How to setup server side pre-receive hook?

Question

I am new to git hooks and server side git functionality. I worked on client side git to commit and push my code and we do git merge using Application Lifecycle management(ALM) tools. I am trying to write git hooks to do some testing on new/modified files in the repository. I am able to write and test client side hooks like pre-commit

Now, I need to add some server side git hook to verify files before merging to master because there is a change to skip client side verification using -no-verify option. When I go through some git hook tutorials, pre-push hook is the server side hook. I tried to create pre-push hook and it is working on client side. Now, How can make it as a server side hook and force to verify files when user try to push changes even with --no-verify option(should not be controled on client).

My big question is how server hook is triggered when we do git push from local branch/repo.

Creation of hook:

Created a hook called pre-commit and placed it under some folder git_hooks/pre-push and also in .git/hooks/pre-push. Now, created a symbolic link for my pre-push script. So, whenever I do git push it will trigger .git/hooks/pre-push which is a symbolic link for my script git_hooks/pre-push

EDIT:

I thought pre-push and pre-receive hooks are same as both are triggered on git push command but pre-push is working only client side, pre-recieve is working on server side. I created pre-receive hook and pushed it to master branch. Now, when I do git push getting this error: cannot spawn hooks/pre-receive: No such file or directory.

I am trying this on both Windows and Linux platforms. On Windows I am getting this error, On Linux it is not even getting triggered. I placed pre-receive hook on master branch on both the platforms.

Solution

You should look into Server side hooks documentation section.

There are three hooks that let you react to different stages of the git push process.

• pre-receive
• update
• post-receive

When you push to server pre-receive hook is triggered. Then for each branch you have pushed the update hook is triggered. When these hooks are finished without errors your patches are applied and post-receive hook is triggered

More detailed DOC about pre-receive hook:

This hook is invoked by git-receive-pack when it reacts to git push and updates reference(s) in its repository. Just before starting to update refs on the remote repository, the pre-receive hook is invoked. Its exit status determines the success or failure of the update.

UPD

To setup pre-receive server side hook you should place script into .git/hooks directory on the server. and name it pre-receive. That is all.
You should not create hooks directory at your repo and commit it. The pre-receive script is outside of repo

UPD
Here is example script:

#!/bin/bash


# check each branch being pushed

echo "pre-receive HOOK"

while read old_sha new_sha refname
do

if git diff "$old_sha" "$new_sha" | grep -qE '^\+(<<<<<<<|>>>>>>>)'; then
    echo "Saw a conflict marker in $(basename "$refname")."
    git diff "$old_sha" "$new_sha" | grep -nE '^\+(<<<<<<<|>>>>>>>)'
    exit 1
fi

if git diff "$old_sha" "$new_sha" | grep -qE '^\+.*\s+$'; then
    echo "Saw whitespaces at EOL."
    git diff "$old_sha" "$new_sha" | grep -nE '^\+.*\s+$'
    exit 1
fi

done

exit 0

Comments

[Techie]

Thanks for your help. I thought pre-push and pre-receive are same but both are different . pre-push is also triggered for git push but only client side. I have created pre-receive hook but I am getting error: cannot spawn hooks/pre-receive: No such file or directory.

[Eugen Konkov]

@Rekha: I have updated answer. You just put pre-receive script on the server into .git/hooks directory. That is all. How to make this script to works properly is different question.

[Techie]

yes. I added that also. hooks/pre-receive: No such file or directory this represents .git/hooks only. File is there but still showing such error. I am not able to figure it out. Some how it is triggering the event but not working properly.

[Eugen Konkov]

@Rekha: I suppose you use pre-push as pre-receive. You can not do that. Look at my script.

[Techie]

I do not have problem with script. I just have simple print statement. First hook should work properly then I can have any type of script based on my requirement right?

[Techie]

@ Eugen Konkov Thanks for your help.

[Eugen Konkov]

@Rekha: The script have 3 parameters: old_sha new_sha refname. You can do anything you want. One requirement is only exit status. When script exits with zero status push is applied. When non zero status - push is not applied and error reported to client.

[Techie]

@ Eugen Konkov Can you just do one more favor for me ? Server repository is on linux platform. How can we put hook in .git/hooks folder as I can not source control the hidden files ?

[Eugen Konkov]

@Rekha: You ssh to server with your repository and put required file into .git/hooks folder in same way as you do that locally. Do not try to put that file under version control. Nobody MUST NOT has right and ability to change that file. Other wise they may bypass restriction implemented by that hook.

[Eugen Konkov]

@Rekha: here is it

[Techie]

@ Eugen Konkov Thanks for your help.