFunc) (string, error) {
+	if !asCurrentUser {
+		return "nobody", nil
+	}
+
+	u, err := currentUser()
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%s:%s", u.Uid, u.Gid), nil
+}
+
 // ffp provides function filters
-func (r *RunFns) ffp(spec runtimeutil.FunctionSpec, api *yaml.RNode) (kio.Filter, error) {
+func (r *RunFns) ffp(spec runtimeutil.FunctionSpec, api *yaml.RNode, currentUser currentUserFunc) (kio.Filter, error) {
 	var resultsFile string
 	if r.ResultsDir != "" {
 		resultsFile = filepath.Join(r.ResultsDir, fmt.Sprintf(
@@ -405,6 +422,10 @@ func (r *RunFns) ffp(spec runtimeutil.FunctionSpec, api *yaml.RNode) (kio.Filter
 	}
 	if !r.DisableContainers && spec.Container.Image != "" {
 		// TODO: Add a test for this behavior
+		uidgid, err := getUIDGID(r.AsCurrentUser, currentUser)
+		if err != nil {
+			return nil, err
+		}
 		c, err := container.NewContainer(
 			runtimeutil.ContainerSpec{
 				Image:         spec.Container.Image,
@@ -412,7 +433,7 @@ func (r *RunFns) ffp(spec runtimeutil.FunctionSpec, api *yaml.RNode) (kio.Filter
 				StorageMounts: r.StorageMounts,
 				Env:           spec.Container.Env,
 			},
-			r.AsCurrentUser,
+			uidgid,
 		)
 		if err != nil {
 			return nil, err

kyaml/runfn/runfn_test.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/user"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -38,6 +39,13 @@ replace: StatefulSet
 `
 )
 
+func currentUser() (*user.User, error) {
+	return &user.User{
+		Uid: "1",
+		Gid: "2",
+	}, nil
+}
+
 func TestRunFns_init(t *testing.T) {
 	instance := RunFns{}
 	instance.init()
@@ -59,8 +67,41 @@ kind:
 	if !assert.NoError(t, err) {
 		return
 	}
-	filter, _ := instance.functionFilterProvider(spec, api)
-	c, err := container.NewContainer(runtimeutil.ContainerSpec{Image: "example.com:version"}, false)
+	filter, _ := instance.functionFilterProvider(spec, api, currentUser)
+	c, err := container.NewContainer(runtimeutil.ContainerSpec{Image: "example.com:version"}, "nobody")
+	if err != nil {
+		t.Fatal(err)
+	}
+	cf := &c
+	cf.Exec.FunctionConfig = api
+	assert.Equal(t, cf, filter)
+}
+
+func TestRunFns_initAsCurrentUser(t *testing.T) {
+	instance := RunFns{
+		AsCurrentUser: true,
+	}
+	instance.init()
+	if !assert.Equal(t, instance.Input, os.Stdin) {
+		t.FailNow()
+	}
+	if !assert.Equal(t, instance.Output, os.Stdout) {
+		t.FailNow()
+	}
+
+	api, err := yaml.Parse(`apiVersion: apps/v1
+kind: 
+`)
+	spec := runtimeutil.FunctionSpec{
+		Container: runtimeutil.ContainerSpec{
+			Image: "example.com:version",
+		},
+	}
+	if !assert.NoError(t, err) {
+		return
+	}
+	filter, _ := instance.functionFilterProvider(spec, api, currentUser)
+	c, err := container.NewContainer(runtimeutil.ContainerSpec{Image: "example.com:version"}, "1:2")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -93,8 +134,8 @@ kind:
 	if !assert.NoError(t, err) {
 		return
 	}
-	filter, _ := instance.functionFilterProvider(spec, api)
-	c, err := container.NewContainer(runtimeutil.ContainerSpec{Image: "example.com:version"}, false)
+	filter, _ := instance.functionFilterProvider(spec, api, currentUser)
+	c, err := container.NewContainer(runtimeutil.ContainerSpec{Image: "example.com:version"}, "nobody")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -869,7 +910,7 @@ replace: StatefulSet
 	var fltrs []*TestFilter
 	instance := RunFns{
 		Path: dir,
-		functionFilterProvider: func(f runtimeutil.FunctionSpec, node *yaml.RNode) (kio.Filter, error) {
+		functionFilterProvider: func(f runtimeutil.FunctionSpec, node *yaml.RNode, currentUser currentUserFunc) (kio.Filter, error) {
 			tf := &TestFilter{
 				Exit: errors.Errorf("message: %s", f.Container.Image),
 			}
@@ -1075,8 +1116,8 @@ func setupTest(t *testing.T) string {
 // getFilterProvider fakes the creation of a filter, replacing the ContainerFiler with
 // a filter to s/kind: Deployment/kind: StatefulSet/g.
 // this can be used to simulate running a filter.
-func getFilterProvider(t *testing.T) func(runtimeutil.FunctionSpec, *yaml.RNode) (kio.Filter, error) {
-	return func(f runtimeutil.FunctionSpec, node *yaml.RNode) (kio.Filter, error) {
+func getFilterProvider(t *testing.T) func(runtimeutil.FunctionSpec, *yaml.RNode, currentUserFunc) (kio.Filter, error) {
+	return func(f runtimeutil.FunctionSpec, node *yaml.RNode, currentUser currentUserFunc) (kio.Filter, error) {
 		// parse the filter from the input
 		filter := yaml.YFilter{}
 		b := &bytes.Buffer{}