Using variables in Nginx location rules

nginx, variables, webserver

Solution

You can't. Nginx doesn't really support variables in config files, and its developers mock everyone who ask for this feature to be added:

"[Variables] are rather costly compared to plain static configuration. [A] macro expansion and "include" directives should be used [with] e.g. sed + make or any other common template mechanism." http://nginx.org/en/docs/faq/variables_in_config.html

You should either write or download a little tool that will allow you to generate config files from placeholder config files.

Update The code below still works, but I've wrapped it all up into a small PHP program/library called Configurator also on Packagist, which allows easy generation of nginx/php-fpm etc config files, from templates and various forms of config data.

e.g. my nginx source config file looks like this:

location  / {
    try_files $uri /routing.php?$args;
    fastcgi_pass   unix:%phpfpm.socket%/php-fpm-www.sock;
    include       %mysite.root.directory%/conf/fastcgi.conf;
}

And then I have a config file with the variables defined:

phpfpm.socket=/var/run/php-fpm.socket
mysite.root.directory=/home/mysite

And then I generate the actual config file using that. It looks like you're a Python guy, so a PHP based example may not help you, but for anyone else who does use PHP:

<?php

require_once('path.php');

$filesToGenerate = array(
    'conf/nginx.conf' => 'autogen/nginx.conf',
    'conf/mysite.nginx.conf' => 'autogen/mysite.nginx.conf',
    'conf/mysite.php-fpm.conf' => 'autogen/mysite.php-fpm.conf',
    'conf/my.cnf' => 'autogen/my.cnf',
);

$environment = 'amazonec2';

if ($argc >= 2){
    $environmentRequired = $argv[1];

    $allowedVars = array(
        'amazonec2',
        'macports',
    );

    if (in_array($environmentRequired, $allowedVars) == true){
        $environment = $environmentRequired;
    }
}
else{
    echo "Defaulting to [".$environment."] environment";
}

$config = getConfigForEnvironment($environment);

foreach($filesToGenerate as $inputFilename => $outputFilename){
    generateConfigFile(PATH_TO_ROOT.$inputFilename, PATH_TO_ROOT.$outputFilename, $config);
}


function    getConfigForEnvironment($environment){
    $config = parse_ini_file(PATH_TO_ROOT."conf/deployConfig.ini", TRUE);
    $configWithMarkers = array();
    foreach($config[$environment] as $key => $value){
        $configWithMarkers['%'.$key.'%'] = $value;
    }

    return  $configWithMarkers;
}


function    generateConfigFile($inputFilename, $outputFilename, $config){

    $lines = file($inputFilename);

    if($lines === FALSE){
        echo "Failed to read [".$inputFilename."] for reading.";
        exit(-1);
    }

    $fileHandle = fopen($outputFilename, "w");

    if($fileHandle === FALSE){
        echo "Failed to read [".$outputFilename."] for writing.";
        exit(-1);
    }

    $search = array_keys($config);
    $replace = array_values($config);

    foreach($lines as $line){
        $line = str_replace($search, $replace, $line);
        fwrite($fileHandle, $line);
    }

    fclose($fileHandle);
}

?>

And then deployConfig.ini looks something like:

[global]

;global variables go here.

[amazonec2]
nginx.log.directory = /var/log/nginx
nginx.root.directory = /usr/share/nginx
nginx.conf.directory = /etc/nginx
nginx.run.directory  = /var/run
nginx.user           = nginx

[macports]
nginx.log.directory = /opt/local/var/log/nginx
nginx.root.directory = /opt/local/share/nginx
nginx.conf.directory = /opt/local/etc/nginx
nginx.run.directory  = /opt/local/var/run
nginx.user           = _www

Problem

In Nginx, I'm trying to define a variable which allows me to configure a sub-folder for all my location blocks. I did this: ``` set $folder '/test'; location $folder/ { [...] } location $folder/something { [...] } ``` Unfortunately, this doesn't seem to work. While Nginx doesn't complain about the syntax, it returns a 404 when requesting `/test/`. If I write the folder in explicitly, it works. So how can I use variables in location blocks?

Original source