stupid buildout tricks
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Stupid Buildout Tricks
Ricardo Newbery
Wednesday, November 9, 2011
First, a basic buildout[buildout]parts = pyramid myapp
[pyramid]recipe = zc.recipe.eggdependent-scripts = trueeggs = pyramidinterpreter = py
[myapp]recipe = collective.recipe.templateinput = templates/myapp.ini.inoutput = ${buildout:directory}/etc/myapp.inikey_a = value_akey_b = value_b
Wednesday, November 9, 2011
The problemMultiple environments (dev, qa, staging, production) requiring different buildout configurations.
$ bin/buildout -c dev.cfg
$ bin/buildout -c qa1.cfg
$ bin/buildout -c qa2.cfg
ad nauseum ...
The non-dev builds are performed by release engineers who have better things to do than to read complicated release notes to figure out the right buildout incantation for the current environment.
Wednesday, November 9, 2011
The solution
Add environment variables into each non-dev environmentand have buildout figure out which config is the right one.
Wednesday, November 9, 2011
First try...
Used a buildout extension to munge the buildout config dynamically. Similar to the way collective.recipe.python works.
Two issues:
1) The variant configs are hard to read.
2) Doesn't play well with mr.developer since "bin/develop" turns off extensions when reading the config.
This was painful so I redid this w/o the buildout extensions...
Wednesday, November 9, 2011
Nothing fancy...$ bin/buildout \ -c config/variant-staging.cfg \ buildout:directory=<<PATH TO BUILDOUT ROOT>>
The "buildout:directory" value fixes the problem where buildout assumes the build context is the directory where the main config resides.
Now, I just need a script to generate this call to buildout...
$ bin/environ
Let's make this script...
Wednesday, November 9, 2011
import osimport sysimport loggingimport subprocess
logger = logging.getLogger('buildout.variants')logger.setLevel(logging.INFO)handler = logging.StreamHandler()handler.setFormatter(logging.Formatter('%(message)s'))logger.propagate = Falselogger.addHandler(handler)log = logger.info
# Is config file specified on command line?config_file = Falseargs_in = sys.argv[1:]while args_in: op = args_in.pop(0) if op[:2] == '-c': config_file = True log("buildout.variants: Disabled.")
# If config file not specified, check for one matching the environmentargs = ['bin/buildout']if not config_file: environ = os.environ.get('BUILDOUT_ENVIRON') if environ: log("buildout.variants: Detected environment '%s'" %environ) config_file = 'config/variant-%s.cfg' %environ if not os.path.exists(config_file): log("buildout.variants: Not found '%s'" %config_file) config_file = False if config_file: args.append('-c%s' %config_file) args.append('buildout:directory=%s' %os.getcwd()) log("buildout.variants: Applying variant '%s'" %config_file) else: log("buildout.variants: No variants found.")
# Run buildoutargs = args + sys.argv[1:]subprocess.call(args)
Wednesday, November 9, 2011
# Is config file specified on command line?
config_file = Falseargs_in = sys.argv[1:]while args_in: op = args_in.pop(0) if op[:2] == '-c': config_file = True log("buildout.variants: Disabled.")
Wednesday, November 9, 2011
# Check the environment
args = ['bin/buildout']
if not config_file: environ = os.environ.get('BUILDOUT_ENVIRON') if environ: log("buildout.variants: Detected '%s'" %environ) config_file = 'config/variant-%s.cfg' %environ if not os.path.exists(config_file): log("buildout.variants: Not found '%s'" %config_file) config_file = False if config_file: args.append('-c%s' %config_file) args.append('buildout:directory=%s' %os.getcwd()) log("buildout.variants: Applying variant '%s'" %config_file) else: log("buildout.variants: No variants found.")
Wednesday, November 9, 2011
# Run buildout script
args = args + sys.argv[1:]subprocess.call(args)
Wednesday, November 9, 2011
release engineers = :-)
Only need to know one command to update a buildout
$ bin/environ
Environment buildouts can always be overridden.
$ bin/environ -c local.cfg
or
$ BUILDOUT_ENVIRON=staging bin/environ
Wednesday, November 9, 2011
Extra credit
All the documentation says to run buildout with...
$ bin/buildout
Let's not confuse the release engineers with yet another way to run a buildout so I just created a custom buildout script (generated by the bootstrap.py) that folds this environment hook into bin/buildout itself.
[customizing buildout script left as an exercise for the reader]
So no more 'bin/environ'. Just 'bin/buildout' again.
Release engineers even happier :-)
Wednesday, November 9, 2011
An alternative
Another way to get environment-aware buildout configurations is with mr.scripty,
http://pypi.python.org/pypi/mr.scripty
Allows defining values in a buildout part with regular python expressions. This is possibly a more general solution although the configs may be a little harder to read. You also can't adjust a buildout config "extends" value with this method.
Wednesday, November 9, 2011
Another problemStaging environment sucks.
Occasionally, stuff in python site packages in staging borks the buildout. I could work on fixing the staging environment but I've got better things to do.
So let's isolate the buildout from site packages.
Some possible solutions...
1) virtualenv
2) zc.buildout, version 1.5.x
Let's show the virtualenv method...
Wednesday, November 9, 2011
Release notes 2.0
Using virtualenv...
$ hg clone <path-to-repo> MyBuildout
$ virtualenv --no-site-packages MyBuildout
$ cd MyBuildout
$ bin/python bootstrap.py
$ bin/buildout
Wednesday, November 9, 2011
A virtualenv bootstrapVirtualenv must be installed, or we need to create a bootstrap.
$ virtualenv.create_bootstrap_script(extra_text)
The extra_text is just some python script to hook in extra behavior during a bootstrap.
extend_parser(optparse_parser): Add or remove options from the parser here.
adjust_options(options, args): Change options or args here.
after_install(options, home_dir): After everything is installed, this function is called.
See the virtualenv docs for details.
Wednesday, November 9, 2011
(cont.)>>> extra_text = """>>> def adjust_options(options, args):>>> >>> # Create virtualenv in current dir>>> args = ['.']>>> >>> # Isolate from system python site-packages>>> options.no_site_packages = True>>>>>> # Use distribute instead of setuptools>>> options.use_distribute = True>>> """>>>>>> import virtualenv>>> out = virtualenv.create_bootstrap_script(extra_text)>>> open('virtualenv.py', 'w').write(out)
Wednesday, November 9, 2011
Release notes 3.0
Virtualenv not installed in system python...
$ hg clone <path-to-repo> MyBuildout
$ cd MyBuildout
$ python2.6 virtualenv.py
$ bin/python bootstrap.py
$ bin/buildout
Wednesday, November 9, 2011
But wait, there's more
Add the following to the virtualenv bootstrap script,
def after_install(options, home_dir): if os.path.exists('bootstrap.py'): logger.notify('Running bootstrap.py') subprocess.call([os.path.join(home_dir, 'bin', 'python'), \ 'bootstrap.py'])
Now bootstrapping virtualenv also bootstraps buildout.
Wednesday, November 9, 2011
Release notes 4.0
$ hg clone <path-to-repo> MyBuildout
$ cd MyBuildout
$ python2.6 virtualenv.py
$ bin/buildout
Wednesday, November 9, 2011
Conclusion
* Much simpler release process... happy release engineers.
* Much simpler release notes... happy developers
* Joy all around.
Wednesday, November 9, 2011
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