id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
1785	Support access to environment variables in config file	spion-h4@…		"Currently nginx doesn't directly support access to environment variables in the config file. This makes it difficult to use it in a 12-factor-app style setup, where the docker container / VM / machine image use environment variables for configuring things such as static assets.

One way to work around this is to use `envsubst` to generate the config file on the fly. However, that means the target config file needs to be writable.

Another one would be to use something like ngx_http_lua_module. The process is two step: first, prevent the variable from being filtered out:

{{{
env MY_STATIC_ASSETS_PATH;
}}}

Then, set a variable using nginx syntax:

{{{
http {
...
  server {
    location /static {
      # set var using Lua
      set_by_lua $static_assets 'return os.getenv(""MY_STATIC_ASSETS_PATH"")';
      alias ""$static_assets""
      ...
    }
  }
}
}}}

Since using the lua module seems heavy-handed for something like this, I'd like to propose a set_from_env directive that does exactly that. The result would be:

{{{
http {
...
  server {
    location /static {
      # set var using built in directive
      set_from_env $static_assets MY_STATIC_ASSETS_PATH;
      alias ""$static_assets""
      ...
    }
  }
}
}}}"	enhancement	new	minor		other	1.15.x					"nginx version: nginx/1.10.3
built with OpenSSL 1.1.0f  25 May 2017 (running with OpenSSL 1.1.0j  20 Nov 2018)
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fdebug-prefix-map=/build/nginx-0TiIP5/nginx-1.10.3=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-z,relro -Wl,-z,now' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-ipv6 --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_addition_module --with-http_geoip_module=dynamic --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module=dynamic --with-http_sub_module --with-http_xslt_module=dynamic --with-stream=dynamic --with-stream_ssl_module --with-mail=dynamic --with-mail_ssl_module --add-dynamic-module=/build/nginx-0TiIP5/nginx-1.10.3/debian/modules/nginx-auth-pam --add-dynamic-module=/build/nginx-0TiIP5/nginx-1.10.3/debian/modules/nginx-dav-ext-module --add-dynamic-module=/build/nginx-0TiIP5/nginx-1.10.3/debian/modules/nginx-echo --add-dynamic-module=/build/nginx-0TiIP5/nginx-1.10.3/debian/modules/nginx-upstream-fair --add-dynamic-module=/build/nginx-0TiIP5/nginx-1.10.3/debian/modules/ngx_http_substitutions_filter_module"