Allow most builds to be archived without writing a file to the disk.

workers/buildlogsarchiver.py

@@ -12,6 +12,7 @@ from app import build_logs, log_archive
 from util.streamingjsonencoder import StreamingJSONEncoder
 
 POLL_PERIOD_SECONDS = 30
+MEMORY_TEMPFILE_SIZE = 64 * 1024  # Large enough to handle approximately 99% of builds in memory
 
 logger = logging.getLogger(__name__)
 sched = BlockingScheduler()
@@ -32,7 +33,7 @@ def archive_redis_buildlogs():
       'logs': entries,
     }
 
-    with SpooledTemporaryFile() as tempfile:
+    with SpooledTemporaryFile(MEMORY_TEMPFILE_SIZE) as tempfile:
       with GzipFile('testarchive', fileobj=tempfile) as zipstream:
         for chunk in StreamingJSONEncoder().iterencode(to_encode):
           zipstream.write(chunk)