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Comment: Reverted from v. 9

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Official R1 documentation snapshot in  https://onap.readthedocs.io/en/latest/submodules/logging-analytics.git/docs/

THIS IS A DRAFT WIP for R2 - ONAP Beijing Release

This document specifies logging conventions to be followed by ONAP component applications.  

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Java is assumed, but conventions may also be implemented by non-Java components. 

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Log4j 2.X is somewhat less common than Logback, but equivalent. It is generally configured by an XML document named log4j.xml. See Configuration.

Log4j 1.X

AvoidStrongly discouraged from Beijing onwards, since 1.X is EOL, and since it does not support escaping, so its output may not be machine-readable. See https://logging.apache.org/log4j/1.2/.

This affects existing OpenDaylight-based components like SDNC and APPC, since ODL releases prior to Carbon bundle bundled Log4j 1.X, and make it difficult to replace. The Common Controller SDK Project project targets ODL Carbon, so the problem should resolve in timeremaining instances of Log4j 1.X should disappear by the time of the Beijing release.

What to Log

The purpose of logging is to capture diagnostic information.

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A Mapped Diagnostic Context (MDC) allows an arbitrary string-valued attribute to be attached to a Java thread. The MDC's value is then emitted with each log message logged by that thread. The set of MDCs associated with a log message is serialized as unordered name-value pairs (see Text Output).

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EELF doesn't directly support MDCs, but SLF4J will receive any MDC that is set its default provider (where com.att.eelf.configuration.SLF4jWrapper is the configured EELF provider)normally logs via SLF4J, and SLF4J will receive any MDC that is set:

Code Block
languagejava
linenumberstrue
import java.util.UUID;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.MDC;
import com.att.eelf.configuration.EELFLogger;
import com.att.eelf.configuration.EELFManager;
// ...
final EELFLogger logger = EELFManager.getInstance().getLogger(this.getClass());
MDC.put("SomeUUID", UUID.randomUUID().toString());
try {
    logger.info("This message will have a UUID-valued 'SomeUUID' MDC attached.");
    // ...
}
finally {
    MDC.clear();
}

...

  • It's only a few calls. 
  • It can be largely abstracted in the case of EELF logging.

TODO: code.

MDCs - the Rest

Other MDCs are logged in a wide range of contexts.

Certain MDCs and their semantics may be specific to EELF log types.

TODO: cross-reference EELF output to v1 doc.

MDC - PartnerName

This field should contain the name of the client application user agent or user invoking the API.

This is often used for heuristic analysis to identify invocations between ONAP individual ONAP components. Its value has never been clearly stipulated, so a common problem has been a lack of consistency. 

There is no clear consensus, but:

  • Use the short name of your component, e.g. xyzdriver. 
  • Values should be human-readable. 
  • Values should be fine-grained enough to disambiguate subcomponents where it's likely to matter. This is subjective. 
  • Be consistent: your component should ALWAYS report same value. 

Real-life examples include MSO, bpmnclient, BPELClient, (all of which are reported by SO), openECOMP (SDNC), vid (VID!) etc. (See the problem?)

Usage overlaps with InvocationID, which doesn't mean PartnerName gets retired, but which might mean it serves a more descriptive purpose. (Since it hasn't proven to be a great way of generating a call graph).

MDC - ServiceName

For EELF Audit log records that capture API requests, this field contains the name of the API invoked at the component creating the record (e.g., Layer3ServiceActivateRequest).

For EELF Audit log records that capture processing as a result of receipt of a message, this field should contain the name of the module that processes the message.

Usage is the same for indexable logs. 

MDCs - the Rest

Other MDCs are logged in a wide range of contexts.

Certain MDCs and their semantics may be specific to EELF log types.

TODO: cross-reference EELF output to v1 doc.

IDMDCDescriptionRequiredEELF Audit

EELF Metric

EELF Error

EELF Debug


RequestIDSee above.Y




InvocationIDSee above.Y




ServiceNameSee above.Y




PartnerNameSee above.Y



1BeginTimestamp

Date-time that processing activities being logged begins. The value should be represented in UTC and formatted per ISO 8601, such as “2015-06-03T13:21:58+00:00”. The time should be shown with the maximum resolution available to the logging component (e.g., milliseconds, microseconds) by including the appropriate number of decimal digits. For example, when millisecond precision is available, the date-time value would be presented as, as “2015-06-03T13:21:58.340+00:00”.

Y



2EndTimestamp

Date-time that processing for the request or event being logged ends. Formatting rules are the same as for the BeginTimestamp field above.

In the case of a request that merely logs an event and has not subsequent processing, the EndTimestamp value may equal the BeginTimestamp value.

Y



3ElapsedTime

This field contains the elapsed time to complete processing of an API call or transaction request (e.g., processing of a message that was received). This value should be the difference between. EndTimestamp and BeginTimestamp fields and must be expressed in milliseconds.

Y



4ServiceInstanceID

This field is optional and should only be included if the information is readily available to the logging component.

IDMDCDescriptionRequiredEELF Audit

EELF Metric

EELF Error

EELF Debug

1BeginTimestamp

Date-time that processing activities being logged begins. The value should be represented in UTC and formatted per ISO 8601, such as “2015-06-03T13:21:58+00:00”. The time should be shown with the maximum resolution available to the logging component (e.g., milliseconds, microseconds) by including the appropriate number of decimal digits. For example, when millisecond precision is available, the date-time value would be presented as, as “2015-06-03T13:21:58.340+00:00”.

Y2EndTimestamp

Date-time that processing for the request or event being logged ends. Formatting rules are the same as for the BeginTimestamp field above.

In the case of a request that merely logs an event and has not subsequent processing, the EndTimestamp value may equal the BeginTimestamp value.

Y3ElapsedTime

This field contains the elapsed time to complete processing of an API call or transaction request (e.g., processing of a message that was received). This value should be the difference between. EndTimestamp and BeginTimestamp fields and must be expressed in milliseconds.

Y4ServiceInstanceID

This field is optional and should only be included if the information is readily available to the logging component.

Transaction requests that create or operate on a particular instance of a service/resource can
identify/reference it via a unique “serviceInstanceID” value. This value can be used as a primary key for
obtaining or updating additional detailed data about that specific service instance from the inventory
(e.g., AAI). In other words:

  • In the case of processing/logging a transaction request for creating a new service instance, the serviceInstanceID value is determined by either a) the MSO client and passed to MSO or b) by MSO itself upon receipt of a such a request.
  • In other cases, the serviceInstanceID value can be used to reference a specific instance of a service as would happen in a “MACD”-type request.
  • ServiceInstanceID is associated with a requestID in log records to facilitate tracing its processing over multiple requests and for a specific service instance. Its value may be left “empty” in subsequent record to the 1 st record where a requestID value is associated with the serviceInstanceID value.

NOTE: AAI won’t have a serviceInstanceUUID for every service instance. For example, no serviceInstanceUUID is available when the request is coming from an application that may import inventory data.

5VirtualServerNamePhysical/virtual server name. Optional: empty if determined that its value can be added by the agent that collects the log files collecting.

). In other words:

  • In the case of processing/logging a transaction request for creating a new service instance, the serviceInstanceID value is determined by either a) the MSO client and passed to MSO or b) by MSO itself upon receipt of a such a request.
  • In other cases, the serviceInstanceID value can be used to reference a specific instance of a service as would happen in a “MACD”-type request.
  • ServiceInstanceID is associated with a requestID in log records to facilitate tracing its processing over multiple requests and for a specific service instance. Its value may be left “empty” in subsequent record to the 1 st record where a requestID value is associated with the serviceInstanceID value.

NOTE: AAI won’t have a serviceInstanceUUID for every service instance. For example, no serviceInstanceUUID is available when the request is coming from an application that may import inventory data.






5VirtualServerNamePhysical/virtual server name. Optional: empty if determined that its value can be added by the agent that collects the log files collecting.




66ServiceName

For Audit log records that capture API requests, this field contains the name of the API invoked at the component creating the record (e.g., Layer3ServiceActivateRequest).

For Audit log records that capture processing as a result of receipt of a message, this field should contain the name of the module that processes the message.

Y7PartnerNameThis field contains the name of the client application user agent or user invoking the API if known.Y8StatusCode

This field indicates the high level status of the request. It must have the value COMPLETE when the request is successful and ERROR when there is a failure.

Y



97ResponseCode

This field contains application-specific error codes. For consistency, common error categorizations should be used.






108ResponseDescription

This field contains a human readable description of the ResponseCode.





1111
9InstanceUUID

If known, this field contains a universally unique identifier used to differentiate between multiple instances of the same (named) log writing service/application. Its value is set at instance creation time (and read by it, e.g., at start/initialization time from the environment). This value should be picked up by the component instance from its configuration file and subsequently used to enable differentiation of log records created by multiple, locally load balanced ONAP component or subcomponent instances that are otherwise identically configured.






1210SeverityOptional: 0, 1, 2, 3 see Nagios monitoring/alerting for specifics/details.




1311TargetEntity

It contains the name of the ONAP component or sub-component, or external entity, at which the operation activities captured in this metrics log record is invoked.

Y



1412TargetServiceNameIt contains the name of the API or operation activities invoked at the TargetEntity.Y



1513Server

This field contains the Virtual Machine (VM) Fully Qualified Domain Name (FQDN) if the server is virtualized. Otherwise, it contains the host name of the logging component.

Y



1614ServerIPAddress

This field contains the logging component host server’s IP address if known (e.g. Jetty container’s listening IP address). Otherwise it is empty.






1715ServerFQDNUnclear, but possibly duplicating one or both of Server and ServerIPAddress.




1816ClientIPAddress

This field contains the requesting remote client application’s IP address if known. Otherwise this field can be empty.






1917ProcessKey

This field can be used to capture the flow of a transaction through the system by indicating the components and operations involved in processing. If present, it can be denoted by a comma separated list of components and applications.






2018RemoteHostUnknown.




2119AlertSeverityUnknown.




2220TargetVirtualEntityUnknown




2321ClassNameDefunct. Doesn't require an MDC.




2422ThreadIDDefunct. Doesn't require an MDC.




2523CustomField1(Defunct now that MDCs are serialized as NVPs.)




2624CustomField2(Defunct now that MDCs are serialized as NVPs.)




2725CustomField3(Defunct now that MDCs are serialized as NVPs.)




2826CustomField4(Defunct now that MDCs are serialized as NVPs.)




Examples

SDC-BE

20170907: audit.log

...

Code Block
languagejava
titleEELF
linenumberstrue
//TODOfinal EELFLogger logger = EELFManager.getAuditLogger();
logger.auditEvent("Entering.");

SLF4J:

Code Block
languagejava
titleSLF4J
linenumberstrue
public static final Marker ENTRY = MarkerFactory.getMarker("ENTRY");
// ... 
final Logger logger = LoggerFactory.getLogger(this.getClass());
logger.debug(ENTRY, "Entering.");

...

Code Block
languagejava
titleEELF
linenumberstrue
linenumberstrue
final EELFLogger logger = EELFManager.getMetricsLogger();
logger.metricsEvent("Exiting.");//TODO

SLF4J:

Code Block
languagejava
titleSLF4J
linenumberstrue
public static final Marker EXIT = MarkerFactory.getMarker("EXIT");
// ... 
final Logger logger = LoggerFactory.getLogger(this.getClass());
logger.debug(EXIT, "Exiting.");

...

Code Block
languagejava
titleSLF4J
linenumberstrue
public static final Marker INVOKE = MarkerFactory.getMarker("INVOKE");
// ...

// Generate and report invocation ID. 

final String invocationID = UUID.randomUUID().toString();
MDC.put(MDC_INVOCATION_ID, invocationID);
try {
    logger.debug(INVOKE_SYNCHRONOUS, "Invoking synchronously ... ");
}
finally {
    MDC.remove(MDC_INVOCATION_ID);
}

// Pass invocationID as HTTP X-InvocationID header.

callDownstreamSystem(invocationID, ... );

TODO: EELF examples of INVOCATION_ID reporting, without changing published APIs.

...

Code Block
languagejava
titleSLF4J
linenumberstrue
public static final Marker INVOKE_SYNCHRONOUS;
static {
    INVOKE_SYNCHRONOUS = MarkerFactory.getMarker("INVOKE");
    INVOKE_SYNCHRONOUS.add(MarkerFactory.getMarker("SYNCHRONOUS"));
}
// ...

// Generate and report invocation ID. 

final String invocationID = UUID.randomUUID().toString();
MDC.put(MDC_INVOCATION_ID, invocationID);
try {
    logger.debug(INVOKE_SYNCHRONOUS, "Invoking synchronously ... ");
}
finally {
    MDC.remove(MDC_INVOCATION_ID);
}

// Pass invocationID as HTTP X-InvocationID header.

callDownstreamSystem(invocationID, ... );

TODO: EELF example of SYNCHRONOUS reporting, without changing published APIs. 

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Logfiles should default to beneath /var/log, and beneath /var/log/ONAP in the case of core ONAP components:

Code Block
languagetext
linenumberstrue
/var/log/ONAP/<component>[/<subcomponent>]/*.log

For the duration of Beijing, logs  will be written to a separate directory, /var/log/ONAP_EELF:

Code Block
languagetext
linenumberstrue
/var/log/ONAP_EELF/<component>[/<subcomponent>]/*.log

...

Code Block
languagetext
linenumberstrue
/etc/onapONAP/<component>[/<subcomponent>]/<provider>.xml

...

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 metric 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.

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