Add function to opportunistically load a bundle (#180)

It is not an error if a bundle cannot be found for this category.
This sets the stage for using bundle configuration in non-bundle
commands.

bundle/bundle.go

@@ -41,8 +41,10 @@ func Load(path string) (*Bundle, error) {
 	return bundle, nil
 }
 
-func LoadFromRoot() (*Bundle, error) {
-	root, err := getRoot()
+// MustLoad returns a bundle configuration.
+// It returns an error if a bundle was not found or could not be loaded.
+func MustLoad() (*Bundle, error) {
+	root, err := mustGetRoot()
 	if err != nil {
 		return nil, err
 	}
@@ -50,6 +52,23 @@ func LoadFromRoot() (*Bundle, error) {
 	return Load(root)
 }
 
+// TryLoad returns a bundle configuration if there is one, but doesn't fail if there isn't one.
+// It returns an error if a bundle was found but could not be loaded.
+// It returns a `nil` bundle if a bundle was not found.
+func TryLoad() (*Bundle, error) {
+	root, err := tryGetRoot()
+	if err != nil {
+		return nil, err
+	}
+
+	// No root is fine in this function.
+	if root == "" {
+		return nil, nil
+	}
+
+	return Load(root)
+}
+
 func (b *Bundle) WorkspaceClient() *databricks.WorkspaceClient {
 	b.clientOnce.Do(func() {
 		var err error

bundle/bundle_test.go

@@ -39,3 +39,42 @@ func TestBundleCacheDir(t *testing.T) {
 	assert.NoError(t, err)
 	assert.True(t, strings.HasPrefix(cacheDir, projectDir))
 }
+
+func TestBundleMustLoadSuccess(t *testing.T) {
+	t.Setenv(envBundleRoot, "./tests/basic")
+	b, err := MustLoad()
+	require.NoError(t, err)
+	assert.Equal(t, "./tests/basic", b.Config.Path)
+}
+
+func TestBundleMustLoadFailureWithEnv(t *testing.T) {
+	t.Setenv(envBundleRoot, "./tests/doesntexist")
+	_, err := MustLoad()
+	require.Error(t, err, "not a directory")
+}
+
+func TestBundleMustLoadFailureIfNotFound(t *testing.T) {
+	chdir(t, t.TempDir())
+	_, err := MustLoad()
+	require.Error(t, err, "unable to find bundle root")
+}
+
+func TestBundleTryLoadSuccess(t *testing.T) {
+	t.Setenv(envBundleRoot, "./tests/basic")
+	b, err := TryLoad()
+	require.NoError(t, err)
+	assert.Equal(t, "./tests/basic", b.Config.Path)
+}
+
+func TestBundleTryLoadFailureWithEnv(t *testing.T) {
+	t.Setenv(envBundleRoot, "./tests/doesntexist")
+	_, err := TryLoad()
+	require.Error(t, err, "not a directory")
+}
+
+func TestBundleTryLoadOkIfNotFound(t *testing.T) {
+	chdir(t, t.TempDir())
+	b, err := TryLoad()
+	assert.NoError(t, err)
+	assert.Nil(t, b)
+}

bundle/root.go

@@ -10,29 +10,56 @@ import (
 
 const envBundleRoot = "BUNDLE_ROOT"
 
-// getRoot returns the bundle root.
-// If the `BUNDLE_ROOT` environment variable is set, we assume its value
-// to be a valid bundle root. Otherwise we try to find it by traversing
-// the path and looking for a project configuration file.
-func getRoot() (string, error) {
+// getRootEnv returns the value of the `BUNDLE_ROOT` environment variable
+// if it set and is a directory. If the environment variable is set but
+// is not a directory, it returns an error. If the environment variable is
+// not set, it returns an empty string.
+func getRootEnv() (string, error) {
 	path, ok := os.LookupEnv(envBundleRoot)
-	if ok {
-		stat, err := os.Stat(path)
-		if err == nil && !stat.IsDir() {
-			err = fmt.Errorf("not a directory")
-		}
-		if err != nil {
-			return "", fmt.Errorf(`invalid bundle root %s="%s": %w`, envBundleRoot, path, err)
-		}
-		return path, nil
+	if !ok {
+		return "", nil
 	}
+	stat, err := os.Stat(path)
+	if err == nil && !stat.IsDir() {
+		err = fmt.Errorf("not a directory")
+	}
+	if err != nil {
+		return "", fmt.Errorf(`invalid bundle root %s="%s": %w`, envBundleRoot, path, err)
+	}
+	return path, nil
+}
+
+// getRootWithTraversal returns the bundle root by traversing the filesystem
+// from the working directory to the root looking for a configuration file.
+func getRootWithTraversal() (string, error) {
 	wd, err := os.Getwd()
 	if err != nil {
 		return "", err
 	}
-	path, err = folders.FindDirWithLeaf(wd, config.FileName)
+	path, err := folders.FindDirWithLeaf(wd, config.FileName)
 	if err != nil {
-		return "", fmt.Errorf(`unable to locate bundle root`)
+		return "", fmt.Errorf(`unable to locate bundle root: %s not found`, config.FileName)
 	}
 	return path, nil
 }
+
+// mustGetRoot returns a bundle root or an error if one cannot be found.
+func mustGetRoot() (string, error) {
+	path, err := getRootEnv()
+	if path != "" || err != nil {
+		return path, err
+	}
+	return getRootWithTraversal()
+}
+
+// tryGetRoot returns a bundle root or an empty string if one cannot be found.
+func tryGetRoot() (string, error) {
+	// Note: an invalid value in the environment variable is still an error.
+	path, err := getRootEnv()
+	if path != "" || err != nil {
+		return path, err
+	}
+	// Note: traversal failing means the bundle root cannot be found.
+	path, _ = getRootWithTraversal()
+	return path, nil
+}

bundle/root_test.go

@@ -34,7 +34,7 @@ func TestRootFromEnv(t *testing.T) {
 	t.Setenv(envBundleRoot, dir)
 
 	// It should pull the root from the environment variable.
-	root, err := getRoot()
+	root, err := mustGetRoot()
 	require.NoError(t, err)
 	require.Equal(t, root, dir)
 }
@@ -44,7 +44,7 @@ func TestRootFromEnvDoesntExist(t *testing.T) {
 	t.Setenv(envBundleRoot, filepath.Join(dir, "doesntexist"))
 
 	// It should pull the root from the environment variable.
-	_, err := getRoot()
+	_, err := mustGetRoot()
 	require.Errorf(t, err, "invalid bundle root")
 }
 
@@ -56,7 +56,7 @@ func TestRootFromEnvIsFile(t *testing.T) {
 	t.Setenv(envBundleRoot, f.Name())
 
 	// It should pull the root from the environment variable.
-	_, err = getRoot()
+	_, err = mustGetRoot()
 	require.Errorf(t, err, "invalid bundle root")
 }
 
@@ -65,7 +65,7 @@ func TestRootIfEnvIsEmpty(t *testing.T) {
 	t.Setenv(envBundleRoot, dir)
 
 	// It should pull the root from the environment variable.
-	_, err := getRoot()
+	_, err := mustGetRoot()
 	require.Errorf(t, err, "invalid bundle root")
 }
 
@@ -87,7 +87,7 @@ func TestRootLookup(t *testing.T) {
 
 	// It should find the project root from $PWD.
 	wd := chdir(t, "./a/b/c")
-	root, err := getRoot()
+	root, err := mustGetRoot()
 	require.NoError(t, err)
 	require.Equal(t, wd, root)
 }
@@ -99,6 +99,6 @@ func TestRootLookupError(t *testing.T) {
 
 	// It can't find a project root from a temporary directory.
 	_ = chdir(t, t.TempDir())
-	_, err := getRoot()
+	_, err := mustGetRoot()
 	require.ErrorContains(t, err, "unable to locate bundle root")
 }

cmd/bundle/root.go

@@ -17,7 +17,7 @@ var rootCmd = &cobra.Command{
 // and configures it on the command's context.
 func ConfigureBundle(cmd *cobra.Command, args []string) error {
 	ctx := cmd.Context()
-	b, err := bundle.LoadFromRoot()
+	b, err := bundle.MustLoad()
 	if err != nil {
 		return err
 	}