feat: SetupDaemonConfig no longer needs a file (#214)

cmd/gubernator-cli/main.go

@@ -89,7 +89,11 @@ func main() {
 		cmdLine := strings.Join(os.Args[1:], " ")
 		logrus.WithContext(ctx).Info("Command line: " + cmdLine)
 
-		conf, err := guber.SetupDaemonConfig(log, configFile)
+		configFileReader, err := os.Open(configFile)
+		if err != nil {
+			return fmt.Errorf("while opening config file: %s", err)
+		}
+		conf, err := guber.SetupDaemonConfig(log, configFileReader)
 		if err != nil {
 			return err
 		}

cmd/gubernator/main.go

@@ -74,7 +74,11 @@ func main() {
 	}
 
 	// Read our config from the environment or optional environment config file
-	conf, err := gubernator.SetupDaemonConfig(logrus.StandardLogger(), configFile)
+	configFileReader, err := os.Open(configFile)
+	if err != nil {
+		log.WithError(err).Fatal("while opening config file")
+	}
+	conf, err := gubernator.SetupDaemonConfig(logrus.StandardLogger(), configFileReader)
 	checkErr(err, "while getting config")
 
 	ctx, cancel := context.WithTimeout(ctx, clock.Second*10)

config.go

@@ -263,17 +263,17 @@ func (d *DaemonConfig) ServerTLS() *tls.Config {
 	return nil
 }
 
-// SetupDaemonConfig returns a DaemonConfig object as configured by reading the provided config file
-// and environment.
-func SetupDaemonConfig(logger *logrus.Logger, configFile string) (DaemonConfig, error) {
+// SetupDaemonConfig returns a DaemonConfig object that is the result of merging the lines
+// in the provided configFile and the environment variables. See `example.conf` for all available config options and their descriptions.
+func SetupDaemonConfig(logger *logrus.Logger, configFile io.Reader) (DaemonConfig, error) {
 	log := logrus.NewEntry(logger)
 	var conf DaemonConfig
 	var logLevel string
 	var logFormat string
 	var advAddr, advPort string
 	var err error
 
-	if configFile != "" {
+	if configFile != nil {
 		log.Infof("Loading env config: %s", configFile)
 		if err := fromEnvFile(log, configFile); err != nil {
 			return conf, err
@@ -628,15 +628,10 @@ func getEnvSlice(name string) []string {
 	return strings.Split(v, ",")
 }
 
-// Take values from a file in the format `GUBER_CONF_ITEM=my-value` and put them into the environment
-// lines that begin with `#` are ignored
-func fromEnvFile(log logrus.FieldLogger, configFile string) error {
-	fd, err := os.Open(configFile)
-	if err != nil {
-		return fmt.Errorf("while opening config file: %s", err)
-	}
-
-	contents, err := io.ReadAll(fd)
+// Take values from a file in the format `GUBER_CONF_ITEM=my-value` and sets them as environment variables.
+// Lines that begin with `#` are ignored
+func fromEnvFile(log logrus.FieldLogger, configFile io.Reader) error {
+	contents, err := io.ReadAll(configFile)
 	if err != nil {
 		return fmt.Errorf("while reading config file '%s': %s", configFile, err)
 	}

config_test.go

@@ -0,0 +1,40 @@
+package gubernator
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParsesGrpcAddress(t *testing.T) {
+	os.Clearenv()
+	s := `
+# a comment
+GUBER_GRPC_ADDRESS=10.10.10.10:9000`
+	daemonConfig, err := SetupDaemonConfig(logrus.StandardLogger(), strings.NewReader(s))
+	require.NoError(t, err)
+	require.Equal(t, "10.10.10.10:9000", daemonConfig.GRPCListenAddress)
+	require.NotEmpty(t, daemonConfig.InstanceID)
+}
+
+func TestDefaultGrpcAddress(t *testing.T) {
+	os.Clearenv()
+	s := `
+# a comment`
+	daemonConfig, err := SetupDaemonConfig(logrus.StandardLogger(), strings.NewReader(s))
+	require.NoError(t, err)
+	require.Equal(t, fmt.Sprintf("%s:81", LocalHost()), daemonConfig.GRPCListenAddress)
+	require.NotEmpty(t, daemonConfig.InstanceID)
+}
+
+func TestDefaultInstanceId(t *testing.T) {
+	os.Clearenv()
+	s := ``
+	daemonConfig, err := SetupDaemonConfig(logrus.StandardLogger(), strings.NewReader(s))
+	require.NoError(t, err)
+	require.NotEmpty(t, daemonConfig.InstanceID)
+}