feat: allow invalid config directories (#1969)

This change will prevent an invalid config directory from shutting down
the auth server. To prevent spamming the logs we wait for the
reloadInterval between each attempt to check the config dir.

---------

Co-authored-by: Chris Stockton <[email protected]>

Author: cstockton

cmd/serve_cmd.go

@@ -34,7 +34,7 @@ func serve(ctx context.Context) {
 	}
 
 	if err := conf.LoadDirectory(watchDir); err != nil {
-		logrus.WithError(err).Fatal("unable to load config from watch dir")
+		logrus.WithError(err).Error("unable to load config from watch dir")
 	}
 
 	config, err := conf.LoadGlobalFromEnv()

internal/reloader/reloader.go

@@ -30,6 +30,7 @@ type Reloader struct {
 	tickerIval time.Duration
 	watchFn    func() (watcher, error)
 	reloadFn   func(dir string) (*conf.GlobalConfiguration, error)
+	addDirFn   func(ctx context.Context, wr watcher, dir string, dur time.Duration) error
 }
 
 func NewReloader(watchDir string) *Reloader {
@@ -39,6 +40,7 @@ func NewReloader(watchDir string) *Reloader {
 		tickerIval: tickerInterval,
 		watchFn:    newFSWatcher,
 		reloadFn:   defaultReloadFn,
+		addDirFn:   defaultAddDirFn,
 	}
 }
 
@@ -74,7 +76,7 @@ func (rl *Reloader) Watch(ctx context.Context, fn ConfigFunc) error {
 	defer tr.Stop()
 
 	// Ignore errors, if watch dir doesn't exist we can add it later.
-	if err := wr.Add(rl.watchDir); err != nil {
+	if err := rl.addDirFn(ctx, wr, rl.watchDir, reloadInterval); err != nil {
 		logrus.WithError(err).Error("reloader: error watching config directory")
 	}
 
@@ -89,8 +91,8 @@ func (rl *Reloader) Watch(ctx context.Context, fn ConfigFunc) error {
 			// being moved and then recreated. I've tested all of these basic
 			// scenarios and wr.WatchList() does not grow which aligns with
 			// the documented behavior.
-			if err := wr.Add(rl.watchDir); err != nil {
-				logrus.WithError(err).Error(err)
+			if err := rl.addDirFn(ctx, wr, rl.watchDir, reloadInterval); err != nil {
+				logrus.WithError(err).Error("reloader: error watching config directory")
 			}
 
 			// Check to see if the config is ready to be relaoded.
@@ -141,6 +143,23 @@ func (rl *Reloader) Watch(ctx context.Context, fn ConfigFunc) error {
 	}
 }
 
+// defaultAddDirFn adds a dir to a watcher with a common error and sleep
+// duration if the directory doesn't exist.
+func defaultAddDirFn(ctx context.Context, wr watcher, dir string, dur time.Duration) error {
+	if err := wr.Add(dir); err != nil {
+		tr := time.NewTicker(dur)
+		defer tr.Stop()
+
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-tr.C:
+			return err
+		}
+	}
+	return nil
+}
+
 func defaultReloadFn(dir string) (*conf.GlobalConfiguration, error) {
 	if err := conf.LoadDirectory(dir); err != nil {
 		return nil, err

internal/reloader/reloader_test.go

@@ -4,13 +4,15 @@ import (
 	"bytes"
 	"context"
 	"errors"
+	"fmt"
 	"os"
 	"path"
 	"path/filepath"
 	"testing"
 	"time"
 
 	"github.com/fsnotify/fsnotify"
+	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
 	"github.com/supabase/auth/internal/conf"
 	"golang.org/x/sync/errgroup"
@@ -49,6 +51,20 @@ func TestWatch(t *testing.T) {
 		}
 	}
 
+	// test watch invalid dir in addDirFn
+	{
+
+		sentinel := errors.New("sentinel")
+		wr := newMockWatcher(sentinel)
+		rl := NewReloader(path.Join(dir, "__not_found__"))
+		rl.watchFn = func() (watcher, error) { return wr, nil }
+
+		err := rl.addDirFn(ctx, wr, "__not_found__", time.Millisecond)
+		if exp, got := sentinel, err; exp != got {
+			assert.Equal(t, exp, got)
+		}
+	}
+
 	// test watch error chan closed
 	{
 		rr := mockReloadRecorder()
@@ -138,6 +154,13 @@ func TestWatch(t *testing.T) {
 		rl := NewReloader(dir)
 		rl.watchFn = func() (watcher, error) { return wr, wr.getErr() }
 		rl.reloadFn = rr.reloadFn
+		rl.addDirFn = func(ctx context.Context, wr watcher, dir string, dur time.Duration) error {
+			if err := wr.Add(dir); err != nil {
+				logrus.WithError(err).Error("reloader: error watching config directory")
+				return err
+			}
+			return nil
+		}
 
 		// Need to lower reload ival to pickup config write quicker.
 		rl.reloadIval = time.Second / 10
@@ -256,6 +279,7 @@ func TestWatch(t *testing.T) {
 				Name: name,
 				Op:   fsnotify.Create,
 			}
+
 			select {
 			case <-egCtx.Done():
 				assert.Nil(t, egCtx.Err())
@@ -411,7 +435,8 @@ func TestReloadCheckAt(t *testing.T) {
 }
 
 func helpTestDir(t testing.TB) (dir string, cleanup func()) {
-	dir = filepath.Join("testdata", t.Name())
+	name := fmt.Sprintf("%v_%v", t.Name(), time.Now().Nanosecond())
+	dir = filepath.Join("testdata", name)
 	err := os.MkdirAll(dir, 0750)
 	if err != nil && !os.IsExist(err) {
 		assert.Nil(t, err)