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Auto-tools/Projects/MozBase

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Revision as of 19:49, 7 January 2013 by Jhammel (talk | contribs) (→‎Mirroring: more usage info)

Overview

Mozbase is a set of easy-to-use Python packages forming a supplemental standard library for Mozilla. It provides consistency and reduces redundancy in automation and other system-level software. All of Mozilla's test harnesses use mozbase to some degree, including Talos, mochitest, reftest, Autophone, and Eideticker.

Repository: https://github.com/mozilla/mozbase

Documentation: http://mozbase.readthedocs.org

Bugs:

Please file bugs against https://bugzilla.mozilla.org/enter_bug.cgi?product=Testing&component=Mozbase

The roadmap of getting mozbase on mozilla-central is detailed at https://wiki.mozilla.org/Auto-tools/Projects/MozBase/Roadmap

Mozbase requires python 2.5, 2.6, or 2.7 however, Talos still requires compatibility with python 2.4 (bug 734466), so mozbase dependencies in http://hg.mozilla.org/build/talos/file/tip/setup.py *must* be kept compatible with python 2.4

Development Practices

If you're developing mozbase code, you're in luck! You've found the right place to read about our development practices. Please do :)

Getting Help with Mozbase

Mozbase is developed by the Automation and Tools team. It is under the governorship of Will Lachance (:wlach) and Jeff Hammel (:jhammel). Please feel free to stop by #ateam on IRC with any questions and we will be happy to help you! Or if something is wrong, please file a bug and we'll look at it as soon as possible.

Installing Mozbase for Development

Initial Setup

(Some of these steps may not be necessary if you've already set up your computer for development.)

  • (windows-only) Launch the 'start-l10n.bat', to get a mozilla-build environment.
  • Install virtualenv, if it's not on your system already. If on Windows, be sure to do this from inside the shell launched via 'start-l10n.bat'.

Installing Mozbase

 virtualenv mozbase
  • Activate the virtualenv:
 cd mozbase; . bin/activate
  • Create a source directory:
 mkdir src
  • Clone mozbase in the source directory:
 cd src; git clone git://github.com/mozilla/mozbase.git
  • Install packages in the virtualenv
 cd mozbase; python setup_development.py

Working on Mozbase and Contributing Patches

Changes to mozbase require peer review of a properly filed bug. Here's a workflow that will help you make changes to mozbase in isolation.

  • If there isn't one already on file, create a bug corresponding to your issue in the mozbase bugzilla component.
  • Inside the mozbase checkout, create a local branch corresponding to your bug:
 git checkout -b bug-xxxxxxx
  • Develop your patch
  • If people commit work to the master branch while you're working on your patch, you can make things up to date by issuing the following commands from your checked out branch:
 git pull origin master
 git rebase master
  • When you're happy with your work, commit your changes, giving them a descriptive title from the bug summary:
 Bug 706981 - Check for DistributionNotFound error
  • Generate a patch for your bug
 git show --format="From: %an <%ae>%n%s%n%b" > bug-xxxx.patch
  • Attach the patch to the bug and ask the appropriate person for review. If further changes are required, you can amend changes to your patch by using 'git commit --amend'. When you're all done, ask someone with mozbase commit privileges to merge your changes into the mozilla mozbase repository.

This is a recommended way of working with mozbase. In general the important things are:

What NOT to do:

  • don't use github issues. We track our development with bugzilla, so if you file a github issue that just makes more work for us to file a corresponding bugzilla issue and have double the issues to close out
  • don't use pull requests. This again requires us to do more work duplicating the pull request and associated patch in bugzilla


Design Principles

  • if we're extending the standard library, we should extend via inheritance
    • we are free to extend and add new methods, but we should support the existing methods when possible

Adding a New Mozbase Package

A new mozbase package should start with version '0.0'. It should be bumped to a real version when released to pypi

Tests

Mozbase packages are accompanied by tests in order to ensure and illustrate proper functionality.

Continuous integration via autobot is at http://k0s.org:8010/

Running the tests

You will need make and gcc in order to run the tests. If you're running windows, this is available in MozillaBuild.

Ensure that all mozbase packages are installed as the tests require them.

Then run the test.py test runner from the root of the git repository: 

   python test.py

This will run all tests from test-manifest.ini which is parsed with ManifestDestiny. On success 'test.py' should print the number of tests run and 'OK': 

   ----------------------------------------------------------------------
   Ran 56 tests in 114.807s
   
   OK

Check-in policy

Review Policy

All changes should be reviewed before landing. The one exception is version bumps. See https://wiki.mozilla.org/Auto-tools/Projects/MozBase#Versioning for how these are done.

If you have admin permissions to the upstream mozbase repository, you can land the reviewed patch on your own. Otherwise you should ask someone else to get the patch landed.

Landing the patch

Please never use the Github auto-merge feature!

To land the patch on the target branch make use of the git merge --squash command, which will land the patch as a single commit. After running this command you will have to issue a new commit message before being able to push the changes. Make sure that you add the right author if the patch wasn't created by yourself. Also use the right commit message format as shown below which includes the bug number and the list of reviewers.

Here an example how to land a patch from the feature branch onto master:

  • git checkout master
  • git checkout -b feature
  • git pull remote feature # or git am patch
  • TEST the patch by running existent tests
  • git merge --squash feature
  • git commit -a -m "Bug XYZ - Add new feature to mozbase; r=reviewer" --author="foo <foo@bar>"
  • git push git@github.com:mozilla/mozbase.git master

Versioning

* NOTE: you need to have a ~/.pypirc file defined (username/password are account credentials for pypi.python.org):
* [server-login]
* username:username
* password:password

The major version should be bumped when the API changes in a non-backwards-compatible way or for other large conceptual changes. Otherwise, the minor version may be bumped. The version doesn't have to be bumped if there is no new release planned for PyPI.

When you bump a version of any mozbase package, it should be released to pypi: 

 python setup.py egg_info -RDb "" sdist register upload

and the github repository should be tagged a la 'mozrunner-1.2'. If multiple package versions are bumped, then the same changeset should be tagged for each of the package versions bumped.

Tagging the version on github: 

git pull --tags mozilla master
git tag mozrunner-1.5.5
git push --tags mozilla master

Using versionbump.py

A script, versionbump.py, located at https://github.com/mozilla/mozbase/blob/master/versionbump.py has been written to perform the steps for mozbase versioning

  • make sure you are on the master branch of the mozbase repository. If you aren't the script will bail out.
  • make sure you don't have any uncommitted changes. If you do, the script will bail out.
  • you should probably pull from git@github.com:mozilla/mozbase.git prior to running the script. If not, the script will attempt to do this for you, though it will not attempt to resolve conflicts
  • as per usual, running 
    versionbump.py --help
    will display usage information and help about CLI options
  • versionbump.py --info
    will display the package versions and their dependencies and exit

In order to bump versions, versionbump.py is used like: 

 versionbump.py mozrunner=5.8 mozprofile=0.5 -m 'bug 123456 - bump mozprofile to 0.5'

You should pass in all the packages that need bumping. If you specify a package which is pegged as an exact dependency of another package (e.g. mozrunner requires mozprofile == 0.5), you must also bump all packages which exactly depend on this package. As an example: 

 versionbump.py mozprofile=0.5

would not work as mozrunner requires mozprofile==0.4 (as of this writing) and all packages in the repository HEAD must be compatible with all other packages in the repository. In addition, packages pegged with '>=' also follow this rule unless --strict is passed.

  • running 
    versionbump.py --diff path/to/file
    will output the resultant diff to the file and revert the repository. The repository will not be tagged nor will anything be uploaded to pypi
  • -m or --message should be passed to the command line in order to finalize the commit, tag the repository, and upload to pypi. If you do not pass -m or --message, the changes will be made to your working copy but not committed. The repository will not be tagged nor will packages be uploaded to pypi
  • --dry-run will print out what versionbump.py will do but no files will be changed or commands actually called

It is encouraged to use --diff and/or --dry-run before actually doing the version bump to make sure that it will do what you expect it to do. In the case where a known error is encountered, versionbump.py will revert to the original (clean) repository state. In the case where an unexpected error is encountered, the repository state is not reverted (so that it is easier to debug what happened).

Limitations of versionbump.py:

  • it is expected that setup.py versions are specified as 
    PACKAGE_VERSION = '1.2.3'
    (or "1.2.3"). They currently all are.
  • versionbump.py can only handle simple dependencies. That is for install_requires, foo, foo == 1.2.3, bar >= 4.5.6 are fine, but foo == 1.1, == 1.2 is not. Mozbase currently only has simple dependencies.

Mirroring

A copy of mozbase is mirrored to mozilla-central for use by software there: http://mxr.mozilla.org/mozilla-central/source/testing/mozbase/ .

All commits should be made against the github mozbase repository, not mozilla-central.

Mozbase packages are mirrored from released versions: https://wiki.mozilla.org/Auto-tools/Projects/MozBase#Versioning . A bug should be filed to mirror the appropriate package stating the reason the package should be mirrored. When appropriate, mozbase packages should be mirrored on version bump.

Since several packages in mozbase are dependent on other mozbase packages, care must be taken to ensure that the versions of the packages on m-c are kept compatible with each other. All packages dependent on the package to be mirrored should also version-bumped and mirrored. Similarly, if any of the packages that the package to be mirrored depends on have not already been mirrored to m-c, these should also be mirrored.

A script has been written to aid with package mirrroring: generate_diff.py . This script:

  • ensures that your copy of mozilla-central is clean. This means no outstanding changes and no untracked files in testing/mozbase. Because `generate_diff.py` manipulates the repository using `hg`, this is necessary.
  • clones a fresh copy of the mozbase repository
  • ensures that the tags associated with the specified packages and associated versions exist
  • checks that the versions specified are internally consistent with what is in m-c

And if everything looks good...

  • generates a diff that will upgrade the specified packages to the specified versions. Unless specified with `-o`, the output will be in the current working directory named after the hash tag of the git repo

Usage: 

 generate_diff.py [options] package1[=version1] <package2=version2> <...>

(as displayed with: `generate_diff.py --help`)

Example: 

 │./generate_diff.py mozcrash=0.3
 Cloning into 'mozbase'...
 remote: Counting objects: 3883, done.
 remote: Compressing objects: 100% (1746/1746), done.
 remote: Total 3883 (delta 2198), reused 3773 (delta 2105)
 Receiving objects: 100% (3883/3883), 1.16 MiB | 241 KiB/s, done.
 Resolving deltas: 100% (2198/2198), done.
 Note: checking out 'mozcrash-0.3'.
 
 You are in 'detached HEAD' state. You can look around, make experimental
 changes and commit them, and you can discard any commits you make in this
 state without impacting any branches by performing another checkout.
 
 If you want to create a new branch to retain commits you create, you may
 do so (now or later) by using -b with the checkout command again. Example:
 
   git checkout -b new_branch_name
 
 HEAD is now at 1634023... Bug 813132 - support tbpl friendly output from mozcrash and python 2.4
 HEAD is now at 1634023... Bug 813132 - support tbpl friendly output from mozcrash and python 2.4
 removing testing/mozbase/mozcrash/README.md
 undeleting testing/mozbase/mozcrash/README.md
 reverting testing/mozbase/mozcrash/mozcrash/__init__.py
 reverting testing/mozbase/mozcrash/mozcrash/mozcrash.py
 reverting testing/mozbase/mozcrash/setup.py
 Diff at /home/jhammel/mozilla/src/mozilla-central/testing/mozbase/1634023250af1cb9bce9ccbf9dfe620e4a95c970.diff

Licensing

Mozbase code will be checked into mozilla-central. Therefore, code should be appropriately licensed with MPL2. See https://www.mozilla.org/MPL/headers/ to find a copy.

Documentation

  • this page is the mozbase project page that gives information for core mozbase developers and about the project itself. Documentation may move to and from this page and the various READMEs and full docs.

Directory Structure and Imports

The mozbase repository contains several packages. Each package should have a directory structure like: 

   ${PACKAGE}
   ${PACKAGE}/setup.py
   ${PACKAGE}/README.md
   ${PACKAGE}/${PACKAGE}
   ${PACKAGE}/${PACKAGE}/__init__.py

Even if the package consists of a single module, this structure should be used (vs. py_modules) and '__init__.py' set to 

   from ${MODULE} import *

(with a sensible '__all__' defined in the module).

This structure serves several purposes:

  • this allows packages to be installed with the 'setup.py' script
  • if packages cannot be installed (for deployment reasons), altering 'sys.path' (or '$PYTHONPATH') can be used to utilize
  • with single-module packages, you get a sensibly named file that is imported in '__init__.py' and can be mirrored easily and it conforms to how all of the other packages work


Downstream packages

Many mozbase packages depend on other mozbase packages. The packages and their versions at https://github.com/mozilla/mozbase should be kept compatible with one another.

Other packages also depend on mozbase: http://k0s.org/mozilla/mozbase/dependencies.html Releases and version changes should be tested against downstream packages to ensure compatibility

PyPI

Releases of mozbase packages are uploaded to the Python Package Index (pypi) so that they may be easily consumed by setuptools and other installers.

Package owners:

  • ahal
  • ctalbert
  • davehunt
  • David.Burns
  • elvis314
  • jgriffin
  • k0s
  • markrcote
  • whimboo
  • wlach

Integration Notes

Notes on integration with existing test harnesses.

Mozbase and Mozharness

Mozbase and mozharness overlap intent with respect to making testing software and tools reusable and easy to write and extend.

mozharness docs: http://escapewindow.com/mozharness/

Production use of mozharness will use mozbase packages from an internal pypi: http://puppetagain.pub.build.mozilla.org/data/python/packages/ (from https://wiki.mozilla.org/ReleaseEngineering/PuppetAgain/Python )

  • mozprocess (basic low level process management)
    • subclass popen
      • open
      • poll
      • kill
      • wait
      • stdout
      • pid
    • readWithTimeout
  • mozfile (os file i/o managemenet)
    • copyfile
    • removedir
    • makedir
  • mozlog (log file management)
    • write
    • init

unique to harnesses

  • mozenv
    • addvars
    • createenv
  • mozprofile
    • addExtension(s)
    • addPref(s)
    • writeProfile
    • copyProfile
    • renameProfile
    • deleteProfile
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