Close resources after failing to startup TSDB (#8031)

* Close resources after failing to startup TSDB

Signed-off-by: arthursens <arthursens2005@gmail.com>

* Return close error instead of logging

Signed-off-by: arthursens <arthursens2005@gmail.com>

* Change named return's name

Signed-off-by: arthursens <arthursens2005@gmail.com>

tsdb/db.go

@@ -553,7 +553,7 @@ func validateOpts(opts *Options, rngs []int64) (*Options, []int64) {
 	return opts, rngs
 }
 
-func open(dir string, l log.Logger, r prometheus.Registerer, opts *Options, rngs []int64) (db *DB, err error) {
+func open(dir string, l log.Logger, r prometheus.Registerer, opts *Options, rngs []int64) (db *DB, returnedErr error) {
 	if err := os.MkdirAll(dir, 0777); err != nil {
 		return nil, err
 	}
@@ -595,6 +595,19 @@ func open(dir string, l log.Logger, r prometheus.Registerer, opts *Options, rngs
 		chunkPool:      chunkenc.NewPool(),
 		blocksToDelete: opts.BlocksToDelete,
 	}
+	defer func() {
+		// Close files if startup fails somewhere.
+		if returnedErr == nil {
+			return
+		}
+
+		var merr tsdb_errors.MultiError
+		merr.Add(returnedErr)
+		merr.Add(errors.Wrap(db.Close(), "close DB after failed startup"))
+
+		returnedErr = merr.Err()
+	}()
+
 	if db.blocksToDelete == nil {
 		db.blocksToDelete = DefaultBlocksToDelete(db)
 	}
@@ -612,10 +625,10 @@ func open(dir string, l log.Logger, r prometheus.Registerer, opts *Options, rngs
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
-	db.compactor, err = NewLeveledCompactor(ctx, r, l, rngs, db.chunkPool)
-	if err != nil {
+	db.compactor, returnedErr = NewLeveledCompactor(ctx, r, l, rngs, db.chunkPool)
+	if returnedErr != nil {
 		cancel()
-		return nil, errors.Wrap(err, "create leveled compactor")
+		return nil, errors.Wrap(returnedErr, "create leveled compactor")
 	}
 	db.compactCancel = cancel
 
@@ -627,15 +640,15 @@ func open(dir string, l log.Logger, r prometheus.Registerer, opts *Options, rngs
 		if opts.WALSegmentSize > 0 {
 			segmentSize = opts.WALSegmentSize
 		}
-		wlog, err = wal.NewSize(l, r, walDir, segmentSize, opts.WALCompression)
-		if err != nil {
-			return nil, err
+		wlog, returnedErr = wal.NewSize(l, r, walDir, segmentSize, opts.WALCompression)
+		if returnedErr != nil {
+			return nil, returnedErr
 		}
 	}
 
-	db.head, err = NewHead(r, l, wlog, rngs[0], dir, db.chunkPool, opts.StripeSize, opts.SeriesLifecycleCallback)
-	if err != nil {
-		return nil, err
+	db.head, returnedErr = NewHead(r, l, wlog, rngs[0], dir, db.chunkPool, opts.StripeSize, opts.SeriesLifecycleCallback)
+	if returnedErr != nil {
+		return nil, returnedErr
 	}
 
 	// Register metrics after assigning the head block.
@@ -1333,7 +1346,9 @@ func (db *DB) Close() error {
 	if db.lockf != nil {
 		merr.Add(db.lockf.Release())
 	}
-	merr.Add(db.head.Close())
+	if db.head != nil {
+		merr.Add(db.head.Close())
+	}
 	return merr.Err()
 }