Interfaces¶

plone.observability registers all of its components through the Zope Component Architecture. Third-party packages extend or replace any of them. This page describes the interfaces; How to add a custom health check, How to add a custom metric provider, and How to add a custom metric formatter show how to register implementations.

`ILivenessCheck`¶

A named utility that reports whether the process is fundamentally alive.

A liveness check must not access ZODB and must not block.

Member	Description
`name`	The check name, reported in the `/live` response.
`__call__()`	Returns a `(ok: bool, message: str)` tuple.

A named utility that reports whether the process can serve requests.

A readiness check may access ZODB.

Member	Description
`name`	The check name, reported in the `/ready` and `/startup` responses.
`__call__()`	Returns a `(ok: bool, message: str)` tuple.

An adapter on OFS.interfaces.IApplication that yields metrics.

Member	Description
`name`	The provider name, used for registration.
`scope`	Default scope for the provider’s metrics, `"instance"` or `"global"`.
`collect()`	A generator yielding `Metric` instances.

A named utility that serializes metrics to a wire format.

Member	Description
`content_type`	The MIME type of the produced output.
`format(metrics)`	Returns the serialized string for an iterable of `Metric` instances.

The formatter name is selected with the format query-string parameter on @@metrics.

The value object yielded by metric providers.

Field	Description
`name`	The metric name, for example `myapp_queue_length`.
`value`	The numeric value.
`type`	The metric type: `gauge`, `counter`, or `info`.
`scope`	`"instance"` or `"global"`.
`help`	A human-readable description.

Import it from plone.observability.metric.

A dependency-optional helper for opening custom trace spans. It is a no-op when the opentelemetry extra is not installed. See Tracing.