kolla-ansible/ansible/library/kolla_docker.py
binhong.hua 3d3f5f1613 add ulimit support for kolla_docker
By default, docker containers inherit ulimit from limits of docker
deamon. On CentOS 7, docker daemon default NOFILE is 1048576.
It can found in /usr/lib/systemd/system/docker.service.
The big limit will cause many problem. we should control it in
production environment.

Change-Id: Iab962446a94ef092977728259d9818b86cfa7f68
2019-01-24 10:54:14 +08:00

991 lines
34 KiB
Python

#!/usr/bin/env python
# Copyright 2015 Sam Yaple
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import json
import os
import shlex
import traceback
import docker
from ansible.module_utils.basic import AnsibleModule
DOCUMENTATION = '''
---
module: kolla_docker
short_description: Module for controlling Docker
description:
- A module targeting at controlling Docker as used by Kolla.
options:
common_options:
description:
- A dict containing common params such as login info
required: False
type: dict
default: dict()
action:
description:
- The action the module should take
required: True
type: str
choices:
- compare_container
- compare_image
- create_volume
- get_container_env
- get_container_state
- pull_image
- remove_container
- remove_image
- remove_volume
- recreate_or_restart_container
- restart_container
- start_container
- stop_container
api_version:
description:
- The version of the api for docker-py to use when contacting docker
required: False
type: str
default: auto
auth_email:
description:
- The email address used to authenticate
required: False
type: str
auth_password:
description:
- The password used to authenticate
required: False
type: str
auth_registry:
description:
- The registry to authenticate
required: False
type: str
auth_username:
description:
- The username used to authenticate
required: False
type: str
command:
description:
- The command to execute in the container
required: False
type: str
detach:
description:
- Detach from the container after it is created
required: False
default: True
type: bool
name:
description:
- Name of the container or volume to manage
required: False
type: str
environment:
description:
- The environment to set for the container
required: False
type: dict
image:
description:
- Name of the docker image
required: False
type: str
ipc_mode:
description:
- Set docker ipc namespace
required: False
type: str
default: None
choices:
- host
cap_add:
description:
- Add capabilities to docker container
required: False
type: list
default: list()
security_opt:
description:
- Set container security profile
required: False
type: list
default: list()
labels:
description:
- List of labels to apply to container
required: False
type: dict
default: dict()
pid_mode:
description:
- Set docker pid namespace
required: False
type: str
default: None
choices:
- host
privileged:
description:
- Set the container to privileged
required: False
default: False
type: bool
remove_on_exit:
description:
- When not detaching from container, remove on successful exit
required: False
default: True
type: bool
restart_policy:
description:
- Determine what docker does when the container exits
required: False
type: str
choices:
- never
- on-failure
- always
- unless-stopped
restart_retries:
description:
- How many times to attempt a restart if restart_policy is set
type: int
default: 10
volumes:
description:
- Set volumes for docker to use
required: False
type: list
volumes_from:
description:
- Name or id of container(s) to use volumes from
required: True
type: list
state:
description:
- Check container status
required: False
type: str
choices:
- running
- exited
- paused
tty:
description:
- Allocate TTY to container
required: False
default: False
type: bool
author: Sam Yaple
'''
EXAMPLES = '''
- hosts: kolla_docker
tasks:
- name: Start container
kolla_docker:
image: ubuntu
name: test_container
action: start_container
- name: Remove container
kolla_docker:
name: test_container
action: remove_container
- name: Pull image without starting container
kolla_docker:
action: pull_image
image: private-registry.example.com:5000/ubuntu
- name: Create named volume
kolla_docker:
action: create_volume
name: name_of_volume
- name: Remove named volume
kolla_docker:
action: remove_volume
name: name_of_volume
- name: Remove image
kolla_docker:
action: remove_image
image: name_of_image
'''
def get_docker_client():
return docker.APIClient
class DockerWorker(object):
def __init__(self, module):
self.module = module
self.params = self.module.params
self.changed = False
# Use this to store arguments to pass to exit_json().
self.result = {}
# TLS not fully implemented
# tls_config = self.generate_tls()
options = {
'version': self.params.get('api_version')
}
self.dc = get_docker_client()(**options)
def generate_tls(self):
tls = {'verify': self.params.get('tls_verify')}
tls_cert = self.params.get('tls_cert'),
tls_key = self.params.get('tls_key'),
tls_cacert = self.params.get('tls_cacert')
if tls['verify']:
if tls_cert:
self.check_file(tls_cert)
self.check_file(tls_key)
tls['client_cert'] = (tls_cert, tls_key)
if tls_cacert:
self.check_file(tls_cacert)
tls['verify'] = tls_cacert
return docker.tls.TLSConfig(**tls)
def check_file(self, path):
if not os.path.isfile(path):
self.module.fail_json(
failed=True,
msg='There is no file at "{}"'.format(path)
)
if not os.access(path, os.R_OK):
self.module.fail_json(
failed=True,
msg='Permission denied for file at "{}"'.format(path)
)
def check_image(self):
find_image = ':'.join(self.parse_image())
for image in self.dc.images():
repo_tags = image.get('RepoTags')
if not repo_tags:
continue
for image_name in repo_tags:
if image_name == find_image:
return image
def check_volume(self):
for vol in self.dc.volumes()['Volumes'] or list():
if vol['Name'] == self.params.get('name'):
return vol
def check_container(self):
find_name = '/{}'.format(self.params.get('name'))
for cont in self.dc.containers(all=True):
if find_name in cont['Names']:
return cont
def get_container_info(self):
container = self.check_container()
if not container:
return None
return self.dc.inspect_container(self.params.get('name'))
def compare_container(self):
container = self.check_container()
if not container or self.check_container_differs():
self.changed = True
return self.changed
def check_container_differs(self):
container_info = self.get_container_info()
return (
self.compare_cap_add(container_info) or
self.compare_security_opt(container_info) or
self.compare_image(container_info) or
self.compare_ipc_mode(container_info) or
self.compare_labels(container_info) or
self.compare_privileged(container_info) or
self.compare_pid_mode(container_info) or
self.compare_volumes(container_info) or
self.compare_volumes_from(container_info) or
self.compare_environment(container_info) or
self.compare_container_state(container_info) or
self.compare_dimensions(container_info) or
self.compare_command(container_info)
)
def compare_ipc_mode(self, container_info):
new_ipc_mode = self.params.get('ipc_mode')
current_ipc_mode = container_info['HostConfig'].get('IpcMode')
if not current_ipc_mode:
current_ipc_mode = None
# only check IPC mode if it is specified
if new_ipc_mode is not None and new_ipc_mode != current_ipc_mode:
return True
return False
def compare_cap_add(self, container_info):
new_cap_add = self.params.get('cap_add', list())
current_cap_add = container_info['HostConfig'].get('CapAdd',
list())
if not current_cap_add:
current_cap_add = list()
if set(new_cap_add).symmetric_difference(set(current_cap_add)):
return True
def compare_security_opt(self, container_info):
ipc_mode = self.params.get('ipc_mode')
pid_mode = self.params.get('pid_mode')
privileged = self.params.get('privileged', False)
# NOTE(jeffrey4l) security opt is disabled when using host ipc mode or
# host pid mode or privileged. So no need to compare security opts
if ipc_mode == 'host' or pid_mode == 'host' or privileged:
return False
new_sec_opt = self.params.get('security_opt', list())
current_sec_opt = container_info['HostConfig'].get('SecurityOpt',
list())
if not current_sec_opt:
current_sec_opt = list()
if set(new_sec_opt).symmetric_difference(set(current_sec_opt)):
return True
def compare_pid_mode(self, container_info):
new_pid_mode = self.params.get('pid_mode')
current_pid_mode = container_info['HostConfig'].get('PidMode')
if not current_pid_mode:
current_pid_mode = None
if new_pid_mode != current_pid_mode:
return True
def compare_privileged(self, container_info):
new_privileged = self.params.get('privileged')
current_privileged = container_info['HostConfig']['Privileged']
if new_privileged != current_privileged:
return True
def compare_image(self, container_info=None):
container_info = container_info or self.get_container_info()
parse_repository_tag = docker.utils.parse_repository_tag
if not container_info:
return True
new_image = self.check_image()
current_image = container_info['Image']
if not new_image:
return True
if new_image['Id'] != current_image:
return True
# NOTE(Jeffrey4l) when new image and the current image have
# the same id, but the tag name different.
elif (parse_repository_tag(container_info['Config']['Image']) !=
parse_repository_tag(self.params.get('image'))):
return True
def compare_labels(self, container_info):
new_labels = self.params.get('labels')
current_labels = container_info['Config'].get('Labels', dict())
image_labels = self.check_image().get('Labels', dict())
for k, v in image_labels.items():
if k in new_labels:
if v != new_labels[k]:
return True
else:
del current_labels[k]
if new_labels != current_labels:
return True
def compare_volumes_from(self, container_info):
new_vols_from = self.params.get('volumes_from')
current_vols_from = container_info['HostConfig'].get('VolumesFrom')
if not new_vols_from:
new_vols_from = list()
if not current_vols_from:
current_vols_from = list()
if set(current_vols_from).symmetric_difference(set(new_vols_from)):
return True
def compare_volumes(self, container_info):
volumes, binds = self.generate_volumes()
current_vols = container_info['Config'].get('Volumes')
current_binds = container_info['HostConfig'].get('Binds')
if not volumes:
volumes = list()
if not current_vols:
current_vols = list()
if not current_binds:
current_binds = list()
if set(volumes).symmetric_difference(set(current_vols)):
return True
new_binds = list()
if binds:
for k, v in binds.items():
new_binds.append("{}:{}:{}".format(k, v['bind'], v['mode']))
if set(new_binds).symmetric_difference(set(current_binds)):
return True
def compare_environment(self, container_info):
if self.params.get('environment'):
current_env = dict()
for kv in container_info['Config'].get('Env', list()):
k, v = kv.split('=', 1)
current_env.update({k: v})
for k, v in self.params.get('environment').items():
if k not in current_env:
return True
if current_env[k] != v:
return True
def compare_container_state(self, container_info):
new_state = self.params.get('state')
current_state = container_info['State'].get('Status')
if new_state != current_state:
return True
def compare_dimensions(self, container_info):
new_dimensions = self.params.get('dimensions')
# NOTE(mgoddard): The names used by Docker are inconsisent between
# configuration of a container's resources and the resources in
# container_info['HostConfig']. This provides a mapping between the
# two.
dimension_map = {
'mem_limit': 'Memory', 'mem_reservation': 'MemoryReservation',
'memswap_limit': 'MemorySwap', 'cpu_period': 'CpuPeriod',
'cpu_quota': 'CpuQuota', 'cpu_shares': 'CpuShares',
'cpuset_cpus': 'CpusetCpus', 'cpuset_mems': 'CpusetMems',
'kernel_memory': 'KernelMemory', 'blkio_weight': 'BlkioWeight',
'ulimits': 'Ulimits'}
unsupported = set(new_dimensions.keys()) - \
set(dimension_map.keys())
if unsupported:
self.module.exit_json(
failed=True, msg=repr("Unsupported dimensions"),
unsupported_dimensions=unsupported)
current_dimensions = container_info['HostConfig']
for key1, key2 in dimension_map.items():
# NOTE(mgoddard): If a resource has been explicitly requested,
# check for a match. Otherwise, ensure is is set to the default.
if key1 in new_dimensions:
if key1 == 'ulimits':
if self.compare_ulimits(new_dimensions[key1],
current_dimensions[key2]):
return True
elif new_dimensions[key1] != current_dimensions[key2]:
return True
elif current_dimensions[key2]:
# The default values of all currently supported resources are
# '' or 0 - both falsey.
return True
def compare_ulimits(self, new_ulimits, current_ulimits):
# The new_ulimits is dict, we need make it to a list of Ulimit
# instance.
new_ulimits = self.build_ulimits(new_ulimits)
def key(ulimit):
return ulimit['Name']
if current_ulimits is None:
current_ulimits = []
return sorted(new_ulimits, key=key) != sorted(current_ulimits, key=key)
def compare_command(self, container_info):
new_command = self.params.get('command')
if new_command is not None:
new_command_split = shlex.split(new_command)
new_path = new_command_split[0]
new_args = new_command_split[1:]
if (new_path != container_info['Path'] or
new_args != container_info['Args']):
return True
def parse_image(self):
full_image = self.params.get('image')
if '/' in full_image:
registry, image = full_image.split('/', 1)
else:
image = full_image
if ':' in image:
return full_image.rsplit(':', 1)
else:
return full_image, 'latest'
def get_image_id(self):
full_image = self.params.get('image')
image = self.dc.images(name=full_image, quiet=True)
return image[0] if len(image) == 1 else None
def pull_image(self):
if self.params.get('auth_username'):
self.dc.login(
username=self.params.get('auth_username'),
password=self.params.get('auth_password'),
registry=self.params.get('auth_registry'),
email=self.params.get('auth_email')
)
image, tag = self.parse_image()
old_image_id = self.get_image_id()
statuses = [
json.loads(line.strip().decode('utf-8')) for line in self.dc.pull(
repository=image, tag=tag, stream=True
)
]
for status in reversed(statuses):
if 'error' in status:
if status['error'].endswith('not found'):
self.module.fail_json(
msg="The requested image does not exist: {}:{}".format(
image, tag),
failed=True
)
else:
self.module.fail_json(
msg="Unknown error message: {}".format(
status['error']),
failed=True
)
new_image_id = self.get_image_id()
self.changed = old_image_id != new_image_id
def remove_container(self):
if self.check_container():
self.changed = True
# NOTE(jeffrey4l): in some case, docker failed to remove container
# filesystem and raise error. But the container info is
# disappeared already. If this happens, assume the container is
# removed.
try:
self.dc.remove_container(
container=self.params.get('name'),
force=True
)
except docker.errors.APIError:
if self.check_container():
raise
def generate_volumes(self):
volumes = self.params.get('volumes')
if not volumes:
return None, None
vol_list = list()
vol_dict = dict()
for vol in volumes:
if len(vol) == 0:
continue
if ':' not in vol:
vol_list.append(vol)
continue
split_vol = vol.split(':')
if (len(split_vol) == 2
and ('/' not in split_vol[0] or '/' in split_vol[1])):
split_vol.append('rw')
vol_list.append(split_vol[1])
vol_dict.update({
split_vol[0]: {
'bind': split_vol[1],
'mode': split_vol[2]
}
})
return vol_list, vol_dict
def parse_dimensions(self, dimensions):
# When the data object contains types such as
# docker.types.Ulimit, Ansible will fail when these are
# returned via exit_json or fail_json. HostConfig is derived from dict,
# but its constructor requires additional arguments.
# to avoid that, here do copy the dimensions and return a new one.
dimensions = dimensions.copy()
supported = {'cpu_period', 'cpu_quota', 'cpu_shares',
'cpuset_cpus', 'cpuset_mems', 'mem_limit',
'mem_reservation', 'memswap_limit',
'kernel_memory', 'blkio_weight', 'ulimits'}
unsupported = set(dimensions) - supported
if unsupported:
self.module.exit_json(failed=True,
msg=repr("Unsupported dimensions"),
unsupported_dimensions=unsupported)
ulimits = dimensions.get('ulimits')
if ulimits:
dimensions['ulimits'] = self.build_ulimits(ulimits)
return dimensions
def build_ulimits(self, ulimits):
ulimits_opt = []
for key, value in ulimits.items():
soft = value.get('soft')
hard = value.get('hard')
ulimits_opt.append(docker.types.Ulimit(name=key,
soft=soft,
hard=hard))
return ulimits_opt
def build_host_config(self, binds):
options = {
'network_mode': 'host',
'ipc_mode': self.params.get('ipc_mode'),
'cap_add': self.params.get('cap_add'),
'security_opt': self.params.get('security_opt'),
'pid_mode': self.params.get('pid_mode'),
'privileged': self.params.get('privileged'),
'volumes_from': self.params.get('volumes_from')
}
dimensions = self.params.get('dimensions')
if dimensions:
dimensions = self.parse_dimensions(dimensions)
options.update(dimensions)
if self.params.get('restart_policy') in ['on-failure',
'always',
'unless-stopped']:
policy = {'Name': self.params.get('restart_policy')}
# NOTE(Jeffrey4l): MaximumRetryCount is only needed for on-failure
# policy
if self.params.get('restart_policy') == 'on-failure':
retries = self.params.get('restart_retries')
policy['MaximumRetryCount'] = retries
options['restart_policy'] = policy
if binds:
options['binds'] = binds
return self.dc.create_host_config(**options)
def _inject_env_var(self, environment_info):
newenv = {
'KOLLA_SERVICE_NAME': self.params.get('name').replace('_', '-')
}
environment_info.update(newenv)
return environment_info
def _format_env_vars(self):
env = self._inject_env_var(self.params.get('environment'))
return {k: "" if env[k] is None else env[k] for k in env}
def build_container_options(self):
volumes, binds = self.generate_volumes()
return {
'command': self.params.get('command'),
'detach': self.params.get('detach'),
'environment': self._format_env_vars(),
'host_config': self.build_host_config(binds),
'labels': self.params.get('labels'),
'image': self.params.get('image'),
'name': self.params.get('name'),
'volumes': volumes,
'tty': self.params.get('tty'),
}
def create_container(self):
self.changed = True
options = self.build_container_options()
self.dc.create_container(**options)
def recreate_or_restart_container(self):
self.changed = True
container = self.check_container()
# get config_strategy from env
environment = self.params.get('environment')
config_strategy = environment.get('KOLLA_CONFIG_STRATEGY')
if not container:
self.start_container()
return
# If config_strategy is COPY_ONCE or container's parameters are
# changed, try to start a new one.
if config_strategy == 'COPY_ONCE' or self.check_container_differs():
self.stop_container()
self.remove_container()
self.start_container()
elif config_strategy == 'COPY_ALWAYS':
self.restart_container()
def start_container(self):
if not self.check_image():
self.pull_image()
container = self.check_container()
if container and self.check_container_differs():
self.stop_container()
self.remove_container()
container = self.check_container()
if not container:
self.create_container()
container = self.check_container()
if not container['Status'].startswith('Up '):
self.changed = True
self.dc.start(container=self.params.get('name'))
# We do not want to detach so we wait around for container to exit
if not self.params.get('detach'):
rc = self.dc.wait(self.params.get('name'))
# NOTE(jeffrey4l): since python docker package 3.0, wait return a
# dict all the time.
if isinstance(rc, dict):
rc = rc['StatusCode']
# Include container's return code, standard output and error in the
# result.
self.result['rc'] = rc
self.result['stdout'] = self.dc.logs(self.params.get('name'),
stdout=True, stderr=False)
self.result['stderr'] = self.dc.logs(self.params.get('name'),
stdout=False, stderr=True)
if self.params.get('remove_on_exit'):
self.stop_container()
self.remove_container()
if rc != 0:
self.module.fail_json(
changed=True,
msg="Container exited with non-zero return code %s" % rc,
**self.result
)
def get_container_env(self):
name = self.params.get('name')
info = self.get_container_info()
if not info:
self.module.fail_json(msg="No such container: {}".format(name))
else:
envs = dict()
for env in info['Config']['Env']:
if '=' in env:
key, value = env.split('=', 1)
else:
key, value = env, ''
envs[key] = value
self.module.exit_json(**envs)
def get_container_state(self):
name = self.params.get('name')
info = self.get_container_info()
if not info:
self.module.fail_json(msg="No such container: {}".format(name))
else:
self.module.exit_json(**info['State'])
def stop_container(self):
name = self.params.get('name')
graceful_timeout = self.params.get('graceful_timeout')
if not graceful_timeout:
graceful_timeout = 10
container = self.check_container()
if not container:
self.module.fail_json(
msg="No such container: {} to stop".format(name))
elif not container['Status'].startswith('Exited '):
self.changed = True
self.dc.stop(name, timeout=graceful_timeout)
def restart_container(self):
name = self.params.get('name')
graceful_timeout = self.params.get('graceful_timeout')
if not graceful_timeout:
graceful_timeout = 10
info = self.get_container_info()
if not info:
self.module.fail_json(
msg="No such container: {}".format(name))
else:
self.changed = True
self.dc.stop(name, timeout=graceful_timeout)
self.dc.start(name)
def create_volume(self):
if not self.check_volume():
self.changed = True
self.dc.create_volume(name=self.params.get('name'), driver='local')
def remove_volume(self):
if self.check_volume():
self.changed = True
try:
self.dc.remove_volume(name=self.params.get('name'))
except docker.errors.APIError as e:
if e.response.status_code == 409:
self.module.fail_json(
failed=True,
msg="Volume named '{}' is currently in-use".format(
self.params.get('name')
)
)
raise
def remove_image(self):
if self.check_image():
self.changed = True
try:
self.dc.remove_image(image=self.params.get('image'))
except docker.errors.APIError as e:
if e.response.status_code == 409:
self.module.fail_json(
failed=True,
msg="Image '{}' is currently in-use".format(
self.params.get('image')
)
)
elif e.response.status_code == 500:
self.module.fail_json(
failed=True,
msg="Server error"
)
raise
def generate_module():
# NOTE(jeffrey4l): add empty string '' to choices let us use
# pid_mode: "{{ service.pid_mode | default ('') }}" in yaml
argument_spec = dict(
common_options=dict(required=False, type='dict', default=dict()),
action=dict(required=True, type='str',
choices=['compare_container', 'compare_image',
'create_volume', 'get_container_env',
'get_container_state', 'pull_image',
'recreate_or_restart_container',
'remove_container', 'remove_image',
'remove_volume', 'restart_container',
'start_container', 'stop_container']),
api_version=dict(required=False, type='str', default='auto'),
auth_email=dict(required=False, type='str'),
auth_password=dict(required=False, type='str', no_log=True),
auth_registry=dict(required=False, type='str'),
auth_username=dict(required=False, type='str'),
command=dict(required=False, type='str'),
detach=dict(required=False, type='bool', default=True),
labels=dict(required=False, type='dict', default=dict()),
name=dict(required=False, type='str'),
environment=dict(required=False, type='dict'),
image=dict(required=False, type='str'),
ipc_mode=dict(required=False, type='str', choices=['',
'host',
'private',
'shareable']),
cap_add=dict(required=False, type='list', default=list()),
security_opt=dict(required=False, type='list', default=list()),
pid_mode=dict(required=False, type='str', choices=['host', '']),
privileged=dict(required=False, type='bool', default=False),
graceful_timeout=dict(required=False, type='int', default=10),
remove_on_exit=dict(required=False, type='bool', default=True),
restart_policy=dict(required=False, type='str', choices=[
'no',
'never',
'on-failure',
'always',
'unless-stopped']),
restart_retries=dict(required=False, type='int', default=10),
state=dict(required=False, type='str', default='running',
choices=['running',
'exited',
'paused']),
tls_verify=dict(required=False, type='bool', default=False),
tls_cert=dict(required=False, type='str'),
tls_key=dict(required=False, type='str'),
tls_cacert=dict(required=False, type='str'),
volumes=dict(required=False, type='list'),
volumes_from=dict(required=False, type='list'),
dimensions=dict(required=False, type='dict', default=dict()),
tty=dict(required=False, type='bool', default=False),
)
required_if = [
['action', 'pull_image', ['image']],
['action', 'start_container', ['image', 'name']],
['action', 'compare_container', ['name']],
['action', 'compare_image', ['name']],
['action', 'create_volume', ['name']],
['action', 'get_container_env', ['name']],
['action', 'get_container_state', ['name']],
['action', 'recreate_or_restart_container', ['name']],
['action', 'remove_container', ['name']],
['action', 'remove_image', ['image']],
['action', 'remove_volume', ['name']],
['action', 'restart_container', ['name']],
['action', 'stop_container', ['name']]
]
module = AnsibleModule(
argument_spec=argument_spec,
required_if=required_if,
bypass_checks=False
)
new_args = module.params.pop('common_options', dict())
# NOTE(jeffrey4l): merge the environment
env = module.params.pop('environment', dict())
if env:
new_args['environment'].update(env)
for key, value in module.params.items():
if key in new_args and value is None:
continue
new_args[key] = value
# if pid_mode = ""/None/False, remove it
if not new_args.get('pid_mode', False):
new_args.pop('pid_mode', None)
# if ipc_mode = ""/None/False, remove it
if not new_args.get('ipc_mode', False):
new_args.pop('ipc_mode', None)
module.params = new_args
return module
def main():
module = generate_module()
try:
dw = DockerWorker(module)
# TODO(inc0): We keep it bool to have ansible deal with consistent
# types. If we ever add method that will have to return some
# meaningful data, we need to refactor all methods to return dicts.
result = bool(getattr(dw, module.params.get('action'))())
module.exit_json(changed=dw.changed, result=result, **dw.result)
except Exception:
module.fail_json(changed=True, msg=repr(traceback.format_exc()),
**dw.result)
if __name__ == '__main__':
main()