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About This Document
THIS IS A DRAFT.Official R1 documentation snapshot in https://onap.readthedocs.io/en/latest/submodules/logging-analytics.git/docs/
THIS was a DRAFT WIP for R1 - ONAP Amsterdam Release - it is deprecated
This document specifies logging conventions to be followed by ONAP component applications.
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ONAP logging is intended to support operability, debugging and reporting on ONAP. These guidelines address:
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Original ONAP Logging guidelines: https://wiki.onap.org/download/attachments/1015849/ONAP%20application%20logging%20guidelines.pdf?api=v2
Introduction
The purpose of ONAP logging is to capture information needed to operate, troubleshoot and report on the performance of the ONAP platform and its constituent components. Log records may be viewed and consumed directly by users and systems, indexed and loaded into a datastore, and used to compute metrics and generate reports.
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- http://www.masterzen.fr/2013/01/13/the-10-commandments-of-logging/
- https://www.loggly.com/blog/how-to-write-effective-logs-for-remote-logging/
- And so on.
Context
TODO: more on the importance of transaction ID propagation.
MDCs
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. The set of MDCs associated with a log message . is serialized as unordered name-value pairs (see Text Output).
A good discussion of MDCs can be found at https://logback.qos.ch/manual/mdc.html.
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This is often referred to by other names, including "Transaction ID", and one of several (pre-standardization) REST header names .ONAP logging including X-ECOMP-RequestID and X-ONAP-RequestID.
ONAP logging uses a universally unique "RequestID" value in log records to track the processing of each client request across all the ONAP components involved in its processing.
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TODO: cross-reference EELF output to v1 doc.
| ID | Order | MDC | Description | Required | EELF Audit | EELF Metric | EELF Error | EELF Debug |
|---|---|---|---|---|---|---|---|---|
| 1 | BeginTimestamp | 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 | |||||
| 2 | EndTimestamp | 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 | |||||
| 3 | ElapsedTime | 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 | |||||
| 4 | ServiceInstanceID | 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
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. | ||||||
| 5 | VirtualServerName | Physical/virtual server name. Optional: empty if determined that its value can be added by the agent that collects the log files collecting. | ||||||
| 6 | ServiceName | 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. | Y | |||||
| 7 | PartnerName | This field contains the name of the client application user agent or user invoking the API if known. | Y | |||||
| 8 | StatusCode | 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 | |||||
| 9 | ResponseCode | This field contains application-specific error codes. For consistency, common error categorizations should be used. | ||||||
| 10 | ResponseDescription | This field contains a human readable description of the ResponseCode. | 11 | |||||
| 11 | InstanceUUID | 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. | ||||||
| 12 | Severity | Optional: 0, 1, 2, 3 see Nagios monitoring/alerting for specifics/details. | ||||||
| 13 | TargetEntity | 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 | |||||
| 14 | TargetServiceName | It contains the name of the API or operation activities invoked at the TargetEntity. | Y | |||||
| 15 | Server | 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 | |||||
| 16 | ServerIPAddress | 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. | ||||||
| 17 | ServerFQDN | Unclear, but possibly duplicating one or both of Server and ServerIPAddress. | ||||||
| 18 | ClientIPAddress | This field contains the requesting remote client application’s IP address if known. Otherwise this field can be empty. | ||||||
| 19 | ProcessKey | 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. | ||||||
| 20 | RemoteHost | Unknown. | ||||||
| 21 | AlertSeverity | Unknown. | ||||||
| 22 | TargetVirtualEntity | Unknown | ||||||
| 23 | ClassName | Defunct. Doesn't require an MDC. | ||||||
| 24 | ThreadID | Defunct. Doesn't require an MDC. | ||||||
| 25 | CustomField1 | (Defunct now that MDCs are serialized as NVPs.) | ||||||
| 26 | CustomField2 | (Defunct now that MDCs are serialized as NVPs.) | ||||||
| 27 | CustomField3 | (Defunct now that MDCs are serialized as NVPs.) | ||||||
| 28 | CustomField4 | (Defunct now that MDCs are serialized as NVPs.) |
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| Code Block |
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root@ip-172-31-93-160:/dockerdata-nfs/onap/sdc/logs/SDC/SDC-BE# tail -f audit.log 2017-09-07T18:04:03.679Z|||||qtp1013423070-72297||ASDC|SDC-BE|||||||N/A|INFO||||10.42.88.30||o.o.s.v.r.s.VendorLicenseModelsImpl||ActivityType=<audit>, Desc=< --Audit-- Create VLM. VLM Name: lm4> |
TODO: this is the earlier output format. Let's find an example which matches the latest line format.
Markers
Markers differ from MDCs in two important ways:
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It must be manually set otherwise.
EELF:
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Marker - EXIT
This should be reported as late in invocation as possible, immediately before unsetting the RequestID and InvocationID MDCs.
It can be automatically reported by EELF, and written to the METRIC log.
It must be manually set otherwise.
Marker - INVOKE
This should be reported by the caller of another ONAP component via REST, including a newly allocated InvocationID, which will be passed to the caller.
TODO: EELF, without changing published APIs.
Marker - SYNCHRONOUS
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//TODO |
SLF4J:
| Code Block | ||||||
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public static final Marker ENTRY = MarkerFactory.getMarker("ENTRY");
// ...
final Logger logger = LoggerFactory.getLogger(this.getClass());
logger.debug(ENTRY, "Entering."); |
Marker - EXIT
This should be reported as late in invocation as possible, immediately before unsetting the RequestID and InvocationID MDCs.
It can be automatically reported by EELF, and written to the METRIC log.
It must be manually set otherwise.
EELF:
| Code Block | ||||||
|---|---|---|---|---|---|---|
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//TODO |
SLF4J:
| Code Block | ||||||
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public static final Marker EXIT = MarkerFactory.getMarker("EXIT");
// ...
final Logger logger = LoggerFactory.getLogger(this.getClass());
logger.debug(EXIT, "Exiting."); |
Marker - INVOKE
This should be reported by the caller of another ONAP component via REST, including a newly allocated InvocationID, which will be passed to the caller.
SLF4J:
| Code Block | ||||||
|---|---|---|---|---|---|---|
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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, without changing published APIs.
Marker - SYNCHRONOUS
This should accompany INVOKE when the invocation is synchronous.
SLF4J:
| Code Block | ||||||
|---|---|---|---|---|---|---|
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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, without changing published APIs.
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ONAP needs to strike a balance between human-readable and machine-readable logs. This means:
- The use of tab as a (\t) as a delimiter.
- Escaping all messages, exceptions, MDC values, Markers, etc. to replace tabs in their content.
- Escaping all newlines with \n so that each entry is on one line.
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The output of which, with MDCs, a Marker and a nested exception, with newlines added for readability looks like:
TODO: remove tab below
| Code Block | ||||
|---|---|---|---|---|
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org.onap.example.component1.subcomponent1.LogbackTest \t2017-08-06T16:09:03.594Z \tERROR \tHere's an error, that's usually bad \tkey1=value1, key2=value2 with space, key5=value5"with"quotes, key3=value3\nwith\nnewlines, key4=value4\twith\ttabs \tjava.lang.RuntimeException: Here's Johnny \n\tat org.onap.example.component1.subcomponent1.LogbackTest.main(LogbackTest.java:24) \nWrapped by: java.lang.RuntimeException: Little pigs, little pigs, let me come in \n\tat org.onap.example.component1.subcomponent1.LogbackTest.main(LogbackTest.java:27) \tAMarker1 \tmain |
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Configuration archetypes can be found in the ONAP codebase. Choose according to your provider, and whether you're logging via EELF. Efforts to standardize them are underway, so the ones you should be looking for are where tab pipe (|) is used as a separator. (Previously it was "|").
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- Choose a Logging provider and/or EELF. Decisions, decisions.
- Create a configuration file based on an existing archetype. See Configuration.
- Read your configuration file when your components initialize logging.
- Write logs to a standard location so that they can be shipped by Filebeat for indexing. See Output Location.
- Report transaction state:
- Retrieve, default and propagate RequestID. See MDC - RequestID.
- At each invocation of one ONAP component by another:
- Initialize and propagate InvocationID. See MDC - Invocation ID.
- Report INVOKE and SYNCHRONOUS markers in caller.
- Report ENTRY and EXIT markers in recipient.
- Write useful logs!
They are unordered.