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Adding support for role dependencies.

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Fixes #3686

Dependencies are enabled by adding a new directory/file named
meta/main.yml to the role. The format of the dependencies are:

dependencies:
- { role: foo, x: 1, y: 2 }
- { role: bar, x: 3, y: 4 }
...

Dependencies inherit variables as they are seen at the time of the
dependency inclusion. For example, if foo(x=1, y=2) has a dependency
on bar(x=3,z=4), then bar will have variables (x=3,y=2,z=4).

Different roles can have dependencies on the same role, and this
variable inheritence allows for the reuse of generic roles quite easily.
For example:

Role 'car' has the following dependencies:
dependencies:
  - { role: wheel, n: 1 }
  - { role: wheel, n: 2 }
  - { role: wheel, n: 3 }
  - { role: wheel, n: 4 }

Role 'wheel' has the following dependencies:
dependencies:
- { role: tire }
- { role: brake }

The role 'car' is then used as follows:
- { role: car, type: honda }

And tasks/main.yml in each role simply contains the following:
- name: {{ type }} whatever {{ n }}
  command: echo ''

TASK: [honda tire 1]
TASK: [honda brake 1]
TASK: [honda wheel 1]
TASK: [honda tire 2]
TASK: [honda brake 2]
TASK: [honda wheel 2]
TASK: [honda tire 3]
TASK: [honda brake 3]
TASK: [honda wheel 3]
TASK: [honda tire 4]
TASK: [honda brake 4]
TASK: [honda wheel 4]
TASK: [I'm a honda]  <- (this is in roles/car/tasks/main.yml)
pull/3855/head
James Cammarata 11 years ago
parent ad595eadea
commit 9a401e73a6
1 changed files with 71 additions and 30 deletions
Show Stats Download Patch File Download Diff File

101
lib/ansible/playbook/play.py
Unescape Escape View File

@ -119,9 +119,64 @@ class Play(object):
# *************************************************
def _load_roles(self, roles, ds):
def _get_role_path(self, role):
"""
Returns the path on disk to the directory containing
the role directories like tasks, templates, etc. Also
returns any variables that were included with the role
"""
orig_path = template(self.basedir,role,self.vars)
role_vars = {}
if type(orig_path) == dict:
# what, not a path?
role_name = orig_path.get('role', None)
if role_name is None:
raise errors.AnsibleError("expected a role name in dictionary: %s" % orig_path)
role_vars = orig_path
orig_path = role_name
path = utils.path_dwim(self.basedir, os.path.join('roles', orig_path))
if not os.path.isdir(path) and not orig_path.startswith(".") and not orig_path.startswith("/"):
path2 = utils.path_dwim(self.basedir, orig_path)
if not os.path.isdir(path2):
raise errors.AnsibleError("cannot find role in %s or %s" % (path, path2))
path = path2
elif not os.path.isdir(path):
raise errors.AnsibleError("cannot find role in %s" % (path))
return (path, role_vars)
def _build_role_dependencies(self, roles, dep_stack, vars={}, level=0):
# this number is arbitrary, but it seems sane
if level > 20:
raise errors.AnsibleError("too many levels of recursion while resolving role dependencies")
for role in roles:
path,role_vars = self._get_role_path(role)
# the meta directory contains the yaml that should
# hold the list of dependencies (if any)
meta = self._resolve_main(utils.path_dwim(self.basedir, os.path.join(path, 'meta')))
if os.path.isfile(meta):
data = utils.parse_yaml_from_file(meta)
if data:
dependencies = data.get('dependencies',[])
for dep in dependencies:
(dep_path,dep_vars) = self._get_role_path(dep)
dep_vars.update(role_vars)
for k in vars.keys():
if not k in dep_vars:
dep_vars[k] = vars[k]
if 'role' in dep_vars:
del dep_vars['role']
self._build_role_dependencies([dep], dep_stack, vars=dep_vars, level=level+1)
dep_stack.append([dep,dep_vars])
# only add the current role when we're at the top level,
# otherwise we'll end up in a recursive loop
if level == 0:
dep_stack.append([role,role_vars])
return dep_stack
def _load_roles(self, roles, ds):
# a role is a name that auto-includes the following if they exist
# <rolename>/tasks/main.yml
# <rolename>/handlers/main.yml
@ -147,52 +202,37 @@ class Play(object):
# flush handlers after pre_tasks
new_tasks.append(dict(meta='flush_handlers'))
# variables if the role was parameterized (i.e. given as a hash)
has_dict = {}
roles = self._build_role_dependencies(roles, [], self.vars)
for role_path in roles:
orig_path = template(self.basedir,role_path,self.vars)
if type(orig_path) == dict:
# what, not a path?
role_name = orig_path.get('role', None)
if role_name is None:
raise errors.AnsibleError("expected a role name in dictionary: %s" % orig_path)
has_dict = orig_path
orig_path = role_name
for role,role_vars in roles:
path,ignore = self._get_role_path(role)
# special vars must be extracted from the dict to the included tasks
special_keys = [ "sudo", "sudo_user", "when", "with_items" ]
special_vars = {}
for k in special_keys:
if k in has_dict:
special_vars[k] = has_dict[k]
path = utils.path_dwim(self.basedir, os.path.join('roles', orig_path))
if not os.path.isdir(path) and not orig_path.startswith(".") and not orig_path.startswith("/"):
path2 = utils.path_dwim(self.basedir, orig_path)
if not os.path.isdir(path2):
raise errors.AnsibleError("cannot find role in %s or %s" % (path, path2))
path = path2
elif not os.path.isdir(path):
raise errors.AnsibleError("cannot find role in %s" % (path))
if k in role_vars:
special_vars[k] = role_vars[k]
task_basepath = utils.path_dwim(self.basedir, os.path.join(path, 'tasks'))
handler_basepath = utils.path_dwim(self.basedir, os.path.join(path, 'handlers'))
vars_basepath = utils.path_dwim(self.basedir, os.path.join(path, 'vars'))
task = self._resolve_main(task_basepath)
handler = self._resolve_main(handler_basepath)
vars_file = self._resolve_main(vars_basepath)
library = utils.path_dwim(self.basedir, os.path.join(path, 'library'))
if not os.path.isfile(task) and not os.path.isfile(handler) and not os.path.isfile(vars_file) and not os.path.isdir(library):
raise errors.AnsibleError("found role at %s, but cannot find %s or %s or %s or %s" % (path, task, handler, vars_file, library))
if os.path.isfile(task):
nt = dict(include=pipes.quote(task), vars=has_dict)
nt = dict(include=pipes.quote(task), vars=role_vars)
for k in special_keys:
if k in special_vars:
nt[k] = special_vars[k]
new_tasks.append(nt)
if os.path.isfile(handler):
nt = dict(include=pipes.quote(handler), vars=has_dict)
nt = dict(include=pipes.quote(handler), vars=role_vars)
for k in special_keys:
if k in special_vars:
nt[k] = special_vars[k]
@ -202,10 +242,9 @@ class Play(object):
if os.path.isdir(library):
utils.plugins.module_finder.add_directory(library)
tasks = ds.get('tasks', None)
tasks = ds.get('tasks', None)
post_tasks = ds.get('post_tasks', None)
handlers = ds.get('handlers', None)
handlers = ds.get('handlers', None)
vars_files = ds.get('vars_files', None)
if type(tasks) != list:
@ -223,8 +262,10 @@ class Play(object):
new_tasks.extend(post_tasks)
# flush handlers after post tasks
new_tasks.append(dict(meta='flush_handlers'))
new_handlers.extend(handlers)
new_vars_files.extend(vars_files)
ds['tasks'] = new_tasks
ds['handlers'] = new_handlers
ds['vars_files'] = new_vars_files

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