42 lines
1.1 KiB
JavaScript
42 lines
1.1 KiB
JavaScript
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import semaphore from 'semaphore';
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export const asyncLock = () => {
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let lock = semaphore(1);
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const acquire = (timeout = 15000) => {
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const promise = new Promise(resolve => {
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// this makes sure a caller doesn't gets stuck forever awaiting on the lock
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const timeoutId = setTimeout(() => {
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// we reset the lock in that case to allow future consumers to use it without being blocked
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lock = semaphore(1);
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resolve(false);
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}, timeout);
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lock.take(() => {
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clearTimeout(timeoutId);
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resolve(true);
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});
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});
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return promise;
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};
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const release = () => {
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try {
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// suppress too many calls to leave error
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lock.leave();
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} catch (e) {
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// calling 'leave' too many times might not be good behavior
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// but there is no reason to completely fail on it
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if (e.message !== 'leave called too many times.') {
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throw e;
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} else {
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console.warn('leave called too many times.');
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lock = semaphore(1);
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}
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}
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};
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return { acquire, release };
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};
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