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"""Charm Helpers saltstack - declare the state of your machines.
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This helper enables you to declare your machine state, rather than
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program it procedurally (and have to test each change to your procedures).
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Your install hook can be as simple as:
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from charmhelpers.contrib.saltstack import (
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install_salt_support()
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update_machine_state('machine_states/dependencies.yaml')
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update_machine_state('machine_states/installed.yaml')
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and won't need to change (nor will its tests) when you change the machine
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It's using a python package called salt-minion which allows various formats for
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specifying resources, such as:
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The docs for all the different state definitions are at:
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http://docs.saltstack.com/ref/states/all/
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* Add test helpers which will ensure that machine state definitions
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are functionally (but not necessarily logically) correct (ie. getting
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salt to parse all state defs.
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* Add a link to a public bootstrap charm example / blogpost.
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* Find a way to obviate the need to use the grains['charm_dir'] syntax
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# Copyright 2013 Canonical Ltd.
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# Charm Helpers Developers <juju@lists.ubuntu.com>
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import charmhelpers.core.host
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import charmhelpers.core.hookenv
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charm_dir = os.environ.get('CHARM_DIR', '')
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salt_grains_path = '/etc/salt/grains'
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def install_salt_support(from_ppa=True):
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"""Installs the salt-minion helper for machine state.
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By default the salt-minion package is installed from
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the saltstack PPA. If from_ppa is False you must ensure
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that the salt-minion package is available in the apt cache.
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subprocess.check_call([
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'/usr/bin/add-apt-repository',
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subprocess.check_call(['/usr/bin/apt-get', 'update'])
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# We install salt-common as salt-minion would run the salt-minion
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charmhelpers.core.host.apt_install('salt-common')
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def update_machine_state(state_path):
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"""Update the machine state using the provided state declaration."""
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juju_config_2_grains()
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subprocess.check_call([
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def juju_config_2_grains():
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"""Insert the juju config as salt grains for use in state templates.
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This includes any current relation-get data, and the charm
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config = charmhelpers.core.hookenv.config()
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# Add the charm_dir which we will need to refer to charm
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# file resources etc.
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config['charm_dir'] = charm_dir
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config['local_unit'] = charmhelpers.core.hookenv.local_unit()
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config.update(charmhelpers.core.hookenv.relation_get())
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# Don't use non-standard tags for unicode which will not
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# work when salt uses yaml.load_safe.
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yaml.add_representer(unicode, lambda dumper,
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value: dumper.represent_scalar(
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u'tag:yaml.org,2002:str', value))
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with open(salt_grains_path, "w+") as fp:
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fp.write(config.yaml())
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lib/charm-helpers/charmhelpers/contrib/saltstack/__init__.py
