Move config parsing to a dedicated pkg

cmd/buildkitd/config/load.go

@@ -0,0 +1,36 @@
+package config
+
+import (
+	"io"
+	"os"
+
+	"github.com/pelletier/go-toml"
+	"github.com/pkg/errors"
+)
+
+// Load loads buildkitd config
+func Load(r io.Reader) (Config, error) {
+	var c Config
+	t, err := toml.LoadReader(r)
+	if err != nil {
+		return c, errors.Wrap(err, "failed to parse config")
+	}
+	err = t.Unmarshal(&c)
+	if err != nil {
+		return c, errors.Wrap(err, "failed to parse config")
+	}
+	return c, nil
+}
+
+// LoadFile loads buildkitd config file
+func LoadFile(fp string) (Config, error) {
+	f, err := os.Open(fp)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return Config{}, nil
+		}
+		return Config{}, errors.Wrapf(err, "failed to load config from %s", fp)
+	}
+	defer f.Close()
+	return Load(f)
+}

cmd/buildkitd/config_test.go → cmd/buildkitd/config/load_test.go

@@ -1,4 +1,4 @@
-package main
+package config
 
 import (
 	"bytes"
@@ -7,7 +7,7 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestConfig(t *testing.T) {
+func TestLoad(t *testing.T) {
 
 	const testConfig = `
 root = "/foo/bar"

cmd/buildkitd/main.go

@@ -204,7 +204,7 @@ func main() {
 		ctx, cancel := context.WithCancel(appcontext.Context())
 		defer cancel()
 
-		cfg, err := LoadFile(c.GlobalString("config"))
+		cfg, err := config.LoadFile(c.GlobalString("config"))
 		if err != nil {
 			return err
 		}
@@ -368,7 +368,7 @@ func defaultConfigPath() string {
 }
 
 func defaultConf() (config.Config, error) {
-	cfg, err := LoadFile(defaultConfigPath())
+	cfg, err := config.LoadFile(defaultConfigPath())
 	if err != nil {
 		var pe *os.PathError
 		if !errors.As(err, &pe) {
@@ -777,6 +777,15 @@ func getDNSConfig(cfg *config.DNSConfig) *oci.DNSConfig {
 	return dns
 }
 
+// parseBoolOrAuto returns (nil, nil) if s is "auto"
+func parseBoolOrAuto(s string) (*bool, error) {
+	if s == "" || strings.ToLower(s) == "auto" {
+		return nil, nil
+	}
+	b, err := strconv.ParseBool(s)
+	return &b, err
+}
+
 func runTraceController(p string, exp sdktrace.SpanExporter) error {
 	server := grpc.NewServer()
 	tracev1.RegisterTraceServiceServer(server, &traceCollector{exporter: exp})