patroni.dcs.etcd3 module¶

exception patroni.dcs.etcd3.AuthFailed(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.InvalidArgument

error = 'etcdserver: authentication failed, invalid user ID or password'¶

exception patroni.dcs.etcd3.AuthNotEnabled(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.FailedPrecondition

error = 'etcdserver: authentication is not enabled'¶

exception patroni.dcs.etcd3.AuthOldRevision(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.InvalidArgument

error = 'etcdserver: revision of auth store is old'¶

exception patroni.dcs.etcd3.DeadlineExceeded(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 4¶

error = 'context deadline exceeded'¶

class patroni.dcs.etcd3.Etcd3(config: Dict[str, Any], mpp: patroni.postgresql.mpp.AbstractMPP)¶

Bases: patroni.dcs.etcd.AbstractEtcd

__init__(config: Dict[str, Any], mpp: patroni.postgresql.mpp.AbstractMPP) → None ¶

Prepare DCS paths, MPP object, initial values for state information and processing dependencies.

Parameters

config – dict, reference to config section of selected DCS. i.e.: zookeeper for zookeeper, etcd for etcd, etc…
mpp – an object implementing AbstractMPP interface.

_abc_impl = <_abc._abc_data object>¶

property _client¶: return correct type of etcd client

_cluster: Optional[patroni.dcs.Cluster]¶

_cluster_from_nodes(nodes: Dict[str, Any]) → patroni.dcs.Cluster ¶

_cluster_valid_till: float¶

_delete_leader(*args: Any, **kwargs: Any) → Any¶

Remove leader key from DCS.

This method should remove leader key if current instance is the leader.

Parameters: leader – Leader object with information about the leader.
Returns: True if successfully committed to DCS.

_do_attempt_to_acquire_leader(retry: patroni.utils.Retry) → bool ¶

_do_refresh_lease(force: bool = False, retry: Optional[patroni.utils.Retry] = None) → bool ¶

_last_failsafe: Optional[Dict[str, str]]¶

_last_lsn: int¶

_last_retain_slots: Dict[str, float]¶

_last_seen: int¶

_last_status: Dict[str, Any]¶

_load_cluster(path: str, loader: Callable[[str], Union[patroni.dcs.Cluster, Dict[int, patroni.dcs.Cluster]]]) → Union[patroni.dcs.Cluster, Dict[int, patroni.dcs.Cluster]]¶

Main abstract method that implements the loading of Cluster instance.

Note

Internally this method should call the loader method that will build Cluster object which represents current state and topology of the cluster in DCS. This method supposed to be called only by the get_cluster() method.

Parameters

path – the path in DCS where to load Cluster(s) from.
loader – one of _postgresql_cluster_loader() or _mpp_cluster_loader().

Raise

DCSError in case of communication problems with DCS. If the current node was running as a primary and exception raised, instance would be demoted.

_mpp_cluster_loader(path: str) → Dict[int, patroni.dcs.Cluster]¶

Load and build all PostgreSQL clusters from a single MPP cluster.

Parameters: path – the path in DCS where to load Cluster(s) from.
Returns: all MPP groups as dict, with group IDs as keys and Cluster objects as values.

_postgresql_cluster_loader(path: str) → patroni.dcs.Cluster ¶

Load and build the Cluster object from DCS, which represents a single PostgreSQL cluster.

Parameters: path – the path in DCS where to load Cluster from.
Returns: Cluster instance.

_update_leader(**kwargs: Any)¶

Update leader key (or session) ttl.

Note

You have to use CAS (Compare And Swap) operation in order to update leader key, for example for etcd prevValue parameter must be used.

If update fails due to DCS not being accessible or because it is not able to process requests (hopefully temporary), the DCSError exception should be raised.

Parameters: leader – a reference to a current leader object.
Returns: True if leader key (or session) has been updated successfully.

_write_failsafe(*args: Any, **kwargs: Any) → Any¶

Write current cluster topology to DCS that will be used by failsafe mechanism (if enabled).

Parameters: value – failsafe topology serialized in JSON format.
Returns: True if successfully committed to DCS.

_write_leader_optime(*args: Any, **kwargs: Any) → Any¶

Write current WAL LSN into /optime/leader key in DCS.

Parameters: last_lsn – absolute WAL LSN in bytes.
Returns: True if successfully committed to DCS.

_write_status(*args: Any, **kwargs: Any) → Any¶

Write current WAL LSN and confirmed_flush_lsn of permanent slots into the /status key in DCS.

Parameters: value – status serialized in JSON format.
Returns: True if successfully committed to DCS.

attempt_to_acquire_leader(**kwargs: Any)¶

Attempt to acquire leader lock.

Note

This method should create /leader key with the value _name.

The key must be created atomically. In case the key already exists it should not be overwritten and False must be returned.

If key creation fails due to DCS not being accessible or because it is not able to process requests (hopefully temporary), the DCSError exception should be raised.

Returns: True if key has been created successfully.

cancel_initialization(*args: Any, **kwargs: Any) → Any¶

Removes the initialize key for a cluster.

Returns: True if successfully committed to DCS.

property cluster_prefix¶

Construct the cluster prefix for the cluster.

Returns: path in the DCS under which we store information about this Patroni cluster.

create_lease() → None ¶

delete_cluster(*args: Any, **kwargs: Any) → Any¶

Delete cluster from DCS.

Returns: True if successfully committed to DCS.

delete_sync_state(*args: Any, **kwargs: Any) → Any¶

Delete the synchronous state from DCS.

Parameters: version – for conditional deletion of the key/object.
Returns: True if delete successful.

initialize(*args: Any, **kwargs: Any) → Any¶

Race for cluster initialization.

This method should atomically create initialize key and return True, otherwise it should return False.

Parameters

create_new – False if the key should already exist (in the case we are setting the system_id).
sysid – PostgreSQL cluster system identifier, if specified, is written to the key.

Returns

True if key has been created successfully.

static member(node: Dict[str, str]) → patroni.dcs.Member ¶

refresh_lease() → bool ¶

set_config_value(*args: Any, **kwargs: Any) → Any¶

Create or update /config key in DCS.

Parameters

value – new value to set in the config key.
version – for conditional update of the key/object.

Returns

True if successfully committed to DCS.

set_failover_value(*args: Any, **kwargs: Any) → Any¶

Create or update /failover key.

Parameters

value – value to set.
version – for conditional update of the key/object.

Returns

True if successfully committed to DCS.

set_history_value(*args: Any, **kwargs: Any) → Any¶

Set value for history in DCS.

Parameters: value – new value of history key/object.
Returns: True if successfully committed to DCS.

set_socket_options(sock: socket.socket, socket_options: Optional[Collection[Tuple[int, int, int]]]) → None ¶

set_sync_state_value(*args: Any, **kwargs: Any) → Any¶

Set synchronous state in DCS.

Parameters

value – the new value of /sync key.
version – for conditional update of the key/object.

Returns

version of the new object or False in case of error.

set_ttl(ttl: int) → Optional[bool]¶: Set the new ttl value for DCS keys.

take_leader(*args: Any, **kwargs: Any) → Any¶

Establish a new leader in DCS.

Note

This method should create leader key with value of _name and ttl of ttl.

Since it could be called only on initial cluster bootstrap it could create this key regardless, overwriting the key if necessary.

Returns: True if successfully committed to DCS.

touch_member(*args: Any, **kwargs: Any) → Any¶

Update member key in DCS.

Note

This method should create or update key with the name with /members/ + _name and the value of data in a given DCS.

Parameters: data – information about an instance (including connection strings).
Returns: True if successfully committed to DCS.

watch(leader_version: Optional[str], timeout: float) → bool ¶

Sleep if the current node is a leader, otherwise, watch for changes of leader key with a given timeout.

Parameters

leader_version – version of a leader key.
timeout – timeout in seconds.

Returns

if True this will reschedule the next run of the HA cycle.

class patroni.dcs.etcd3.Etcd3Client(config: Dict[str, Any], dns_resolver: patroni.dcs.etcd.DnsCachingResolver, cache_ttl: int = 300)¶

Bases: patroni.dcs.etcd.AbstractEtcdClientWithFailover

ERROR_CLS¶: alias of patroni.dcs.etcd3.Etcd3Error

__init__(config: Dict[str, Any], dns_resolver: patroni.dcs.etcd.DnsCachingResolver, cache_ttl: int = 300) → None ¶: Initialize self. See help(type(self)) for accurate signature.

_abc_impl = <_abc._abc_data object>¶

_do_auth_request(base_uri: str, kwargs: Dict[str, Any], method: str, fields: Dict[str, Any], retry: Optional[patroni.utils.Retry] = None) → Dict[str, Any]¶

Special method for handling authentication when discovering cluster members.

We can’t use call_rpc() method for this purpose because it may cause infinite recursion.

Parameters

base_uri – base url for authentication request, e.g. http://etcd:2379/v3
kwargs – common request parameters, e.g. headers.
method – /auth/authenticate
fields – authentication fields, e.g. {‘name’: ‘user’, ‘password’: ‘pass’}.
retry – optional retry configuration, ignored.

_do_member_list_request(url: str, retry: Optional[patroni.utils.Retry] = None, **kwargs: Any) → Any¶

Special method for handling member list requests.

Parameters

url – base url for member list request, e.g. http://etcd:2379/v3/cluster/member/list
kwargs – common request parameters, e.g. headers.
retry – optional retry configuration, ignored.

_ensure_version_prefix(base_uri: str, **kwargs: Any) → None ¶

_get_headers() → Dict[str, str]¶

_get_members(base_uri: str, **kwargs: Any) → List[str]¶: returns: list of clientURLs

_handle_server_response(response: urllib3.response.HTTPResponse) → Dict[str, Any]¶: Handles the server response

_prepare_get_members(etcd_nodes: int) → Dict[str, Any]¶: returns: request parameters

_prepare_request(kwargs: Dict[str, Any], params: Optional[Dict[str, Any]] = None, method: Optional[str] = None) → Callable[[…], urllib3.response.HTTPResponse]¶: returns: request_executor

authenticate(*, retry: Optional[patroni.utils.Retry] = None, auth_request_func: Optional[Callable[[…], Dict[str, Any]]] = None) → bool ¶

Authenticate with the Etcd v3 cluster.

Parameters

retry – optional retry configuration.
auth_request_func – optional custom authentication request function, if not provided, call_rpc() method will be used.

authenticate_on_start(auth_request_func: Optional[Callable[[…], Dict[str, Any]]] = None)¶

Authenticate with Etcd v3 at startup and exit on invalid credentials.

Parameters: auth_request_func – optional custom authentication request function, if not provided, call_rpc() will be used.

call_rpc(method: str, fields: Dict[str, Any], retry: Optional[patroni.utils.Retry] = None) → Dict[str, Any]¶

deleteprefix(key: str, *, retry: Optional[patroni.utils.Retry] = None) → Dict[str, Any]¶

deleterange(*args: Any, **kwargs: Any) → Any¶

handle_auth_errors(func: Callable[[…], Any], *args: Any, auth_request_func: Optional[Callable[[…], Dict[str, Any]]] = None, retry: Optional[patroni.utils.Retry] = None, **kwargs: Any) → Any¶

Handle authentication errors for the given function.

Parameters

func – function to call.
args – positional arguments for the function.
auth_request_func – optional custom authentication request function, if not provided, call_rpc() method will be used.
retry – optional retry configuration.
kwargs – keyword arguments for the function.

lease_grant(*args: Any, **kwargs: Any) → Any¶

lease_keepalive(*args: Any, **kwargs: Any) → Any¶

prefix(key: str, serializable: bool = True, *, retry: Optional[patroni.utils.Retry] = None) → Dict[str, Any]¶

put(*args: Any, **kwargs: Any) → Any¶

range(*args: Any, **kwargs: Any) → Any¶

txn(*args: Any, **kwargs: Any) → Any¶

watchprefix(key: str, start_revision: Optional[str] = None, filters: Optional[List[Dict[str, Any]]] = None, read_timeout: Optional[float] = None) → urllib3.response.HTTPResponse¶

watchrange(key: str, range_end: Optional[Union[bytes, str]] = None, start_revision: Optional[str] = None, filters: Optional[List[Dict[str, Any]]] = None, read_timeout: Optional[float] = None) → urllib3.response.HTTPResponse¶: returns: response object

exception patroni.dcs.etcd3.Etcd3ClientError(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3Exception

__init__(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None) → None ¶: Initialize self. See help(type(self)) for accurate signature.

as_dict() → Dict[str, Any]¶

classmethod get_subclasses() → Iterator[Type[patroni.dcs.etcd3.Etcd3ClientError]]¶

exception patroni.dcs.etcd3.Etcd3Error(value: Any)¶: Bases: patroni.exceptions.DCSError

exception patroni.dcs.etcd3.Etcd3Exception(message=None, payload=None)¶: Bases: etcd.EtcdException

exception patroni.dcs.etcd3.Etcd3WatchCanceled(message=None, payload=None)¶: Bases: patroni.dcs.etcd3.Etcd3Exception

exception patroni.dcs.etcd3.FailedPrecondition(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 9¶

class patroni.dcs.etcd3.GRPCCode(value)¶

Bases: enum.IntEnum

An enumeration.

Aborted = 10¶

AlreadyExists = 6¶

Canceled = 1¶

DataLoss = 15¶

DeadlineExceeded = 4¶

FailedPrecondition = 9¶

Internal = 13¶

InvalidArgument = 3¶

NotFound = 5¶

OK = 0¶

OutOfRange = 11¶

PermissionDenied = 7¶

ResourceExhausted = 8¶

Unauthenticated = 16¶

Unavailable = 14¶

Unimplemented = 12¶

Unknown = 2¶

exception patroni.dcs.etcd3.InvalidArgument(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 3¶

exception patroni.dcs.etcd3.InvalidAuthToken(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 16¶

error = 'etcdserver: invalid auth token'¶

class patroni.dcs.etcd3.KVCache(dcs: patroni.dcs.etcd3.Etcd3, client: patroni.dcs.etcd3.PatroniEtcd3Client)¶

Bases: patroni.dcs.etcd.StaleEtcdNodeGuard, threading.Thread

__init__(dcs: patroni.dcs.etcd3.Etcd3, client: patroni.dcs.etcd3.PatroniEtcd3Client) → None ¶

This constructor should always be called with keyword arguments. Arguments are:

group should be None; reserved for future extension when a ThreadGroup class is implemented.

target is the callable object to be invoked by the run() method. Defaults to None, meaning nothing is called.

name is the thread name. By default, a unique name is constructed of the form “Thread-N” where N is a small decimal number.

args is the argument tuple for the target invocation. Defaults to ().

kwargs is a dictionary of keyword arguments for the target invocation. Defaults to {}.

If a subclass overrides the constructor, it must make sure to invoke the base class constructor (Thread.__init__()) before doing anything else to the thread.

_build_cache() → None ¶

_do_watch(revision: str) → None ¶

static _finish_response(response: urllib3.response.HTTPResponse) → None ¶

_process_event(event: Dict[str, Any]) → None ¶

_process_message(message: Dict[str, Any]) → None ¶

copy() → List[Dict[str, Any]]¶

delete(name: str, mod_revision: str) → Tuple[bool, Optional[Dict[str, Any]]]¶

get(name: str) → Optional[Dict[str, Any]]¶

is_ready() → bool ¶: Must be called only when holding the lock on condition

kill_stream() → None ¶

run() → None ¶

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

set(value: Dict[str, Any], overwrite: bool = False) → Tuple[bool, Optional[Dict[str, Any]]]¶

exception patroni.dcs.etcd3.LeaseNotFound(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.NotFound

error = 'etcdserver: requested lease not found'¶

exception patroni.dcs.etcd3.NotFound(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 5¶

class patroni.dcs.etcd3.PatroniEtcd3Client(*args: Any, **kwargs: Any)¶

Bases: patroni.dcs.etcd3.Etcd3Client

__init__(*args: Any, **kwargs: Any) → None ¶: Initialize self. See help(type(self)) for accurate signature.

_abc_impl = <_abc._abc_data object>¶

_cluster_version: Tuple[int, …]¶

_restart_watcher() → None ¶

_wait_cache(timeout: float) → None ¶

call_rpc(method: str, fields: Dict[str, Any], retry: Optional[patroni.utils.Retry] = None) → Dict[str, Any]¶

configure(etcd3: patroni.dcs.etcd3.Etcd3) → None ¶

get_cluster(path: str) → List[Dict[str, Any]]¶

set_base_uri(value: str) → None ¶

start_watcher() → None ¶

txn(compare: Dict[str, Any], success: Dict[str, Any], failure: Optional[Dict[str, Any]] = None, *, retry: Optional[patroni.utils.Retry] = None) → Dict[str, Any]¶

exception patroni.dcs.etcd3.PermissionDenied(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 7¶

error = 'etcdserver: permission denied'¶

exception patroni.dcs.etcd3.Unavailable(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 14¶

exception patroni.dcs.etcd3.Unknown(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.Etcd3ClientError

code = 2¶

exception patroni.dcs.etcd3.UnsupportedEtcdVersion(value: Any)¶: Bases: patroni.exceptions.PatroniException

exception patroni.dcs.etcd3.UserEmpty(code: Optional[int] = None, error: Optional[str] = None, status: Optional[int] = None)¶

Bases: patroni.dcs.etcd3.InvalidArgument

error = 'etcdserver: user name is empty'¶

patroni.dcs.etcd3._handle_auth_errors(func: Callable[[…], Any]) → Any¶

patroni.dcs.etcd3._raise_for_data(data: Union[bytes, str, Dict[str, Any]], status_code: Optional[int] = None) → patroni.dcs.etcd3.Etcd3ClientError ¶

patroni.dcs.etcd3.base64_decode(v: str) → str ¶

patroni.dcs.etcd3.base64_encode(v: Union[str, bytes]) → str ¶

patroni.dcs.etcd3.build_range_request(key: str, range_end: Optional[Union[bytes, str]] = None) → Dict[str, Any]¶

patroni.dcs.etcd3.prefix_range_end(v: str) → bytes ¶

patroni.dcs.etcd3.to_bytes(v: Union[str, bytes]) → bytes ¶