zuul/zuul
Code Issues Proposed changes

Web: don't update the status cache more than once

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Once the cache expires, if multiple requestors are requesting
the status info, they all might submit gearman jobs to request
an updated status.  Instead, surround the cache check/update
with a lock so that once it expires, the first request submits
the job, all subsequent requests wait for the response and then
return the newly cached data.

Change-Id: Ifb3bfe2fe2fe5e179e53d05409897e2955a2797e
This commit is contained in:
James E. Blair
2018-09-25 14:55:47 -07:00
parent 507be8c5bf
commit 824ca389b8
1 changed files with 8 additions and 6 deletions
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14
zuul/web/__init__.py
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@@ -200,6 +200,7 @@ class ZuulWebAPI(object):
self.cache_time = {}
self.cache_expiry = 1
self.static_cache_expiry = zuulweb.static_cache_expiry
self.status_lock = threading.Lock()
@cherrypy.expose
@cherrypy.tools.json_out(content_type='application/json; charset=utf-8')
@@ -234,12 +235,13 @@ class ZuulWebAPI(object):
return ret
def _getStatus(self, tenant):
if tenant not in self.cache or \
(time.time() - self.cache_time[tenant]) > self.cache_expiry:
job = self.rpc.submitJob('zuul:status_get',
{'tenant': tenant})
self.cache[tenant] = json.loads(job.data[0])
self.cache_time[tenant] = time.time()
with self.status_lock:
if tenant not in self.cache or \
(time.time() - self.cache_time[tenant]) > self.cache_expiry:
job = self.rpc.submitJob('zuul:status_get',
{'tenant': tenant})
self.cache[tenant] = json.loads(job.data[0])
self.cache_time[tenant] = time.time()
payload = self.cache[tenant]
if payload.get('code') == 404:
raise cherrypy.HTTPError(404, payload['message'])