uWSGI 1.9.15

Changelog [20130829]


  • fixed jvm options hashmap (#364)
  • fixed python3 wsgi.file_wrapper
  • fixed python3 –catch-exceptions
  • fixed type in pypy wsgi.input.read
  • better symbol detection for pypy
  • improved ruby libraries management on heroku
  • fixed http-keepalive memleak
  • fixed spooler body management under CPython
  • fixed unshare() usage of ‘fs’
  • fixed UWSGI_PROFILE usage when building plugins with –plugin
  • improved SmartOS support and added OmniOS support

New features

The PTY plugin

This new plugin allows you to generate pseudoterminals and attach them to your workers.

Pseudoterminals are then reachable via network (UNIX or TCP sockets).

You can use them for shared debugging or to have input channels on your webapps.

The plugin is in early stage of development (very few features) and it is not built in by default, but you can already make funny things like:

plugin = pty,rack
; generate a new pseudoterminal on port 5000 and map it to the first worker
pty-socket =

; classic options
master = true
processes = 2
rack = myapp.ru
socket = /tmp/uwsgi.socket

; run a ruby interactive console (will use the pseudoterminal)
; we use pry as it kick asses
rbshell = require 'pry';binding.pry

now you can access the pseudoterminal with

uwsgi --plugin pty --pty-connect

you can run the client in various windows, it will be shared by all of the peers (all will access the same pseudoterminal).

We are sure new funny uses for it will popup pretty soon

preliminary documentation is available at The Pty plugin

strict mode

One of the most common error when writing uWSGI config files, are typos in option names.

As you can add any option in uWSGI config files, the system will accept anythyng you will write even if it is not a real uWSGI option.

While this approach is very powerful and allow lot of funny hacks, it can causes lot of headaches too.

If you want to check all of your options in one step, you can now add the –strict option. Unknown options will trigger a fatal error.

fallback configs

Being very cheap (in term of resources) and supporting lot of operating systems and architectures, uWSGI is heavily used in embedded systems.

One of the common feature in such devices is the “reset to factory defaults”.

uWSGI now natively support this kind of operation, thanks to the –fallback-config option.

If a uWSGI instance dies with exit(1) and a fallback-config is specified, the binary will be re-exec()’d with the new config as the only argument.

Let’s see an example of a configuration with unbindable address (unprivileged user trying to bind to privileged port)

uid = 1000
gid = 1000
socket = :80

and a fallback one (bind to unprivileged port 8080)

uid = 1000
gid = 1000
socket = :8080

run it (as root, as we want to drop privileges):

sudo uwsgi --ini wrong.ini --fallback-config right.ini

you will get in your logs:

bind(): Permission denied [core/socket.c line 755]
Thu Aug 29 07:26:26 2013 - !!! /Users/roberta/uwsgi/uwsgi (pid: 12833) exited with status 1 !!!
Thu Aug 29 07:26:26 2013 - !!! Fallback config to right.ini !!!
[uWSGI] getting INI configuration from right.ini
*** Starting uWSGI 1.9.15-dev-4046f76 (64bit) on [Thu Aug 29 07:26:26 2013] ***

–perl-exec and –perl-exec-post-fork

You can now run custom perl code before and after the fork() calls.

Both options simply take the perl script as the argument


This api function has been added to the python and pypy plugins. It allows you to iterate the keys of a local uWSGI cache.

It returns a list.

added %(ftime) to logformat

this is like ‘ltime’ but honouring the –log-date format

protect destruction of UNIX sockets when another instance binds them

on startup uWSGI now get the inode of the just created unix socket.

On vacuum if the inode is changed the unlink of the socket is skipped.

This should help avoiding sysadmin destructive race conditions or misconfigurations


this is like –worker-exec but happens after post_fork hooks

allow post_fork hook on general plugins

general plugins (the ones without the .request hook) can now expose the .post_fork hook

–call hooks

In the same spirit of exec-* hooks, call hooks works in the same way but directly calling functions in the current process address space (they have to be exposed as valid symbols)

take this c source (call it hello.c):

#include <stdio.h>

void i_am_hello_world_for_uwsgi() {
    printf("Hello World!!!\n");

and compile it as a shared library:

gcc -o libhello.so -shared -fPIC hello.c

now choose when (and where) to call it in uWSGI:

./uwsgi --help | grep -- --call-
 --call-pre-jail                        call the specified function before jailing
 --call-post-jail                       call the specified function after jailing
 --call-in-jail                         call the specified function in jail after initialization
 --call-as-root                         call the specified function before privileges drop
 --call-as-user                         call the specified function after privileges drop
 --call-as-user-atexit                  call the specified function before app exit and reload
 --call-pre-app                         call the specified function before app loading
 --call-post-app                        call the specified function after app loading
 --call-as-vassal                       call the specified function() before exec()ing the vassal
 --call-as-vassal1                      call the specified function(char *) before exec()ing the vassal
 --call-as-vassal3                      call the specified function(char *, uid_t, gid_t) before exec()ing the vassal
 --call-as-emperor                      call the specified function() in the emperor after the vassal has been started
 --call-as-emperor1                     call the specified function(char *) in the emperor after the vassal has been started
 --call-as-emperor2                     call the specified function(char *, pid_t) in the emperor after the vassal has been started
 --call-as-emperor4                     call the specified function(char *, pid_t, uid_t, gid_t) in the emperor after the vassal has been started

options ending with a number are variants expecting arguments (the suffix is the number of arguments they take)

we want to call our function just before our application is loaded:

; load the shared library
dlopen = ./libhello.so
; set the hook
call-pre-app = i_am_hello_world_for_uwsgi

your custom function will be called just before app loading.

Take in account those functions are called in the process address space, so you can make all sort of (black) magic with them.

Note: dlopen is a wrapper for the dlopen() function, so all the same rules apply (read: USE ABSOLUTE PATHS !!!)

init_func support for plugins, and –need-plugin variant

when loading a plugin you can call a symbol defined in it soon after dlopen():

uwsgi --plugin "foobar|myfunc" ...

uWSGI will call the ‘myfunc’ symbol exposed by the ‘foobar’ plugin

–need-plugin is like –plugin but will exit(1) the process if plugin loading fails

added commodity loader for the pecan framework

Author: Ryan Petrello

A new python loader (–pecan) has been added for the pecan WSGI framework




during the build phase you can remove include headers with the UWSGI_REMOVE_INCLUDES environment variable.

This is useful for cross-compilation where some automatically detected includes could be wrong


We already have various options in the uWSGI core to set Expires header.

This router has been added to allow customizing them:

route = /^foobar1(.*)/ expires:filename=foo$1poo,value=30
route = /^foobar2(.*)/ expires:unix=${time[unix]},value=30

the router takes a filename mtime or a unix time, adds ‘value’ to it, and return it as an http date.

announce Legion’s death on reload/shutdown

Every legion member will now announce its death as soon as a reload (or a shutdown) of the instance is triggered

The GlusterFS plugin (beta)

This new plugin make use ot the new glusterfs c api, avoiding the overhead of fuse when serving files stored on glusterfs servers.

The plugin supports the multiprocess and multithreads modes, while async modes are currently in beta.

Documentation is available: The GlusterFS plugin


all of the gateways (fastrouter, httprouter, rawrouter, sslrouter ...) has to be run under the master process.

By specifying –force-gateway, you will bypass this limit

preliminary python3 profiler (beta)

The –profiler pycall/pyline profilers have been added to python3. They are beta quality (they leaks memory), but should be usable.

file monitor support for OpenBSD,NetBSD,DragonFlyBSD

Both –fs-reload and the @fmon decorator now work on this operating systems.


you can force the startup “current working directory” (used by –vacuum and the reloading subsystem) with this option.

It is useful in chroot setups where the binary executable change its place.


This options allows you to add additional group ids to the current process. You can specify it multiple times.

Emperor and Linux namespaces improvements

Thanks to the cooperation with the pythonanywhere.com guys the Emperor has been improved for better Linux namespaces integration.

The –emperor-use-clone option allows you to use clone() instead of fork() for your vassal’s spawn. In this way you can create the vassals directly in a new namespace. The function takes the same parameters of the –unshare one

uwsgi --emperor /etc/vassals --emperor-use-clone pid,uts

will create each vassal in a new pid and uts namespace


uwsgi --emperor /etc/vassals --emperor-use-clone pid,uts,net,ipc,fs

will basically use all of the currently available namespaces.

Two new exec (and call) hooks are available:

–exec-as-emperor will run commands in the emperor soon after a vassal has been spawn (setting 4 env vars, UWSGI_VASSAL_CONFIG, UWSGI_VASSAL_PID, UWSGI_VASSAL_UID and UWSGI_VASSAL_GID)

–exec-as-vassal will run commands in the vassal just before calling exec() (so directly in the new namespaces)


As dealing with the Linux network namespace introduces lot of race conditions (especially when working with virtual ethernets), this new option allows you to pause an instance until a network interface is available.

This is useful when waiting for the emperor to move a veth to the vassal namespace, avoiding the vassal to run commands on the interface before is available

emperor = /etc/uwsgi/vassals
emperor-use-clone = pid,net,fs,ipc,uts
; each vassal should have its veth pair, so the following commands should be improved
exec-as-emperor = ip link del veth0
exec-as-emperor = ip link add veth0 type veth peer name veth1
; do not use the $(UWSGI_VASSAL_PID) form, otherwise the config parser will expand it on startup !!!
exec-as-emperor = ip link set veth1 netns $UWSGI_VASSAL_PID
; suspend until the emperor attach veth1
wait-for-interface = veth1
; the following hook will be run only after veth1 is available
exec-as-root = hostname vassal001
exec-as-root = ifconfig lo up
exec-as-root = ifconfig veth1
uid = vassal001
gid = vassal001
socket = :3031


uWSGI 1.9.15 has been released on August 29th 2013. You can download it from: