// Copyright 2016 The Prometheus Authors // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package fileutil import ( "os" "path/filepath" "testing" "github.com/prometheus/tsdb/testutil" ) func TestLocking(t *testing.T) { dir := testutil.NewTemporaryDirectory("test_flock", t) defer dir.Close() fileName := filepath.Join(dir.Path(), "LOCK") if _, err := os.Stat(fileName); err == nil { t.Fatalf("File %q unexpectedly exists.", fileName) } lock, existed, err := Flock(fileName) if err != nil { t.Fatalf("Error locking file %q: %s", fileName, err) } if existed { t.Errorf("File %q reported as existing during locking.", fileName) } // File must now exist. if _, err = os.Stat(fileName); err != nil { t.Errorf("Could not stat file %q expected to exist: %s", fileName, err) } // Try to lock again. lockedAgain, existed, err := Flock(fileName) if err == nil { t.Fatalf("File %q locked twice.", fileName) } if lockedAgain != nil { t.Error("Unsuccessful locking did not return nil.") } if !existed { t.Errorf("Existing file %q not recognized.", fileName) } if err := lock.Release(); err != nil { t.Errorf("Error releasing lock for file %q: %s", fileName, err) } // File must still exist. if _, err = os.Stat(fileName); err != nil { t.Errorf("Could not stat file %q expected to exist: %s", fileName, err) } // Lock existing file. lock, existed, err = Flock(fileName) if err != nil { t.Fatalf("Error locking file %q: %s", fileName, err) } if !existed { t.Errorf("Existing file %q not recognized.", fileName) } if err := lock.Release(); err != nil { t.Errorf("Error releasing lock for file %q: %s", fileName, err) } }