Rules

Rules transform JMX MBean attributes into Prometheus metrics. Rules are evaluated in order and processing stops at the first matching rule. Attributes that do not match any configured rule are not collected.

Rule fields

Field	Description
pattern	Regular expression matched against the rule input. Capture groups can be used by other fields. Required when name is set.
name	Metric name. Capture groups from pattern can be used. If omitted, the default format is used.
value	Static value or capture-group expression. If omitted, the scraped MBean value is used.
valueFactor	Number multiplied by the selected value. Useful for unit conversion. Default is 1.0.
labels	Map of label names to label values. name must also be set.
help	Metric help text. name must also be set.
cache	Cache match and mismatch results for this rule. Default is false. Do not use for rules that match bean values.
type	Metric type. Supported values include GAUGE, COUNTER, and UNTYPED; UNTYPED maps to the implementation's unknown type.
attrNameSnakeCase	Convert the attribute name to snake case before matching and default formatting. Default is false.

help or labels without name is invalid. name without pattern is invalid.

Pattern input

Rules match this input shape:

domain<beanPropertyName1=beanPropertyValue1, beanPropertyName2=beanPropertyValue2, ...><key1, key2, ...>attrName: value

Part	Description
domain	ObjectName domain before the colon.
beanPropertyName/Value	ObjectName properties after the colon.
keyN	Composite or tabular data path elements.
attrName	Attribute name, or tabular column name.
value	Attribute value.

Default format

When a rule matches without name, the collector uses the default format:

domain_beanPropertyValue1_key1_key2_...keyN_attrName{beanPropertyName2="beanPropertyValue2", ...} value

Metric names and label names are sanitized by the metrics library. Invalid characters are replaced or normalized for Prometheus compatibility.

Examples

Collect everything with the default format:

rules:
- pattern: ".*"

Create a named metric with labels:

rules:
- pattern: 'java.lang<type=Memory><HeapMemoryUsage>used: (.*)'
  name: jvm_heap_memory_used_bytes
  value: '$1'
  labels:
    area: heap
  help: Used heap memory in bytes.
  type: GAUGE

Convert milliseconds to seconds:

rules:
- pattern: '.*ProcessingTimeMillis: (.*)'
  name: application_processing_time_seconds
  value: '$1'
  valueFactor: 0.001
  type: GAUGE

Counter example:

rules:
- pattern: '.*RequestCount: (.*)'
  name: application_requests_total
  value: '$1'
  type: COUNTER