Metrics

Referentielijsten produces application metrics (using Open Telemetry).

Note

The exact metric names that show up may be transformed, e.g. Prometheus replaces periods with underscores, and processing pipelines may add prefixes or suffixes.

Important

Some metrics are defined as “global scope”.

These metrics are typically derived from application state introspection, e.g. by performing database (read) queries to aggregate some information. Usually those correspond to an Asynchronous Gauge.

Multiple replicas and/or instances of the same service will produce the same values of the metrics. You need to apply some kind of aggregation to de-duplicate these values. The attribute scope="global" acts as a marker for these type of metrics.

With PromQL for example, you can use avg on the assumption that all values will be equal, so the average will also be identical:

avg by (type) (otel_referentielijsten_auth_user_count{scope="global"})

Generic

http.server.duration: Captures how long each HTTP request took, in ms. The metric produces histogram data.
http.server.request.duration (not active): The future replacement of http.server.duration, in seconds. Currently not enabled, but the code is in the Open Telemetry SDK instrumentation already and could possibly be opted-in to.

Application specific

Accounts

referentielijsten.auth.user_count

Reports the number of users in the database. This is a global metric, you must take care in de-duplicating results. Additional attributes are:

scope - fixed, set to global to enable de-duplication.
type - the user type. all, staff or superuser.

Sample PromQL query:

max by (type) (last_over_time(
  otel_referentielijsten_auth_user_count{scope="global"}
  [1m]
))

referentielijsten.auth.login_failures

A counter incremented every time a user login fails (typically because of invalid credentials). Does not include the second factor, if enabled. Additional attributes:

http_target - the request path where the login failure occurred, if this happened in a request context.

referentielijsten.auth.user_lockouts

A counter incremented every time a user is locked out because they reached the maximum number of failed attempts. Additional attributes:

http_target - the request path where the login failure occurred, if this happened in a request context.
username - username of the user trying to log in.

referentielijsten.auth.logins

Counter incrementing on every successful login by a user. Additional attributes:

http_target - the request path where the login failure occurred, if this happened in a request context.
username - username of the user trying to log in.

referentielijsten.auth.logouts

Counter incrementing every time a user logs out. Additional attributes:

username - username of the user who logged out.

Tabels

referentielijsten.tabel.creates: Reports the number of tabels created.
referentielijsten.tabel.updates: Reports the number of tabels updated.
referentielijsten.tabel.deletes: Reports the number of tabels deleted.

These metrics provide insight into changes to reference list structures. They help to monitor growth, update frequency, and the stability of data models.

Sample PromQL query:

sum by (otel_scope_name) (otel_referentielijsten_tabel_updates_total)

Items

referentielijsten.item.creates: Reports the number of items created.
referentielijsten.item.updates: Reports the number of items updated.
referentielijsten.item.deletes: Reports the number of items deleted.

These metrics indicate how many records within reference lists are being modified. They help detect data maintenance patterns, operational spikes, or unusual update/delete activity.

Sample PromQL query:

sum by (otel_scope_name) (otel_referentielijsten_item_creates_total)