.. _container_deployment:

*****************************
`Container Deployment`:index:
*****************************

pgAdmin can be deployed in a container using the image at:

    https://hub.docker.com/r/dpage/pgadmin4/

PostgreSQL Utilities
********************

The PostgreSQL utilities *pg_dump*, *pg_dumpall*, *pg_restore* and *psql* are
included in the container to allow backups to be created and restored and other
maintenance functions to be executed. Multiple versions are included in the
following directories to allow use with different versions of the database
server:

* PostgreSQL 9.5: */usr/local/pgsql-9.5*
* PostgreSQL 9.6: */usr/local/pgsql-9.6*
* PostgreSQL 10: */usr/local/pgsql-10*
* PostgreSQL 11: */usr/local/pgsql-11*
* PostgreSQL 12: */usr/local/pgsql-12*

The most recent version of the utilities is used by default; this may be
changed in the :ref:`preferences`.

Environment Variables
*********************

The container will accept the following variables at startup:

**PGADMIN_DEFAULT_EMAIL**

This is the email address used when setting up the initial administrator account
to login to pgAdmin. This variable is required and must be set at launch time.

**PGADMIN_DEFAULT_PASSWORD**

This is the password used when setting up the initial administrator account to
login to pgAdmin. This variable is required and must be set at launch time.

**PGADMIN_ENABLE_TLS**

*Default: <null>*

If left un-set, the container will listen on port 80 for connections in plain
text. If set to any value, the container will listen on port 443 for TLS
connections.

When TLS is enabled, a certificate and key must be provided. Typically these
should be stored on the host file system and mounted from the container. The
expected paths are /certs/server.cert and /certs/server.key

**PGADMIN_LISTEN_ADDRESS**

*Default: [::]*

Specify the local address that the servers listens on. The default should work
for most users - in IPv4-only environments, this may need to be set to
0.0.0.0.

**PGADMIN_LISTEN_PORT**

*Default: 80 or 443 (if TLS is enabled)*

Allows the port that the server listens on to be set to a specific value rather
than using the default.

**PGADMIN_SERVER_JSON_FILE**

*Default: /pgadmin4/servers.json*

Override the default file path for the server definition list. See the
/pgadmin4/servers.json mapped file below for more information.

**GUNICORN_ACCESS_LOGFILE**

*Default: -* (stdout)

Specify an output file in which to store the Gunicorn access logs, instead of
sending them to stdout.

**GUNICORN_THREADS**

*Default: 25*

Adjust the number of threads the Gunicorn server uses to handle incoming
requests. This should typically be left as-is, except in highly loaded systems
where it may be increased.

**PGADMIN_CONFIG_**

This is a variable prefix that can be used to override any of the configuration
options in pgAdmin's *config.py* file. Add the *PGADMIN_CONFIG_* prefix to any
variable name from *config.py* and give the value in the format 'string value'
for strings, True/False for booleans or 123 for numbers. See below for an
example.

Settings are written to */pgadmin4/config_distro.py* within the container, which
is read after */pgadmin4/config.py* and before */pgadmin4/config_local.py*.
Any settings given will therefore override anything in config.py, but can be
overridden by settings in config_local.py.

See :ref:`config_py` for more information on the available configuration settings.

Mapped Files and Directories
****************************

The following files or directories can be mapped from the container onto the
host machine to allow configuration to be customised and shared between
instances.

.. warning:: Warning: pgAdmin runs as the *pgadmin* user (UID: 5050) in the
    *pgadmin* group (GID: 5050) in the container. You must ensure that all files
    are readable, and where necessary (e.g. the working/session directory)
    writeable for this user on the host machine. For example:

    .. code-block:: bash

        sudo chown -R 5050:5050 <host_directory>

    On some filesystems that do not support extended attributes, it may not be
    possible to run pgAdmin without specifying a value for *PGADMIN_LISTEN_PORT*
    that is greater than 1024. In such cases, specify an alternate port when
    launching the container by adding the environment variable, for example:

    .. code-block:: bash

        -e 'PGADMIN_LISTEN_PORT=5050'

    Don't forget to adjust any host-container port mapping accordingly.

**/var/lib/pgadmin**

This is the working directory in which pgAdmin stores session data, user files,
configuration files, and it's configuration database. Mapping this directory
onto the host machine gives you an easy way to maintain configuration between
invocations of the container.

**/pgadmin4/config_local.py**

This file can be used to override configuration settings in pgAdmin. Settings
found in config.py can be overridden with deployment specific values if
required. Settings in config_local.py will also override anything specified in
the container environment through *PGADMIN_CONFIG_* prefixed variables.

**/pgadmin4/servers.json**

If this file is mapped, server definitions found in it will be loaded at launch
time. This allows connection information to be pre-loaded into the instance of
pgAdmin in the container. Note that server definitions are only loaded on first
launch, i.e. when the configuration database is created, and not on subsequent
launches using the same configuration database.

**/certs/server.cert**

If TLS is enabled, this file will be used as the servers TLS certificate.

**/certs/server.key**

If TLS is enabled, this file will be used as the key file for the servers TLS
certificate.

Examples
********

Run a simple container over port 80:

.. code-block:: bash

    docker pull dpage/pgadmin4
    docker run -p 80:80 \
        -e 'PGADMIN_DEFAULT_EMAIL=user@domain.com' \
        -e 'PGADMIN_DEFAULT_PASSWORD=SuperSecret' \
        -d dpage/pgadmin4

Run a simple container over port 80, setting some configuration options:

.. code-block:: bash

    docker pull dpage/pgadmin4
    docker run -p 80:80 \
        -e 'PGADMIN_DEFAULT_EMAIL=user@domain.com' \
        -e 'PGADMIN_DEFAULT_PASSWORD=SuperSecret' \
        -e 'PGADMIN_CONFIG_ENHANCED_COOKIE_PROTECTION=True' \
        -e 'PGADMIN_CONFIG_LOGIN_BANNER="Authorised users only!"' \
        -e 'PGADMIN_CONFIG_CONSOLE_LOG_LEVEL=10' \
        -d dpage/pgadmin4

Run a TLS secured container using a shared config/storage directory in
/private/var/lib/pgadmin on the host, and servers pre-loaded from
/tmp/servers.json on the host:

.. code-block:: bash

    docker pull dpage/pgadmin4
    docker run -p 443:443 \
        -v /private/var/lib/pgadmin:/var/lib/pgadmin \
        -v /path/to/certificate.cert:/certs/server.cert \
        -v /path/to/certificate.key:/certs/server.key \
        -v /tmp/servers.json:/pgadmin4/servers.json \
        -e 'PGADMIN_DEFAULT_EMAIL=user@domain.com' \
        -e 'PGADMIN_DEFAULT_PASSWORD=SuperSecret' \
        -e 'PGADMIN_ENABLE_TLS=True' \
        -d dpage/pgadmin4

Reverse Proxying
****************

Sometimes it's desirable to have users connect to pgAdmin through a reverse
proxy rather than directly to the container it's running in. The following
examples show how this can be achieved. With traditional reverse proxy servers
such as `Nginx <https://www.nginx.com/>`_, pgAdmin is running in a container on
the same host, with port 5050 on the host mapped to port 80 on the container,
for example:

.. code-block:: bash

    docker pull dpage/pgadmin4
    docker run -p 5050:80 \
        -e "PGADMIN_DEFAULT_EMAIL=user@domain.com" \
        -e "PGADMIN_DEFAULT_PASSWORD=SuperSecret" \
        -d dpage/pgadmin4

pgAdmin X-Forwarded-* Configuration
-----------------------------------

pgAdmin needs to understand how many proxies set each header so it knows what
values to trust. The configuration parameters for the X-Forwarded-* options
which are used for this purpose are shown below, along with their default
values.

pgAdmin is configured by default to be able to run behind a reverse proxy even
on a non-standard port and these config options don't normally need to be
changed. If you're running an unusual configuration (such as multiple reverse
proxies) you can adjust the configuration to suit.

.. code-block:: python

    # Number of values to trust for X-Forwarded-For
    PROXY_X_FOR_COUNT = 1

    # Number of values to trust for X-Forwarded-Proto.
    PROXY_X_PROTO_COUNT = 0

    # Number of values to trust for X-Forwarded-Host.
    PROXY_X_HOST_COUNT = 0

    # Number of values to trust for X-Forwarded-Port.
    PROXY_X_PORT_COUNT = 1

    # Number of values to trust for X-Forwarded-Prefix.
    PROXY_X_PREFIX_COUNT = 0

HTTP via Nginx
--------------

A configuration similar to the following can be used to create a simple HTTP
reverse proxy listening for all hostnames with `Nginx
<https://www.nginx.com/>`_:

.. code-block:: nginx

    server {
        listen 80;
        server_name _;

        location / {
            proxy_set_header Host $host;
            proxy_pass http://localhost:5050/;
            proxy_redirect off;
        }
    }

If you wish to host pgAdmin under a subdirectory rather than on the root of the
server, you must specify the location and set the *X-Script-Name* header which
tells the pgAdmin container how to rewrite paths:

.. code-block:: nginx

    server {
        listen 80;
        server_name _;

        location /pgadmin4/ {
            proxy_set_header X-Script-Name /pgadmin4;
            proxy_set_header Host $host;
            proxy_pass http://localhost:5050/;
            proxy_redirect off;
        }
    }

If Nginx is also running in a container, there is no need to map the pgAdmin
port to the host, provided the two containers are running in the same Docker
network. In such a configuration, the *proxy_pass* option would be changed to
point to the pgAdmin container within the Docker network.

HTTPS via Nginx
---------------

The following configuration can be used to serve pgAdmin over HTTPS to the user
whilst the backend container is serving plain HTTP to the proxy server. In this
configuration we not only set *X-Script-Name*, but also *X-Scheme* to tell the
pgAdmin server to generate any URLs using the correct scheme. A redirect from
HTTP to HTTPS is also included. The certificate and key paths may need to be
adjusted as appropriate to the specific deployment:

.. code-block:: nginx

    server {
        listen 80;
        return 301 https://$host$request_uri;
    }

    server {
        listen 443;
        server_name _;

        ssl_certificate /etc/nginx/server.cert;
        ssl_certificate_key /etc/nginx/server.key;

        ssl on;
        ssl_session_cache builtin:1000 shared:SSL:10m;
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_ciphers HIGH:!aNULL:!eNULL:!EXPORT:!CAMELLIA:!DES:!MD5:!PSK:!RC4;
        ssl_prefer_server_ciphers on;

        location /pgadmin4/ {
            proxy_set_header X-Script-Name /pgadmin4;
            proxy_set_header X-Scheme $scheme;
            proxy_set_header Host $host;
            proxy_pass http://localhost:5050/;
            proxy_redirect off;
        }
    }

Traefik
-------

Configuring `Traefik <https://traefik.io/>`_ is straightforward for either HTTP
or HTTPS when running pgAdmin in a container as it will automatically configure
itself to serve content from containers that are running on the local machine,
virtual hosting them at *<container_name>.<domain_name>*, where the domain
name is that specified in the Traefik configuration. The container is typically
launched per the example below:

.. code-block:: bash

    docker pull dpage/pgadmin4
    docker run --name "pgadmin4" \
        -e "PGADMIN_DEFAULT_EMAIL=user@domain.com" \
        -e "PGADMIN_DEFAULT_PASSWORD=SuperSecret" \
        -d dpage/pgadmin4

Note that the TCP/IP port has not been mapped to the host as it was in the
Nginx example, and the container name has been set to a known value as it will
be used as the hostname and may need to be added to the DNS zone file.

The following configuration will listen on ports 80 and 443, redirecting 80 to
443, using the default certificate shipped with Traefik. See the Traefik
documentation for options to use certificates from LetsEncrypt or other issuers.

.. code-block:: ini

    defaultEntryPoints = ["http", "https"]

    [entryPoints]
      [entryPoints.http]
        address = ":80"
          [entryPoints.http.redirect]
            entryPoint = "https"
      [entryPoints.https]
        address = ":443"
          [entryPoints.https.tls]

    [docker]
    domain = "domain_name"
    watch = true

If you wish to host pgAdmin under a subdirectory using Traefik, the
configuration changes are typically made to the way the container is launched
and not to Traefik itself. For example, to host pgAdmin under */pgadmin4/*
instead of at the root directory, the Traefik configuration above may be used if
the container is launched like this:

.. code-block:: bash

    docker pull dpage/pgadmin4
    docker run --name "pgadmin4" \
        -e "PGADMIN_DEFAULT_EMAIL=user@domain.com" \
        -e "PGADMIN_DEFAULT_PASSWORD=SuperSecret" \
        -e "SCRIPT_NAME=/pgadmin4" \
        -l "traefik.frontend.rule=PathPrefix:/pgadmin4" \
        -d dpage/pgadmin4

The *SCRIPT_NAME* environment variable has been set to tell the container it is
being hosted under a subdirectory (in the same way as the *X-Script-Name* header
is used with Nginx), and a label has been added to tell Traefik to route
requests under the subdirectory to this container.