OMERO.web deployment
====================

OMERO.web is the web application component of the OMERO platform which
allows for the management, visualization (in a fully multi-dimensional
image viewer) and annotation of images from a web browser. It also
includes the ability to manage users and groups.


OMERO.web is an integral part of the OMERO platform and can be deployed
with:

-  `WSGI <http://wsgi.readthedocs.org>`_ using a WSGI capable web server
   such as
   `nginx <http://nginx.org/>`_ and `gunicorn <http://docs.gunicorn.org/>`_
   (you can also use `Apache 2.2+ <http://httpd.apache.org/>`_ with
   `mod\_wsgi <http://www.modwsgi.org/>`_ enabled but this is not
   recommended for new installations as support has been deprecated as of
   OMERO 5.2.6 and is likely to be dropped during the 5.3.x line)
-  The built-in Django lightweight development server (for **testing**
   only; see the :doc:`/developers/Web/Deployment` page).

If you need help configuring your firewall rules, see the
:doc:`/sysadmins/server-security` page.

Prerequisites
-------------

-  OMERO and its prerequisites (see :doc:`server-installation`).

-  Python 2.7

   -  `Pillow`_ should be available for your distribution. We currently do not 
       support version 3.0+.

   -  `Matplotlib`_ should be available for your distribution

-  A WSGI capable web server


.. _unix_omero_web_deployment:

Deployment (Unix/Linux)
-----------------------

There are a number of good ways to easily deploy OMERO.web.
If you have installed Nginx or Apache, OMERO can automatically generate a
configuration file for your web server. The location of the file will depend
on your system, please refer to your web server's manual. See
:ref:`customizing_your_omero_web_installation_unix` for additional
customization options.

.. toctree::
    :maxdepth: 1
    :titlesonly:

    install-web/install-apache
    install-web/install-nginx

.. note:: Support for Apache deployment is deprecated as of OMERO 5.2.6 and is
    likely be dropped during the 5.3.x line.
    
    If your organization's policies only allow Apache to be used as the external-facing web-server you should configure Apache to proxy connections to an Nginx instance running on your OMERO server i.e. use Apache as a reverse proxy. For more details see
    `Apache mod_proxy documentation <https://httpd.apache.org/docs/current/mod/mod_proxy.html>`_.

Logging in to OMERO.web
-----------------------

Once you have deployed and started the server, you can use your browser
to access the OMERO.webclient:

-  **http://your\_host/omero** OR, for development server:
   **http://localhost:4080**

.. figure:: /images/installation-images/login.png
   :align: center
   :width: 55%
   :alt: OMERO.web login

   OMERO.web login

.. _unix_omero_web_maintenance:

OMERO.web Maintenance (Unix/Linux)
----------------------------------

-  Session cookies :property:`omero.web.session_expire_at_browser_close`:

   -  A boolean that determines whether to expire the session when the user
      closes their browser.
      See :djangodoc:`Django Browser-length sessions vs. persistent
      sessions documentation <topics/http/sessions/#browser-length-vs-persistent-sessions>`
      for more details. Default: ``True``.

      ::

          $ bin/omero config set omero.web.session_expire_at_browser_close "True"

   -  The age of session cookies, in seconds. Default: ``86400``.

      ::

          $ bin/omero config set omero.web.session_cookie_age 86400

-  Session engine:

   -  Each session for a logged-in user in OMERO.web is kept in the session 
      store. Stale sessions can cause the store to grow with time. OMERO.web 
      uses by default the OS file system as the session store backend and 
      does not automatically purge stale sessions, see
      :djangodoc:`Django file-based session documentation <topics/http/sessions/#using-file-based-sessions>`
      for more details. It is therefore the responsibility of the OMERO 
      administrator to purge the session cache using the provided management 
      command:

      ::

          $ bin/omero web clearsessions

      It is recommended to call this command on a regular basis, for example 
      as a :ref:`daily cron job<linux_walkthrough_regular_tasks>`, see
      :djangodoc:`Django clearing the session store documentation <topics/http/sessions/#clearing-the-session-store>`
      for more information.

   -  OMERO.web offers alternative session backends to automatically 
      delete stale data using the cache session store backend, see
      :djangodoc:`Django cached session documentation <topics/http/sessions/#using-cached-sessions>`
      for more details. After installing all the cache prerequisites set the following::

          $ bin/omero config set omero.web.session_engine django.contrib.sessions.backends.cache

      - `Memcached <https://memcached.org/>`_::

          $ bin/omero config set omero.web.caches '{"default": { "BACKEND": "django.core.cache.backends.memcached.MemcachedCache", "LOCATION": "127.0.0.1:11211", "TIMEOUT": "86400" } }'

      - EXPERIMENTAL: `Redis 2.4+ <http://redis.io/>`_ requires `django-redis-cache 1.6.5+ <http://django-redis-cache.readthedocs.org/en/latest/intro_quick_start.html>`_::

          $ pip install django-redis-cache>=1.6.5
          $ bin/omero config set omero.web.caches '{"default": {"BACKEND": "redis_cache.RedisCache", "LOCATION": "127.0.0.1:6379"}}'

.. note::
    The generated Nginx and Apache configuration files will automatically
    display a maintenance page if an attempt is made to access OMERO.web whilst
    it is not running.


.. _customizing_your_omero_web_installation_unix:

Customizing your OMERO.web installation
---------------------------------------

By default OMERO.web expects to be run from the root URL of the web server.
This can be changed by setting :property:`omero.web.prefix` and
:property:`omero.web.static_url`. For example, to make OMERO.web appear at
`http://example.org/omero/`:

::

    $ bin/omero config set omero.web.prefix '/omero'
    $ bin/omero config set omero.web.static_url '/omero/static/'

and regenerate your web-server configuration (see :ref:`unix_omero_web_deployment`).

The front-end webserver (Nginx, Apache) can be setup to run on a different
host from OMERO.web. You will need to set
:property:`omero.web.application_server.host` to ensure OMERO.web is
accessible on an external IP.

All configuration options can be found on various sections of
:ref:`web_index` developers documentation. For the full list, refer to
:ref:`web_configuration` properties or:

::

	$ bin/omero web -h

.. Note:: Depending on the deployment choice, OMERO.web will not activate
    configuration changes until either gunicorn is restarted using
    ``bin/omero web restart`` (nginx) or the Apache webserver has been
    reloaded.

The most popular configuration options include:

-  Debug mode, see :property:`omero.web.debug`.

-  Customizing OMERO clients e.g to add your own logo to the login page
   (:property:`omero.web.login_logo`) or use an index page as an alternative
   landing page for users (:property:`omero.web.index_template`). See
   :doc:`/sysadmins/customization` for further information.

-  Enabling a public user see :doc:`/sysadmins/public`.