Gerrit2 - Installation
======================

You need Apache Maven to compile the code, and a SQL database
to house the Gerrit2 metadata.  PostgreSQL is currently the only
supported database.

Important Links
---------------

Apache Maven:

* http://maven.apache.org/download.html[Download]
* http://maven.apache.org/run-maven/index.html[Running Maven]

PostgreSQL:

* http://www.postgresql.org/docs/[Documentation]

Build Gerrit
------------

Build the application distribution:

====
  cd appdist
  mvn clean install
  cd appdist/target/gerrit-*-bin.dir/gerrit-*
====

The first build may take a while as dependencies are searched
for and downloaded from Maven distribution repositories.

Unfortunately you need to install to your local Maven repository
(typically under `~/.m2`) in order to fully build all of the source
based dependencies.  Core dependencies for Gerrit are still under
active development and have not made final releases yet.

Setting up the Database
-----------------------

Currently PostgreSQL is the only supported database.  H2 may also
work, but hasn't been tested in a while.  The primary concern is
having support for the database in the gworm project.

PostgreSQL
~~~~~~~~~~

Create a Gerrit specific user as a normal user (no superuser access)
and assign it an encrypted password:

====
  createuser -A -D -P -E gerrit2
====

Create the database to store the Gerrit metadata, and set the user
you just created as the owner of that database:

====
  createdb -E UTF-8 -O gerrit2 reviewdb
====

Initialize the Schema
---------------------

Create the Gerrit 2 Tables
~~~~~~~~~~~~~~~~~~~~~~~~~~

Either run CreateSchema from the command line (requires writing
a `GerritServer.properties`, see `GerritServer.properties_example`
under `devdb/src/main/config`):

====
  bin/gerrit2.sh --config=GerritServer.properties CreateSchema
====

Or, run the application once in a container to force it to initialize
the database schema before accessing it.  (See below for deployment
setup documentation.)  If you use this approach, it is recommended
that you stop the application before continuing with the setup.

Add Indexes
~~~~~~~~~~~

A script should be run to create the query indexes, so Gerrit
can avoid table scans when looking up information.  Run the
`sql/query_index.sql` script through your database's query tool.

e.g. with PostgreSQL:

====
  psql -f sql/query_index.sql reviewdb
====

Configure site_path
~~~~~~~~~~~~~~~~~~~

This directory holds server-specific configuration files and
assets used to customize the deployment.  Gerrit needs read
access (but not write access) to the directory.  The path
is stored in `system_config.site_path`, so you will need to
update the database with this value.

====
  mkdir /home/gerrit/cfg
  cd /home/gerrit/cfg

  ssh-keygen -t rsa -P '' -f ssh_host_rsa_key
  ssh-keygen -t dsa -P '' -f ssh_host_dsa_key

  psql -c "UPDATE system_config SET site_path='/home/gerrit/cfg'" reviewdb
====

The SSH keys generated here are used as the host keys for the
internal SSH daemon run by Gerrit.  You may wish to backup these
key files to ensure they can be restored in the event of a disaster.

The private key files (`ssh_host_rsa_key`, `ssh_host_dsa_key`) should
be readable *only* by the account that is executing Gerrit2's web
application container.  It is a security risk to make these files
readable by anyone else.

Create Git Repository Base
~~~~~~~~~~~~~~~~~~~~~~~~~~

This directory holds the Git repositories that Gerrit knows about
and can service.  Gerrit needs write access to this directory and
any Git repository stored within it.

====
  mkdir /srv/git
  psql -c "UPDATE system_config SET git_base_path='/srv/git'" reviewdb
====

You may wish to consider also exporting this directory over the
anonymous git:// protocol, as it is more efficient than Gerrit's
internal ssh daemon.  See the `git-daemon` documentation for details
on how to configure this if anonymous access is desired.

* http://www.kernel.org/pub/software/scm/git/docs/git-daemon.html[man git-daemon]

Futher Configuration
~~~~~~~~~~~~~~~~~~~~

Gerrit2 supports some site-specific customizations.  These are
optional and are not required to run a server, but may be desired.

* link:config-sso.html[Single Sign-On Systems]
* link:config-headerfooter.html[Site Header/Footer]
* link:config-gitweb.html[Gitweb Integration]
* link:config-gerrit.html[Other system_config Settings]

Application Deployment
-----------------------

Jetty
~~~~~

These directions will configure Gerrit as the default web
application, allowing URLs like `http://example.com/4543` to
jump directly to change 4543.

Download and unzip a release version of Jetty.  From here on we
call the unpacked directory `$JETTY_HOME`.

* http://dist.codehaus.org/jetty/[Jetty Downloads]

Copy Gerrit into the deployment:
====
  cp jdbc/c3p0-*.jar $JETTY_HOME/lib/plus/
  cp jdbc/postgresql-*.jdbc*.jar $JETTY_HOME/lib/plus/
  cp www/jetty_gerrit.xml $JETTY_HOME/contexts/gerrit.xml
  cp www/gerrit-*.war $JETTY_HOME/webapps/gerrit.war

  rm -f $JETTY_HOME/context/test.xml
====

Edit `$JETTY_HOME/contexts/gerrit.xml` to correctly configure the
database connection, especially the user and password fields.

To start automatically when the system boots, consider a start
script such as the following in `/etc/init.d/gerrit2-jetty`

====
  #!/bin/sh
  
  export JETTY_HOST=127.0.0.1
  export JETTY_PORT=8081
  export JETTY_USER=gerrit2
  export JETTY_PID=/var/run/jetty$JETTY_PORT.pid
  export JETTY_HOME=/home/$JETTY_USER/jetty
  export JAVA_HOME=/usr/lib/jvm/java-6-sun-1.6.0.07/jre
  
  JAVA_OPTIONS=""
  JAVA_OPTIONS="$JAVA_OPTIONS -Djetty.host=$JETTY_HOST"
  export JAVA_OPTIONS
  
  exec $JETTY_HOME/bin/jetty.sh "$@"
====

To deploy on port 80, or to use SSL, you should configure Jetty
to listen on another port, such as 127.0.0.1:8081 (like the start
script above does) and then follow the <<apache2,reverse proxy>>
section below.

[TIP]
Under Jetty, restarting the web application (e.g. after modifying
`system_config`) is as simple as touching the config file:
`$JETTY_HOME/contexts/gerrit.xml`

Other Servlet Containers
~~~~~~~~~~~~~~~~~~~~~~~~

Deploy the `www/gerrit-*.war` file to your application server as
`gerrit.war`.

Configure the JNDI DataSource `jdbc/ReviewDb` for the Gerrit web
application context to point to the database you just created.
Don't forget to ensure your JNDI configuration can load the
necessary JDBC drivers.

[[apache2]]
Apache2 Reverse Proxy
~~~~~~~~~~~~~~~~~~~~~

Enable the necessary Apache2 modules:

====
  a2enmod proxy_http
  a2enmod disk_cache   ; # optional, but helps performance
====

then setup a VirtualHost to proxy to Gerrit's servlet container,
setting the `ProxyPass` line to use the port number you configured
in your servlet container's configuration:

=======================================
	<VirtualHost *>
	  ServerName review.example.com
	#
	  ProxyRequests Off
	  ProxyVia Off
	  ProxyPreserveHost On
	#
	  <Proxy *>
		Order deny,allow
		Allow from all
	  </Proxy>
	  ProxyPass / http://127.0.0.1:8081/
	#
	  <IfModule mod_disk_cache.c>
		CacheEnable disk /
		CacheIgnoreHeaders Set-Cookie
	  </IfModule>
	</VirtualHost>
=======================================

To enable SSL, see the Apache server documentation.


Administrator Setup
-------------------

Login to Gerrit through the web interface, so that a user account
is initialized for you.

Add your newly created account to the "Administrators" group,
so that you can manage the site through the web interface:

====
  psql reviewdb
  INSERT INTO account_group_members
    (account_id, group_id)
  VALUES (
    (SELECT account_id FROM accounts
     WHERE preferred_email='you@example.com'),
    (SELECT admin_group_id FROM system_config)
  );
====

Group memberships are cached, so you need to either restart Gerrit,
or try flushing the caches over SSH.

Since SSH cache flushing requires being in the "Administrators"
group you may run into a chicken-and-egg problem, where you cannot
flush the cache to make yourself an administrator because you are
not yet an administrator.  Therefore, restarting the application
is the recommended bootstrap technique.

To flush the server's caches over SSH, ensure you have an SSH key
(you can add one through the web UI under Settings, SSH Keys),
and then run:

====
  ssh -p 29418 you@example.com gerrit flush-caches
====

Project Setup
-------------

See link:project-setup.html[Project Setup] for further details on
how to register a project with Gerrit.