patroni.dcs.etcd module

class patroni.dcs.etcd.AbstractEtcd(config: Dict[str, Any], client_cls: Type[patroni.dcs.etcd.AbstractEtcdClientWithFailover], retry_errors_cls: Union[Type[Exception], Tuple[Type[Exception], ...]])

Bases: patroni.dcs.AbstractDCS

get_etcd_client(config: Dict[str, Any], client_cls: Type[patroni.dcs.etcd.AbstractEtcdClientWithFailover]) → patroni.dcs.etcd.AbstractEtcdClientWithFailover
handle_etcd_exceptions(func: Callable[[...], Any], *args, **kwargs) → Any
reload_config(config: Union[Config, Dict[str, Any]]) → None

Load and set relevant values from configuration.

Sets loop_wait, ttl and retry_timeout properties.

Parameters:config – Loaded configuration information object or dictionary of key value pairs.
retry(method: Callable[[...], Any], *args, **kwargs) → Any
set_retry_timeout(retry_timeout: int) → None

Set the new value for retry_timeout.

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

Set the new ttl value for DCS keys.

ttl

Get current ttl value.

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

Bases: abc.ABC, etcd.client.Client

api_execute(path: str, method: str, params: Optional[Dict[str, Any]] = None, timeout: Optional[float] = None) → Any

Executes the query.

static get_srv_record(host: str) → List[Tuple[str, int]]
machines

Original machines method(property) of etcd.Client class raise exception when it failed to get list of etcd cluster members. This method is being called only when request failed on one of the etcd members during api_execute call. For us it’s more important to execute original request rather then get new topology of etcd cluster. So we will catch this exception and return empty list of machines. Later, during next api_execute call we will forcefully update machines_cache.

Also this method implements the same timeout-retry logic as api_execute, because the original method was retrying 2 times with the read_timeout on each node.

After the next refactoring the whole logic was moved to the _get_machines_list() method.

machines_cache
reload_config(config: Dict[str, Any]) → None
set_base_uri(value: str) → None
set_machines_cache_ttl(cache_ttl: int) → None
set_read_timeout(timeout: float) → None
class patroni.dcs.etcd.DnsCachingResolver(cache_time: float = 600.0, cache_fail_time: float = 30.0)

Bases: threading.Thread

remove(host: str, port: int) → None
resolve(host: str, port: int) → List[Tuple[socket.AddressFamily, socket.SocketKind, int, str, Union[Tuple[str, int], Tuple[str, int, int, int]]]]
resolve_async(host: str, port: int, attempt: int = 0) → 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.

class patroni.dcs.etcd.Etcd(config: Dict[str, Any])

Bases: patroni.dcs.etcd.AbstractEtcd

attempt_to_acquire_leader(**kwargs)
cancel_initialization(*args, **kwargs) → Any
delete_cluster(*args, **kwargs) → Any
delete_sync_state(*args, **kwargs) → Any
initialize(*args, **kwargs) → Any
static member(node: etcd.EtcdResult) → patroni.dcs.Member
set_config_value(*args, **kwargs) → Any
set_failover_value(*args, **kwargs) → Any
set_history_value(*args, **kwargs) → Any
set_sync_state_value(*args, **kwargs) → Any
set_ttl(ttl: int) → Optional[bool]

Set the new ttl value for DCS keys.

take_leader(*args, **kwargs) → Any
touch_member(*args, **kwargs) → Any
watch(leader_version: Optional[int], 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.etcd.EtcdClient(config: Dict[str, Any], dns_resolver: patroni.dcs.etcd.DnsCachingResolver, cache_ttl: int = 300)

Bases: patroni.dcs.etcd.AbstractEtcdClientWithFailover

ERROR_CLS

alias of EtcdError

exception patroni.dcs.etcd.EtcdError(value: Any)

Bases: patroni.exceptions.DCSError

exception patroni.dcs.etcd.EtcdRaftInternal(message=None, payload=None)

Bases: etcd.EtcdException

Raft Internal Error

patroni.dcs.etcd.catch_etcd_errors(func: Callable[[...], Any]) → Any