WSGIImportScript

Description:

Specify a script file to be loaded on process start.

Syntax:

WSGIImportScript path [ options ]

Context:

server config

The WSGIImportScript directive can be used to specify a script file to be loaded when a process starts. Options must be provided to indicate the name of the process group and the application group into which the script will be loaded.

For example, to preload a script into a daemon process group called mygroup, using the main Python interpreter:

WSGIDaemonProcess mygroup processes=2 threads=15
WSGIImportScript /web/wsgi-scripts/myapp.wsgi \
    process-group=mygroup application-group=%{GLOBAL}

The options which must supplied to the WSGIImportScript directive are:

process-group=name

Specifies the name of the process group for which the script file will be loaded.

The name of the process group can be set to the special value ‘%{GLOBAL}’ which denotes that the script file be loaded for the Apache child processes. Any other value names a daemon mode process group set up using the WSGIDaemonProcess directive.

application-group=name

Specifies the name of the application group within the specified process for which the script file will be loaded.

The name of the application group can be set to the special value ‘%{GLOBAL}’ which denotes that the script file be loaded within the context of the main Python interpreter. Otherwise, will be loaded into the sub interpreter for the specified application group.

Because the script files are loaded prior to beginning to accept any requests, any delay in loading the script will not cause actual requests to be blocked. As such, the WSGIImportScript can be used to preload a WSGI application script file on process start so that it is ready when actual user requests arrive. For where there are multiple processes handling requests, this can reduce or eliminate the apparent stalling of an application when performing a restart of Apache or a daemon mode process group.

For most setups the same effect can be obtained more concisely by supplying both process-group and application-group options to the WSGIScriptAlias directive, which auto-preloads the script. WSGIImportScript is the appropriate choice when the WSGI application isn’t being mounted via WSGIScriptAlias (for example, configurations that use SetHandler wsgi-script directly), or when additional script files need to be preloaded into the same process group alongside the main one.