Zvika Nadav
Jun 20, 2018 · 2 min read

Last week we installed Sentry On-Premise to one of our customers.

One of the developers there complained that he couldn’t capture errors to the new Sentry via Django using Raven.
Checking the configuration, the DSN was set correctly.

When we ran Raven test to check the connection, everything seemed to be OK with output message of:

Sending a test message… Event ID was 'dafe440f48914de098a6f2c5aa6edca6'

Unfortunately, we couldn’t see any proper error registered to Sentry, so we checked again running:

tcpdump port 443

to refute a network issue possibility.

After some research, we imported logging with sentry error levels by adding the following code to the manage.py file:

import logging
logger = logging.getLogger(‘sentry.errors’)
logger.setLevel(logging.INFO)
logger.addHandler(logging.StreamHandler())

Trying to execute the raven test again, we faced the following error:

Sentry responded with an error: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:590)>

SSL was valid using “Let’s Encrypt” service , but we couldn't understand why it fails verifying the SSL certificate.

Well, it seemed like there was a current issue with Raven which didn’t support SNI (Server Name Indication, an extension to TLS protocol).
We resolved this issue by adding the following configuration to raven:

from raven.transport.requests import RequestsHTTPTransport RAVEN_CONFIG = { 
‘dsn’: ‘…’,
‘transport’: RequestsHTTPTransport,
}

Everything is now working and the developers have started using the new Sentry server.

Further information if you are interested:
https://raven.readthedocs.io/en/stable/transports.html
https://support.comodo.com/index.php?/Knowledgebase/Article/View/1120/38/what-is-sni-and-how-it-works
https://github.com/getsentry/raven-python/issues/523

ProdOpsIO

Fusion of Engineering and Operations

Thanks to Orenus and Omer Hamerman

Zvika Nadav

Written by

Dev & Ops @ prodops.io

ProdOpsIO

ProdOpsIO

Fusion of Engineering and Operations

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch
Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore
Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade