import functools
import random
import threading
import time
import grpc
import grpc._channel
from six.moves import queue
import etcd3.etcdrpc as etcdrpc
import etcd3.exceptions as exceptions
import etcd3.leases as leases
import etcd3.locks as locks
import etcd3.members
import etcd3.transactions as transactions
import etcd3.utils as utils
import etcd3.watch as watch
_EXCEPTIONS_BY_CODE = {
grpc.StatusCode.INTERNAL: exceptions.InternalServerError,
grpc.StatusCode.UNAVAILABLE: exceptions.ConnectionFailedError,
grpc.StatusCode.DEADLINE_EXCEEDED: exceptions.ConnectionTimeoutError,
grpc.StatusCode.FAILED_PRECONDITION: exceptions.PreconditionFailedError,
}
_FAILED_EP_CODES = [
grpc.StatusCode.UNAVAILABLE,
grpc.StatusCode.DEADLINE_EXCEEDED,
grpc.StatusCode.INTERNAL
]
class Transactions(object):
def __init__(self):
self.value = transactions.Value
self.version = transactions.Version
self.create = transactions.Create
self.mod = transactions.Mod
self.put = transactions.Put
self.get = transactions.Get
self.delete = transactions.Delete
self.txn = transactions.Txn
class KVMetadata(object):
def __init__(self, keyvalue, header):
self.key = keyvalue.key
self.create_revision = keyvalue.create_revision
self.mod_revision = keyvalue.mod_revision
self.version = keyvalue.version
self.lease_id = keyvalue.lease
self.response_header = header
class Status(object):
def __init__(self, version, db_size, leader, raft_index, raft_term):
self.version = version
self.db_size = db_size
self.leader = leader
self.raft_index = raft_index
self.raft_term = raft_term
class Alarm(object):
def __init__(self, alarm_type, member_id):
self.alarm_type = alarm_type
self.member_id = member_id
[docs]class Endpoint(object):
"""Represents an etcd cluster endpoint.
:param str host: Endpoint host
:param int port: Endpoint port
:param bool secure: Use secure channel, default True
:param creds: Credentials to use for secure channel, required if
secure=True
:type creds: grpc.ChannelCredentials, optional
:param time_retry: Seconds to wait before retrying this endpoint after
failure, default 300.0
:type time_retry: int or float
:param opts: Additional gRPC options
:type opts: dict, optional
"""
def __init__(self, host, port, secure=True, creds=None, time_retry=300.0,
opts=None):
self.host = host
self.netloc = "{host}:{port}".format(host=host, port=port)
self.secure = secure
self.protocol = 'https' if secure else 'http'
if self.secure and creds is None:
raise ValueError(
'Please set TLS credentials for secure connections')
self.credentials = creds
self.time_retry = time_retry
self.in_use = False
self.last_failed = 0
self.channel = self._mkchannel(opts)
def close(self):
self.channel.close()
[docs] def fail(self):
"""Transition the endpoint to a failed state."""
self.in_use = False
self.last_failed = time.time()
[docs] def use(self):
"""Transition the endpoint to an active state."""
if self.is_failed():
raise ValueError('Trying to use a failed node')
self.in_use = True
self.last_failed = 0
return self.channel
def __str__(self):
return "Endpoint({}://{})".format(self.protocol, self.netloc)
[docs] def is_failed(self):
"""Check if the current endpoint is failed."""
return ((time.time() - self.last_failed) < self.time_retry)
def _mkchannel(self, opts):
if self.secure:
return grpc.secure_channel(self.netloc, self.credentials,
options=opts)
else:
return grpc.insecure_channel(self.netloc, options=opts)
class EtcdTokenCallCredentials(grpc.AuthMetadataPlugin):
"""Metadata wrapper for raw access token credentials."""
def __init__(self, access_token):
self._access_token = access_token
def __call__(self, context, callback):
metadata = (('token', self._access_token),)
callback(metadata, None)
[docs]class MultiEndpointEtcd3Client(object):
"""
etcd v3 API client with multiple endpoints.
When failover is enabled, requests still will not be auto-retried.
Instead, the application may retry the request, and the ``Etcd3Client``
will then attempt to send it to a different endpoint that has not recently
failed. If all configured endpoints have failed and are not ready to be
retried, an ``exceptions.NoServerAvailableError`` will be raised.
:param endpoints: Endpoints to use in lieu of host and port
:type endpoints: Iterable(Endpoint), optional
:param timeout: Timeout for all RPC in seconds
:type timeout: int or float, optional
:param user: Username for authentication
:type user: str, optional
:param password: Password for authentication
:type password: str, optional
:param bool failover: Failover between endpoints, default False
"""
def __init__(self, endpoints=None, timeout=None, user=None, password=None,
failover=False):
self.metadata = None
self.failover = failover
# Cache GRPC stubs here
self._stubs = {}
# Step 1: setup endpoints
self.endpoints = {ep.netloc: ep for ep in endpoints}
self._current_endpoint_label = random.choice(
list(self.endpoints.keys())
)
# Step 2: if auth is enabled, call the auth endpoint
self.timeout = timeout
self.call_credentials = None
cred_params = [c is not None for c in (user, password)]
if all(cred_params):
auth_request = etcdrpc.AuthenticateRequest(
name=user,
password=password
)
resp = self.authstub.Authenticate(auth_request, self.timeout)
self.metadata = (('token', resp.token),)
self.call_credentials = grpc.metadata_call_credentials(
EtcdTokenCallCredentials(resp.token))
elif any(cred_params):
raise Exception(
'if using authentication credentials both user and password '
'must be specified.'
)
self.transactions = Transactions()
def _create_stub_property(name, stub_class):
def get_stub(self):
stub = self._stubs.get(name)
if stub is None:
stub = self._stubs[name] = stub_class(self.channel)
return stub
return property(get_stub)
authstub = _create_stub_property("authstub", etcdrpc.AuthStub)
kvstub = _create_stub_property("kvstub", etcdrpc.KVStub)
clusterstub = _create_stub_property("clusterstub", etcdrpc.ClusterStub)
leasestub = _create_stub_property("leasestub", etcdrpc.LeaseStub)
maintenancestub = _create_stub_property(
"maintenancestub", etcdrpc.MaintenanceStub
)
def get_watcher(self):
watchstub = etcdrpc.WatchStub(self.channel)
return watch.Watcher(
watchstub,
timeout=self.timeout,
call_credentials=self.call_credentials,
metadata=self.metadata
)
@property
def watcher(self):
watcher = self._stubs.get("watcher")
if watcher is None:
watcher = self._stubs["watcher"] = self.get_watcher()
return watcher
@watcher.setter
def watcher(self, value):
self._stubs["watcher"] = value
def _clear_old_stubs(self):
old_watcher = self._stubs.get("watcher")
self._stubs.clear()
if old_watcher:
old_watcher.close()
@property
def _current_endpoint_label(self):
return self._current_ep_label
@_current_endpoint_label.setter
def _current_endpoint_label(self, value):
if getattr(self, "_current_ep_label", None) is not value:
self._clear_old_stubs()
self._current_ep_label = value
@property
def endpoint_in_use(self):
"""Get the current endpoint in use."""
if self._current_endpoint_label is None:
return None
return self.endpoints[self._current_endpoint_label]
@property
def channel(self):
"""
Get an available channel on the first node that's not failed.
Raises an exception if no node is available
"""
try:
return self.endpoint_in_use.use()
except ValueError:
if not self.failover:
raise
# We're failing over. We get the first non-failed channel
# we encounter, and use it by calling this function again,
# recursively
for label, endpoint in self.endpoints.items():
if endpoint.is_failed():
continue
self._current_endpoint_label = label
return self.channel
raise exceptions.NoServerAvailableError(
"No endpoint available and not failed")
[docs] def close(self):
"""Call the GRPC channel close semantics."""
possible_watcher = self._stubs.get("watcher")
if possible_watcher:
possible_watcher.close()
for endpoint in self.endpoints.values():
endpoint.close()
def __enter__(self):
return self
def __exit__(self, *args):
self.close()
@staticmethod
def get_secure_creds(ca_cert, cert_key=None, cert_cert=None):
cert_key_file = None
cert_cert_file = None
with open(ca_cert, 'rb') as f:
ca_cert_file = f.read()
if cert_key is not None:
with open(cert_key, 'rb') as f:
cert_key_file = f.read()
if cert_cert is not None:
with open(cert_cert, 'rb') as f:
cert_cert_file = f.read()
return grpc.ssl_channel_credentials(
ca_cert_file,
cert_key_file,
cert_cert_file
)
def _manage_grpc_errors(self, exc):
code = exc.code()
if code in _FAILED_EP_CODES:
# This sets the current node to failed.
# If others are available, they will be used on
# subsequent requests.
self.endpoint_in_use.fail()
self._clear_old_stubs()
exception = _EXCEPTIONS_BY_CODE.get(code)
if exception is None:
raise
raise exception()
def _handle_errors(payload):
@functools.wraps(payload)
def handler(self, *args, **kwargs):
try:
return payload(self, *args, **kwargs)
except grpc.RpcError as exc:
self._manage_grpc_errors(exc)
return handler
def _handle_generator_errors(payload):
@functools.wraps(payload)
def handler(self, *args, **kwargs):
try:
for item in payload(self, *args, **kwargs):
yield item
except grpc.RpcError as exc:
self._manage_grpc_errors(exc)
return handler
def _build_get_range_request(self, key,
range_end=None,
limit=None,
revision=None,
sort_order=None,
sort_target='key',
serializable=False,
keys_only=False,
count_only=False,
min_mod_revision=None,
max_mod_revision=None,
min_create_revision=None,
max_create_revision=None):
range_request = etcdrpc.RangeRequest()
range_request.key = utils.to_bytes(key)
range_request.keys_only = keys_only
range_request.count_only = count_only
range_request.serializable = serializable
if range_end is not None:
range_request.range_end = utils.to_bytes(range_end)
if limit is not None:
range_request.limit = limit
if revision is not None:
range_request.revision = revision
if min_mod_revision is not None:
range_request.min_mod_revision = min_mod_revision
if max_mod_revision is not None:
range_request.max_mod_revision = max_mod_revision
if min_create_revision is not None:
range_request.min_mod_revision = min_create_revision
if max_create_revision is not None:
range_request.min_mod_revision = max_create_revision
sort_orders = {
None: etcdrpc.RangeRequest.NONE,
'ascend': etcdrpc.RangeRequest.ASCEND,
'descend': etcdrpc.RangeRequest.DESCEND,
}
request_sort_order = sort_orders.get(sort_order)
if request_sort_order is None:
raise ValueError('unknown sort order: "{}"'.format(sort_order))
range_request.sort_order = request_sort_order
sort_targets = {
None: etcdrpc.RangeRequest.KEY,
'key': etcdrpc.RangeRequest.KEY,
'version': etcdrpc.RangeRequest.VERSION,
'create': etcdrpc.RangeRequest.CREATE,
'mod': etcdrpc.RangeRequest.MOD,
'value': etcdrpc.RangeRequest.VALUE,
}
request_sort_target = sort_targets.get(sort_target)
if request_sort_target is None:
raise ValueError('sort_target must be one of "key", '
'"version", "create", "mod" or "value"')
range_request.sort_target = request_sort_target
return range_request
[docs] @_handle_errors
def get_response(self, key, **kwargs):
"""Get the value of a key from etcd."""
range_request = self._build_get_range_request(
key,
**kwargs
)
return self.kvstub.Range(
range_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] def get(self, key, **kwargs):
"""
Get the value of a key from etcd.
example usage:
.. code-block:: python
>>> import etcd3
>>> etcd = etcd3.client()
>>> etcd.get('/thing/key')
'hello world'
:param key: key in etcd to get
:returns: value of key and metadata
:rtype: bytes, ``KVMetadata``
"""
range_response = self.get_response(key, **kwargs)
if range_response.count < 1:
return None, None
else:
kv = range_response.kvs.pop()
return kv.value, KVMetadata(kv, range_response.header)
[docs] @_handle_errors
def get_prefix_response(self, key_prefix, **kwargs):
"""Get a range of keys with a prefix."""
if any(kwarg in kwargs for kwarg in ("key", "range_end")):
raise TypeError("Don't use key or range_end with prefix")
range_request = self._build_get_range_request(
key=key_prefix,
range_end=utils.prefix_range_end(utils.to_bytes(key_prefix)),
**kwargs
)
return self.kvstub.Range(
range_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] def get_prefix(self, key_prefix, **kwargs):
"""
Get a range of keys with a prefix.
:param key_prefix: first key in range
:param keys_only: if True, retrieve only the keys, not the values
:returns: sequence of (value, metadata) tuples
"""
range_response = self.get_prefix_response(key_prefix, **kwargs)
return (
(kv.value, KVMetadata(kv, range_response.header))
for kv in range_response.kvs
)
[docs] @_handle_errors
def get_range_response(self, range_start, range_end, sort_order=None,
sort_target='key', **kwargs):
"""Get a range of keys."""
range_request = self._build_get_range_request(
key=range_start,
range_end=range_end,
sort_order=sort_order,
sort_target=sort_target,
**kwargs
)
return self.kvstub.Range(
range_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] def get_range(self, range_start, range_end, **kwargs):
"""
Get a range of keys.
:param range_start: first key in range
:param range_end: last key in range
:returns: sequence of (value, metadata) tuples
"""
range_response = self.get_range_response(range_start, range_end,
**kwargs)
for kv in range_response.kvs:
yield (kv.value, KVMetadata(kv, range_response.header))
[docs] @_handle_errors
def get_all_response(self, sort_order=None, sort_target='key',
keys_only=False):
"""Get all keys currently stored in etcd."""
range_request = self._build_get_range_request(
key=b'\0',
range_end=b'\0',
sort_order=sort_order,
sort_target=sort_target,
keys_only=keys_only,
)
return self.kvstub.Range(
range_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] def get_all(self, **kwargs):
"""
Get all keys currently stored in etcd.
:param keys_only: if True, retrieve only the keys, not the values
:returns: sequence of (value, metadata) tuples
"""
range_response = self.get_all_response(**kwargs)
for kv in range_response.kvs:
yield (kv.value, KVMetadata(kv, range_response.header))
def _build_put_request(self, key, value, lease=None, prev_kv=False):
put_request = etcdrpc.PutRequest()
put_request.key = utils.to_bytes(key)
put_request.value = utils.to_bytes(value)
put_request.lease = utils.lease_to_id(lease)
put_request.prev_kv = prev_kv
return put_request
[docs] @_handle_errors
def put(self, key, value, lease=None, prev_kv=False):
"""
Save a value to etcd.
Example usage:
.. code-block:: python
>>> import etcd3
>>> etcd = etcd3.client()
>>> etcd.put('/thing/key', 'hello world')
:param key: key in etcd to set
:param value: value to set key to
:type value: bytes
:param lease: Lease to associate with this key.
:type lease: either :class:`.Lease`, or int (ID of lease)
:param prev_kv: return the previous key-value pair
:type prev_kv: bool
:returns: a response containing a header and the prev_kv
:rtype: :class:`.rpc_pb2.PutResponse`
"""
put_request = self._build_put_request(key, value, lease=lease,
prev_kv=prev_kv)
return self.kvstub.Put(
put_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] @_handle_errors
def put_if_not_exists(self, key, value, lease=None):
"""
Atomically puts a value only if the key previously had no value.
This is the etcdv3 equivalent to setting a key with the etcdv2
parameter prevExist=false.
:param key: key in etcd to put
:param value: value to be written to key
:type value: bytes
:param lease: Lease to associate with this key.
:type lease: either :class:`.Lease`, or int (ID of lease)
:returns: state of transaction, ``True`` if the put was successful,
``False`` otherwise
:rtype: bool
"""
status, _ = self.transaction(
compare=[self.transactions.create(key) == '0'],
success=[self.transactions.put(key, value, lease=lease)],
failure=[],
)
return status
[docs] @_handle_errors
def replace(self, key, initial_value, new_value):
"""
Atomically replace the value of a key with a new value.
This compares the current value of a key, then replaces it with a new
value if it is equal to a specified value. This operation takes place
in a transaction.
:param key: key in etcd to replace
:param initial_value: old value to replace
:type initial_value: bytes
:param new_value: new value of the key
:type new_value: bytes
:returns: status of transaction, ``True`` if the replace was
successful, ``False`` otherwise
:rtype: bool
"""
status, _ = self.transaction(
compare=[self.transactions.value(key) == initial_value],
success=[self.transactions.put(key, new_value)],
failure=[],
)
return status
def _build_delete_request(self, key,
range_end=None,
prev_kv=False):
delete_request = etcdrpc.DeleteRangeRequest()
delete_request.key = utils.to_bytes(key)
delete_request.prev_kv = prev_kv
if range_end is not None:
delete_request.range_end = utils.to_bytes(range_end)
return delete_request
[docs] @_handle_errors
def delete(self, key, prev_kv=False, return_response=False):
"""
Delete a single key in etcd.
:param key: key in etcd to delete
:param prev_kv: return the deleted key-value pair
:type prev_kv: bool
:param return_response: return the full response
:type return_response: bool
:returns: True if the key has been deleted when
``return_response`` is False and a response containing
a header, the number of deleted keys and prev_kvs when
``return_response`` is True
"""
delete_request = self._build_delete_request(key, prev_kv=prev_kv)
delete_response = self.kvstub.DeleteRange(
delete_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
if return_response:
return delete_response
return delete_response.deleted >= 1
[docs] @_handle_errors
def delete_prefix(self, prefix):
"""Delete a range of keys with a prefix in etcd."""
delete_request = self._build_delete_request(
prefix,
range_end=utils.prefix_range_end(utils.to_bytes(prefix))
)
return self.kvstub.DeleteRange(
delete_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] @_handle_errors
def status(self):
"""Get the status of the responding member."""
status_request = etcdrpc.StatusRequest()
status_response = self.maintenancestub.Status(
status_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
for m in self.members:
if m.id == status_response.leader:
leader = m
break
else:
# raise exception?
leader = None
return Status(status_response.version,
status_response.dbSize,
leader,
status_response.raftIndex,
status_response.raftTerm)
[docs] @_handle_errors
def add_watch_callback(self, *args, **kwargs):
"""
Watch a key or range of keys and call a callback on every response.
If timeout was declared during the client initialization and
the watch cannot be created during that time the method raises
a ``WatchTimedOut`` exception.
:param key: key to watch
:param callback: callback function
:returns: watch_id. Later it could be used for cancelling watch.
"""
try:
return self.watcher.add_callback(*args, **kwargs)
except queue.Empty:
raise exceptions.WatchTimedOut()
[docs] @_handle_errors
def add_watch_prefix_callback(self, key_prefix, callback, **kwargs):
"""
Watch a prefix and call a callback on every response.
If timeout was declared during the client initialization and
the watch cannot be created during that time the method raises
a ``WatchTimedOut`` exception.
:param key_prefix: prefix to watch
:param callback: callback function
:returns: watch_id. Later it could be used for cancelling watch.
"""
kwargs['range_end'] = \
utils.prefix_range_end(utils.to_bytes(key_prefix))
return self.add_watch_callback(key_prefix, callback, **kwargs)
[docs] @_handle_errors
def watch_response(self, key, **kwargs):
"""
Watch a key.
Example usage:
.. code-block:: python
responses_iterator, cancel = etcd.watch_response('/doot/key')
for response in responses_iterator:
print(response)
:param key: key to watch
:returns: tuple of ``responses_iterator`` and ``cancel``.
Use ``responses_iterator`` to get the watch responses,
each of which contains a header and a list of events.
Use ``cancel`` to cancel the watch request.
"""
response_queue = queue.Queue()
def callback(response):
response_queue.put(response)
watch_id = self.add_watch_callback(key, callback, **kwargs)
canceled = threading.Event()
def cancel():
canceled.set()
response_queue.put(None)
self.cancel_watch(watch_id)
def iterator():
try:
while not canceled.is_set():
response = response_queue.get()
if response is None:
canceled.set()
if isinstance(response, Exception):
canceled.set()
raise response
if not canceled.is_set():
yield response
except grpc.RpcError as exc:
self._manage_grpc_errors(exc)
return iterator(), cancel
[docs] def watch(self, key, **kwargs):
"""
Watch a key.
Example usage:
.. code-block:: python
events_iterator, cancel = etcd.watch('/doot/key')
for event in events_iterator:
print(event)
:param key: key to watch
:returns: tuple of ``events_iterator`` and ``cancel``.
Use ``events_iterator`` to get the events of key changes
and ``cancel`` to cancel the watch request.
"""
response_iterator, cancel = self.watch_response(key, **kwargs)
return utils.response_to_event_iterator(response_iterator), cancel
[docs] def watch_prefix_response(self, key_prefix, **kwargs):
"""
Watch a range of keys with a prefix.
:param key_prefix: prefix to watch
:returns: tuple of ``responses_iterator`` and ``cancel``.
"""
kwargs['range_end'] = \
utils.prefix_range_end(utils.to_bytes(key_prefix))
return self.watch_response(key_prefix, **kwargs)
[docs] def watch_prefix(self, key_prefix, **kwargs):
"""
Watch a range of keys with a prefix.
:param key_prefix: prefix to watch
:returns: tuple of ``events_iterator`` and ``cancel``.
"""
kwargs['range_end'] = \
utils.prefix_range_end(utils.to_bytes(key_prefix))
return self.watch(key_prefix, **kwargs)
[docs] @_handle_errors
def watch_once_response(self, key, timeout=None, **kwargs):
"""
Watch a key and stop after the first response.
If the timeout was specified and response didn't arrive method
will raise ``WatchTimedOut`` exception.
:param key: key to watch
:param timeout: (optional) timeout in seconds.
:returns: ``WatchResponse``
"""
response_queue = queue.Queue()
def callback(response):
response_queue.put(response)
watch_id = self.add_watch_callback(key, callback, **kwargs)
try:
return response_queue.get(timeout=timeout)
except queue.Empty:
raise exceptions.WatchTimedOut()
finally:
self.cancel_watch(watch_id)
[docs] def watch_once(self, key, timeout=None, **kwargs):
"""
Watch a key and stop after the first event.
If the timeout was specified and event didn't arrive method
will raise ``WatchTimedOut`` exception.
:param key: key to watch
:param timeout: (optional) timeout in seconds.
:returns: ``Event``
"""
response = self.watch_once_response(key, timeout=timeout, **kwargs)
return response.events[0]
[docs] def watch_prefix_once_response(self, key_prefix, timeout=None, **kwargs):
"""
Watch a range of keys with a prefix and stop after the first response.
If the timeout was specified and response didn't arrive method
will raise ``WatchTimedOut`` exception.
"""
kwargs['range_end'] = \
utils.prefix_range_end(utils.to_bytes(key_prefix))
return self.watch_once_response(key_prefix, timeout=timeout, **kwargs)
[docs] def watch_prefix_once(self, key_prefix, timeout=None, **kwargs):
"""
Watch a range of keys with a prefix and stop after the first event.
If the timeout was specified and event didn't arrive method
will raise ``WatchTimedOut`` exception.
"""
kwargs['range_end'] = \
utils.prefix_range_end(utils.to_bytes(key_prefix))
return self.watch_once(key_prefix, timeout=timeout, **kwargs)
[docs] @_handle_errors
def cancel_watch(self, watch_id):
"""
Stop watching a key or range of keys.
:param watch_id: watch_id returned by ``add_watch_callback`` method
"""
self.watcher.cancel(watch_id)
def _ops_to_requests(self, ops):
"""
Return a list of grpc requests.
Returns list from an input list of etcd3.transactions.{Put, Get,
Delete, Txn} objects.
"""
request_ops = []
for op in ops:
if isinstance(op, transactions.Put):
request = self._build_put_request(op.key, op.value,
op.lease, op.prev_kv)
request_op = etcdrpc.RequestOp(request_put=request)
request_ops.append(request_op)
elif isinstance(op, transactions.Get):
request = self._build_get_range_request(op.key, op.range_end)
request_op = etcdrpc.RequestOp(request_range=request)
request_ops.append(request_op)
elif isinstance(op, transactions.Delete):
request = self._build_delete_request(op.key, op.range_end,
op.prev_kv)
request_op = etcdrpc.RequestOp(request_delete_range=request)
request_ops.append(request_op)
elif isinstance(op, transactions.Txn):
compare = [c.build_message() for c in op.compare]
success_ops = self._ops_to_requests(op.success)
failure_ops = self._ops_to_requests(op.failure)
request = etcdrpc.TxnRequest(compare=compare,
success=success_ops,
failure=failure_ops)
request_op = etcdrpc.RequestOp(request_txn=request)
request_ops.append(request_op)
else:
raise Exception(
'Unknown request class {}'.format(op.__class__))
return request_ops
[docs] @_handle_errors
def transaction(self, compare, success=None, failure=None):
"""
Perform a transaction.
Example usage:
.. code-block:: python
etcd.transaction(
compare=[
etcd.transactions.value('/doot/testing') == 'doot',
etcd.transactions.version('/doot/testing') > 0,
],
success=[
etcd.transactions.put('/doot/testing', 'success'),
],
failure=[
etcd.transactions.put('/doot/testing', 'failure'),
]
)
:param compare: A list of comparisons to make
:param success: A list of operations to perform if all the comparisons
are true
:param failure: A list of operations to perform if any of the
comparisons are false
:return: A tuple of (operation status, responses)
"""
compare = [c.build_message() for c in compare]
success_ops = self._ops_to_requests(success)
failure_ops = self._ops_to_requests(failure)
transaction_request = etcdrpc.TxnRequest(compare=compare,
success=success_ops,
failure=failure_ops)
txn_response = self.kvstub.Txn(
transaction_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
responses = []
for response in txn_response.responses:
response_type = response.WhichOneof('response')
if response_type in ['response_put', 'response_delete_range',
'response_txn']:
responses.append(response)
elif response_type == 'response_range':
range_kvs = []
for kv in response.response_range.kvs:
range_kvs.append((kv.value,
KVMetadata(kv, txn_response.header)))
responses.append(range_kvs)
return txn_response.succeeded, responses
[docs] @_handle_errors
def lease(self, ttl, lease_id=None):
"""
Create a new lease.
All keys attached to this lease will be expired and deleted if the
lease expires. A lease can be sent keep alive messages to refresh the
ttl.
:param ttl: Requested time to live
:param lease_id: Requested ID for the lease
:returns: new lease
:rtype: :class:`.Lease`
"""
lease_grant_request = etcdrpc.LeaseGrantRequest(TTL=ttl, ID=lease_id)
lease_grant_response = self.leasestub.LeaseGrant(
lease_grant_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
return leases.Lease(lease_id=lease_grant_response.ID,
ttl=lease_grant_response.TTL,
etcd_client=self)
[docs] @_handle_errors
def revoke_lease(self, lease_id):
"""
Revoke a lease.
:param lease_id: ID of the lease to revoke.
"""
lease_revoke_request = etcdrpc.LeaseRevokeRequest(ID=lease_id)
self.leasestub.LeaseRevoke(
lease_revoke_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
@_handle_generator_errors
def refresh_lease(self, lease_id):
keep_alive_request = etcdrpc.LeaseKeepAliveRequest(ID=lease_id)
request_stream = [keep_alive_request]
for response in self.leasestub.LeaseKeepAlive(
iter(request_stream),
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata):
yield response
@_handle_errors
def get_lease_info(self, lease_id):
# only available in etcd v3.1.0 and later
ttl_request = etcdrpc.LeaseTimeToLiveRequest(ID=lease_id,
keys=True)
return self.leasestub.LeaseTimeToLive(
ttl_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] @_handle_errors
def lock(self, name, ttl=60):
"""
Create a new lock.
:param name: name of the lock
:type name: string or bytes
:param ttl: length of time for the lock to live for in seconds. The
lock will be released after this time elapses, unless
refreshed
:type ttl: int
:returns: new lock
:rtype: :class:`.Lock`
"""
return locks.Lock(name, ttl=ttl, etcd_client=self)
[docs] @_handle_errors
def add_member(self, urls):
"""
Add a member into the cluster.
:returns: new member
:rtype: :class:`.Member`
"""
member_add_request = etcdrpc.MemberAddRequest(peerURLs=urls)
member_add_response = self.clusterstub.MemberAdd(
member_add_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
member = member_add_response.member
return etcd3.members.Member(member.ID,
member.name,
member.peerURLs,
member.clientURLs,
etcd_client=self)
[docs] @_handle_errors
def remove_member(self, member_id):
"""
Remove an existing member from the cluster.
:param member_id: ID of the member to remove
"""
member_rm_request = etcdrpc.MemberRemoveRequest(ID=member_id)
self.clusterstub.MemberRemove(
member_rm_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] @_handle_errors
def update_member(self, member_id, peer_urls):
"""
Update the configuration of an existing member in the cluster.
:param member_id: ID of the member to update
:param peer_urls: new list of peer urls the member will use to
communicate with the cluster
"""
member_update_request = etcdrpc.MemberUpdateRequest(ID=member_id,
peerURLs=peer_urls)
self.clusterstub.MemberUpdate(
member_update_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
@property
def members(self):
"""
List of all members associated with the cluster.
:type: sequence of :class:`.Member`
"""
member_list_request = etcdrpc.MemberListRequest()
member_list_response = self.clusterstub.MemberList(
member_list_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
for member in member_list_response.members:
yield etcd3.members.Member(member.ID,
member.name,
member.peerURLs,
member.clientURLs,
etcd_client=self)
[docs] @_handle_errors
def compact(self, revision, physical=False):
"""
Compact the event history in etcd up to a given revision.
All superseded keys with a revision less than the compaction revision
will be removed.
:param revision: revision for the compaction operation
:param physical: if set to True, the request will wait until the
compaction is physically applied to the local database
such that compacted entries are totally removed from
the backend database
"""
compact_request = etcdrpc.CompactionRequest(revision=revision,
physical=physical)
self.kvstub.Compact(
compact_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] @_handle_errors
def defragment(self):
"""Defragment a member's backend database to recover storage space."""
defrag_request = etcdrpc.DefragmentRequest()
self.maintenancestub.Defragment(
defrag_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
[docs] @_handle_errors
def hash(self):
"""
Return the hash of the local KV state.
:returns: kv state hash
:rtype: int
"""
hash_request = etcdrpc.HashRequest()
return self.maintenancestub.Hash(hash_request).hash
def _build_alarm_request(self, alarm_action, member_id, alarm_type):
alarm_request = etcdrpc.AlarmRequest()
if alarm_action == 'get':
alarm_request.action = etcdrpc.AlarmRequest.GET
elif alarm_action == 'activate':
alarm_request.action = etcdrpc.AlarmRequest.ACTIVATE
elif alarm_action == 'deactivate':
alarm_request.action = etcdrpc.AlarmRequest.DEACTIVATE
else:
raise ValueError('Unknown alarm action: {}'.format(alarm_action))
alarm_request.memberID = member_id
if alarm_type == 'none':
alarm_request.alarm = etcdrpc.NONE
elif alarm_type == 'no space':
alarm_request.alarm = etcdrpc.NOSPACE
else:
raise ValueError('Unknown alarm type: {}'.format(alarm_type))
return alarm_request
[docs] @_handle_errors
def create_alarm(self, member_id=0):
"""Create an alarm.
If no member id is given, the alarm is activated for all the
members of the cluster. Only the `no space` alarm can be raised.
:param member_id: The cluster member id to create an alarm to.
If 0, the alarm is created for all the members
of the cluster.
:returns: list of :class:`.Alarm`
"""
alarm_request = self._build_alarm_request('activate',
member_id,
'no space')
alarm_response = self.maintenancestub.Alarm(
alarm_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
return [Alarm(alarm.alarm, alarm.memberID)
for alarm in alarm_response.alarms]
[docs] @_handle_errors
def list_alarms(self, member_id=0, alarm_type='none'):
"""List the activated alarms.
:param member_id:
:param alarm_type: The cluster member id to create an alarm to.
If 0, the alarm is created for all the members
of the cluster.
:returns: sequence of :class:`.Alarm`
"""
alarm_request = self._build_alarm_request('get',
member_id,
alarm_type)
alarm_response = self.maintenancestub.Alarm(
alarm_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
for alarm in alarm_response.alarms:
yield Alarm(alarm.alarm, alarm.memberID)
[docs] @_handle_errors
def disarm_alarm(self, member_id=0):
"""Cancel an alarm.
:param member_id: The cluster member id to cancel an alarm.
If 0, the alarm is canceled for all the members
of the cluster.
:returns: List of :class:`.Alarm`
"""
alarm_request = self._build_alarm_request('deactivate',
member_id,
'no space')
alarm_response = self.maintenancestub.Alarm(
alarm_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
return [Alarm(alarm.alarm, alarm.memberID)
for alarm in alarm_response.alarms]
[docs] @_handle_errors
def snapshot(self, file_obj):
"""Take a snapshot of the database.
:param file_obj: A file-like object to write the database contents in.
"""
snapshot_request = etcdrpc.SnapshotRequest()
snapshot_response = self.maintenancestub.Snapshot(
snapshot_request,
self.timeout,
credentials=self.call_credentials,
metadata=self.metadata
)
for response in snapshot_response:
file_obj.write(response.blob)
[docs]class Etcd3Client(MultiEndpointEtcd3Client):
"""
etcd v3 API client.
:param host: Host to connect to, 'localhost' if not specified
:type host: str, optional
:param port: Port to connect to on host, 2379 if not specified
:type port: int, optional
:param ca_cert: Filesystem path of etcd CA certificate
:type ca_cert: str or os.PathLike, optional
:param cert_key: Filesystem path of client key
:type cert_key: str or os.PathLike, optional
:param cert_cert: Filesystem path of client certificate
:type cert_cert: str or os.PathLike, optional
:param timeout: Timeout for all RPC in seconds
:type timeout: int or float, optional
:param user: Username for authentication
:type user: str, optional
:param password: Password for authentication
:type password: str, optional
:param dict grpc_options: Additional gRPC options
:type grpc_options: dict, optional
"""
def __init__(self, host='localhost', port=2379, ca_cert=None,
cert_key=None, cert_cert=None, timeout=None, user=None,
password=None, grpc_options=None):
# Step 1: verify credentials
cert_params = [c is not None for c in (cert_cert, cert_key)]
if ca_cert is not None:
if all(cert_params):
credentials = self.get_secure_creds(
ca_cert,
cert_key,
cert_cert
)
self.uses_secure_channel = True
elif any(cert_params):
# some of the cert parameters are set
raise ValueError(
'to use a secure channel ca_cert is required by itself, '
'or cert_cert and cert_key must both be specified.')
else:
credentials = self.get_secure_creds(ca_cert, None, None)
self.uses_secure_channel = True
else:
self.uses_secure_channel = False
credentials = None
# Step 2: create Endpoint
ep = Endpoint(host, port, secure=self.uses_secure_channel,
creds=credentials, opts=grpc_options)
super(Etcd3Client, self).__init__(endpoints=[ep], timeout=timeout,
user=user, password=password)
def client(host='localhost', port=2379,
ca_cert=None, cert_key=None, cert_cert=None, timeout=None,
user=None, password=None, grpc_options=None):
"""Return an instance of an Etcd3Client."""
return Etcd3Client(host=host,
port=port,
ca_cert=ca_cert,
cert_key=cert_key,
cert_cert=cert_cert,
timeout=timeout,
user=user,
password=password,
grpc_options=grpc_options)