#!/usr/bin/python # # (c) 2015, Steve Gargan <steve.gargan@gmail.com> # (c) 2018 Genome Research Ltd. # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt) from __future__ import absolute_import, division, print_function __metaclass__ = type DOCUMENTATION = ''' module: consul_kv short_description: Manipulate entries in the key/value store of a consul cluster description: - Allows the retrieval, addition, modification and deletion of key/value entries in a consul cluster via the agent. The entire contents of the record, including the indices, flags and session are returned as C(value). - If the C(key) represents a prefix then note that when a value is removed, the existing value if any is returned as part of the results. - See http://www.consul.io/docs/agent/http.html#kv for more details. requirements: - python-consul - requests author: - Steve Gargan (@sgargan) - Colin Nolan (@colin-nolan) options: state: description: - The action to take with the supplied key and value. If the state is 'present' and `value` is set, the key contents will be set to the value supplied and `changed` will be set to `true` only if the value was different to the current contents. If the state is 'present' and `value` is not set, the existing value associated to the key will be returned. The state 'absent' will remove the key/value pair, again 'changed' will be set to true only if the key actually existed prior to the removal. An attempt can be made to obtain or free the lock associated with a key/value pair with the states 'acquire' or 'release' respectively. a valid session must be supplied to make the attempt changed will be true if the attempt is successful, false otherwise. type: str choices: [ absent, acquire, present, release ] default: present key: description: - The key at which the value should be stored. type: str required: yes value: description: - The value should be associated with the given key, required if C(state) is C(present). type: str recurse: description: - If the key represents a prefix, each entry with the prefix can be retrieved by setting this to C(yes). type: bool retrieve: description: - If the I(state) is C(present) and I(value) is set, perform a read after setting the value and return this value. default: True type: bool session: description: - The session that should be used to acquire or release a lock associated with a key/value pair. type: str token: description: - The token key identifying an ACL rule set that controls access to the key value pair type: str cas: description: - Used when acquiring a lock with a session. If the C(cas) is C(0), then Consul will only put the key if it does not already exist. If the C(cas) value is non-zero, then the key is only set if the index matches the ModifyIndex of that key. type: str flags: description: - Opaque positive integer value that can be passed when setting a value. type: str host: description: - Host of the consul agent. type: str default: localhost port: description: - The port on which the consul agent is running. type: int default: 8500 scheme: description: - The protocol scheme on which the consul agent is running. type: str default: http validate_certs: description: - Whether to verify the tls certificate of the consul agent. type: bool default: 'yes' ''' EXAMPLES = ''' # If the key does not exist, the value associated to the "data" property in `retrieved_key` will be `None` # If the key value is empty string, `retrieved_key["data"]["Value"]` will be `None` - name: Retrieve a value from the key/value store community.general.consul_kv: key: somekey register: retrieved_key - name: Add or update the value associated with a key in the key/value store community.general.consul_kv: key: somekey value: somevalue - name: Remove a key from the store community.general.consul_kv: key: somekey state: absent - name: Add a node to an arbitrary group via consul inventory (see consul.ini) community.general.consul_kv: key: ansible/groups/dc1/somenode value: top_secret - name: Register a key/value pair with an associated session community.general.consul_kv: key: stg/node/server_birthday value: 20160509 session: "{{ sessionid }}" state: acquire ''' from ansible.module_utils._text import to_text try: import consul from requests.exceptions import ConnectionError python_consul_installed = True except ImportError: python_consul_installed = False from ansible.module_utils.basic import AnsibleModule # Note: although the python-consul documentation implies that using a key with a value of `None` with `put` has a # special meaning (https://python-consul.readthedocs.io/en/latest/#consul-kv), if not set in the subsequently API call, # the value just defaults to an empty string (https://www.consul.io/api/kv.html#create-update-key) NOT_SET = None def _has_value_changed(consul_client, key, target_value): """ Uses the given Consul client to determine if the value associated to the given key is different to the given target value. :param consul_client: Consul connected client :param key: key in Consul :param target_value: value to be associated to the key :return: tuple where the first element is the value of the "X-Consul-Index" header and the second is `True` if the value has changed (i.e. the stored value is not the target value) """ index, existing = consul_client.kv.get(key) if not existing: return index, True try: changed = to_text(existing['Value'], errors='surrogate_or_strict') != target_value return index, changed except UnicodeError: # Existing value was not decodable but all values we set are valid utf-8 return index, True def execute(module): state = module.params.get('state') if state == 'acquire' or state == 'release': lock(module, state) elif state == 'present': if module.params.get('value') is NOT_SET: get_value(module) else: set_value(module) elif state == 'absent': remove_value(module) else: module.exit_json(msg="Unsupported state: %s" % (state, )) def lock(module, state): consul_api = get_consul_api(module) session = module.params.get('session') key = module.params.get('key') value = module.params.get('value') if not session: module.fail( msg='%s of lock for %s requested but no session supplied' % (state, key)) index, changed = _has_value_changed(consul_api, key, value) if changed and not module.check_mode: if state == 'acquire': changed = consul_api.kv.put(key, value, cas=module.params.get('cas'), acquire=session, flags=module.params.get('flags')) else: changed = consul_api.kv.put(key, value, cas=module.params.get('cas'), release=session, flags=module.params.get('flags')) module.exit_json(changed=changed, index=index, key=key) def get_value(module): consul_api = get_consul_api(module) key = module.params.get('key') index, existing_value = consul_api.kv.get(key, recurse=module.params.get('recurse')) module.exit_json(changed=False, index=index, data=existing_value) def set_value(module): consul_api = get_consul_api(module) key = module.params.get('key') value = module.params.get('value') if value is NOT_SET: raise AssertionError('Cannot set value of "%s" to `NOT_SET`' % key) index, changed = _has_value_changed(consul_api, key, value) if changed and not module.check_mode: changed = consul_api.kv.put(key, value, cas=module.params.get('cas'), flags=module.params.get('flags')) stored = None if module.params.get('retrieve'): index, stored = consul_api.kv.get(key) module.exit_json(changed=changed, index=index, key=key, data=stored) def remove_value(module): ''' remove the value associated with the given key. if the recurse parameter is set then any key prefixed with the given key will be removed. ''' consul_api = get_consul_api(module) key = module.params.get('key') index, existing = consul_api.kv.get( key, recurse=module.params.get('recurse')) changed = existing is not None if changed and not module.check_mode: consul_api.kv.delete(key, module.params.get('recurse')) module.exit_json(changed=changed, index=index, key=key, data=existing) def get_consul_api(module, token=None): return consul.Consul(host=module.params.get('host'), port=module.params.get('port'), scheme=module.params.get('scheme'), verify=module.params.get('validate_certs'), token=module.params.get('token')) def test_dependencies(module): if not python_consul_installed: module.fail_json(msg="python-consul required for this module. " "see https://python-consul.readthedocs.io/en/latest/#installation") def main(): module = AnsibleModule( argument_spec=dict( cas=dict(type='str'), flags=dict(type='str'), key=dict(type='str', required=True, no_log=False), host=dict(type='str', default='localhost'), scheme=dict(type='str', default='http'), validate_certs=dict(type='bool', default=True), port=dict(type='int', default=8500), recurse=dict(type='bool'), retrieve=dict(type='bool', default=True), state=dict(type='str', default='present', choices=['absent', 'acquire', 'present', 'release']), token=dict(type='str', no_log=True), value=dict(type='str', default=NOT_SET), session=dict(type='str'), ), supports_check_mode=True ) test_dependencies(module) try: execute(module) except ConnectionError as e: module.fail_json(msg='Could not connect to consul agent at %s:%s, error was %s' % ( module.params.get('host'), module.params.get('port'), e)) except Exception as e: module.fail_json(msg=str(e)) if __name__ == '__main__': main()