EELF guidelines stipulate that an application should output log records to four separate files:
- audit
- metrics
- error
- debug
This applies only to EELF logging. Components which log directly to a provider may choose to emit the same set of logs, but most do not.
Audit Log
An audit log is required for EELF-enabled components, and provides a summary view of the processing of a (e.g., transaction) request within an application. It captures activity requests that are received by an ONAP component, and includes such information as the time the activity is initiated, then it finishes, and the API that is invoked at the component.
Audit log records are intended to capture the high level view of activity within an ONAP component. Specifically, an API request handled by an ONAP component is reflected in a single Audit log record that captures the time the request was received, the time that processing was completed, as well as other information about the API request (e.g., API name, on whose behalf it was invoked, etc).
Metrics Log
A metrics log is required for EELF-enabled components, and provides a more detailed view into the processing of a transaction within an application. It captures the beginning and ending of activities needed to complete it. These can include calls to or interactions with other ONAP or non-ONAP entities.
Suboperations invoked as part of the processing of the API request are logged in the Metrics log. For example, when a call is made to another ONAP component or external (i.e., non-ONAP) entity, a Metrics log record captures that call. In such a case, the Metrics log record indicates (among other things) the time the call is made, when it returns, the entity that is called, and the API invoked on that entity. The Metrics log record contain the same RequestID as the Audit log record so the two can be correlated.
Note that a single request may result in multiple Audit log records at an ONAP component and may result in multiple Metrics log records generated by the component when multiple suboperations are required to satisfy the API request captured in the Audit log record.
Error Log
An error log is required for EELF-enabled components, and is intended to capture info, warn, error and fatal conditions sensed (“exception handled”) by the software components.
This includes previous logs that went to application.log
Debug Log
A debug log is optional for EELF-enabled components, and is intended to capture whatever data may be needed to debug and correct abnormal conditions of the application.
Engine.out
Console logging may also be present, and is intended to capture “system/infrastructure” records. That is stdout and stderr assigned to a single “engine.out” file in a directory configurable (e.g. as an environment/shell variable) by operations personnel.
Application Log (deprecated)
see example in https://git.onap.org/oom/tree/kubernetes/portal/charts/portal-sdk/resources/config/deliveries/properties/ONAPPORTALSDK/logback.xml
We no longer support this 5th log file - see error.log
Log File Locations
There are several locations where logs are available on the host, on the nfs share and in each application and filebeat container