filterprocessor

README

Filter Processor

Supported pipeline types: metrics

The filter processor can be configured to include or exclude metrics based on metric name in the case of the 'strict' or 'regexp' match types, or based on other metric attributes in the case of the 'expr' match type. Please refer to config.go for the config spec.

It takes a pipeline type, of which only metrics is supported, followed by an action:

• include: Any names NOT matching filters are excluded from remainder of pipeline
• exclude: Any names matching filters are excluded from remainder of pipeline

For the actions the following parameters are required:

• match_type: strict|regexp|expr
• metric_names: (only for a match_type of 'strict' or 'regexp') list of strings or re2 regex patterns
• expressions: (only for a match_type of 'expr') list of expr expressions (see "Using an 'expr' match_type" below)
• resource_attributes: ResourceAttributes defines a list of possible resource attributes to match metrics against. A match occurs if any resource attribute matches at least one expression in this given list.

More details can found at include/exclude metrics.

Examples:

processors:
  filter/1:
    metrics:
      include:
        match_type: regexp
        metric_names:
          - prefix/.*
          - prefix_.*
        resource_attributes:
          - Key: container.name
            Value: app_container_1
      exclude:
        match_type: strict
        metric_names:
          - hello_world
          - hello/world

Refer to the config files in testdata for detailed examples on using the processor.

Using an 'expr' match_type

In addition to matching metric names with the 'strict' or 'regexp' match types, the filter processor supports matching entire Metrics using the expr expression engine.

The 'expr' filter evaluates the supplied boolean expressions per datapoint on a metric, and returns a result for the entire metric. If any datapoint evaluates to true then the entire metric evaluates to true, otherwise false.

Made available to the expression environment are the following:

• MetricName a variable containing the current Metric's name
• Label(name) a function that takes a label name string as an argument and returns a string: the value of a label with that name if one exists, or ""
• HasLabel(name) a function that takes a label name string as an argument and returns a boolean: true if the datapoint has a label with that name, false otherwise

Example:

processors:
  filter/1:
    metrics:
      exclude:
        match_type: expr
        expressions:
        - MetricName == "my.metric" && Label("my_label") == "abc123"

The above config will filter out any Metric that both has the name "my.metric" and has at least one datapoint with a label of 'my_label="abc123"'.

Support for multiple expressions

As with "strict" and "regexp", multiple "expr" expressions are allowed.

For example, the following two filters have the same effect: they filter out metrics named "system.cpu.time" and "system.disk.io".

processors:
  filter/expr:
    metrics:
      exclude:
        match_type: expr
        expressions:
          - MetricName == "system.cpu.time"
          - MetricName == "system.disk.io"
  filter/strict:
    metrics:
      exclude:
        match_type: strict
        metric_names:
          - system.cpu.time
          - system.disk.io

The expressions are effectively ORed per datapoint. So for the above 'expr' configuration, given a datapoint, if its parent Metric's name is "system.cpu.time" or "system.disk.io" then there's a match. The conditions are tested against all the datapoints in a Metric until there's a match, in which case the entire Metric is considered a match, and in the above example the Metric will be excluded. If after testing all the datapoints in a Metric against all the expressions there isn't a match, the entire Metric is considered to be not matching.

Filter metrics using resource attributes

In addition to the names, metrics can be filtered using resource attributes. resource_attributes takes a list of resource attributes to filter metrics against.

Following example will include only the metrics coming from app_container_1 (the value for container.name resource attribute is app_container_1).

processors:
  filter:
    metrics:
      include:
        match_type: strict
        metric_names:
          - hello_world
          - hello/world
        resource_attributes:
          - Key: container.name
            Value: app_container_1

Following example will exclude all the metrics coming from app_container_1 (the value for container.name resource attribute is app_container_1).

processors:
  filter:
    metrics:
      exclude:
        match_type: strict
        metric_names:
          - hello_world
          - hello/world
        resource_attributes:
          - Key: container.name
            Value: app_container_1

We can also use regexp to filter metrics using resource attributes. Following example will include only the metrics coming from app_container_1 or app_container_2 (the value for container.name resource attribute is either app_container_1 or app_container_2).

processors:
  filter:
    metrics:
      exclude:
        match_type: regexp
        metric_names:
          - hello_world
          - hello/world
        resource_attributes:
          - Key: container.name
            Value: (app_container_1|app_container_1)

Documentation

Overview

Package filterprocessor implements a processor for filtering (dropping) metrics and/or spans by various properties.

Index

• func NewFactory() component.ProcessorFactory
• type Config
• type MetricFilters

Functions

func NewFactory

func NewFactory() component.ProcessorFactory

NewFactory returns a new factory for the Filter processor.

Types

type Config

type Config struct {
	configmodels.ProcessorSettings `mapstructure:",squash"`
	Metrics                        MetricFilters `mapstructure:"metrics"`
}

Config defines configuration for Resource processor.

type MetricFilters

type MetricFilters struct {
	// Include match properties describe metrics that should be included in the Collector Service pipeline,
	// all other metrics should be dropped from further processing.
	// If both Include and Exclude are specified, Include filtering occurs first.
	Include *filtermetric.MatchProperties `mapstructure:"include"`

	// Exclude match properties describe metrics that should be excluded from the Collector Service pipeline,
	// all other metrics should be included.
	// If both Include and Exclude are specified, Include filtering occurs first.
	Exclude *filtermetric.MatchProperties `mapstructure:"exclude"`
}

MetricFilter filters by Metric properties.