This tutorial explains the installation and configuration of the Gerrit code review system .

What is Gerrit?

Gerrit is a web based code review system, facilitating online code reviews for projects using the Git version control system. The user interface of Gerrit is based on
Google Web Toolkit and its Git implementation is based on JGit.
A contributor can use Gerrit to suggest a code change. Other developers can review the code change and suggest improvements. If a Gerrit change request needs improvement, it is possible to update it with a new set of changes. Once the suggested changes are accepted by the reviewers, they can be applied via Gerrit to the underlying Git repository.

Gerrit makes code reviews easier by showing changes in a side-by-side display. It also allows the reviewer to add comments to every single line changed.Development takes place at the Gerrit project hosted by Google Code.

sudo apt-get install openjdk-7-jre

sudo update-alternatives --config java

There are 3 choices for the alternative java (providing /usr/bin/java).
  Selection    Path                                     Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-6-oracle/jre/bin/java   67        auto mode
  1            /usr/lib/jvm/java-6-oracle/jre/bin/java   67        manual mode
  2            /usr/lib/jvm/java-6-sun/jre/bin/java      63        manual mode
* 3            /usr/lib/jvm/java-7-oracle/jre/bin/java   66        manual mode

java -version
  java version "1.7.0_21"
  ...

sudo apt-get install gitweb

mkdir ~/gerrit/

cd ~/gerrit/

wget https://gerrit-releases.storage.googleapis.com/gerrit-2.10-rc0.war

CREATE USER 'gerrit'@'localhost' IDENTIFIED BY 'yourpassword';
CREATE DATABASE reviewdb;
GRANT ALL ON reviewdb.* TO 'gerrit'@'localhost';
FLUSH PRIVILEGES;
exit;

java -jar gerrit*.war init

you can also set subfolder

java -jar gerrit*.war init -d ~/gerrit/subfolder

Table 1. Gerrit setup options

Processing 2. Gerrit setup options

Setting up gerrit (2.10-rc0) ...
Starting Gerrit Code Review : gerrit
No Gerrit site found. Will Initialize Gerrit first...

*** Gerrit Code Review 2.10
***
Create '/root/gerrit/review_site' [Y/n]?

*** Git Repositories
***
Location of Git repositories   [git]:

*** SQL Database
***
Database server type           [H2/?]: mysql

Gerrit Code Review is not shipped with MySQL Connector/J 5.1.10
**  This library is required for your configuration. **
Download and install it now [Y/n]?
Downloading http://repo2.maven.org/maven2/mysql/mysql-connector-java/5.1.10/mysql-connector-java-5.1.10.jar ... OK
Checksum mysql-connector-java-5.1.10.jar OK
Server hostname                [localhost]:
Server port                    [(MYSQL default)]:
Database name                  [reviewdb]:
Database username              [gerrit2]: gerrit
gerrit2's password             : yourpassword
confirm password : yourpassword

*** User Authentication
***
Authentication method          [OPENID/?]: http
Get username from custom HTTP header [y/N]? y
SSO logout URL                 :

*** Email Delivery
***
SMTP server hostname           [localhost]: smtp.gmail.com
SMTP server port               [(default)]: 587
SMTP encryption                [NONE/?]: TLS
SMTP username                  : [email protected]
SMTP password                  : you_password

*** Container Process
***
Run as                         [gerrit]:
Java runtime                   [/usr/lib/jvm/java-7-oracle/jre]: /usr/lib/jvm/java-7-oracle/jre

Copy gerrit.war to /root/gerrit/bin/gerrit.war [Y/n]? Y
Copying gerrit.war to /root/gerrit/bin/gerrit.war

*** SSH Daemon
***
Listen on address              [*]:
Listen on port                 [29418]:

Gerrit Code Review is not shipped with Bouncy Castle Crypto v144
  If available, Gerrit can take advantage of features
  in the library, but will also function without it.
Download and install it now [Y/n]?
Downloading http://www.bouncycastle.org/download/bcprov-jdk16-144.jar ... OK
Checksum bcprov-jdk16-144.jar OK
Generating SSH host key ... rsa... dsa... done

*** HTTP Daemon
***
Behind reverse proxy           [y/N]? y
Proxy uses SSL (https://)      [y/N]? n
Listen on address              [*]:
Listen on port                 [8081]:
Canonical URL                  [http://review.probam.net/]: https://your-domain.com/

Gerrit can be launched manually:

~/gerrit/bin/gerrit.sh start

Troubleshooting:

some time you will facing some issues and you got FAILD when trying to start Gerrit

“gc.startTime” is not configured

INFO  com.google.gerrit.server.config.ScheduleConfig : gc schedule parameter "gc.startTime" is not configured

Section gc allows to configure the git garbage collection and schedules it to run periodically. It will be triggered and executed sequentially for all projects.  more info

Examples:

[gc]
  startTime = Fri 12:00
  interval  = 2 day

Error opening database “Sleep interrupted” [8000-173] :

com.google.gerrit.server.cache.h2.H2CacheFactory : Enabling disk cache /.../cache

to get rid of this error , run

java -jar gerrit*.war reindex

Plugins :

built-in plugins you can setup during installation

• commit-message-length-validator v2.10-rc0
• download-commands v2.10-rc0
• replication v2.10-rc0
• reviewnotes v2.10-rc0
• singleusergroup v2.10-rc0

Additional Plugins (pre-compiled) we going to install them

• github 2.10-SNAPSHOT (github-oauth && github-plugin)
• gravatar-avatar-provider v2.9-rc1-315-g375f3bf
• deleteproject v2.9-rc2-619-g4afa3f5

GitHub authentication

Build the Gerrit GitHub plugin

The Gerrit GitHub plugin can be found under the Gerrit plugins/github repository on https://gerrit-review.googlesource.com/#/admin/projects/plugins/github. It is open source under the Apache 2.0 license and can be cloned and built using the Java 6 JDK or higher and Maven.

Download (github-oauth*.jar, the GitHub OAuth library for authenticating Gerrit users)
Install the GitHub OAuth filter into the Gerrit libraries (/lib under the Gerrit site directory)

The GitHub OAuth JAR file needs to copied to the Gerrit /lib directory; this is required to allow Gerrit to use it for filtering all HTTP requests and enforcing the GitHub three-step authentication process:

Download (github-plugin*.jar, the Gerrit plugin for integrating with GitHub repositories and pull requests)
Install the GitHub Plugin into the Gerrit plugins (/plugins under the Gerrit site directory)

The GitHub plugin includes the additional support for the overall configuration, the advanced GitHub repositories replication, and the integration of pull requests into the Code Review process.

Register Gerrit as a GitHub OAuth application

Before going through the Gerrit init, we need to tell GitHub to trust Gerrit as a partner application. This is done through the generation of a ClientId/ClientSecret pair associated to the exact Gerrit URLs that will be used for initiating the 3-step OAuth authentication.

We can register a new application in GitHub through the URL https://github.com/settings/applications/new, where the following three fields are requested:

• Application name : It is the logical name of the application authorized to access GitHub, for example, Gerrit.
• Main URL : The Gerrit canonical web URL used for redirecting to GitHub OAuth authentication, for example, https://myhost.mydomain:port.
• Callback URL : The URL that GitHub should redirect to when the OAuth authentication is successfully completed, for example, https://myhost.mydomain:port/#/.

Running Gerrit init to configure GitHub OAuth

$ ~/gerrit/bin/gerrit.sh stop 
Stopping Gerrit Code Review: OK 
$ cd /opt/gerrit 
$ java -jar gerrit.war init  
[...] 
*** User Authentication
***
Authentication method          []: 
HTTP RETURN
Get username from custom HTTP header [Y/n]? 
Y RETURN
Username HTTP header           []: 
GITHUB_USER RETURN
SSO logout URL                 : 
/oauth/reset RETURN
*** GitHub Integration
***
GitHub URL                     [https://github.com]: 
RETURN
Use GitHub for Gerrit login ?  [Y/n]? 
Y RETURN
ClientId                       []: 
384cbe2e8d98192f9799 RETURN
ClientSecret                   []: 
f82c3f9b3802666f2adcc4 RETURN
Initialized ~/gerrit 

Restart Gerrit

~/gerrit/bin/gerrit.sh restart

Using GitHub login and anonymous read support  for Gerrit

Gerrit is now fully configured to register and authenticate users through GitHub OAuth. When opening the browser to access any Gerrit web pages, we are automatically redirected to the GitHub for login.

The best part in this tutorial you will able to open Gerrit pages for anonymous users !!
(put in etc/gerrit.config)

[auth]
    type = HTTP
    httpHeader = GITHUB_USER
    httpDisplayNameHeader = GITHUB_NAME
    httpEmailHeader = GITHUB_EMAIL
    loginUrl = /login
    loginText = GitHub Sign-in
    registerPageUrl = /plugins/github-plugin/static/account.html
    gitBasicAuth = true

Check Installed Plugins :

ssh <user>@<host> -p29418 gerrit plugin ls

Install Gravatar Provider Plugin:

ssh <user>@<host> -p29418 gerrit plugin install -n gravatar.jar \ 
http://ci.gerritforge.com/view/Plugins-master/job/Plugin_gravatar_master/lastSuccessfulBuild/artifact/gravatar.jar

Install Delete Project Plugin:

ssh <user>@<host> -p29418 gerrit plugin install -n delete-project.jar \ 
http://ci.gerritforge.com/view/Plugins-master/job/Plugin_delete-project_master/lastSuccessfulBuild/artifact/delete-project.jar

Themes :

The new change screen is deactivated by default. It can be activated system-wide by changing the gerrit.changeScreen setting to CHANGE_SCREEN2. Users can deactivate it by setting OLD_UI on their user preferences page.

[gerrit]
    changeScreen = CHANGE_SCREEN2

 Play with Colors

[theme]
    backgroundColor = FCFEEF
    textColor = 000000
    trimColor = D4E9A9
    selectionColor = FFFFCC
    topMenuColor = D4E9A9
    changeTableOutdatedColor = F08080
[theme "signed-in"]
    backgroundColor = FFFFFF

TIPS:

if you are using gerrit on remote server and you need to work with Gerrit remotely , you can enable allowRemoteAdmin

[plugins]
    allowRemoteAdmin = true;

Sources and References in this Tutorial :

• http://gerrit-review.googlesource.com/Documentation/
• https://www.packtpub.com/books/content/using-gerrit-github
• http://www.vogella.com/tutorials/Gerrit/article.html

Regards,
Hany alsamman