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baca6faa1c
This mimics the locking leveldb is performing anyway. Advantages of doing it separately: - Should we ever replace the leveldb implementation by one without double-start protection, we are still good. - In contrast to leveldb, the new code creates a meaningful error message.
68 lines
1.6 KiB
Go
68 lines
1.6 KiB
Go
package flock
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import (
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"os"
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"path/filepath"
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"testing"
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"github.com/prometheus/prometheus/utility/test"
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)
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func TestLocking(t *testing.T) {
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dir := test.NewTemporaryDirectory("test_flock", t)
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defer dir.Close()
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fileName := filepath.Join(dir.Path(), "LOCK")
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if _, err := os.Stat(fileName); err == nil {
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t.Fatalf("File %q unexpectedly exists.", fileName)
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}
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lock, existed, err := New(fileName)
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if err != nil {
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t.Fatalf("Error locking file %q: %s", fileName, err)
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}
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if existed {
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t.Errorf("File %q reported as existing during locking.", fileName)
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}
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// File must now exist.
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if _, err := os.Stat(fileName); err != nil {
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t.Errorf("Could not stat file %q expected to exist: %s", fileName, err)
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}
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// Try to lock again.
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lockedAgain, existed, err := New(fileName)
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if err == nil {
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t.Fatalf("File %q locked twice.", fileName)
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}
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if lockedAgain != nil {
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t.Error("Unsuccessful locking did not return nil.")
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}
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if !existed {
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t.Errorf("Existing file %q not recognized.", fileName)
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}
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if err := lock.Release(); err != nil {
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t.Errorf("Error releasing lock for file %q: %s", fileName, err)
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}
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// File must still exist.
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if _, err := os.Stat(fileName); err != nil {
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t.Errorf("Could not stat file %q expected to exist: %s", fileName, err)
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}
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// Lock existing file.
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lock, existed, err = New(fileName)
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if err != nil {
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t.Fatalf("Error locking file %q: %s", fileName, err)
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}
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if !existed {
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t.Errorf("Existing file %q not recognized.", fileName)
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}
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if err := lock.Release(); err != nil {
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t.Errorf("Error releasing lock for file %q: %s", fileName, err)
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}
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}
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