Webtools:SVN Guidelines

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UNDER REVIEW! This document is currently under review. Please contact clouserw with input. Once content is verified, this notice will be removed.

Gotchas

• Don't ever submit a log without a description or corresponding bug number (if applicable) -- blank changelogs should not happen
• Talk to your team
  • Don't duplicate effort
  • Be aware of other patches in progress
  • Talk to each other to ensure that your patches won't cause regressions
  • Run the usual smoke tests and (ideally) some sort of automated script that can spot SNAFUs immediately
• Don't file IT requests for production updates every hour, and don't email them every 5 minutes (or text-message them either) -- your best bet is to group your updates and push them weekly.

Examples

• Examples on this page assume:
  • You're using the command line client over ssh
  • You're editing the mozilla.com site - modify as necessary
  • You're familiar with SVN, (or at least have read our Introduction)

General Tagging Rules (quick version)

• Staging and production are as close to the same thing as we can make them.
  • If production is using vhost blocks in a .conf, staging should too
  • Code for both should always be from the same production tag.
  • (Programmers should be developing and testing on their own branches, or /trunk/)

Tagging for Staging / Production

• Basic process is: check out production, merge your changes, commit production
• Our example assumes:
  • All patches are done and checked into trunk
  • You've checked out svn+ssh://svn.mozilla.org/projects/mozilla.com/tags/production to /data/mozilla.com
  • The last revision of the production tag is revision 100. This can be found by running `svn info` in /data/mozilla.com/ and looking at the "Last Changed Rev:" line
  • The last revision of the trunk is 150. We're using a number here instead of HEAD to avoid having someone commit while you're in the middle of these steps and mess things up
• From the production tag's directory, merge the changes (If you'd like to see what's going to change without actually changing it, add --dry-run)

[clouserw@fattony /data/mozilla.com]$ svn merge -r 100:150 svn+ssh://svn.mozilla.org/projects/mozilla.com/trunk

• Find out the diffs between the production revision and the current head

[clouserw@fattony /data/mozilla.com]$ svn diff -r 100

• When you're SURE that the patches are correct/make sense, you need to commit it (substitute your rev # for 150):

[clouserw@fattony /data/mozilla.com]$ svn commit -m "Merging revisions 100:150 /trunk/ into /tags/production/"

When to push

• Only initiate a request if you are sure you are not causing a serious regression
• For major updates, you should contact major parties and discuss the update -- at least briefly -- so they are aware. When in doubt, just email everyone.  :)

Requesting an update in production

• File an IT Request when you are sure you are ready to go
• Include in the request the path to the previous snapshot tag, so an easy rollback can occur! Also include any other rollback instructions.
• Assign the appropriate severity -- note that critical or blocker pages the oncall.

Actually pushing updates

• Updating production should be a simple step, and should always be consistent if we follow this procedure:

[root@do-stage01]$ svn up

• Note: If configuration or db changes are required, specify the order and the action in the request bug
• Please paste the last line of output into the bug (Should be something like "Updated to revision 15")

After the push

• Always be available after updates are pushed
• Tell the community you have made an update -- blog, planet, etc.
• Keep an eye open for what's going on, file an IT request or page sysadmin for a rollback if necessary

Rolling back

• Sysadmins, if the developer did things right, you should be able to rollback by using:

[root@do-stage01]$ cd /data/live/www.mozilla.com/
[root@do-stage01]$ svn switch svn+ssh://svn.mozilla.org/projects/mozilla.com/tags/prod_<given datetime of revision>

• If you just want whichever is before where you're at, and you don't have a number, you can see them all with:

[root@do-stage01]$ svn ls svn+ssh://svn.mozilla.org/projects/mozilla.com/tags

• Don't forget any database/config changes that need to be rolled back