nuwsgi 2.0.19.1

Fork of the official uWSGI server

nuwsgi

This project is a fork of uwsgi.

nuwsgi is mostly a re-packaging of mainstream uwsgi with added functionality from this Pull Request

Background

uwsgi has a feature called harakiri which is often used as a last resort option to prevent slow endpoints and/or bugs from taking too much production resources by killing the worker after a specific timeout.

The downside is that it uses SIGKILL (ie kill -9) which terminates the process abruptly. This creates a number of problems, especially with observability tools: request metadata like traces and errors won't be flushed, which makes harder to find the underlying issue that is causing the timeout.

Solution

nuwsgi adds 3 extra flags to control harakiri's behavior:

• harakiri-graceful-timeout additional timeout for the worker to attempt a graceful shutdown. The application can catch the termination signal and perform an "emergency shutdown"
• harakiri-graceful-signal determines which signal should be used for graceful harakiri (default SIGTERM)
• harakiri-graceful-queue-threshold only triggers a harakiri if/when the listen queue crosses a threshold. Harakiri continues to be checked until the conditions are met

The combination of those 3 features allow the operator to:

• gracefully shutdown your application by catching a signal
• add some extra time for the graceful shutdown to happen
• allow requests to continue running past harakiri timeout if the listen queue (backlog) is under a threshold
• do a hardkill if the graceful shutdown takes too long

Examples:

$ uwsgi --master --http :8080 --harakiri 1 \
        --wsgi-file tests/harakiri.py \
	--py-call-osafterfork \
	--lazy-apps \
	--enable-threads \
	--threads 2 \
	--harakiri-graceful-timeout 1 \
	--harakiri-graceful-signal 31

Installation:

pip install nuwsgi=2.0.19.1

Despite the different package name, the binary name is the same so you can use uwsgi as usual.

Why fork?

I created the fork so I could deploy the changes before they get merged to the mainstream project:

The binary, code, build process, and version numbers are exactly the same as mainstream uwsgi. This is the Pull Request

The fork is (hopefully) temporary and will be discontinued(but not deleted) after the PR is merged

Mainstream uwsgi:

Official docs: https://uwsgi-docs.readthedocs.org/en/latest/