Section 3.2. Obtaining the Source Code

3.2. Obtaining the Source Code

The Asterisk source code can be obtained either through FTP or CVS. We will show you how to acquire the source with both methods , although you only need to use one of them to retrieve the packages (FTP is the preferred method).

3.2.1. Obtaining Asterisk Source Code from FTP

The Asterisk source code can be obtained from the Digium FTP server, located at ftp://ftp.digium.com. The easiest way to obtain the stable release is through the use of the program wget .

Stable and Head

Asterisk comes in two different flavors, generally referred to as stable and head . Stable, as the name implies, is the established branch of Asterisk for use in production systems. The head branch is what the developers use to test new features and bug fixes .

Bug fixes (not features) are merged over to the stable branch after a reasonable period of testing. It is entirely possible that the development branch may be broken at certain points during testing; thus, the stable branch is what you will want to run your production system on, and it is what we will be using throughout this book.

You can obtain stable releases via FTP. Both the stable and head branches of Asterisk can also be obtained from CVS, as explained later in this chapter. However, it is important to note the difference between releases and CVS . Releases are snapshots from the stable CVS tree, tagged with a version number and released via the FTP server when a new stable release is deemed ready. Note that the stable CVS branch is not a releaseit's a work in a progress, and it may be buggy (i.e., not so stable after all). The FTP tarballs are the actual releases.

To summarize, use only stable releases obtained via the FTP server for production systems.

Note that we will be making use of the /usr/src/ directory to extract and compile the Asterisk source. Also be aware that you will need root access to write files to the /usr/src/ directory and to install Asterisk and its associated packages.

To obtain the latest stable source code via wget , enter the following commands on the command line:

 #  cd /usr/src/  #  wget --passive-ftp ftp.digium.com/pub/asterisk/asterisk-1.*.tar.gz  #  wget --passive-ftp ftp.digium.com/pub/asterisk/asterisk-sounds-*.tar.gz  #  wget --passive-ftp ftp.digium.com/pub/zaptel/zaptel-*.tar.gz  #  wget --passive-ftp ftp.digium.com/pub/libpri/libpri-*.tar.gz  

As long as Digium doesn't change the way they put things on the FTP site, the wget command will automagically get the latest version. You may also replace the wildcard mask ( * ) with the currently available software version.

Now that you've retrieved the files for Asterisk and the Digium hardware, you are ready to extract the code.

3.2.2. Extracting the Source Code

If you use wget to obtain the source code from the FTP server, you will need to extract it before compiling. If you didn't download the packages to /usr/src/ , either move them there now, or specify the full path to their location. We will be using the GNU tar application to extract the source code from the compressed archive. This is a simple process that can be achieved through the use of the following commands:

 #  cd /usr/src/  #  tar zxvf zaptel-*.tar.gz  #  tar zxvf libpri-*.tar.gz  #  tar zxvf asterisk-*.tar.gz  #  tar zxvf asterisk-sounds*.tar.gz  

These commands will extract the packages and source code to their respective directories.

3.2.3. Obtaining Asterisk Source Code from CVS

The Concurrent Versioning System (CVS) is a tool that provides a central repository that large (and diverse) development teams can use to manage the multitude of files associated with a development project. When a change is made, it is committed to the CVS server, where it is immediately available for download and compilation. Another added benefit of using CVS is that the version for any particular file can be rolled back to a certain instance, so that if something was working at one point but a change causes it to break, you can easily revert to the working version. This is true for the entire tree as well. If you find that installing the latest version of Asterisk causes any part of the system to break, you can "roll back" to an earlier point in time and investigate the cause of the problem.

If you are a developer looking to obtain the latest updates to the source code, you will need to get them from the CVS servers. You can also download the stable branch via CVS:

• Export the CVSROOT path:

   #  cd /usr/src/  #  export CVSROOT=:pserver:anoncvs:[e-mail]:/usr/cvsroot  

  
  

• Download HEAD from CVS:

   #  cvs checkout zaptel libpri asterisk  

  
  

• Download STABLE 1.0 from CVS:

   #  cvs checkout -r v1-0 zaptel libpri asterisk  

  
  

• Download STABLE 1.2 from CVS:

   #  cvs checkout -r v1-2 zaptel libpri asterisk  

  
  

• Download optional modules from CVS:

   #  cvs checkout asterisk-sounds asterisk-addons  

  
  

Again, note that the stable branch available from CVS is not a release and should not be used for production systems.