Configurable discovery files (#4491)

* Configurable discovery

* Add test for mixed config

* Mixed config parsing

* Builder update

* Mixed config test

* Add tests for handling mix configuration

* Lint fixes

* Lint issues fixes

Author: denis256

internal/discovery/discovery.go

@@ -75,6 +75,9 @@ type Discovery struct {
 	// hiddenDirMemo is a memoization of hidden directories.
 	hiddenDirMemo []string
 
+	// configFilenames is the list of config filenames to discover. If nil, defaults are used.
+	configFilenames []string
+
 	// maxDependencyDepth is the maximum depth of the dependency tree to discover.
 	maxDependencyDepth int
 
@@ -103,6 +106,9 @@ type Discovery struct {
 // DiscoveryOption is a function that modifies a Discovery.
 type DiscoveryOption func(*Discovery)
 
+// DefaultConfigFilenames are the default Terragrunt config filenames used in discovery.
+var DefaultConfigFilenames = []string{config.DefaultTerragruntConfigPath, config.DefaultStackFile}
+
 // NewDiscovery creates a new Discovery.
 func NewDiscovery(dir string, opts ...DiscoveryOption) *Discovery {
 	discovery := &Discovery{
@@ -190,6 +196,12 @@ func (d *Discovery) WithDiscoveryContext(discoveryContext *DiscoveryContext) *Di
 	return d
 }
 
+// WithConfigFilenames sets the configFilenames field to the given list.
+func (d *Discovery) WithConfigFilenames(filenames []string) *Discovery {
+	d.configFilenames = filenames
+	return d
+}
+
 // String returns a string representation of a DiscoveredConfig.
 func (c *DiscoveredConfig) String() string {
 	return c.Path
@@ -281,6 +293,12 @@ func (d *Discovery) isInHiddenDirectory(path string) bool {
 func (d *Discovery) Discover(ctx context.Context, l log.Logger, opts *options.TerragruntOptions) (DiscoveredConfigs, error) {
 	var cfgs DiscoveredConfigs
 
+	// Set default config filenames if not set
+	filenames := d.configFilenames
+	if len(filenames) == 0 {
+		filenames = DefaultConfigFilenames
+	}
+
 	processFn := func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return errors.New(err)
@@ -294,29 +312,26 @@ func (d *Discovery) Discover(ctx context.Context, l log.Logger, opts *options.Te
 			return nil
 		}
 
-		switch filepath.Base(path) {
-		case config.DefaultTerragruntConfigPath:
-			cfg := &DiscoveredConfig{
-				Type: ConfigTypeUnit,
-				Path: filepath.Dir(path),
-			}
+		base := filepath.Base(path)
+		for _, fname := range filenames {
+			if base == fname {
+				cfgType := ConfigTypeUnit
+				if fname == config.DefaultStackFile {
+					cfgType = ConfigTypeStack
+				}
 
-			if d.discoveryContext != nil {
-				cfg.DiscoveryContext = d.discoveryContext
-			}
+				cfg := &DiscoveredConfig{
+					Type: cfgType,
+					Path: filepath.Dir(path),
+				}
+				if d.discoveryContext != nil {
+					cfg.DiscoveryContext = d.discoveryContext
+				}
 
-			cfgs = append(cfgs, cfg)
-		case config.DefaultStackFile:
-			cfg := &DiscoveredConfig{
-				Type: ConfigTypeStack,
-				Path: filepath.Dir(path),
-			}
+				cfgs = append(cfgs, cfg)
 
-			if d.discoveryContext != nil {
-				cfg.DiscoveryContext = d.discoveryContext
+				break
 			}
-
-			cfgs = append(cfgs, cfg)
 		}
 
 		return nil

internal/discovery/discovery_test.go

@@ -483,3 +483,24 @@ exclude {
 		assert.Nil(t, unit3.Parsed.Exclude)
 	}
 }
+
+func TestDiscoveryWithSingleCustomConfigFilename(t *testing.T) {
+	t.Parallel()
+
+	tmpDir := t.TempDir()
+	unit1Dir := filepath.Join(tmpDir, "unit1")
+	err := os.MkdirAll(unit1Dir, 0755)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(unit1Dir, "custom1.hcl"), []byte(""), 0644)
+	require.NoError(t, err)
+
+	discoveryObj := discovery.NewDiscovery(tmpDir).WithConfigFilenames([]string{"custom1.hcl"})
+	opts, err := options.NewTerragruntOptionsForTest(tmpDir)
+	require.NoError(t, err)
+
+	configs, err := discoveryObj.Discover(t.Context(), logger.CreateLogger(), opts)
+	require.NoError(t, err)
+
+	units := configs.Filter(discovery.ConfigTypeUnit).Paths()
+	assert.ElementsMatch(t, []string{unit1Dir}, units)
+}

internal/runner/runnerpool/builder.go

@@ -3,6 +3,7 @@ package runnerpool
 import (
 	"context"
 
+	"github.com/gruntwork-io/terragrunt/config"
 	"github.com/gruntwork-io/terragrunt/internal/discovery"
 	"github.com/gruntwork-io/terragrunt/internal/runner/common"
 	"github.com/gruntwork-io/terragrunt/options"
@@ -19,6 +20,7 @@ func Build(ctx context.Context, l log.Logger, terragruntOptions *options.Terragr
 		WithParseExclude().
 		WithDiscoverDependencies().
 		WithSuppressParseErrors().
+		WithConfigFilenames([]string{config.DefaultTerragruntConfigPath}).
 		WithDiscoveryContext(&discovery.DiscoveryContext{Cmd: terragruntOptions.TerraformCommand})
 
 	discovered, err := d.Discover(ctx, l, terragruntOptions)

test/fixtures/mixed-config/app/main.tf

@@ -0,0 +1 @@
+

test/fixtures/mixed-config/app/terragrunt.hcl

@@ -0,0 +1,5 @@
+
+unit "app1" {
+  source = "../unit"
+  path   = "app1"
+}

test/fixtures/mixed-config/stack/terragrunt.stack.hcl

@@ -13,6 +13,10 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+const (
+	testFixtureMixedConfig = "fixtures/mixed-config"
+)
+
 func TestRunnerPoolDiscovery(t *testing.T) {
 	t.Parallel()
 
@@ -82,3 +86,16 @@ func TestRunnerPoolTerragruntDestroyOrder(t *testing.T) {
 	// module-e must be destroyed before module-d
 	assert.Less(t, index["module-e"], index["module-d"], "module-e should be destroyed before module-d")
 }
+
+func TestRunnerPoolStackConfigIgnored(t *testing.T) {
+	t.Parallel()
+
+	tmpEnvPath := helpers.CopyEnvironment(t, testFixtureMixedConfig)
+	helpers.CleanupTerraformFolder(t, tmpEnvPath)
+	testPath := util.JoinPath(tmpEnvPath, testFixtureMixedConfig)
+
+	_, stderr, err := helpers.RunTerragruntCommandWithOutput(t, "terragrunt run --experiment runner-pool --queue-include-external --all --non-interactive --working-dir "+testPath+" -- apply")
+	require.NoError(t, err)
+	require.NotContains(t, stderr, "Error: Unsupported block type")
+	require.NotContains(t, stderr, "Blocks of type \"unit\" are not expected here")
+}

test/fixtures/mixed-config/unit/main.tf

@@ -4258,3 +4258,16 @@ func TestVersionIsInvokedInDifferentDirectory(t *testing.T) {
 	assert.Len(t, matches, 2, "Expected exactly one occurrence of '-version' command, found %d", len(matches))
 	assert.Contains(t, stderr, "prefix=dependency-with-custom-version msg=Running command: "+wrappedBinary()+" -version")
 }
+
+func TestMixedStackConfigIgnored(t *testing.T) {
+	t.Parallel()
+
+	tmpEnvPath := helpers.CopyEnvironment(t, testFixtureMixedConfig)
+	helpers.CleanupTerraformFolder(t, tmpEnvPath)
+	testPath := util.JoinPath(tmpEnvPath, testFixtureMixedConfig)
+
+	_, stderr, err := helpers.RunTerragruntCommandWithOutput(t, "terragrunt run --all --non-interactive --working-dir "+testPath+" -- apply")
+	require.NoError(t, err)
+	require.NotContains(t, stderr, "Error: Unsupported block type")
+	require.NotContains(t, stderr, "Blocks of type \"unit\" are not expected here")
+}