Add azd env get-value (#4080)

* Test aks

* Add get-value

* Undo aks string

* Remove formatter

* Add tests

Author: jongio

cli/azd/cmd/env.go

@@ -79,6 +79,12 @@ func envActions(root *actions.ActionDescriptor) *actions.ActionDescriptor {
 		DefaultFormat:  output.EnvVarsFormat,
 	})
 
+	group.Add("get-value", &actions.ActionDescriptorOptions{
+		Command:        newEnvGetValueCmd(),
+		FlagsResolver:  newEnvGetValueFlags,
+		ActionResolver: newEnvGetValueAction,
+	})
+
 	return group
 }
 
@@ -592,6 +598,104 @@ func (eg *envGetValuesAction) Run(ctx context.Context) (*actions.ActionResult, e
 	return nil, eg.formatter.Format(env.Dotenv(), eg.writer, nil)
 }
 
+func newEnvGetValueFlags(cmd *cobra.Command, global *internal.GlobalCommandOptions) *envGetValueFlags {
+	flags := &envGetValueFlags{}
+	flags.Bind(cmd.Flags(), global)
+
+	return flags
+}
+
+func newEnvGetValueCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "get-value <keyName>",
+		Short: "Get specific environment value.",
+	}
+	cmd.Args = cobra.MaximumNArgs(1)
+
+	return cmd
+}
+
+type envGetValueFlags struct {
+	internal.EnvFlag
+	global *internal.GlobalCommandOptions
+}
+
+func (eg *envGetValueFlags) Bind(local *pflag.FlagSet, global *internal.GlobalCommandOptions) {
+	eg.EnvFlag.Bind(local, global)
+	eg.global = global
+}
+
+type envGetValueAction struct {
+	azdCtx     *azdcontext.AzdContext
+	console    input.Console
+	envManager environment.Manager
+	writer     io.Writer
+	flags      *envGetValueFlags
+	args       []string
+}
+
+func newEnvGetValueAction(
+	azdCtx *azdcontext.AzdContext,
+	envManager environment.Manager,
+	console input.Console,
+	writer io.Writer,
+	flags *envGetValueFlags,
+	args []string,
+
+) actions.Action {
+	return &envGetValueAction{
+		azdCtx:     azdCtx,
+		console:    console,
+		envManager: envManager,
+		writer:     writer,
+		flags:      flags,
+		args:       args,
+	}
+}
+
+func (eg *envGetValueAction) Run(ctx context.Context) (*actions.ActionResult, error) {
+	if len(eg.args) < 1 {
+		return nil, fmt.Errorf("no key name provided")
+	}
+
+	keyName := eg.args[0]
+
+	name, err := eg.azdCtx.GetDefaultEnvironmentName()
+	if err != nil {
+		return nil, err
+	}
+	// Note: if there is not an environment yet, GetDefaultEnvironmentName() returns empty string (not error)
+	// and later, when envManager.Get() is called with the empty string, azd returns an error.
+	// But if there is already an environment (default to be selected), azd must honor the --environment flag
+	// over the default environment.
+	if eg.flags.EnvironmentName != "" {
+		name = eg.flags.EnvironmentName
+	}
+	env, err := eg.envManager.Get(ctx, name)
+	if errors.Is(err, environment.ErrNotFound) {
+		return nil, fmt.Errorf(
+			`environment '%s' does not exist. You can create it with "azd env new %s"`,
+			name,
+			name,
+		)
+	} else if err != nil {
+		return nil, fmt.Errorf("ensuring environment exists: %w", err)
+	}
+
+	values := env.Dotenv()
+	keyValue, exists := values[keyName]
+	if !exists {
+		return nil, fmt.Errorf("key '%s' not found in the environment values", keyName)
+	}
+
+	// Directly write the key value to the writer
+	if _, err := fmt.Fprintln(eg.writer, keyValue); err != nil {
+		return nil, fmt.Errorf("writing key value: %w", err)
+	}
+
+	return nil, nil
+}
+
 func getCmdEnvHelpDescription(*cobra.Command) string {
 	return generateCmdHelpDescription(
 		"Manage your application environments. With this command group, you can create a new environment or get, set,"+

cli/azd/cmd/testdata/TestUsage-azd-env-get-value.snap

@@ -0,0 +1,19 @@
+
+Get specific environment value.
+
+Usage
+  azd env get-value <keyName> [flags]
+
+Flags
+        --docs               	: Opens the documentation for azd env get-value in your web browser.
+    -e, --environment string 	: The name of the environment to use.
+    -h, --help               	: Gets help for get-value.
+
+Global Flags
+    -C, --cwd string 	: Sets the current working directory.
+        --debug      	: Enables debugging and diagnostics logging.
+        --no-prompt  	: Accepts the default value instead of prompting, or it fails if there is no default.
+
+Find a bug? Want to let us know how we're doing? Fill out this brief survey: https://aka.ms/azure-dev/hats.
+
+

cli/azd/cmd/testdata/TestUsage-azd-env.snap

@@ -10,6 +10,7 @@ Usage
   azd env [command]
 
 Available Commands
+  get-value 	: Get specific environment value.
   get-values	: Get all environment values.
   list      	: List environments.
   new       	: Create a new environment and set it as the default.

cli/azd/test/functional/env_test.go

@@ -260,6 +260,59 @@ func Test_CLI_Env_Values_MultipleEnvironments(t *testing.T) {
 	require.Equal(t, values["envName2"], envName2)
 }
 
+func Test_CLI_Env_GetValue(t *testing.T) {
+	ctx, cancel := newTestContext(t)
+	defer cancel()
+
+	dir := tempDirWithDiagnostics(t)
+	t.Logf("DIR: %s", dir)
+
+	cli := azdcli.NewCLI(t)
+	cli.WorkingDirectory = dir
+
+	err := copySample(dir, "storage")
+	require.NoError(t, err, "failed expanding sample")
+
+	// Create an environment
+	envName := randomEnvName()
+	envNew(ctx, t, cli, envName, false)
+
+	// Set key1
+	envSetValue(ctx, t, cli, "key1", "value1")
+
+	// Get key1 value
+	value := envGetValue(ctx, t, cli, "key1")
+	require.Equal(t, "value1", value)
+
+	// Set key2
+	envSetValue(ctx, t, cli, "key2", "value2")
+
+	// Get key2 value
+	value = envGetValue(ctx, t, cli, "key2")
+	require.Equal(t, "value2", value)
+
+	// Modify key1
+	envSetValue(ctx, t, cli, "key1", "modified1")
+
+	// Get modified key1 value
+	value = envGetValue(ctx, t, cli, "key1")
+	require.Equal(t, "modified1", value)
+
+	// Test non-existent key
+	res, err := cli.RunCommand(ctx, "env", "get-value", "non_existent_key")
+	require.Error(t, err)
+	require.Contains(t, res.Stdout, "key 'non_existent_key' not found in the environment values")
+}
+
+func envGetValue(ctx context.Context, t *testing.T, cli *azdcli.CLI, key string) string {
+	args := []string{"env", "get-value", key}
+
+	result, err := cli.RunCommand(ctx, args...)
+	require.NoError(t, err)
+
+	return strings.TrimSpace(result.Stdout)
+}
+
 func requireIsDefault(t *testing.T, list []contracts.EnvListEnvironment, envName string) {
 	for _, env := range list {
 		if env.Name == envName {