Buggedtech – Open Source & Other Geeky Stuffs

Ever wonder how to create a post-commit hook in subversion? That’s so easy. All you have to do is peek into your repositories’ hooks directory. Meaning, you will need to go to the directory where your repositories are located and look into the “hook” subdirectory. For instance, if your repository is “projectA” located in “/var/svn/repos” you will have to look into “/var/svn/repos/projectA/hooks”.

Inside the “hooks” directory, you will see “post-commit.tmpl”. That’s the post-commit template. Open that file and read the comments. But if you don’t want to read the comments, then all you need to take note are the following:

• A post-commit hook has only “post-commit” as the name. In Windows, it could either be post-commit.bat or post-commit.exe
• At least, the owner of the group is the same as the user that runs httpd(I’m assuming here that your svn server runs through apache or other http server)
• post-commit must be executable by the file owner
• 1st parameter to post commit is the REPO_PATH in our example, it is /var/svn/repos/projectA
• 2nd parameter is the revision number just committed.
• when using external programs inside post-commit and other hooks, use the full path(example: to use awk you will use something like /usr/bin/awk)
• if you need to display something on the user’s screen after a commit, make sure to send a return 1(or in error) and pass standard output(file descriptor 1) to standard error (file descriptor 2)

Let’s have an example for you to have something to start on. Suppose you are asked to say “Thank you” for every commit, you would do the following:

1. vi /var/svn/repos/projectA/hooks/post-commit
2. Put the following inside

   #!/bin/bash

   /bin/echo "Thank you" 1>&2
   exit 1

3. Save the file and quit(in vi, it would be then :wq)
4. Assuming ‘apache’ is the owner of httpd, you will run “chown apache /var/svn/repos/projectA/hooks/post-commit”
5. Make post-commit executable using the command “chmod u+x /var/svn/repos/projectA/hooks/post-commit”

On a working copy of projectA, make some changes and commit. If you followed the instructions above, you wil see something like:

buggedtech$ vi test1
buggedtech$ svn ci -m"test"
Sending        test1
Transmitting file data .
Committed revision 4.

Warning: post-commit hook failed (exit code 1) with output:
Thank You