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structured_metadata

Warning

Structured metadata is an experimental feature and is subject to change in future releases of Grafana Loki.

The structured_metadata stage is an action stage that takes data from the extracted map and modifies the structured metadata that is sent to Loki with the log entry.

Warning

Structured metadata will be rejected by Loki unless you enable the allow_structured_metadata per tenant configuration (in the limits_config).

Schema

yaml
structured_metadata:
  # Key is REQUIRED and the name for the label of structured metadata that will be created.
  # Value is optional and will be the name from extracted data whose value
  # will be used for the value of the label. If empty, the value will be
  # inferred to be the same as the key.
  [ <string>: [<string>] ... ]

Examples

For the given pipeline:

yaml
- json:
    expressions:
      stream: stream
      traceID: traceID
- labels:
    stream:
- structured_metadata:
    traceID:

Given the following log line:

{"log":"log message\n","stream":"stderr","traceID":"0242ac120002",time":"2019-04-30T02:12:41.8443515Z"}

The first stage would extract stream with a value of stderr and traceID with a value of 0242ac120002 into the extracted data set. The labels stage would turn that stream and stderr key-value pair into a stream label. The structured_metadata stage would attach the traceID and 0242ac120002 key-value pair as a structured metadata to the log line.