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: patroni.dcs.etcd3.PatroniEtcd3Client

return correct type of etcd client

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

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
_abc_impl = <_abc._abc_data object>
_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) → bool
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, retry: Optional[patroni.utils.Retry] = None, **kwargs: Any) → Any
lease_grant(*args: Any, **kwargs: Any) → Any
lease_keepalive(ID: str, *, retry: Optional[patroni.utils.Retry] = None) → Optional[str]
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
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
_abc_impl = <_abc._abc_data object>
_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