Copy host env to container for env/envfile option

Add a function to process env/envfile specified by users
and set value for env with no value has been set.

Fixes: containerd#1487

Signed-off-by: bin liu <liubin0329@gmail.com>

cmd/nerdctl/run.go

@@ -456,21 +456,28 @@ func createContainer(cmd *cobra.Command, ctx context.Context, client *containerd
 	if err != nil {
 		return nil, nil, err
 	}
+
+	var envs []string
+
 	if envFiles := strutil.DedupeStrSlice(envFile); len(envFiles) > 0 {
-		env, err := parseEnvVars(envFiles)
+		envs, err = parseEnvVars(envFiles)
 		if err != nil {
 			return nil, nil, err
 		}
-		opts = append(opts, oci.WithEnv(env))
 	}
 
 	env, err := cmd.Flags().GetStringArray("env")
 	if err != nil {
 		return nil, nil, err
 	}
 	if env := strutil.DedupeStrSlice(env); len(env) > 0 {
-		opts = append(opts, oci.WithEnv(env))
+		envs = append(envs, env...)
+	}
+
+	if envs, err = withOSEnv(envs); err != nil {
+		return nil, nil, err
 	}
+	opts = append(opts, oci.WithEnv(envs))
 
 	if flagI {
 		if flagD {
@@ -1145,6 +1152,34 @@ func parseEnvVars(paths []string) ([]string, error) {
 	return vars, nil
 }
 
+func withOSEnv(envs []string) ([]string, error) {
+	newEnvs := make([]string, len(envs))
+
+	// from /~https://github.com/docker/cli/blob/v22.06.0-beta.0/opts/env.go#L18
+	getEnv := func(val string) (string, error) {
+		arr := strings.SplitN(val, "=", 2)
+		if arr[0] == "" {
+			return "", errors.New("invalid environment variable: " + val)
+		}
+		if len(arr) > 1 {
+			return val, nil
+		}
+		if envVal, ok := os.LookupEnv(arr[0]); ok {
+			return arr[0] + "=" + envVal, nil
+		}
+		return val, nil
+	}
+	for i := range envs {
+		env, err := getEnv(envs[i])
+		if err != nil {
+			return nil, err
+		}
+		newEnvs[i] = env
+	}
+
+	return newEnvs, nil
+}
+
 func generateSharingPIDOpts(ctx context.Context, targetCon containerd.Container) ([]oci.SpecOpts, error) {
 	opts := make([]oci.SpecOpts, 0)
 

cmd/nerdctl/run_test.go

@@ -150,6 +150,7 @@ func TestRunCIDFile(t *testing.T) {
 func TestRunEnvFile(t *testing.T) {
 	t.Parallel()
 	base := testutil.NewBase(t)
+	base.Env = append(os.Environ(), "HOST_ENV=ENV-IN-HOST")
 
 	tID := testutil.Identifier(t)
 	file1, err := os.CreateTemp("", tID)
@@ -165,23 +166,30 @@ func TestRunEnvFile(t *testing.T) {
 	path2 := file2.Name()
 	defer file2.Close()
 	defer os.Remove(path2)
-	err = os.WriteFile(path2, []byte("# this is a comment line\nTESTKEY2=TESTVAL2"), 0666)
+	err = os.WriteFile(path2, []byte("# this is a comment line\nTESTKEY2=TESTVAL2\nHOST_ENV"), 0666)
 	assert.NilError(base.T, err)
 
 	base.Cmd("run", "--rm", "--env-file", path1, "--env-file", path2, testutil.CommonImage, "sh", "-c", "echo -n $TESTKEY1").AssertOutExactly("TESTVAL1")
 	base.Cmd("run", "--rm", "--env-file", path1, "--env-file", path2, testutil.CommonImage, "sh", "-c", "echo -n $TESTKEY2").AssertOutExactly("TESTVAL2")
+	base.Cmd("run", "--rm", "--env-file", path1, "--env-file", path2, testutil.CommonImage, "sh", "-c", "echo -n $HOST_ENV").AssertOutExactly("ENV-IN-HOST")
 }
 
 func TestRunEnv(t *testing.T) {
 	t.Parallel()
 	base := testutil.NewBase(t)
+	base.Env = append(os.Environ(), "CORGE=corge-value-in-host", "GARPLY=garply-value-in-host")
 	base.Cmd("run", "--rm",
 		"--env", "FOO=foo1,foo2",
 		"--env", "BAR=bar1 bar2",
 		"--env", "BAZ=",
-		"--env", "QUX",
+		"--env", "QUX", // not exported in OS
 		"--env", "QUUX=quux1",
 		"--env", "QUUX=quux2",
+		"--env", "CORGE", // OS exported
+		"--env", "GRAULT=grault_key=grault_value", // value contains `=` char
+		"--env", "GARPLY=", // OS exported
+		"--env", "WALDO=", // not exported in OS
+
 		testutil.CommonImage, "env").AssertOutWithFunc(func(stdout string) error {
 		if !strings.Contains(stdout, "\nFOO=foo1,foo2\n") {
 			return errors.New("got bad FOO")
@@ -198,6 +206,19 @@ func TestRunEnv(t *testing.T) {
 		if !strings.Contains(stdout, "\nQUUX=quux2\n") {
 			return errors.New("got bad QUUX")
 		}
+		if !strings.Contains(stdout, "\nCORGE=corge-value-in-host\n") {
+			return errors.New("got bad CORGE")
+		}
+		if !strings.Contains(stdout, "\nGRAULT=grault_key=grault_value\n") {
+			return errors.New("got bad GRAULT")
+		}
+		if !strings.Contains(stdout, "\nGARPLY=\n") && runtime.GOOS != "windows" {
+			return errors.New("got bad GARPLY")
+		}
+		if !strings.Contains(stdout, "\nWALDO=\n") && runtime.GOOS != "windows" {
+			return errors.New("got bad WALDO")
+		}
+
 		return nil
 	})
 }