Prometheus - Label (Dimension, Column)

About

A label is a dimension/column in a metric (row) and allows dimensional data model

This metric:

api_http_requests_total{method="POST", handler="/messages"}

is equivalent to

{name="api_http_requests_total", method="POST", handler="/messages"}

and has 3 metrics:

• name
• method
• and handler

Any given combination of labels for the same metric name identifies a particular dimensional instantiation of that metric (for example: all HTTP requests that used the method POST to the /api/tracks handler).

The query language allows filtering and aggregation based on these dimensions.

Changing any label value, including adding or removing a label, will create a new time series.

Example

api_http_requests_total{method="POST", handler="/messages"}

where:

• the metric name is api_http_requests_total
• the labels are:
  • method=“POST”
  • handler=“/messages”

Syntax

name=value

Example of two labels:

method="POST"
handler="/messages"

Properties

Name

Label names may contain:

• ASCII letters,
• numbers,
• as well as underscores.

They must match the regex [a-zA-Z_][a-zA-Z0-9_]*.

Label names beginning with __ are reserved for internal use.

More … naming

Value

Label values may contain any Unicode characters.

A label with an empty label value is considered equivalent to a label that does not exist.