Stupid Buildout Tricks

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