patroni.tags module

Tags handling.

class patroni.tags.Tags

Bases: abc.ABC

An abstract class that encapsulates all the tags logic.

Child classes that want to use provided facilities must implement tags abstract property.

Note

Due to backward-compatibility reasons, old tags may have a less strict type conversion than new ones.

_abc_impl = <_abc._abc_data object>

static _filter_tags(tags: Dict[str, Any]) → Dict[str, Any]

Get tags configured for this node, if any.

Handle both predefined Patroni tags and custom defined tags.

Note

A custom tag is any tag added to the configuration tags section that is not one of clonefrom, nofailover, noloadbalance,``nosync`` or nostream.

For most of the Patroni predefined tags, the returning object will only contain them if they are enabled as they all are boolean values that default to disabled. However nofailover tag is always returned if failover_priority tag is defined. In this case, we need both values to see if they are contradictory and the nofailover value should be used.

Returns

a dictionary of tags set for this node. The key is the tag name, and the value is the corresponding tag value.

property clonefrom

True if clonefrom tag is True, else False.

property failover_priority

Common logic for obtaining the value of failover_priority from tags if defined.

If nofailover is defined as True, this will return 0. Otherwise, it will return the value of failover_priority, defaulting to 1 if it’s not defined or invalid.

property nofailover

Common logic for obtaining the value of nofailover from tags if defined.

If nofailover is not defined, this methods returns True if failover_priority is non-positive, False otherwise.

property noloadbalance

True if noloadbalance is True, else False.

property nostream

True if nostream is True, else False.

property nosync

True if nosync is True, else False.

property replicatefrom

Value of replicatefrom tag, if any.

abstract property tags

Configured tags.

Must be implemented in a child class.