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82 lines
1.9 KiB
82 lines
1.9 KiB
13 years ago
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# lockfile
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A very polite lock file utility, which endeavors to not litter, and to
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wait patiently for others.
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## Usage
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```javascript
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var lockFile = require('lockfile')
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// opts is optional, and defaults to {}
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lockFile.lock('some-file.lock', opts, function (er, fd) {
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// if the er happens, then it failed to acquire a lock.
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// if there was not an error, then the fd is opened in
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// wx mode. If you want to write something to it, go ahead.
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// do my stuff, free of interruptions
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// then, some time later, do:
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lockFile.unlock('some-file.lock', function (er) {
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// er means that an error happened, and is probably bad.
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})
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})
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```
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## Methods
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Sync methods return the value/throw the error, others don't. Standard
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node fs stuff.
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All known locks are removed when the process exits. Of course, it's
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possible for certain types of failures to cause this to fail, but a best
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effort is made to not be a litterbug.
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### lockFile.lock(path, [opts], cb)
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Acquire a file lock on the specified path. Returns the FD.
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### lockFile.lockSync(path, [opts])
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Acquire a file lock on the specified path
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### lockFile.unlock(path, cb)
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Close and unlink the lockfile.
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### lockFile.unlockSync(path)
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Close and unlink the lockfile.
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### lockFile.check(path, [opts], cb)
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Check if the lockfile is locked and not stale.
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Returns boolean.
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### lockFile.checkSync(path, [opts], cb)
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Check if the lockfile is locked and not stale.
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Callback is called with `cb(error, isLocked)`.
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## Options
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### opts.wait
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A number of milliseconds to wait for locks to expire before giving up.
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Only used by lockFile.lock. Relies on fs.watch. If the lock is not
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cleared by the time the wait expires, then it returns with the original
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error.
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### opts.stale
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A number of milliseconds before locks are considered to have expired.
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### opts.retries
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Used by lock and lockSync. Retry `n` number of times before giving up.
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### opts.retryWait
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Used by lock. Wait `n` milliseconds before retrying.
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