feat: provider config parsers are able to resolve filepaths

pkg/config/config.go

@@ -2,8 +2,10 @@ package config
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"os"
+	"path/filepath"
 
 	"github.com/BurntSushi/toml"
 )
@@ -68,6 +70,9 @@ type StaticConfig struct {
 
 	// Internal: parsed provider configs (not exposed to TOML package)
 	parsedClusterProviderConfigs map[string]ProviderConfig
+
+	// Internal: the config.toml directory, to help resolve relative file paths
+	configDirPath string
 }
 
 type GroupVersionKind struct {
@@ -76,23 +81,48 @@ type GroupVersionKind struct {
 	Kind    string `toml:"kind,omitempty"`
 }
 
-// Read reads the toml file and returns the StaticConfig.
-func Read(configPath string) (*StaticConfig, error) {
+type ReadConfigOpt func(cfg *StaticConfig)
+
+func withDirPath(path string) ReadConfigOpt {
+	return func(cfg *StaticConfig) {
+		cfg.configDirPath = path
+	}
+}
+
+// Read reads the toml file and returns the StaticConfig, with any opts applied.
+func Read(configPath string, opts ...ReadConfigOpt) (*StaticConfig, error) {
 	configData, err := os.ReadFile(configPath)
 	if err != nil {
 		return nil, err
 	}
-	return ReadToml(configData)
+
+	// get and save the absolute dir path to the config file, so that other config parsers can use it
+	absPath, err := filepath.Abs(configPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to resolve absolute path to config file: %w", err)
+	}
+	dirPath := filepath.Dir(absPath)
+
+	cfg, err := ReadToml(configData, append(opts, withDirPath(dirPath))...)
+	if err != nil {
+		return nil, err
+	}
+
+	return cfg, nil
 }
 
-// ReadToml reads the toml data and returns the StaticConfig.
-func ReadToml(configData []byte) (*StaticConfig, error) {
+// ReadToml reads the toml data and returns the StaticConfig, with any opts applied
+func ReadToml(configData []byte, opts ...ReadConfigOpt) (*StaticConfig, error) {
 	config := Default()
 	md, err := toml.NewDecoder(bytes.NewReader(configData)).Decode(config)
 	if err != nil {
 		return nil, err
 	}
 
+	for _, opt := range opts {
+		opt(config)
+	}
+
 	if err := config.parseClusterProviderConfigs(md); err != nil {
 		return nil, err
 	}
@@ -111,13 +141,15 @@ func (c *StaticConfig) parseClusterProviderConfigs(md toml.MetaData) error {
 		c.parsedClusterProviderConfigs = make(map[string]ProviderConfig, len(c.ClusterProviderConfigs))
 	}
 
+	ctx := withConfigDirPath(context.Background(), c.configDirPath)
+
 	for strategy, primitive := range c.ClusterProviderConfigs {
 		parser, ok := getProviderConfigParser(strategy)
 		if !ok {
 			continue
 		}
 
-		providerConfig, err := parser(primitive, md)
+		providerConfig, err := parser(ctx, primitive, md)
 		if err != nil {
 			return fmt.Errorf("failed to parse config for ClusterProvider '%s': %w", strategy, err)
 		}

pkg/config/provider_config.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/BurntSushi/toml"
@@ -12,7 +13,27 @@ type ProviderConfig interface {
 	Validate() error
 }
 
-type ProviderConfigParser func(primitive toml.Primitive, md toml.MetaData) (ProviderConfig, error)
+type ProviderConfigParser func(ctx context.Context, primitive toml.Primitive, md toml.MetaData) (ProviderConfig, error)
+
+type configDirPathKey struct{}
+
+func withConfigDirPath(ctx context.Context, dirPath string) context.Context {
+	return context.WithValue(ctx, configDirPathKey{}, dirPath)
+}
+
+func ConfigDirPathFromContext(ctx context.Context) string {
+	val := ctx.Value(configDirPathKey{})
+
+	if val == nil {
+		return ""
+	}
+
+	if strVal, ok := val.(string); ok {
+		return strVal
+	}
+
+	return ""
+}
 
 var (
 	providerConfigParsers = make(map[string]ProviderConfigParser)

pkg/config/provider_config_test.go

@@ -1,7 +1,9 @@
 package config
 
 import (
+	"context"
 	"errors"
+	"path/filepath"
 	"testing"
 
 	"github.com/BurntSushi/toml"
@@ -42,7 +44,7 @@ func (p *ProviderConfigForTest) Validate() error {
 	return nil
 }
 
-func providerConfigForTestParser(primitive toml.Primitive, md toml.MetaData) (ProviderConfig, error) {
+func providerConfigForTestParser(ctx context.Context, primitive toml.Primitive, md toml.MetaData) (ProviderConfig, error) {
 	var providerConfigForTest ProviderConfigForTest
 	if err := md.PrimitiveDecode(primitive, &providerConfigForTest); err != nil {
 		return nil, err
@@ -131,7 +133,7 @@ func (s *ProviderConfigSuite) TestReadConfigUnregisteredProviderConfig() {
 }
 
 func (s *ProviderConfigSuite) TestReadConfigParserError() {
-	RegisterProviderConfig("test", func(primitive toml.Primitive, md toml.MetaData) (ProviderConfig, error) {
+	RegisterProviderConfig("test", func(ctx context.Context, primitive toml.Primitive, md toml.MetaData) (ProviderConfig, error) {
 		return nil, errors.New("parser error forced by test")
 	})
 	invalidConfigPath := s.writeConfig(`
@@ -152,6 +154,35 @@ func (s *ProviderConfigSuite) TestReadConfigParserError() {
 	})
 }
 
+func (s *ProviderConfigSuite) TestConfigDirPathInContext() {
+	var capturedDirPath string
+	RegisterProviderConfig("test", func(ctx context.Context, primitive toml.Primitive, md toml.MetaData) (ProviderConfig, error) {
+		capturedDirPath = ConfigDirPathFromContext(ctx)
+		var providerConfigForTest ProviderConfigForTest
+		if err := md.PrimitiveDecode(primitive, &providerConfigForTest); err != nil {
+			return nil, err
+		}
+		return &providerConfigForTest, nil
+	})
+	configPath := s.writeConfig(`
+		cluster_provider_strategy = "test"
+		[cluster_provider_configs.test]
+		bool_prop = true
+		str_prop = "a string"
+		int_prop = 42
+	`)
+
+	absConfigPath, err := filepath.Abs(configPath)
+	s.Require().NoError(err, "test error: getting the absConfigPath should not fail")
+
+	_, err = Read(configPath)
+	s.Run("provides config directory path in context to parser", func() {
+		s.Require().NoError(err, "Expected no error reading config")
+		s.NotEmpty(capturedDirPath, "Expected non-empty directory path in context")
+		s.Equal(filepath.Dir(absConfigPath), capturedDirPath, "Expected directory path to match config file directory")
+	})
+}
+
 func TestProviderConfig(t *testing.T) {
 	suite.Run(t, new(ProviderConfigSuite))
 }