Attach labels (tags) to logs

[svetlanabrennan]

Description

We need to support adding labels (tags) to logs.

TLDR:

• Labels disabled by default
• Labels should be prefixed with "tags."
• Labels are added to common attributes, not individual logs.
• Allows individual labels to be excluded

Dependent on this issue that adds configurations to the agents to enable this feature: https://github.com/newrelic/node-newrelic/issues/2713

Implementation details:

• If application_logging.forwarding.labels.enabled is set to true, all labels MUST be attached in common attributes unless there is matching entry in application_logging.forwarding.labels.exclude.
• The attribute key MUST be the prefix tags. followed by the label name.
• Except for tags., the attribute MUST match the case of the original label. Example, MYLABEL;Value1 becomes "tags.MYLABEL": "Value1".
• Add supportability metric for labels - Supportability/Logging/Labels/{language}/{enabled\|disabled}. MUST be generated by agents when labels on application logging is enabled. disabled SHOULD be generated if possible, although some agents' implementation may preclude it. It is expected to be sent once per agent connect (not per harvest).|

Example newrelic.config bit from .NET showing labels with no exclude configuration:

<labels>label1:value1;LABEL2:value2;LABEL2-ALSO:value3</labels>

Example log_event_data payload based on above newrelic.config:

[{
   "common": {
     "attributes": {
       "entity.guid": <ENTITY_GUID>,
       "entity.name": "My Application",
       "hostname": "my-host-name",
       "tags.label1": "value1",
       "tags.LABEL2": "value2",
       "tags.LABEL2-ALSO":"value3"
     }
   },
   "logs": [{
       "timestamp": <TIMESTAMP_IN_UNIX_EPOCH_MILLSECONDS>,
       "level": "INFO"
       "message": "User 'xyz' logged in",
       "span.id": "123456789ADF",
       "trace.id": "ADF09876565"
     }]
}]

Same example above, but with the following exclude configuration (.NET agent XML):

<applicationLogging>
  <forwarding>
    <labels enabled="true" exclude="label2" />
  </forwarding>
</applicationLogging>

Example log_event_data payload based on above newrelic.config - no longer has LABEL2, but still has LABEL2-ALSO:

[{
   "common": {
     "attributes": {
       "entity.guid": <ENTITY_GUID>,
       "entity.name": "My Application",
       "hostname": "my-host-name",
       "tags.label1": "value1",
       "tags.LABEL2-ALSO":"value3"
     }
   },
   "logs": [{
       "timestamp": <TIMESTAMP_IN_UNIX_EPOCH_MILLSECONDS>,
       "level": "INFO"
       "message": "User 'xyz' logged in",
       "span.id": "123456789ADF",
       "trace.id": "ADF09876565"
     }]
}]

Link to labels spec.

Discovery doc about labels.

[workato-integration[bot]]

https://new-relic.atlassian.net/browse/NR-338335