opentelemetry-java-contrib/samplers

Samplers

Declarative configuration

The following samplers support declarative configuration:

• RuleBasedRoutingSampler

To use:

• Add a dependency on io.opentelemetry:opentelemetry-sdk-extension-incubator:<version>
• Follow the instructions to configure OpenTelemetry with declarative configuration.
• Configure the .tracer_provider.sampler to include the rule_based_routing sampler.

NOTE: Not yet available for use with the OTEL java agent, but should be in the near future. Please check back for updates.

Schema for rule_based_routing sampler:

# The fallback sampler to the use if the criteria is not met.
fallback_sampler:
  always_on:
# Filter to spans of this span_kind. Must be one of: SERVER, CLIENT, INTERNAL, CONSUMER, PRODUCER.
span_kind: SERVER   # only apply to server spans
# List of rules describing spans to drop. Spans are dropped if they match one of the rules.
rules:
  # The action to take when the rule is matches. Must be of: DROP, RECORD_AND_SAMPLE.
  - action: DROP
    # The span attribute to match against.
    attribute: url.path
    # The pattern to compare the span attribute to.
    pattern: /actuator.*

rule_based_routing sampler can be used anywhere a sampler is used in the configuration model. For example, the following YAML demonstrates a typical configuration, setting rule_based_routing sampler as the root sampler of parent_based sampler. In this configuration:

• The parent_based sampler samples based on the sampling status of the parent.
• Or, if there is no parent, delegates to the rule_based_routing sampler.
• The rule_based_routing sampler drops spans where kind=SERVER and url.full matches /actuator.*, else it samples and records.

// ... the rest of the configuration file is omitted for brevity
// For more examples see: https://github.com/open-telemetry/opentelemetry-configuration/blob/main/README.md#starter-templates
tracer_provider:
  sampler:
    parent_based:
      # Configure the parent_based sampler's root sampler to be rule_based_routing sampler.
      root:
        rule_based_routing:
          # Fallback to the always_on sampler if the criteria is not met.
          fallback_sampler:
            always_on:
          # Only apply to SERVER spans.
          span_kind: SERVER
          rules:
            # Drop spans where url.path matches the regex /actuator.* (i.e. spring boot actuator endpoints).
            - action: DROP
              attribute: url.path
              pattern: /actuator.*

Component owners

• Jack Berg, New Relic
• Trask Stalnaker, Microsoft

Learn more about component owners in component_owners.yml.