Add WithSyncDirectory to optionally fsync the directory after the rename #42
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Greetings from quis@ :) |
| @@ -167,6 +168,16 @@ func (t *PendingFile) CloseAtomicallyReplace() error { | |||
| return err | |||
| } | |||
| t.done = true | |||
| if t.syncDirectory { | |||
| dh, err := os.OpenFile(filepath.Dir(t.path), os.O_WRONLY, 0) | |||
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On Linux this doesn't work. (Error: open <file>: is a directory)
Simply os.Open(filepath.Dir(t.path)) does work instead.
See also:
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https://linux.die.net/man/2/fsync
On some UNIX systems (but not Linux), fd must be a writable file descriptor.
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https://austin-group-l.opengroup.narkive.com/vC4Fjvsn/fsync-ing-a-directory-file-descriptor
On Linux, you would
typically open in read-only (O_RDONLY) the directory (O_WRONLY would
fail otherwise), and call fsync() on the returned file descriptor.
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This is a good point — could you add a test so that the feature is exercised in the CI pipeline?
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Sorry for letting this PR linger for so long. It’s been a busy time recently.
The reason why the renameio package currently doesn’t provide this feature is so that the user has more control over when a sync happens (as applications often write many files), but I don’t mind adding this for use-cases where only a single file needs to be written reliably.
| @@ -167,6 +168,16 @@ func (t *PendingFile) CloseAtomicallyReplace() error { | |||
| return err | |||
| } | |||
| t.done = true | |||
| if t.syncDirectory { | |||
| dh, err := os.OpenFile(filepath.Dir(t.path), os.O_WRONLY, 0) | |||
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This is a good point — could you add a test so that the feature is exercised in the CI pipeline?
WithSyncDirectory configures renameio to fsync the directory after renaming
the file. If that succeeds it's guaranteed the file will be in the new state
even after a crash.