dogslow-sentry 2.0.0b1

Overview

Dogslow is a Django watchdog middleware that logs tracebacks of slow requests. Dogslow-sentry requires Python 3.7+, Django 2.2+.

It started as an internal project inside Bitbucket to help trace operational problems.

In 2021, the dogslow-sentry fork was created to add Sentry-specific information to reports, like full stack trace, request information, fingerprint for issue grouping, breadcrumbs, etc.

Installation

Install dogslow-sentry:

$ pip install dogslow-sentry

Then add dogslow_sentry.WatchdogMiddleware to your Django settings file:

MIDDLEWARE = [
    'dogslow_sentry.WatchdogMiddleware',
    ...
]

For best results, make it one of the first middlewares that is run.

Configuration

Naturally, dogslow-sentry expects a working Sentry configuration for Django.

You can use the following configuration in your settings.py file to tune the watchdog:

# Watchdog is enabled by default, to temporarily disable, set to False:
DOGSLOW = True

# Log requests taking longer than 25 seconds:
DOGSLOW_TIMER = 25

# Enable logging to Sentry
DOGSLOW_SENTRY = True

# Also log slow request tracebacks to Python logger
DOGSLOW_LOGGER = 'dogslow_sentry'
DOGSLOW_LOG_LEVEL = 'WARNING'

# Tuple of url pattern names that should not be monitored:
# (defaults to none -- everything monitored)
DOGSLOW_IGNORE_URLS = ('some_view', 'other_view')

Usage

Every incoming HTTP request gets a 25 second timeout in the watchdog. If a request does not return within that time, the watchdog activates and takes a peek at the request thread’s stack and writes the backtrace (including all local stack variables – Django style) to a log file.

Note that dogslow only takes a peek at the thread’s stack. It does not interrupt the request, or influence it in any other way. Using dogslow is therefore safe to use in production.

Caveats

Dogslow uses multithreading. It has a single background thread that handles the watchdog timeouts and takes the tracebacks, so that the original request threads are not interrupted. This has some consequences.