Fix config and clean up interface

internal/cmd/beta/server/grpcurl_utils.go

@@ -27,7 +27,7 @@ func getDescriptorSource(ctx context.Context, cfg *config.Config) (grpcurl.Descr
 }
 
 func dialServer(ctx context.Context, cfg *config.Config) (*grpc.ClientConn, error) {
-	tlsConf, err := runmetls.LoadClientConfig(cfg.Server.Tls.CertFile, cfg.Server.Tls.KeyFile)
+	tlsConf, err := runmetls.LoadClientConfig(*cfg.Server.Tls.CertFile, *cfg.Server.Tls.KeyFile)
 	if err != nil {
 		return nil, err
 	}

internal/cmd/beta/server/server_start_cmd.go

@@ -29,8 +29,8 @@ func serverStartCmd() *cobra.Command {
 
 					serverCfg := &server.Config{
 						Address:    cfg.Server.Address,
-						CertFile:   cfg.Server.Tls.CertFile,
-						KeyFile:    cfg.Server.Tls.KeyFile,
+						CertFile:   *cfg.Server.Tls.CertFile, // guaranteed by autoconfig
+						KeyFile:    *cfg.Server.Tls.KeyFile,  // guaranteed by autoconfig
 						TLSEnabled: cfg.Server.Tls.Enabled,
 					}
 

internal/config/autoconfig/autoconfig.go

@@ -85,7 +85,8 @@ func getClient(cfg *config.Config, logger *zap.Logger) (*runnerv2client.Client,
 	var opts []grpc.DialOption
 
 	if cfg.Server.Tls != nil && cfg.Server.Tls.Enabled {
-		tlsConfig, err := runmetls.LoadClientConfig(cfg.Server.Tls.CertFile, cfg.Server.Tls.KeyFile)
+		// It's ok to dereference TLS fields because they are checked in [getRootConfig].
+		tlsConfig, err := runmetls.LoadClientConfig(*cfg.Server.Tls.CertFile, *cfg.Server.Tls.KeyFile)
 		if err != nil {
 			return nil, errors.WithStack(err)
 		}
@@ -268,7 +269,7 @@ func getRootConfig(cfgLoader *config.Loader, userCfgDir UserConfigDir) (*config.
 	items, err := cfgLoader.RootConfigs()
 	switch err {
 	case nil:
-		if cfg, err = config.ParseMultipleYAMLs(items...); err != nil {
+		if cfg, err = config.ParseYAML(items...); err != nil {
 			return nil, err
 		}
 	case config.ErrRootConfigNotFound:
@@ -280,11 +281,13 @@ func getRootConfig(cfgLoader *config.Loader, userCfgDir UserConfigDir) (*config.
 	if cfg.Server != nil && cfg.Server.Tls != nil && cfg.Server.Tls.Enabled {
 		tls := cfg.Server.Tls
 
-		if tls.CertFile == "" {
-			tls.CertFile = filepath.Join(string(userCfgDir), "runme", "tls", "cert.pem")
+		if tls.CertFile == nil {
+			path := filepath.Join(string(userCfgDir), "runme", "tls", "cert.pem")
+			tls.CertFile = &path
 		}
-		if tls.KeyFile == "" {
-			tls.KeyFile = filepath.Join(string(userCfgDir), "runme", "tls", "key.pem")
+		if tls.KeyFile == nil {
+			path := filepath.Join(string(userCfgDir), "runme", "tls", "key.pem")
+			tls.KeyFile = &path
 		}
 	}
 

internal/config/config.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	_ "embed"
+	"encoding/json"
 	"os"
 	"path/filepath"
 	"strings"
@@ -9,15 +11,35 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-func ParseYAML(data []byte) (*Config, error) {
-	return ParseMultipleYAMLs(data)
-}
+//go:embed runme.default.yaml
+var defaultRunmeYAML []byte
 
-func ParseMultipleYAMLs(items ...[]byte) (*Config, error) {
-	if len(items) == 0 {
-		return nil, errors.New("no configuration items")
+func init() {
+	// Ensure the default configuration is valid.
+	_, err := newDefault()
+	if err != nil {
+		panic(err)
 	}
+}
+
+func newDefault() (*Config, error) {
+	return ParseYAML(defaultRunmeYAML)
+}
 
+func Default() *Config {
+	cfg, _ := newDefault()
+	return cfg
+}
+
+// ParseYAML parses the given YAML items and returns a configuration object.
+// Multiple items are merged into a single configuration. It uses a default
+// configuration as a base.
+func ParseYAML(items ...[]byte) (*Config, error) {
+	items = append([][]byte{defaultRunmeYAML}, items...)
+	return parseYAML(items...)
+}
+
+func parseYAML(items ...[]byte) (*Config, error) {
 	version, err := parseVersionFromYAML(items[0])
 	if err != nil {
 		return nil, err
@@ -64,15 +86,36 @@ func parseVersionFromYAML(data []byte) (string, error) {
 	return result.Version, nil
 }
 
+// parseAndMergeV1alpha1 parses items, which are raw YAML blobs,
+// one-by-one into a single map. Then, marshals the map into raw JSON.
+// Finally, unmarshals the JSON into a [Config] object.
+// Double unmarshaling is required to take advantage of the
+// auto-generated [Config.UnmarshalJSON] method which does
+// validation.
 func parseAndMergeV1alpha1(items ...[]byte) (*Config, error) {
-	var config Config
+	m := make(map[string]interface{})
 
 	for _, data := range items {
-		if err := yaml.Unmarshal(data, &config); err != nil {
-			return nil, errors.Wrap(err, "failed to unmarshal yaml")
+		if err := yaml.Unmarshal(data, &m); err != nil {
+			return nil, errors.Wrap(err, "failed to parse v1alpha1 config")
 		}
 	}
 
+	flatten, err := json.Marshal(m)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to parse v1alpha1 config")
+	}
+
+	var config Config
+
+	if err := json.Unmarshal(flatten, &config); err != nil {
+		return nil, errors.Wrap(err, "failed to parse v1alpha1 config")
+	}
+
+	if err := validateConfig(&config); err != nil {
+		return nil, errors.Wrap(err, "failed to validate v1alpha1 config")
+	}
+
 	return &config, nil
 }
 
@@ -83,11 +126,11 @@ func validateConfig(cfg *Config) error {
 	}
 
 	if err := validateInsideCwd(cfg.Project.Root, cwd); err != nil {
-		return errors.Wrap(err, "failed to validate project dir")
+		return errors.Wrap(err, "project.root")
 	}
 
 	if err := validateInsideCwd(cfg.Project.Filename, cwd); err != nil {
-		return errors.Wrap(err, "failed to validate filename")
+		return errors.Wrap(err, "project.filename")
 	}
 
 	return nil

internal/config/config.schema.json

@@ -37,7 +37,8 @@
           "type": "object",
           "properties": {
             "use_system_env": {
-              "type": "boolean"
+              "type": "boolean",
+              "default": false
             },
             "sources": {
               "type": "array",
@@ -129,9 +130,7 @@
             }
           },
           "required": [
-            "enabled",
-            "cert_file",
-            "key_file"
+            "enabled"
           ]
         }
       },