Copyright (c) 2006, 2018 Oracle and/or its affiliates. All rights reserved.

OpenGrok - a wicked fast source browser

1. Introduction
2. Requirements
3. Usage
4. OpenGrok install
5. OpenGrok setup
6. Optional Command Line Interface Usage
7. Change web application properties or name
8. Information for developers
9. Tuning OpenGrok for large code bases
10. Authors
11. Contact us

1. Introduction

OpenGrok is a fast and usable source code search and cross reference engine, written in Java. It helps you search, cross-reference and navigate your source tree. It can understand various program file formats and version control histories of many source code management systems.

Official page of the project is on: http://opengrok.github.com/OpenGrok/

2. Requirements

• Latest Java (at least 1.8) http://www.oracle.com/technetwork/java/
• A servlet container like Tomcat (8.x or later) supporting Servlet 2.5 and JSP 2.1 http://tomcat.apache.org/
• Exuberant Ctags or Universal Ctags http://ctags.sourceforge.net/ https://ctags.io/
• Source Code Management installation depending on type of repositories indexed
• If you want to build OpenGrok:
  • Ant (1.9.4 and later) http://ant.apache.org/ or Maven https://maven.apache.org/
  • JFlex http://www.jflex.de/
  • Netbeans (optional, at least 8.2, will need Ant 1.9.4) http://netbeans.org/

3. Usage

OpenGrok usually runs in servlet container (e.g. Tomcat).

SRC_ROOT environment variable refers to the directory containing your source tree. OpenGrok analyzes the source tree and builds a search index along with cross-referenced hypertext versions of the source files. These generated data files will be stored in directory referred to with environment variable called DATA_ROOT.

3.1 Projects

OpenGrok has a concept of Projects - one project is one directory underneath SRC_ROOT directory which usually contains a checkout of a project sources. (this can be branch, version, ...)

Projects effectively replace the need to have more web applications, each with opengrok .war file. Instead it leaves you with one indexer and one web application serving multiple source code repositories - projects. Then you have a simple update script and simple index refresher script in place, which simplifies management of more repositories.

A nice concept is to have a naming convention for directories underneath SRC_ROOT, thereby creating a good overview of projects (e.g. name-version-branch).

For example, the SRC_ROOT directory can contain the following directories:

• openssl-head
• openssl-0.9.8-stable
• openssl-1.0.0-stable

Each of these directories was created with cvs checkout command (with appropriate arguments to get given branch) and will be treated by OpenGrok as a project.

3.2 Messages

See https://github.com/oracle/opengrok/wiki/Messages

4. OpenGrok install

Grab a tar ball from https://github.com/oracle/opengrok/releases and extract it.

See https://github.com/OpenGrok/platform for OS specific integration.

5. OpenGrok setup

To setup OpenGrok it is needed to prepare the source code, let OpenGrok index it and start the web application.

5.1 Setting up the sources

Source base should be available locally for OpenGrok to work efficiently. No changes are required to your source tree. If the code is under source control management (SCM) OpenGrok requires the checked out source tree under SRC_ROOT.

By itself OpenGrok does not perform the setup of the source code repositories or synchronization of the source code with its origin. This needs to be done by the user or by using automatic scripts.

It is possible for SCM systems which are not distributed (Subversion, CVS) to use a remote repository but this is not recommended due to the performance penalty. Special option when running the OpenGrok indexer is needed to enable remote repository support (-r on).

In order for history indexing to work for any SCM system it is necessary to have environment for given SCM systems installed and in a path accessible by OpenGrok.

Note that OpenGrok ignores symbolic links.

If you want to skip indexing the history of a particular directory (and all of it's subdirectories), you can touch .opengrok_skip_history file at the root of that directory. If you want to disable history generation for all repositories globally, then set OPENGROK_GENERATE_HISTORY environment variable to off during indexing.

5.2 Using Opengrok shell wrapper script to create indexes

For *nix systems there is a shell script called OpenGrok which simplifies most of the tasks. It has been tested on Solaris and Linux distributions.

5.2.1 Deploy the web application

First please change to opengrok directory where the OpenGrok shell script is stored (can vary on your system).

Note that now you might need to change to user which owns the target directories for data, e.g. on Solaris you'd do:

pfexec su - webservd
cd /usr/opengrok/bin

and run

./OpenGrok deploy

This command will do some sanity checks and will deploy the source.war in its directory to one of detected web application containers. Please follow the error message it provides.

If it fails to discover your container, please refer to optional steps on changing web application properties below, which explains how to do this.

Note that OpenGrok script expects the directory /var/opengrok to be available to user running opengrok with all permissions. In root user case it will create all the directories needed, otherwise you have to manually create the directory and grant all permissions to the user used.

5.2.2 Populate DATA_ROOT Directory

During this process the indexer will generate OpenGrok XML configuration file configuration.xml and sends the updated configuration to your web app.

The indexing can take a lot of time. After this is done, indexer automatically attempts to upload newly generated configuration to the web application. Most probably you will not be able to use Opengrok before this is done for the first time.

Please change to opengrok directory (can vary on your system)

cd /usr/opengrok/bin

and run, if your SRC_ROOT is prepared under /var/opengrok/src

./OpenGrok index

otherwise (if SRC_ROOT is in different directory) run:

./OpenGrok index <absolute_path_to_your_SRC_ROOT>

The above command attempts to upload the latest index status reflected into configuration.xml to a running source web application. Once above command finishes without errors (e.g. SEVERE: Failed to send configuration to localhost:2424), you should be able to enjoy your OpenGrok and search your sources using latest indexes and setup.

It is assumed that any SCM commands are reachable in one of the components of the PATH environment variable (e.g. git command for Git repositories). Likewise, this should be maintained in the environment of the user which runs the web server instance.

Congratulations, you should now be able to point your browser to http://<YOUR_WEBAPP_SERVER>:<WEBAPPSRV_PORT>/source to work with your fresh OpenGrok installation! :-)

At this time we'd like to point out some customization to OpenGrok script for advanced users. A common case would be, that you want the data in some other directory than /var/opengrok. This can be easily achieved by using environment variable OPENGROK_INSTANCE_BASE.

E.g. if OpenGrok data directory is /tank/opengrok and source root is in /tank/source then to get more verbosity run the indexer as:

OPENGROK_VERBOSE=true OPENGROK_INSTANCE_BASE=/tank/opengrok
./OpenGrok index /tank/source

Since above will also change default location of config file, beforehand(or restart your web container after creating this symlink) I suggest doing below for our case of having OpenGrok instance in /tank/opengrok:

ln -s /tank/opengrok/etc/configuration.xml /var/opengrok/etc/configuration.xml

More customizations can be found inside the script, you just need to have a look at it, eventually create a configuration out of it and use OPENGROK_CONFIGURATION environment variable to point to it. Obviously such setups can be used for nightly cron job updates of index or other automated purposes.

5.2.3 Partial reindex

There is inherent time window between after the source code is updated (highlighted in step 5.1 above) and before indexer completes. During this time window the index does not match the source code. To alleviate this limitation, one can kick off update of all source repositories in parallel and once all the mirroring completes perform complete reindex. This does not really help in case when some of the source code repositories are slow to sync, e.g. because the latency to their origin is significant, because the overall mirroring process has to wait for all the projects to finish syncing before running the indexer. To overcome this limitation, the index of each project can be created just after the mirroring of this project finishes.

Indexing of all projects (i.e. OpenGrok index /var/opengrok/src) in order to discover new and remove deleted projects from the configuration can be avoided. One can start with no index and no projects and then incrementally add them and index them.

It basically works like this:

1. bootstrap initial configuration: OpenGrok bootstrap

• this will create /var/opengrok/etc/configuration.xml with basic set of properties. If more is needed use:

  Messages -n config -t set "set propertyXY = valueFOO"
  

2. add a new project foo:

Messages -t foo -n project add

• the project foo is now visible in the configuration however is not yet searchable. Store the config in a file so that indexer can see the project and its repositories:

  Messages -n config -t getconf > /var/opengrok/etc/configuration.xml
  

3. index the project. It will become searchable after that.

OPENGROK_READ_XML_CONFIGURATION=/var/opengrok/etc/configuration.xml
OpenGrok indexpart /foo

4. make the project indexed status of the project persistent so that if webapp is redeployed the project will be still visible:

Messages -n config -t getconf > /var/opengrok/etc/configuration.xml

If an add message is sent that matches existing project, the list of repositories for that project will be refreshed. This is handy when repositories are added/deleted.

5.2.3.1 Logging when running partial reindex

When running the indexer the logs are being written to single file. Since multiple indexers are being run in parallel in step 2, their logs have to be separated. To do this, create logging.properties file for each project using the /var/opengrok/logging.properties file as template. The only line which can differ would be this:

java.util.logging.FileHandler.pattern = /var/opengrok/log/myproj/opengrok%g.%u.log

Note the path component myproj which separates the logs for given project to this directory. The creation of the per-project directory and the logging.properties file can be easily done in a script.

The command used in step 2 can thus look like this:

OPENGROK_LOGGER_CONFIG_PATH=/var/opengrok/myproj.logging
OPENGROK_READ_XML_CONFIGURATION=/var/opengrok/etc/configuration.xml
OpenGrok indexpart /myproj

The last argument is path relative to SRC_ROOT.

5.4 Using command line interface to create indexes

There are 2 (or 3) steps needed for this task.

5.4.1 Populate DATA_ROOT Directory

• Option 1. OpenGrok: There is a sample shell script OpenGrok that is suitable for using in a cron job to run regularly. Modify the variables in the script to point appropriate directories, or as the code suggests factor your local configuration into a separate file and simplify future upgrades.

• Option 2. opengrok.jar: You can also directly use the Java application. If the sources are all located in a directory SRC_ROOT and the data and hypertext files generated by OpenGrok are to be stored in DATA_ROOT, run

  java -jar opengrok.jar -s $SRC_ROOT -d $DATA_ROOT

  See opengrok.jar manual below for more details.

5.4.5 Custom ctags configuration

To make ctags recognize additional symbols/definitions/etc. it is possible to specify configuration file with extra configuration options for ctags.

This can be done by setting OPENGROK_CTAGS_OPTIONS_FILE environment variable when running the OpenGrok shell script (or directly with the -o option for opengrok.jar). Default location for the configuration file in the OpenGrok shell script is etc/ctags.config under the OpenGrok base directory (by default the full path to the file will be /var/opengrok/etc/ctags.config).

Sample configuration file for Solaris code base is delivered in the doc/ directory.

5.6 Introduce own mapping for an extension to analyzer

OpenGrok script doesn't support this out of box, so you'd need to add it there. Usually to StdInvocation() function after line -jar ${OPENGROK_JAR}. It would look like this:

-A cs:org.opensolaris.opengrok.analysis.PlainAnalyzer

(this will map extension .cs to PlainAnalyzer) You should even be able to override OpenGroks analyzers using this option.

5.7 Logging

Both indexer and web app emit extensive log messages.

OpenGrok is shipped with the logging.properties file that contains logging configuration.

The OpenGrok shell script will automatically use this file if found under the base directory. It can also be set using the OPENGROK_LOGGER_CONFIG_PATH environment variable.

If not using the shell script, the path to the configuration file can be set using the -Djava.util.logging.config.file=/PATH/TO/MY/logging.properties java parameter.

6. Optional Command Line Interface Usage

You need to pass location of project file + the query to Search class, e.g. for fulltext search for project with above generated configuration.xml you'd do:

java -cp ./opengrok.jar org.opensolaris.opengrok.search.Search -R \
    /var/opengrok/etc/configuration.xml -f fulltext_search_string

For quick help run:

java -cp ./opengrok.jar org.opensolaris.opengrok.search.Search

7. Change web application properties or name

See https://github.com/oracle/opengrok/wiki/Webapp-configuration

8. Information for developers

See https://github.com/oracle/opengrok/wiki/Developer-intro and https://github.com/oracle/opengrok/wiki/Developers

9. Tuning OpenGrok for large code bases

See https://github.com/oracle/opengrok/wiki/Tuning-for-large-code-bases

10. Authors

The project has been originally conceived in Sun Microsystems by Chandan B.N.

• Chandan B.N, (originally Sun Microsystems)
• Trond Norbye, norbye.org
• Knut Pape, eBriefkasten.de
• Martin Englund, (originally Sun Microsystems)
• Knut Anders Hatlen, Oracle.
• Lubos Kosco, Oracle. http://blogs.oracle.com/taz/
• Vladimir Kotal, Oracle. http://blogs.oracle.com/vlad/
• Krystof Tulinger

11. Contact us

Feel free to participate in discussion on the mailing lists:

opengrok-users@yahoogroups.com (user topics)

opengrok-dev@yahoogroups.com (developers' discussion)

To subscribe, send email to <mailing_list_name>-subscribe@yahoogroups.com