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Refactoring delegate_to code
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Now, instead of relying on hostvars on the executor side, we compile
the vars for the delegated to host in a special internal variable and
have the PlayContext object look for things there when applying task/
var overrides, which is much cleaner and takes advantage of the code
already dealing with all of the magic variable variations.

Fixes #12127
Fixes #12079
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@jimi-c
jimi-c committed Sep 18, 2015
1 parent fa69e8e commit 1f5584a
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Showing 3 changed files with 55 additions and 77 deletions.
84 changes: 12 additions & 72 deletions lib/ansible/executor/task_executor.py
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Original file line number Diff line number Diff line change
Expand Up @@ -474,7 +474,18 @@ def _get_connection(self, variables):
self._play_context.remote_addr = self._host.address

if self._task.delegate_to is not None:
self._compute_delegate(variables)
# since we're delegating, we don't want to use interpreter values
# which would have been set for the original target host
for i in variables.keys():
if i.startswith('ansible_') and i.endswith('_interpreter'):
del variables[i]
# now replace the interpreter values with those that may have come
# from the delegated-to host
delegated_vars = variables.get('ansible_delegated_vars', dict())
if isinstance(delegated_vars, dict):
for i in delegated_vars:
if i.startswith("ansible_") and i.endswith("_interpreter"):
variables[i] = delegated_vars[i]

conn_type = self._play_context.connection
if conn_type == 'smart':
Expand Down Expand Up @@ -529,74 +540,3 @@ def _get_action_handler(self, connection, templar):

return handler

def _compute_delegate(self, variables):

# get the vars for the delegate by its name
try:
self._display.debug("Delegating to %s" % self._task.delegate_to)
if self._task.delegate_to in C.LOCALHOST and self._task.delegate_to not in variables['hostvars']:
this_info = dict(ansible_connection="local")
for alt_local in C.LOCALHOST:
if alt_local in variables['hostvars']:
this_info = variables['hostvars'][self._task.delegate_to]
if this_info == Undefined:
this_info = dict(ansible_connection="local")
break
else:
this_info = variables['hostvars'][self._task.delegate_to]

except Exception as e:
# make sure the inject is empty for non-inventory hosts
this_info = {}
self._display.debug("Delegate to lookup failed due to: %s" % str(e))

conn = this_info.get('ansible_connection')
if conn:
self._play_context.connection = conn
if conn in ('smart', 'paramiko'):
# smart and paramiko connections will be using some kind of ssh,
# so use 'ssh' for the string to check connection variables
conn_test = 'ssh'
else:
conn_test = conn
else:
# default to ssh for the connection variable test, as
# that's the historical default
conn_test = 'ssh'

# get the real ssh_address for the delegate and allow ansible_ssh_host to be templated
self._play_context.remote_addr = this_info.get('ansible_%s_host' % conn_test, this_info.get('ansible_host', self._task.delegate_to))
self._play_context.remote_user = this_info.get('ansible_%s_user' % conn_test, this_info.get('ansible_user', self._play_context.remote_user))
self._play_context.port = this_info.get('ansible_%s_port' % conn_test, this_info.get('ansible_port', self._play_context.port))
self._play_context.password = this_info.get('ansible_%s_pass' % conn_test, this_info.get('ansible_pass', self._play_context.password))
self._play_context.private_key_file = this_info.get('ansible_%s_private_key_file' % conn_test, self._play_context.private_key_file)

# because of the switch from su/sudo -> become, the become pass for the
# delegated-to host may be in one of several fields, so try each until
# (maybe) one is found.
for become_pass in ('ansible_become_password', 'ansible_become_pass', 'ansible_sudo_password', 'ansible_sudo_pass'):
if become_pass in this_info:
self._play_context.become_pass = this_info[become_pass]
break

# Last chance to get private_key_file from global variables.
# this is useful if delegated host is not defined in the inventory
if self._play_context.private_key_file is None:
self._play_context.private_key_file = this_info.get('ansible_ssh_private_key_file', None)

if self._play_context.private_key_file is None:
key = this_info.get('private_key_file', None)
if key:
self._play_context.private_key_file = os.path.expanduser(key)

# since we're delegating, we don't want to use interpreter values
# which would have been set for the original target host
for i in variables.keys():
if i.startswith('ansible_') and i.endswith('_interpreter'):
del variables[i]
# now replace the interpreter values with those that may have come
# from the delegated-to host
for i in this_info:
if i.startswith("ansible_") and i.endswith("_interpreter"):
variables[i] = this_info[i]

11 changes: 9 additions & 2 deletions lib/ansible/playbook/play_context.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -279,10 +279,16 @@ def set_task_and_variable_override(self, task, variables):
setattr(new_info, attr, attr_val)

# next, use the MAGIC_VARIABLE_MAPPING dictionary to update this
# connection info object with 'magic' variables from the variable list
# connection info object with 'magic' variables from the variable list.
# If the value 'ansible_delegated_vars' is in the variables, it means
# we have a delegated-to host, so we check there first before looking
# at the variables in general
delegated_vars = variables.get('ansible_delegated_vars', dict())
for (attr, variable_names) in iteritems(MAGIC_VARIABLE_MAPPING):
for variable_name in variable_names:
if variable_name in variables:
if isinstance(delegated_vars, dict) and variable_name in delegated_vars:
setattr(new_info, attr, delegated_vars[variable_name])
elif variable_name in variables:
setattr(new_info, attr, variables[variable_name])

# make sure we get port defaults if needed
Expand All @@ -296,6 +302,7 @@ def set_task_and_variable_override(self, task, variables):
elif new_info.become_method == 'su' and new_info.su_pass:
setattr(new_info, 'become_pass', new_info.su_pass)


# finally, in the special instance that the task was specified
# as a local action, override the connection in case it was changed
# during some other step in the process
Expand Down
37 changes: 34 additions & 3 deletions lib/ansible/vars/__init__.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@
from ansible import constants as C
from ansible.cli import CLI
from ansible.errors import AnsibleError
from ansible.inventory.host import Host
from ansible.parsing import DataLoader
from ansible.plugins.cache import FactCache
from ansible.template import Templar
Expand Down Expand Up @@ -127,7 +128,7 @@ def _preprocess_vars(self, a):
return data


def get_vars(self, loader, play=None, host=None, task=None, include_hostvars=True, use_cache=True):
def get_vars(self, loader, play=None, host=None, task=None, include_hostvars=True, include_delegate_to=True, use_cache=True):
'''
Returns the variables, with optional "context" given via the parameters
for the play, host, and task (which could possibly result in different
Expand Down Expand Up @@ -276,6 +277,38 @@ def get_vars(self, loader, play=None, host=None, task=None, include_hostvars=Tru
if task._role:
all_vars['role_path'] = task._role._role_path

# if we have a task and we're delegating to another host, figure out the
# variables for that host now so we don't have to rely on hostvars later
if task.delegate_to is not None and include_delegate_to:
# we unfortunately need to template the delegate_to field here,
# as we're fetching vars before post_validate has been called on
# the task that has been passed in
templar = Templar(loader=loader, variables=all_vars)
delegated_host_name = templar.template(task.delegate_to)

# now try to find the delegated-to host in inventory, or failing that,
# create a new host on the fly so we can fetch variables for it
delegated_host = None
if self._inventory is not None:
delegated_host = self._inventory.get_host(delegated_host_name)
# try looking it up based on the address field, and finally
# fall back to creating a host on the fly to use for the var lookup
if delegated_host is None:
for h in self._inventory.get_hosts(ignore_limits_and_restrictions=True):
# check if the address matches, or if both the delegated_to host
# and the current host are in the list of localhost aliases
if h.address == delegated_host_name or h.name in C.LOCALHOST and delegated_host_name in C.LOCALHOST:
delegated_host = h
break
else:
delegated_host = Host(name=delegated_host_name)
else:
delegated_host = Host(name=delegated_host_name)

# now we go fetch the vars for the delegated-to host and save them in our
# master dictionary of variables to be used later in the TaskExecutor/PlayContext
all_vars['ansible_delegated_vars'] = self.get_vars(loader=loader, play=play, host=delegated_host, task=task, include_delegate_to=False, include_hostvars=False)

if self._inventory is not None:
all_vars['inventory_dir'] = self._inventory.basedir()
if play:
Expand All @@ -287,10 +320,8 @@ def get_vars(self, loader, play=None, host=None, task=None, include_hostvars=Tru
all_vars['play_hosts'] = host_list
all_vars['ansible_play_hosts'] = host_list


# the 'omit' value alows params to be left out if the variable they are based on is undefined
all_vars['omit'] = self._omit_token

all_vars['ansible_version'] = CLI.version_info(gitinfo=False)

if 'hostvars' in all_vars and host:
Expand Down

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