patroni.dcs.consul module

class patroni.dcs.consul.Consul(config: Dict[str, Any])

Bases: AbstractDCS

adjust_ttl() → None

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(**kwargs: Any) → Any

Removes the initialize key for a cluster.

Returns:

True if successfully committed to DCS.

create_session() → None

delete_cluster(**kwargs: Any) → Any

Delete cluster from DCS.

Returns:

True if successfully committed to DCS.

delete_sync_state(**kwargs: Any) → Any

Delete the synchronous state from DCS.

Parameters:

version – for conditional deletion of the key/object.

Returns:

True if delete successful.

deregister_service(**kwargs: Any) → Any

initialize(**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]) → Member

refresh_session() → bool

register_service(**kwargs: Any) → 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: Any, **kwargs: Any) → Any

set_config_value(**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(**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(**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_retry_timeout(retry_timeout: int) → None

Set the new value for retry_timeout.

set_sync_state_value(**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() → bool

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(**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.

property ttl: int

Get current ttl value.

update_service(**kwargs: Any) → 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.consul.ConsulClient(*args: Any, **kwargs: Any)

Bases: Consul

connect(*args: Any, **kwargs: Any) → HTTPClient

http_connect(*args: Any, **kwargs: Any) → HTTPClient

reload_config(config: Dict[str, Any]) → None

exception patroni.dcs.consul.ConsulError(value: Any)

Bases: DCSError

exception patroni.dcs.consul.ConsulInternalError

Bases: ConsulException

An internal Consul server error occurred

class patroni.dcs.consul.HTTPClient(host: str = '127.0.0.1', port: int = 8500, token: Optional[str] = None, scheme: str = 'http', verify: bool = True, cert: Optional[str] = None, ca_cert: Optional[str] = None)

Bases: object

static response(response: HTTPResponse) → Response

set_read_timeout(timeout: float) → None

set_ttl(ttl: int) → bool

property ttl: int

uri(path: str, params: Union[None, Dict[str, Any], List[Tuple[str, Any]], Tuple[Tuple[str, Any], ...]] = None) → str

exception patroni.dcs.consul.InvalidSession

Bases: ConsulException

invalid session

exception patroni.dcs.consul.InvalidSessionTTL

Bases: ConsulException

Session TTL is too small or too big

class patroni.dcs.consul.Response(code, headers, body, content)

Bases: NamedTuple

body: str

Alias for field number 2

code: int

Alias for field number 0

content: bytes

Alias for field number 3

headers: Optional[Union[Mapping[str, str], Mapping[bytes, bytes]]]

Alias for field number 1

patroni.dcs.consul.catch_consul_errors(func: Callable[[...], Any]) → Callable[[...], Any]

patroni.dcs.consul.force_if_last_failed(func: Callable[[...], Any]) → Callable[[...], Any]

patroni.dcs.consul.service_name_from_scope_name(scope_name: str) → str

Translate scope name to service name which can be used in dns.

230 = 253 - len(‘replica.’) - len(‘.service.consul’)