Added comments to explain the playbook code.

pull/3/head
Michael DeHaan 13 years ago
parent 17a6ddb7ee
commit c0ac0e9b62

@ -49,8 +49,11 @@ class PlayBook(object):
remote_pass =C.DEFAULT_REMOTE_PASS,
verbose=False):
# runner is reused between calls
# TODO, once ansible-playbook is it's own script this will
# have much LESS parameters to the constructor and will
# read most everything per pattern from the playbook
# and this will be greatly simplified
self.host_list = host_list
self.module_path = module_path
self.forks = forks
@ -59,25 +62,32 @@ class PlayBook(object):
self.remote_pass = remote_pass
self.verbose = verbose
# list of changes/invocations/failure counts per host
# store the list of changes/invocations/failure counts
# as a dictionary of integers keyed off the hostname
self.processed = {}
self.dark = {}
self.changed = {}
self.invocations = {}
self.failures = {}
# playbook file can be passed in as a path or
# as file contents (to support API usage)
if type(playbook) == str:
playbook = yaml.load(file(playbook).read())
self.playbook = playbook
def run(self):
''' run against all patterns in the playbook '''
''' run all patterns in the playbook '''
# loop through all patterns and run them
for pattern in self.playbook:
self._run_pattern(pattern)
if self.verbose:
print "\n"
# summarize the results
results = {}
for host in self.processed.keys():
results[host] = {
@ -96,20 +106,33 @@ class PlayBook(object):
'''
if host_list is None:
# pruned host lists occur when running triggered
# actions where not all hosts have changed
# though top-level tasks will pass in "None" here
host_list = self.host_list
# load the module name and parameters from the task
# entry
instructions = task['do']
(comment, module_details) = instructions
tokens = shlex.split(module_details)
module_name = tokens[0]
module_args = tokens[1:]
# tasks can be direct (run on all nodes matching
# the pattern) or conditional, where they ran
# as the result of a change handler on a subset
# of all of the hosts
if self.verbose:
if not conditional:
print "\nTASK [%s]" % (comment)
else:
print "\nNOTIFIED [%s]" % (comment)
# load up an appropriate ansible runner to
# run the task in parallel
runner = ansible.runner.Runner(
pattern=pattern,
module_name=module_name,
@ -123,6 +146,10 @@ class PlayBook(object):
)
results = runner.run()
# walk through the results and build up
# summary information about successes and
# failures. TODO: split into subfunction
dark = results.get("dark", [])
contacted = results.get("contacted", [])
ok_hosts = contacted.keys()
@ -165,8 +192,11 @@ class PlayBook(object):
else:
self.changed[host] = self.changed[host] + 1
# flag which notify handlers need to be run
# this will be on a SUBSET of the actual host list. For instance
# a file might need to be written on only half of the nodes so
# we would only trigger restarting Apache on half of the nodes
subtasks = task.get('notify', [])
if len(subtasks) > 0:
for host, results in contacted.items():
@ -174,19 +204,22 @@ class PlayBook(object):
for subtask in subtasks:
self._flag_handler(handlers, subtask, host)
# TODO: if a host fails in any task, remove it from
# the host list immediately
def _flag_handler(self, handlers, match_name, host):
'''
if a task has any notify elements, flag handlers for run
at end of execution cycle for hosts that have indicated
changes have been made
'''
# for all registered handlers in the ansible playbook
# for this particular pattern group
for x in handlers:
attribs = x["do"]
name = attribs[0]
if match_name == name:
# flag the handler with the list of hosts
# it needs to be run on, it will be run later
if not x.has_key("run"):
x['run'] = []
x['run'].append(host)
@ -196,22 +229,31 @@ class PlayBook(object):
run a list of tasks for a given pattern, in order
'''
# get configuration information about the pattern
pattern = pg['pattern']
tasks = pg['tasks']
handlers = pg['handlers']
user = pg.get('user', C.DEFAULT_REMOTE_USER)
self.host_list = pg.get('hosts', '/etc/ansible/hosts')
if self.verbose:
print "PLAY: [%s] from [%s] ********** " % (pattern, self.host_list)
# run all the top level tasks, these get run on every node
for task in tasks:
self._run_task(
pattern=pattern,
task=task,
handlers=handlers,
remote_user=user)
# handlers only run on certain nodes, they are flagged by _flag_handlers
# above. They only run on nodes when things mark them as changed, and
# handlers only get run once. For instance, the system is designed
# such that multiple config files if changed can ask for an Apache restart
# but Apache will only be restarted once (at the end).
for task in handlers:
if type(task.get("run", None)) == list:
self._run_task(
@ -223,5 +265,8 @@ class PlayBook(object):
remote_user=user
)
# end of execution for this particular pattern. Multiple patterns
# can be in a single playbook file

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