Gunicorn - Pycon FR 2014

Presenation of the new design of gunicorn and changes in the communnity.

Transcript

1. the thundering herd and other concurrency programming challenges Pycon FR 2014 - Lyon By Benoit Chesneau http:/ /goo.gl/QBW0DH
2. GUNICORN DESIGN
3. prefork-worker model share sockets between OS processes (workers) each worker waits (accepts) for a connection an arbiter supervises the workers gunicorn design
4. arbiter worker spawn & share sockets spawn workers, share the socket
5. prefork-worker model share sockets between OS processes (workers) each worker waits (accepts) for a connection an arbiter supervises the workers gunicorn design
6. arbiter worker notify aliveness monitor workers kill
7. the arbiter workflow check the 
 signal queue handle the signal not empty empty murder workers sleep manage workers
8. different concurrency strategy different platforms support not only WSGI embedded: no proxy more… different kind of workers
9. sync worker accept only 1 connection at a time async/non blocking workers accept many connections sync workers, always behind a proxy Does your application have blocking operations? Does your application send/receive messages/ events (HTTP2, Pipelines, Websockets, SSE, PUSH…)? Which one to choose?
10. THE THUNDERING HERD
 PROBLEM
11. All process can be awoken on accept for the same connection can trigger EAGAIN increase the CPU usage for nothing. not true with modern OSes for 1 socket the thundering herd problem
12. ticket Gunicorn#792, Introduce signaling between workers and the arbiter using a Pipe Use our own internal messaging implementation the arbiter checks if the a socket can read Workers asks for more work or notify they are alive fixing thundering herd: how to solve it
13. arbiter worker new signaling send message
14. Messages Arbiter Worker ACCEPT:SOCKET ALIVE:TIMESTAMP ACCEPT
15. the arbiter has a new job All workers need to be updated new signaling API to be handled by the worker: an helper module will be provided introduce complexity
16. with one socket, let all workers accepting if wanted depending on the load, bypass the signaling possible optimisations
17. ONE COMMAND TO RULE THEM ALL
18. no more gunicorn_django, gunicorn_paster fix preloading issue offer the same experience for all WSGI applications new settings: —paste, —pythonpath, —env, 
 —reload Only one command in 20.0 (deprecations are removed) gunicorn - the only command
19. Enhance the user experience
20. ticket Gunicorn#837 plugins everywhere: logging, workers more embeddable: the gunicorn engine A new organization: 
 http:/ /github.com/gunicorn WIP: Deadline 2014/12 Enhance the user experience.
21. ? @benoitc Support me https:/ /gratipay.com/benoitc/