feat: add exec-plugin argument and environment support

kyaml/fn/runtime/exec/exec.go

@@ -21,6 +21,9 @@ type Filter struct {
 	// Args are the arguments to the executable
 	Args []string `yaml:"args,omitempty"`
 
+	// Env is exposed to the environment
+	Env []string `yaml:"env,omitempty"`
+
 	// WorkingDir is the working directory that the executable
 	// should run in
 	WorkingDir string
@@ -35,6 +38,7 @@ func (c *Filter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 
 func (c *Filter) Run(reader io.Reader, writer io.Writer) error {
 	cmd := exec.Command(c.Path, c.Args...) //nolint:gosec
+	cmd.Env = append(os.Environ(), c.Env...)
 	cmd.Stdin = reader
 	cmd.Stdout = writer
 	cmd.Stderr = os.Stderr

kyaml/fn/runtime/exec/exec_test.go

@@ -17,7 +17,7 @@ import (
 func TestFunctionFilter_Filter(t *testing.T) {
 	wd, err := os.Getwd()
 	require.NoError(t, err)
-	var tests = []struct {
+	tests := []struct {
 		name           string
 		input          []string
 		functionConfig string
@@ -57,8 +57,9 @@ metadata:
 			},
 			expectedError: "",
 			instance: exec.Filter{
-				Path:       "sed",
-				Args:       []string{"s/Deployment/StatefulSet/g"},
+				Path:       "sh",
+				Env:        []string{"TARGET=StatefulSet"},
+				Args:       []string{"-c", `sed "s/Deployment/$TARGET/g"`},
 				WorkingDir: wd,
 			},
 		},

kyaml/fn/runtime/runtimeutil/functiontypes.go

@@ -141,6 +141,12 @@ type FunctionSpec struct {
 
 type ExecSpec struct {
 	Path string `json:"path,omitempty" yaml:"path,omitempty"`
+
+	// Args is a slice of args that will be passed as arguments to script
+	Args []string `json:"args,omitempty" yaml:"args,omitempty"`
+
+	// Env is a slice of env string that will be exposed to container
+	Env []string `json:"envs,omitempty" yaml:"envs,omitempty"`
 }
 
 // ContainerSpec defines a spec for running a function as a container

kyaml/runfn/runfn.go

@@ -287,8 +287,8 @@ func (r RunFns) getFunctionsFromFunctions() ([]kio.Filter, error) {
 	return r.getFunctionFilters(true, r.Functions...)
 }
 
-// mergeContainerEnv will merge the envs specified by command line (imperative) and config
-// file (declarative). If they have same key, the imperative value will be respected.
+// mergeContainerEnv is container-specific and will merge the envs specified by command line (imperative)
+// and config file (declarative). If they have same key, the imperative value will be respected.
 func (r RunFns) mergeContainerEnv(envs []string) []string {
 	imperative := runtimeutil.NewContainerEnvFromStringSlice(r.Env)
 	declarative := runtimeutil.NewContainerEnvFromStringSlice(envs)
@@ -303,6 +303,28 @@ func (r RunFns) mergeContainerEnv(envs []string) []string {
 	return declarative.Raw()
 }
 
+// mergeExecEnv will merge the envs specified by command line (imperative) and config
+// file (declarative). If they have same key, the imperative value will be respected.
+func (r RunFns) mergeExecEnv(envs []string) []string {
+	envMap := map[string]string{}
+
+	for _, env := range append(envs, r.Env...) {
+		res := strings.Split(env, "=")
+		//nolint:gomnd
+		if len(res) == 2 {
+			envMap[res[0]] = res[1]
+		}
+	}
+
+	mergedEnv := []string{}
+	for key, value := range envMap {
+		mergedEnv = append(mergedEnv, fmt.Sprintf("%s=%s", key, value))
+	}
+	// Sort the envs to make the output deterministic
+	sort.Strings(mergedEnv)
+	return mergedEnv
+}
+
 func (r RunFns) getFunctionFilters(global bool, fns ...*yaml.RNode) (
 	[]kio.Filter, error) {
 	var fltrs []kio.Filter
@@ -535,6 +557,8 @@ func (r *RunFns) ffp(spec runtimeutil.FunctionSpec, api *yaml.RNode, currentUser
 	if r.EnableExec && spec.Exec.Path != "" {
 		ef := &exec.Filter{
 			Path:       spec.Exec.Path,
+			Args:       spec.Exec.Args,
+			Env:        r.mergeExecEnv(spec.Exec.Env),
 			WorkingDir: r.WorkingDir,
 		}
 

kyaml/runfn/runfn_test.go

@@ -1371,3 +1371,55 @@ func TestRunFns_mergeContainerEnv(t *testing.T) {
 		})
 	}
 }
+
+func TestRunFns_mergeExecEnv(t *testing.T) {
+	testcases := []struct {
+		name      string
+		instance  RunFns
+		inputEnvs []string
+		expect    []string
+	}{
+		{
+			name:     "all empty",
+			instance: RunFns{},
+			expect:   []string{},
+		},
+		{
+			name:      "empty command line envs",
+			instance:  RunFns{},
+			inputEnvs: []string{"foo=bar"},
+			expect:    []string{"foo=bar"},
+		},
+		{
+			name: "empty declarative envs",
+			instance: RunFns{
+				Env: []string{"foo=bar"},
+			},
+			expect: []string{"foo=bar"},
+		},
+		{
+			name: "same key",
+			instance: RunFns{
+				Env: []string{"foo=bar"},
+			},
+			inputEnvs: []string{"foo=bar1"},
+			expect:    []string{"foo=bar"},
+		},
+		{
+			name: "same exported key",
+			instance: RunFns{
+				Env: []string{"foo=bar"},
+			},
+			inputEnvs: []string{"foo1=bar1"},
+			expect:    []string{"foo1=bar1", "foo=bar"},
+		},
+	}
+
+	for i := range testcases {
+		tc := testcases[i]
+		t.Run(tc.name, func(t *testing.T) {
+			envs := tc.instance.mergeExecEnv(tc.inputEnvs)
+			assert.Equal(t, tc.expect, envs)
+		})
+	}
+}