2012-12-22

Forking GIT project to Gerrit

Going through your own changes before you decide to carry on is a pretty good idea. I treat it myself as a form of checkpoint: I can approve my changes at any time, but the more important thing is: I can find all the hacks I made along the way.

It turns out to be a pretty good idea to use Gerrit even when you contribute your changes to other repositories, or even when you want to keep your custom changes to yourself and at the same time be able to stay up to date with remote changes.

So how does that work, in short?

  1. Open up Gerrit website and navigate to Projects. Create a new project, that will be a fork of another repository. Create initial commit, it may make things easier;
  2. Open Access configuration for this project. Create new reference refs/* and add 
    1. permission Push merge commits to project owners group (that will allow you to invoke git push);
    2. permission Forge commiter identity - this will be required by Gerrit to accept the changes you are not an author of.
  3. Clone this repository;
  4. Branch off the master branch;
  5. Add new upstream: git remote add upstream ;
  6. Merge the upstream's master branch to your local master branch
  7. Push changes to gerrit using git push origin master.

That's pretty much it. Good thing about mixture like the above is: you can - at any time in the future - recreate this exact configuration. It will work. You will also be able to push changes - once reviewed - to your upstream repository.

Good luck!

Gerrit Code Review - setup

Gerrit Code Review has given me a hard time when I first tried it out.

It wasn't such a big problem to have it installed, as it was to have it configured. Whenever I was done with initial setup, it kept failing on attempt to register first user, and the problem re-emerged some time later, when I decided to upgrade the system.

My biggest fail back then was to set things up manually. I added user to specific groups by hand, thinking that the setup script was not mature enough to handle it for me. While searching around for how i did this last time i stumbled upon a short [ticket](, which helped me realize, that it was all so much out of sync, it just couldn't handle the upgrade.

Ultimately, every time I set up the review site from scratch, the attempt to register first user ended up with the following message:

[2012-12-22 18:58:24,835] WARN / : Unexpected error during authentication
java.util.NoSuchElementException
 at java.util.ArrayList$Itr.next(ArrayList.java:794)
 at com.google.gerrit.server.account.AccountManager.create(AccountManager.java:291)
 at com.google.gerrit.server.account.AccountManager.authenticate(AccountManager.java:122)
 at com.google.gerrit.httpd.auth.openid.OpenIdServiceImpl.doAuth(OpenIdServiceImpl.java:409)
 at com.google.gerrit.httpd.auth.openid.OpenIdLoginServlet.doPost(OpenIdLoginServlet.java:50)
 at com.google.gerrit.httpd.auth.openid.OpenIdLoginServlet.doGet(OpenIdLoginServlet.java:40)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)

Here's a step-by-step procedure that will help you set things up right the first time you try.

Prerequisites:

  • Linux box, 
  • Sun JAVA virtual machine - version 1.6 or later, 
  • PostgreSQL installed and running

Here's what you do:

  1. As root: Prepare Gerrit repository folder, say
    mkdir /var/repositories

  2. As root: Change permissions on this folder, allowing your gerrit2 user full access:
    chown -R gerrit2 /var/repositories
  3. As gerrit2: Initialize a new repository:
    git init --bare /var/repositories/All-Projects.git
  4. As gerrit2: Create new PostgreSQL user:
    createuser -A -D -P -E gerrit2
  5. As gerrit2: Create new PostgreSQL database:
    createdb -E UTF-8 -O gerrit2 reviewdb
  6. As gerrit2: Download the latest gerrit2 installation package and launch the setup:
    java -jar gerrit-full-2.5.1.war init \
        -d /home/gerrit2/review_site
  7. Finally, navigate to Gerrit web site and register your new user:
    xdg-open http://localhost:8080/#/admin/projects
Now, if you are facing complete reinstallation of your system, and upgrading is simply not possible (say, you did the same thing I did previously), here's what you need to do:
  1. As gerrit2: stop the review site:
    cd ~/review_site bin/gerrit.sh stop
  2. As postgres: drop the database:
    dropdb reviewdb
  3. As gerrit2: remove the All-Projects repo:
    rm -rf /var/repositories/All-Projects.git
Yes, this will purge the history of your reviews. It sucks - well, kind of. Ultimately you will get fully functional review site, which is pretty much what counts more.

Next step is usually to trim the approval categories. It feels kind-of wrong to manipulate the database directly, but then, at the same time, it feels stupid to go through verification of own changes.

Typically, one could do this by invoking:

ssh server gerrit gsql
delete from approval_categories \
    [where category_id="VRIF" or category_id="CRVW"]
delete from approval_category_values \
    [where category_id ...]

The contents of these two tables are:


gerrit> select * from approval_categories;
 name        | abbreviated_name | position | function_name | copy_min_score | category_id
 ------------+------------------+----------+---------------+----------------+------------
 Verified    | V                | 0        | MaxWithBlock  | N              | VRIF
 Code Review | R                | 1        | MaxWithBlock  | Y              | CRVW
(2 rows; 14 ms)

gerrit> select * from approval_category_values; name                                            | category_id | value
 ------------------------------------------------+-------------+------
 Verified                                        | VRIF        | 1
 No score                                        | VRIF        | 0
 Fails                                           | VRIF        | -1
 Looks good to me, approved                      | CRVW        | 2
 Looks good to me, but someone else must approve | CRVW        | 1
 No score                                        | CRVW        | 0
 I would prefer that you didn't submit this      | CRVW        | -1
 Do not submit                                   | CRVW        | -2
(8 rows; 7 ms)

so, nothing's lost - just delete the contents. Gerrit still does need an approval category. To add them, execute:

ssh server gerrit gsql

insert into approval_categories values \
    ("Approved", 'A', 0, MaxNoBlock, 'Y', "APRV");
insert into approval_category_values values \
    ('No Score', 'APRV', 0);
insert into approval_category_values values \
    ('Approved', 'APRV', 1);

and restart the server (for some, invoking flush-caches would work, too).