add a log rotation worker

Fixes #609.

workers/logrotateworker.py

@@ -0,0 +1,95 @@
+import logging
+import json
+import time
+
+from datetime import timedelta, datetime
+from itertools import chain
+
+import features
+from app import app, storage
+from data.database import UseThenDisconnect
+from data.model import db_transaction
+from data.model.log import (get_stale_logs, get_stale_logs_start_id,
+                            get_stale_logs_end_id, delete_stale_logs)
+from util.registry.gzipwrap import GzipWrap
+from workers.globalworkerbase import GlobalWorker
+
+logger = logging.getLogger(__name__)
+
+WORKER_FREQUENCY = 3600
+STALE_AFTER = timedelta(days=30)
+MIN_LOGS_PER_ROTATION = 10000
+BATCH_SIZE = 500
+SAVE_PATH = app.config.get('ACTION_LOG_ARCHIVE_PATH')
+SAVE_LOCATION = app.config.get('ACTION_LOG_ARCHIVE_LOCATION')
+
+class LogRotateWorker(GlobalWorker):
+  """ Worker used to rotate old logs out the database and into storage. """
+  def __init__(self):
+    super(LogRotateWorker, self).__init__(app, sleep_period_seconds=WORKER_FREQUENCY)
+
+  def perform_global_work(self):
+    logger.debug('Attempting to rotate log entries')
+    with UseThenDisconnect(app.config):
+      with db_transaction():
+        cutoff = datetime.now() - STALE_AFTER
+        start_id = get_stale_logs_start_id()
+        end_id = get_stale_logs_end_id(cutoff)
+
+        if start_id is None or end_id is None:
+          logger.warning('No logs to be archived.')
+          return
+
+        logger.debug('Found starting ID %s and ending ID %s', start_id, end_id)
+
+        approx_count = end_id - start_id
+        if approx_count < MIN_LOGS_PER_ROTATION:
+          logger.debug('Not enough stale logs to warrant rotation (approx %d)', approx_count)
+          return
+
+        # Build a generator of all the logs we want to archive in batches of 500.
+        log_generator = (_ for _ in ())
+        logs_to_fetch = range(start_id, end_id+1)
+        while len(logs_to_fetch) != 0:
+          (batch, logs_to_fetch) = _take(BATCH_SIZE, logs_to_fetch)
+          logger.debug('Reading archived logs from IDs %s to %s', batch[0], batch[-1])
+          batch_generator = (pretty_print_in_json(log) + '\n'
+                             for log in get_stale_logs(batch[0], batch[-1]))
+          log_generator = chain(log_generator, batch_generator)
+
+        logger.debug('Archiving logs from IDs %s to %s', start_id, end_id)
+        filename = '%s%d-%d.txt.gz' % (SAVE_PATH, start_id, end_id)
+        storage.stream_write(SAVE_LOCATION, filename, GzipWrap(log_generator))
+
+        logs_to_delete = range(start_id, end_id+1)
+        while len(logs_to_delete) != 0:
+          (batch, logs_to_delete) = _take(BATCH_SIZE, logs_to_delete)
+          logger.debug('Deleting archived logs from IDs %s to %s', batch[0], batch[-1])
+          delete_stale_logs(batch[0], batch[-1])
+
+
+def _take(count, lst):
+  return lst[:count], lst[count:]
+
+def pretty_print_in_json(log):
+  """ Pretty prints a LogEntry in JSON. """
+  return json.dumps({'kind_id': log.kind_id,
+                     'account_id': log.account_id,
+                     'performer_id': log.performer_id,
+                     'repository_id': log.repository_id,
+                     'datetime': str(log.datetime),
+                     'ip': str(log.ip),
+                     'metadata_json': json.loads(str(log.metadata_json))})
+
+
+def main():
+  if not features.ACTION_LOG_ROTATION or None in [SAVE_PATH, SAVE_LOCATION]:
+    while True:
+      time.sleep(100000)
+
+  worker = LogRotateWorker()
+  worker.start()
+
+
+if __name__ == "__main__":
+  main()