| _LOCK_KEY = "network-error-logging:lock" |
| _TIMEOUT = 5 # seconds |
| |
| def wait_for_lock(request): |
| t0 = time.time() |
| while time.time() - t0 < _TIMEOUT: |
| time.sleep(0.5) |
| value = request.server.stash.take(key=_LOCK_KEY) |
| if value is None: |
| return True |
| return False |
| |
| def lock(request, report_id): |
| with request.server.stash.lock: |
| # Loop until the lock is free |
| if not wait_for_lock(request): |
| return (503, [], "Cannot obtain lock") |
| request.server.stash.put(key=_LOCK_KEY, value=report_id) |
| return "Obtained lock for %s" % report_id |
| |
| def unlock(request, report_id): |
| with request.server.stash.lock: |
| lock_holder = request.server.stash.take(key=_LOCK_KEY) |
| if lock_holder != request_id: |
| # Return the lock holder to the stash |
| request.server.stash.put(key=_LOCK_KEY, value=lock_holder) |
| return (503, [], "Cannot release lock held by %s" % lock_holder) |
| return "Released lock for %s" % report_id |
| |
| def main(request, response): |
| op = request.GET.first("op") |
| report_id = request.GET.first("reportID") |
| if op == "lock": |
| return lock(request, report_id) |
| elif op == "unlock": |
| return unlock(request, report_id) |
| else: |
| return (400, [], "Invalid op") |
