Configuration logic

Configuration logic

Starting from 1.1 certain logic constructs are available.

The following statements are currently supported:

for .. endfor
if-dir / if-not-dir
if-env / if-not-env
if-exists / if-not-exists
if-file / if-not-file
if-opt / if-not-opt
if-reload / if-not-reload – undocumented

Each of these statements exports a context value you can access with thespecial placeholder %(). For example, the “for” statement sets %() tothe current iterated value.

Warning

Recursive logic is not supported and will cause uWSGI to promptly exit.

for

For iterates over space-separated strings. The following three code blocks are equivalent.

[uwsgi]
master = true
; iterate over a list of ports
for = 3031 3032 3033 3034 3035
socket = 127.0.0.1:%(_)
endfor =
module = helloworld

<uwsgi>
  <master/>
  <for>3031 3032 3033 3034 3035</for>
    <socket>127.0.0.1:%(_)</socket>
  <endfor/>
  <module>helloworld</module>
</uwsgi>

uwsgi --for="3031 3032 3033 3034 3035" --socket="127.0.0.1:%(_)" --endfor --module helloworld

Note that the for-loop is applied to each line inside the blockseparately, not to the block as a whole. For example, this:

[uwsgi]
for = a b c
socket = /var/run/%(_).socket
http-socket = /var/run/%(_)-http.socket
endfor =

is expanded to:

[uwsgi]
socket = /var/run/a.socket
socket = /var/run/b.socket
socket = /var/run/c.socket
http-socket = /var/run/a-http.socket
http-socket = /var/run/b-http.socket
http-socket = /var/run/c-http.socket

if-env

Check if an environment variable is defined, putting its value in the contextplaceholder.

[uwsgi]
if-env = PATH
print = Your path is %(_)
check-static = /var/www
endif =
socket = :3031

if-exists

Check for the existence of a file or directory. The context placeholder is setto the filename found.

[uwsgi]
http = :9090
; redirect all requests if a file exists
if-exists = /tmp/maintenance.txt
route = .* redirect:/offline
endif =

Note

The above example uses uWSGI internal routing.

if-file

Check if the given path exists and is a regular file. The context placeholderis set to the filename found.

<uwsgi>
  <plugins>python</plugins>
  <http-socket>:8080</http-socket>
  <if-file>settings.py</if-file>
    <module>django.core.handlers.wsgi:WSGIHandler()</module>
  <endif/>
</uwsgi>

if-dir

Check if the given path exists and is a directory. The context placeholder isset to the filename found.

uwsgi:
  socket: 4040
  processes: 2
  if-dir: config.ru
  rack: %(_)
  endif:

if-opt

Check if the given option is set, or has a given value. The contextplaceholder is set to the value of the option reference.

To check if an option was set, pass just the option name to if-opt.

uwsgi:
  cheaper: 3
  if-opt: cheaper
  print: Running in cheaper mode, with initially %(_) processes
  endif:

To check if an option was set to a specific value, passoption-name=value to if-opt.

uwsgi:
  # Set busyness parameters if it was chosen
  if-opt: cheaper-algo=busyness
  cheaper-busyness-max: 25
  cheaper-busyness-min: 10
  endif:

Due to the way uWSGI parses its configs, you can only refer to optionsthat uWSGI has previously seen. In particular, this means:

Only options that are set above the if-opt option are taken intoaccount. This includes any options set by previous include (ortype specific includes like ini) options, but does not includeoptions set by previous inherit options).
if-opt is processed after expanding magic variables, but beforeexpanding placeholders and other variables. So if you use if-optto compare the value of an option, check against the value as statedin the config file, with only the magic variables filled in.

If you use the context placeholder %(_) inside the if-optblock, you should be ok: any placeholders will later be expanded.

If an option is specified multiple times, only the value of the firstone will be seen by if-opt.
Only explicitly set values will be seen, not implicit defaults.