Nginx Configuration

Dokku uses nginx as its server for routing requests to specific applications. By default, access and error logs are written for each app to /var/log/nginx/${APP}-access.log and /var/log/nginx/${APP}-error.log respectively

nginx:access-logs <app> [-t]             # Show the nginx access logs for an application (-t follows)
nginx:build-config <app>                 # (Re)builds nginx config for given app
nginx:error-logs <app> [-t]              # Show the nginx error logs for an application (-t follows)

Customizing the nginx configuration

New

Introduced in 0.5.0

Dokku uses a templating library by the name of sigil to generate nginx configuration for each app. If you'd like to provide a custom template for your application, there are a couple options:

Copy the following example template to a file named nginx.conf.sigil and either:
check it into the root of your app repo
ADD it to your dockerfile WORKDIR
if your dockerfile has no WORKDIR, ADD it to the /app folder

Info

When using a custom nginx.conf.sigil file, depending upon your application configuration, you may be exposing the file externally. As this file is extracted before the container is run, you can, safely delete it in a custom entrypoint.sh configured in a Dockerfile ENTRYPOINT.

Example Custom Template

Use case: add an X-Served-By header to requests

server {
  listen      [::]:{{ .NGINX_PORT }};
  listen      {{ .NGINX_PORT }};
  server_name {{ .NOSSL_SERVER_NAME }};
  access_log  /var/log/nginx/{{ .APP }}-access.log;
  error_log   /var/log/nginx/{{ .APP }}-error.log;

  # set a custom header for requests
  add_header X-Served-By www-ec2-01;

  gzip on;
  gzip_min_length  1100;
  gzip_buffers  4 32k;
  gzip_types    text/css text/javascript text/xml text/plain text/x-component application/javascript application/x-javascript application/json application/xml  application/rss+xml font/truetype application/x-font-ttf font/opentype application/vnd.ms-fontobject image/svg+xml;
  gzip_vary on;
  gzip_comp_level  6;

  location    / {
    proxy_pass  http://{{ .APP }};
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $http_host;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header X-Forwarded-Port $server_port;
    proxy_set_header X-Request-Start $msec;
  }
  include {{ .DOKKU_ROOT }}/{{ .APP }}/nginx.conf.d/*.conf;
}

upstream {{ .APP }} {
{{ range .DOKKU_APP_LISTENERS | split " " }}
  server {{ . }};
{{ end }}
}

Available template variables

{{ .APP }}                          Application name
{{ .APP_SSL_PATH }}                 Path to SSL certificate and key
{{ .DOKKU_ROOT }}                   Global dokku root directory (ex: app dir would be `{{ .DOKKU_ROOT }}/{{ .APP }}`)
{{ .DOKKU_APP_LISTENERS }}          List of IP:PORT pairs of app containers
{{ .NGINX_PORT }}                   Non-SSL nginx listener port (same as `DOKKU_NGINX_PORT` config var)
{{ .NGINX_SSL_PORT }}               SSL nginx listener port (same as `DOKKU_NGINX_SSL_PORT` config var)
{{ .NOSSL_SERVER_NAME }}            List of non-SSL VHOSTS
{{ .PROXY_PORT_MAP }}               List of port mappings (same as `DOKKU_PROXY_PORT_MAP` config var)
{{ .PROXY_UPSTREAM_PORTS }}         List of configured upstream ports (derived from `DOKKU_PROXY_PORT_MAP` config var)
{{ .RAW_TCP_PORTS }}                List of exposed tcp ports as defined by Dockerfile `EXPOSE` directive (**Dockerfile apps only**)
{{ .SSL_INUSE }}                    Boolean set when an app is SSL-enabled
{{ .SSL_SERVER_NAME }}              List of SSL VHOSTS

Info

NOTE: Application config variables are available for use in custom templates. To do so, use the form of {{ var "FOO" }} to access a variable named FOO.

Example HTTP to HTTPS Custom Template

Use case: a simple dockerfile app that includes EXPOSE 80

server {
  listen      [::]:80;
  listen      80;
  server_name {{ .NOSSL_SERVER_NAME }};

  access_log  /var/log/nginx/{{ .APP }}-access.log;
  error_log   /var/log/nginx/{{ .APP }}-error.log;

  return 301 https://$host:443$request_uri;
}
server {
  listen      [::]:443 ssl spdy;
  listen      443 ssl spdy;
  {{ if .SSL_SERVER_NAME }}server_name {{ .SSL_SERVER_NAME }}; {{ end }}

  access_log  /var/log/nginx/{{ .APP }}-access.log;
  error_log   /var/log/nginx/{{ .APP }}-error.log;

  ssl_certificate     {{ .APP_SSL_PATH }}/server.crt;
  ssl_certificate_key {{ .APP_SSL_PATH }}/server.key;

  keepalive_timeout   70;
  add_header          Alternate-Protocol  443:npn-spdy/2;
  location    / {
    proxy_pass  http://{{ .APP }};
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $http_host;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header X-Forwarded-Port $server_port;
    proxy_set_header X-Request-Start $msec;
  }
  include {{ .DOKKU_ROOT }}/{{ .APP }}/nginx.conf.d/*.conf;
}

upstream {{ .APP }} {
{{ range .DOKKU_APP_LISTENERS | split " " }}
  server {{ . }};
{{ end }}
}

Example using new proxy port mapping

{{ range $port_map := .PROXY_PORT_MAP | split " " }}
{{ $port_map_list := $port_map | split ":" }}
{{ $scheme := index $port_map_list 0 }}
{{ $listen_port := index $port_map_list 1 }}
{{ $upstream_port := index $port_map_list 2 }}

server {
  listen      [::]:{{ $listen_port }};
  listen      {{ $listen_port }};
  server_name {{ $.NOSSL_SERVER_NAME }};
  access_log  /var/log/nginx/{{ $.APP }}-access.log;
  error_log   /var/log/nginx/{{ $.APP }}-error.log;

  location    / {

    gzip on;
    gzip_min_length  1100;
    gzip_buffers  4 32k;
    gzip_types    text/css text/javascript text/xml text/plain text/x-component application/javascript application/x-javascript application/json application/xml  application/rss+xml font/truetype application/x-font-ttf font/opentype application/vnd.ms-fontobject image/svg+xml;
    gzip_vary on;
    gzip_comp_level  6;

    proxy_pass  http://{{ $.APP }}-{{ $upstream_port }};
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $http_host;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header X-Forwarded-Port $server_port;
    proxy_set_header X-Request-Start $msec;
  }
  include {{ $.DOKKU_ROOT }}/{{ $.APP }}/nginx.conf.d/*.conf;
}

{{ range $upstream_port := $.PROXY_UPSTREAM_PORTS | split " " }}
upstream {{ $.APP }}-{{ $upstream_port }} {
{{ range $listeners := $.DOKKU_APP_LISTENERS | split " " }}
{{ $listener_list := $listeners | split ":" }}
{{ $listener_ip := index $listener_list 0 }}
{{ $listener_port := index $listener_list 1 }}
  server {{ $listener_ip }}:{{ $upstream_port }};{{ end }}
}
{{ end }}

Customizing via configuration files included by the default templates

The default nginx.conf template will include everything from your apps nginx.conf.d/ subdirectory in the main server {} block (see above):

include {{ .DOKKU_ROOT }}/{{ .APP }}/nginx.conf.d/*.conf;

That means you can put additional configuration in separate files, for example to limit the uploaded body size to 50 megabytes, do

mkdir /home/dokku/myapp/nginx.conf.d/
echo 'client_max_body_size 50M;' > /home/dokku/myapp/nginx.conf.d/upload.conf
chown dokku:dokku /home/dokku/myapp/nginx.conf.d/upload.conf
service nginx reload

The example above uses additional configuration files directly on the dokku host. Unlike the nginx.conf.sigil file, these additional files will not be copied over from your application repo, and thus need to be placed in the /home/dokku/myapp/nginx.conf.d/ directory manually.