command: tofu show -config (opentofu#2820)

Signed-off-by: Babur Ayanlar <babur.ayanlar@ableton.com>

Author: baa-ableton

CHANGELOG.md

@@ -1,5 +1,8 @@
 ## 1.11.0 (Unreleased)
 
+ENHANCEMENTS:
+
+* `tofu show` now supports a `-config` option, to be used in conjunction with `-json` to produce a machine-readable summary of the configuration without first creating a plan. ([#2820](https://github.com/opentofu/opentofu/pull/2820))
 
 ## Previous Releases
 

internal/command/arguments/show.go

@@ -49,6 +49,11 @@ const (
 	//
 	// For this target type, [Show.TargetArg] is the plan file to load.
 	ShowPlan
+
+	// ShowConfig represents a request to show the current configuration.
+	//
+	// This target type does not use [Show.TargetArg].
+	ShowConfig
 )
 
 // ParseShow processes CLI arguments, returning a Show value and errors.
@@ -63,11 +68,13 @@ func ParseShow(args []string) (*Show, tfdiags.Diagnostics) {
 	var jsonOutput bool
 	var stateTarget bool
 	var planTarget string
+	var configTarget bool
 	cmdFlags := extendedFlagSet("show", nil, nil, show.Vars)
 	cmdFlags.BoolVar(&jsonOutput, "json", false, "json")
 	cmdFlags.BoolVar(&show.ShowSensitive, "show-sensitive", false, "displays sensitive values")
 	cmdFlags.BoolVar(&stateTarget, "state", false, "show the latest state snapshot")
 	cmdFlags.StringVar(&planTarget, "plan", "", "show the plan from a saved plan file")
+	cmdFlags.BoolVar(&configTarget, "config", false, "show the current configuration")
 
 	if err := cmdFlags.Parse(args); err != nil {
 		diags = diags.Append(tfdiags.Sourceless(
@@ -77,15 +84,25 @@ func ParseShow(args []string) (*Show, tfdiags.Diagnostics) {
 		))
 	}
 
+	// If -config is specified, -json is required
+	if configTarget && !jsonOutput {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"JSON output required for configuration",
+			"The -config option requires -json to be specified.",
+		))
+		return show, diags
+	}
+
 	switch {
 	case jsonOutput:
 		show.ViewType = ViewJSON
 	default:
 		show.ViewType = ViewHuman
 	}
 
-	if planTarget == "" && !stateTarget {
-		// If neither of the target type options was provided then we're
+	if planTarget == "" && !stateTarget && !configTarget {
+		// If none of the target type options was provided then we're
 		// in the legacy mode where the target type is implied by
 		// the number of arguments.
 		args = cmdFlags.Args()
@@ -131,11 +148,16 @@ func ParseShow(args []string) (*Show, tfdiags.Diagnostics) {
 		show.TargetType = ShowPlan
 		show.TargetArg = planTarget
 	}
+	if configTarget {
+		targetTypes++
+		show.TargetType = ShowConfig
+		show.TargetArg = ""
+	}
 	if targetTypes != 1 {
 		diags = diags.Append(tfdiags.Sourceless(
 			tfdiags.Error,
 			"Conflicting object types to show",
-			"The -state and -plan=FILENAME options are mutually-exclusive, to specify which kind of object to show.",
+			"The -state, -plan=FILENAME, and -config options are mutually-exclusive, to specify which kind of object to show.",
 		))
 	}
 	return show, diags

internal/command/arguments/show_test.go

@@ -82,6 +82,14 @@ func TestParseShow_valid(t *testing.T) {
 				ViewType:   ViewJSON,
 			},
 		},
+		"configuration with json": {
+			[]string{"-config", "-json"},
+			&Show{
+				TargetType: ShowConfig,
+				TargetArg:  "",
+				ViewType:   ViewJSON,
+			},
+		},
 	}
 
 	for name, tc := range testCases {
@@ -155,7 +163,7 @@ func TestParseShow_invalid(t *testing.T) {
 				tfdiags.Sourceless(
 					tfdiags.Error,
 					"Conflicting object types to show",
-					"The -state and -plan=FILENAME options are mutually-exclusive, to specify which kind of object to show.",
+					"The -state, -plan=FILENAME, and -config options are mutually-exclusive, to specify which kind of object to show.",
 				),
 			},
 		},
@@ -185,6 +193,49 @@ func TestParseShow_invalid(t *testing.T) {
 				),
 			},
 		},
+		"configuration without json": {
+			[]string{"-config"},
+			&Show{
+				ViewType: ViewNone,
+			},
+			tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Error,
+					"JSON output required for configuration",
+					"The -config option requires -json to be specified.",
+				),
+			},
+		},
+		"configuration with state": {
+			[]string{"-config", "-state", "-json"},
+			&Show{
+				TargetType: ShowConfig,
+				TargetArg:  "",
+				ViewType:   ViewJSON,
+			},
+			tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Error,
+					"Conflicting object types to show",
+					"The -state, -plan=FILENAME, and -config options are mutually-exclusive, to specify which kind of object to show.",
+				),
+			},
+		},
+		"configuration with plan": {
+			[]string{"-config", "-plan=tfplan", "-json"},
+			&Show{
+				TargetType: ShowConfig,
+				TargetArg:  "",
+				ViewType:   ViewJSON,
+			},
+			tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Error,
+					"Conflicting object types to show",
+					"The -state, -plan=FILENAME, and -config options are mutually-exclusive, to specify which kind of object to show.",
+				),
+			},
+		},
 	}
 
 	for name, tc := range testCases {

internal/command/arguments/showtargettype_string.go

@@ -43,8 +43,8 @@ func marshalExpression(ex hcl.Expression) expression {
 		return ret
 	}
 
-	val, _ := ex.Value(nil)
-	if val != cty.NilVal {
+	val, valueDiags := ex.Value(nil)
+	if val != cty.NilVal && !valueDiags.HasErrors() {
 		valJSON, _ := ctyjson.Marshal(val, val.Type())
 		ret.ConstantValue = valJSON
 	}

internal/command/jsonconfig/expression.go

@@ -53,6 +53,7 @@ func (e *errUnusableDataMisc) Unwrap() error {
 
 // ShowCommand is a Command implementation that reads and outputs the
 // contents of a OpenTofu plan or state file.
+// write about config here
 type ShowCommand struct {
 	Meta
 	viewType arguments.ViewType
@@ -135,6 +136,7 @@ Target selection options:
 
     -state          The latest state snapshot, if any.
     -plan=FILENAME  The plan from a saved plan file.
+    -config         Show the current configuration (requires -json).
 
   If no target selection options are provided, -state is the default.
 
@@ -188,6 +190,8 @@ func (c *ShowCommand) show(ctx context.Context, targetType arguments.ShowTargetT
 		return c.showFromLatestStateSnapshot(ctx, enc)
 	case arguments.ShowPlan:
 		return c.showFromSavedPlanFile(ctx, targetArg, enc)
+	case arguments.ShowConfig:
+		return c.showConfiguration(ctx)
 	case arguments.ShowUnknownType:
 		// This is a legacy case where we just have a filename and need to
 		// try treating it as either a saved plan file or a local state
@@ -526,3 +530,56 @@ func getStateFromBackend(ctx context.Context, b backend.Backend, workspace strin
 	stateFile := statemgr.Export(stateStore)
 	return stateFile, nil
 }
+
+// showConfiguration returns a function that will display the current configuration
+// in JSON format. This is a new feature that requires -json to be specified.
+func (c *ShowCommand) showConfiguration(ctx context.Context) (showRenderFunc, tfdiags.Diagnostics) {
+	var diags tfdiags.Diagnostics
+
+	// Check if the directory is empty
+	empty, err := configs.IsEmptyDir(".")
+	if err != nil {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"Error validating configuration directory",
+			fmt.Sprintf("OpenTofu encountered an unexpected error while verifying that the given configuration directory is valid: %s.", err),
+		))
+		return nil, diags
+	}
+	if empty {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"No configuration files",
+			"This directory contains no OpenTofu configuration files.",
+		))
+		return nil, diags
+	}
+
+	// Load the configuration
+	config, configDiags := c.loadConfig(ctx, ".")
+	diags = diags.Append(configDiags)
+	if configDiags.HasErrors() {
+		return nil, diags
+	}
+
+	// Load provider schemas (without state)
+	schemas, schemaDiags := c.MaybeGetSchemas(ctx, nil, config)
+	diags = diags.Append(schemaDiags)
+	if schemaDiags.HasErrors() {
+		return nil, diags
+	}
+	if schemas == nil {
+		diags = diags.Append(tfdiags.Sourceless(
+			tfdiags.Error,
+			"Failed to load provider schemas",
+			"The configuration cannot be shown without provider schema information.",
+		))
+		return nil, diags
+	}
+
+	// Return a function that will render the configuration as JSON
+	return func(view views.Show) int {
+		// Display the configuration using the view
+		return view.DisplayConfig(config, schemas)
+	}, diags
+}