5 .. This work is licensed under a Creative Commons Attribution 4.0 International License.
6 .. http://creativecommons.org/licenses/by/4.0
7 .. Copyright © 2017 AT&T Intellectual Property. All rights reserved.
9 Logging Enhancements Project
10 ==================================================
15 ONAP consists of many components and containers, and consequently writes
16 to many logfiles. The volume of logger output may be enormous,
17 especially when debugging. Large, disparate logfiles are difficult to
18 monitor and analyze, and tracing requests across many files, file
19 systems and containers is untenable without tooling.
21 The problem of decentralized logger output is addressed by analytics
22 pipelines such as \ `*Elastic
23 Stack* <https://www.elastic.co/products>`__ (ELK). Elastic Stack
24 consumes logs, indexes their contents
25 in \ `*Elasticsearch* <https://www.elastic.co/products/elasticsearch>`__,
26 and makes them accessible, queryable and navigable via a sophisticated
28 Discover* <https://www.elastic.co/guide/en/kibana/current/discover.html>`__.
29 This elevates the importance of standardization and machine-readability.
30 Logfiles can remain browsable, but output can be simplified.
32 Logger configurations in ONAP are diverse and idiosyncratic. Addressing
33 these issues will prevent costs from being externalized to consumers
34 such as analytics. It also affords the opportunity to remedy any issues
35 with the handling and propagation of contextual information such as
36 transaction identifiers (presently passed as \ **X-ECOMP-RequestID **-
37 to be\ ** X-ONAP-RequestID**). This propagation is critical to tracing
38 requests as they traverse ONAP and related systems, and is the basis for
39 many analytics functions.
41 Rationalized logger configuration and output also paves the way for
42 other high-performance logger transports, including publishing directly
43 to analytics via SYSLOG
44 (`*RFC3164* <https://www.ietf.org/rfc/rfc3164.txt>`__, \ `*RFC5425* <https://www.ietf.org/rfc/rfc5425.txt>`__, \ `*RFC5426* <https://www.ietf.org/rfc/rfc5426.txt>`__)
45 and streams, and mechanisms for durability.
47 Each change is believed to be individually beneficial:
49 1. The intention is to consolidate the required setup within this
50 project however some changes and bug fixes might have to be applied
51 in the relative component project, requiring each components'
52 co-operation on the contribution.
54 2. There is an economy of scale if everything can happen under a single
57 3. Standardization benefits all, including those who want to deviate
60 ONAP Application Logging Guidelines v1.1
61 ========================================
65 The purpose of ONAP logging is to capture information needed to operate,
66 troubleshoot and report on the performance of the ONAP platform and its
67 constituent components. Log records may be viewed and consumed directly
68 by users and systems, indexed and loaded into a datastore, and used to
69 compute metrics and generate reports.
71 The processing of a single client request will often involve multiple
72 ONAP components and/or subcomponents (interchangeably referred to as
73 ‘application’ in this document). The ability to track flows across
74 components is critical to understanding ONAP’s behavior and performance.
75 ONAP logging uses a universally unique RequestID value in log records to
76 track the processing of every client request through all the ONAP
77 components involved in its processing.
79 A reference configuration of \ `*Elastic
80 Stack * <https://www.elastic.co/products>`__\ can be deployed
81 using \ `*ONAP Operations
82 Manager* <https://wiki.onap.org/display/DW/ONAP+Operations+Manager+Project>`__.
84 This document gives conventions you can follow to generate conformant,
85 indexable logging output from your component.
89 ONAP prescribes conventions. The use of certain APIs and providers is
90 recommended, but they are not mandatory. Most components log
91 via \ `*EELF* <https://github.com/att/EELF>`__ or `*SLF4J* <https://www.slf4j.org/>`__ to
93 like \ `*Logback* <https://logback.qos.ch/>`__ or `*Log4j* <https://logging.apache.org/log4j/2.x/>`__.
97 EELF is the\ ** Event and Error Logging Framework**, described
98 at \ `*https://github.com/att/EELF* <https://github.com/att/EELF>`__.
100 EELF abstracts your choice of logging provider, and decorates the
101 familiar Logger contracts with features like:
107 - Generated wiki documentation.
109 - Separate audit, metric, security and debug logs.
111 EELF is a facade, so logging output is configured in two ways:
113 1. By selection of a logging provider such as Logback or Log4j,
114 typically via the classpath.
116 2. By way of a provider configuration document,
117 typically \ **logback.xml** or **log4j.xml**.
118 See \ `*Providers* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-Providers>`__.
122 `*SLF4J* <https://www.slf4j.org/>`__ is a logging facade, and a humble
123 masterpiece. It combines what's common to all major, modern Java logging
124 providers into a single interface. This decouples the caller from the
125 provider, and encourages the use of what's universal, familiar and
128 EELF also logs via SLF4J's abstractions.
132 Logging providers are normally enabled by their presence in the
133 classpath. This means the decision may have been made for you, in some
134 cases implicitly by dependencies. If you have a strong preference then
135 you can change providers, but since the implementation is typically
136 abstracted behind EELF or SLF4J, it may not be worth the effort.
140 Logback is the most commonly used provider. It is generally configured
141 by an XML document named \ **logback.xml**.
142 See \ `*Configuration* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-Configuration>`__.
146 Log4j 2.X is somewhat less common than Logback, but equivalent. It is
147 generally configured by an XML document
148 named \ **log4j.xml**. See \ `*Configuration* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-Configuration>`__.
152 Avoid, since 1.X is EOL, and since it does not support escaping, so its
154 machine-readable. See \ `*https://logging.apache.org/log4j/1.2/* <https://logging.apache.org/log4j/1.2/>`__.
156 This affects existing OpenDaylight-based components like SDNC and APPC,
157 since ODL releases prior
158 to \ `*Carbon* <https://www.opendaylight.org/what-we-do/current-release>`__ bundle
159 Log4j 1.X, and make it difficult to replace. The \ `*Common Controller
161 Project* <https://wiki.onap.org/display/DW/Common+Controller+SDK+Project>`__ project
162 targets ODL Carbon, so the problem should resolve in time.
166 The purpose of logging is to capture diagnostic information.
168 An important aspect of this is analytics, which requires tracing of
169 requests between components. In a large, distributed system such as ONAP
170 this is critical to understanding behavior and performance.
172 Messages, Levels, Components and Categories
174 It isn't the aim of this document to reiterate the basics, so advice
177 - Use a logger. Consider using EELF.
179 - Write log messages in English.
181 - Write meaningful messages. Consider what will be useful to consumers
184 - Use errorcodes to characterise exceptions.
186 - Log at the appropriate level. Be aware of the volume of logs that
189 - Log in a machine-readable format. See Conventions.
191 - Log for analytics as well as troubleshooting.
193 Others have written extensively on this:
195 - `*http://www.masterzen.fr/2013/01/13/the-10-commandments-of-logging/* <http://www.masterzen.fr/2013/01/13/the-10-commandments-of-logging/>`__
197 - `*https://www.loggly.com/blog/how-to-write-effective-logs-for-remote-logging/* <https://www.loggly.com/blog/how-to-write-effective-logs-for-remote-logging/>`__
203 **TODO: more on the importance of transaction ID propagation.**
207 A Mapped Diagnostic Context (MDC) allows an arbitrary string-valued
208 attribute to be attached to a Java thread. The MDC's value is then
209 emitted with each log message. The set of MDCs associated with a log
210 message is serialized as unordered name-value pairs (see `*Text
211 Output* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-TextOutput>`__).
213 A good discussion of MDCs can be found
214 at \ `*https://logback.qos.ch/manual/mdc.html* <https://logback.qos.ch/manual/mdc.html>`__.
218 - Must be set as early in invocation as possible.
220 - Must be unset on exit.
226 +------+-------------------------------------------------------------------------------------+
227 | 1 | import java.util.UUID; |
229 | 2 | import org.slf4j.Logger; |
231 | 3 | import org.slf4j.LoggerFactory; |
233 | 4 | import org.slf4j.MDC; |
237 | 6 | final Logger logger = LoggerFactory.getLogger(this.getClass()); |
239 | 7 | MDC.put("SomeUUID", UUID.randomUUID().toString()); |
243 | 9 | logger.info("This message will have a UUID-valued 'SomeUUID' MDC attached."); |
251 | 13 | MDC.clear(); |
254 +------+-------------------------------------------------------------------------------------+
256 EELF doesn't directly support MDCs, but SLF4J will receive any MDC that
257 is set (where **com.att.eelf.configuration.SLF4jWrapper** is the
258 configured EELF provider):
260 +------+-------------------------------------------------------------------------------------+
261 | 1 | import java.util.UUID; |
263 | 2 | import org.slf4j.Logger; |
265 | 3 | import org.slf4j.LoggerFactory; |
267 | 4 | import org.slf4j.MDC; |
269 | 5 | import com.att.eelf.configuration.EELFLogger; |
271 | 6 | import com.att.eelf.configuration.EELFManager; |
275 | 8 | final EELFLogger logger = EELFManager.getInstance().getLogger(this.getClass()); |
277 | 9 | MDC.put("SomeUUID", UUID.randomUUID().toString()); |
281 | 11 | logger.info("This message will have a UUID-valued 'SomeUUID' MDC attached."); |
289 | 15 | MDC.clear(); |
292 +------+-------------------------------------------------------------------------------------+
296 Output of MDCs must ensure that:
298 - All reported MDCs are logged with both name AND value. Logging output
299 should not treat any MDCs as special.
301 - All MDC names and values are escaped.
303 Escaping in Logback configuration can be achieved with:
305 +-----+------------------------------------------------------------------+
306 | 1 | %replace(%replace(%mdc){'\\t','\\\\\\\\t'}){'\\n','\\\\\\\\n'} |
307 +-----+------------------------------------------------------------------+
311 This is often referred to by other names, including "Transaction ID",
312 and one of several (pre-standardization) REST header names
313 including \ **X-ECOMP-RequestID** and **X-ONAP-RequestID**.
315 ONAP logging uses a universally unique "**RequestID"** value in log
316 records to track the processing of each client request across all the
317 ONAP components involved in its processing.
321 - Is logged as a \ **RequestID** MDC.
323 - Is propagated between components in REST calls as
324 an \ **X-TransactionID** HTTP header.
326 Receiving the \ **X-TransactionID** will vary by component according to
327 APIs and frameworks. In general:
329 +-----+--------------------------------------------------------------------------+
330 | 1 | import javax.ws.rs.core.HttpHeaders; |
334 | 3 | final HttpHeaders headers = ...; |
338 | 5 | String txId = headers.getRequestHeaders().getFirst("X-TransactionID"); |
340 | 6 | if (StringUtils.isBlank(txId)) { |
342 | 7 | txId = UUID.randomUUID().toString(); |
346 | 9 | MDC.put("RequestID", txID); |
347 +-----+--------------------------------------------------------------------------+
349 Setting the \ **X-TransactionID** likewise will vary. For example:
351 +-----+---------------------------------------------------+
352 | 1 | final String txID = MDC.get("RequestID"); |
354 | 2 | HttpURLConnection cx = ...; |
358 | 4 | cx.setRequestProperty("X-TransactionID", txID); |
359 +-----+---------------------------------------------------+
361 **MDC - InvocationID**
363 **InvocationID** is similar to \ **RequestID**, but
364 where \ **RequestID** correlates records relating a single, top-level
365 invocation of ONAP as it traverses many
366 systems, \ **InvocationID** correlates log entries relating to a single
367 invocation of a single component. Typically this means via REST, but in
368 certain cases an \ **InvocationID** may be allocated without a new
369 invocation, e.g. when a request is retried.
371 **RequestID** and** InvocationID** allow an execution graph to be
372 derived. This requires that:
374 - The relationship between \ **RequestID** and **InvocationID** is
377 - The relationship between caller and recipient is reported for each
380 The proposed approach is that:
384 - Issue a new, unique \ **InvocationID** UUID for each downstream
387 - Log the new \ **InvocationID**, indicating the intent to invoke:
389 - With Markers \ **INVOKE**, and \ **SYNCHRONOUS** if the
390 invocation is synchronous.
392 - With their own \ **InvocationID** still set as an MDC.
394 - Pass the \ **InvocationID** as an \ **X-InvocationID** REST
397 - Invoked components:
399 - Retrieve the \ **InvocationID** from REST headers upon invocation,
400 or generate a UUID default.
402 - Set the \ **InvocationID** MDC.
404 - Write a log entry with the Marker \ **ENTRY**. (In EELF this will
405 be to the AUDIT log).
407 - Act as per Callers in all downstream requests.
409 - Write a log entry with the Marker \ **EXIT** upon return. (In EELF
410 this will be to the METRIC log).
412 - Unset all MDCs on exit.
414 That seems onerous, but:
416 - It's only a few calls.
418 - It can be largely abstracted in the case of EELF logging.
424 Other MDCs are logged in a wide range of contexts.
426 Certain MDCs and their semantics may be specific to EELF log types.
428 **TODO: cross-reference EELF output to v1 doc.**
430 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
431 | **ID** | **MDC** | **Description** | **Required** | **EELF Audit** | **EELF Metric** | **EELF Error** | **EELF Debug** |
432 +==========+=======================+================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================+================+==================+===================+==================+==================+
433 | 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 | | | | |
434 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
435 | 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. | Y | | | | |
437 | | | In the case of a request that merely logs an event and has not subsequent processing, the EndTimestamp value may equal the BeginTimestamp value. | | | | | |
438 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
439 | 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 | | | | |
440 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
441 | 4 | ServiceInstanceID | This field is optional and should only be included if the information is readily available to the logging component. | | | | | |
443 | | | | Transaction requests that create or operate on a particular instance of a service/resource can | | | | | |
444 | | | | identify/reference it via a unique “serviceInstanceID” value. This value can be used as a primary key for | | | | | |
445 | | | | obtaining or updating additional detailed data about that specific service instance from the inventory | | | | | |
446 | | | | (e.g., AAI). In other words: | | | | | |
448 | | | - 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. | | | | | |
450 | | | - 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. | | | | | |
452 | | | - 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. | | | | | |
454 | | | 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. | | | | | |
455 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
456 | 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. | | | | | |
457 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
458 | 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). | Y | | | | |
460 | | | 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. | | | | | |
461 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
462 | 7 | PartnerName | This field contains the name of the client application user agent or user invoking the API if known. | Y | | | | |
463 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
464 | 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 | | | | |
465 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
466 | 9 | ResponseCode | This field contains application-specific error codes. For consistency, common error categorizations should be used. | | | | | |
467 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
468 | 10 | ResponseDescription | This field contains a human readable description of the \ **ResponseCode**. | | | | | 11 |
469 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
470 | 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. | | | | | |
471 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
472 | 12 | Severity | Optional: 0, 1, 2, 3 see \ `*Nagios* <https://en.wikipedia.org/wiki/Nagios>`__ monitoring/alerting for specifics/details. | | | | | |
473 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
474 | 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 | | | | |
475 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
476 | 14 | TargetServiceName | It contains the name of the API or operation activities invoked at the TargetEntity. | Y | | | | |
477 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
478 | 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 | | | | |
479 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
480 | 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. | | | | | |
481 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
482 | 17 | ServerFQDN | Unclear, but possibly duplicating one or both of \ **Server** and **ServerIPAddress**. | | | | | |
483 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
484 | 18 | ClientIPAddress | This field contains the requesting remote client application’s IP address if known. Otherwise this field can be empty. | | | | | |
485 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
486 | 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. | | | | | |
487 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
488 | 20 | RemoteHost | Unknown. | | | | | |
489 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
490 | 21 | AlertSeverity | Unknown. | | | | | |
491 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
492 | 22 | TargetVirtualEntity | Unknown | | | | | |
493 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
494 | 23 | ClassName | Defunct. Doesn't require an MDC. | | | | | |
495 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
496 | 24 | ThreadID | Defunct. Doesn't require an MDC. | | | | | |
497 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
498 | 25 | CustomField1 | (Defunct now that MDCs are serialized as NVPs.) | | | | | |
499 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
500 | 26 | CustomField2 | (Defunct now that MDCs are serialized as NVPs.) | | | | | |
501 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
502 | 27 | CustomField3 | (Defunct now that MDCs are serialized as NVPs.) | | | | | |
503 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
504 | 28 | CustomField4 | (Defunct now that MDCs are serialized as NVPs.) | | | | | |
505 +----------+-----------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------+------------------+-------------------+------------------+------------------+
513 +-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
514 | root@ip-172-31-93-160:/dockerdata-nfs/onap/sdc/logs/SDC/SDC-BE# tail -f audit.log |
516 | 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> |
517 +-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
519 **TODO: this is the earlier output format. Let's find an example which
520 matches the latest line format.**
524 Markers differ from MDCs in two important ways:
526 1. They have a name, but no value. They are a tag.
528 2. Their scope is limited to logger calls which specifically reference
530 not \ `*ThreadLocal* <https://docs.oracle.com/javase/8/docs/api/java/lang/ThreadLocal.html>`__.
536 +-----+-----------------------------------------------------------------------+
537 | 1 | import org.slf4j.Logger; |
539 | 2 | import org.slf4j.LoggerFactory; |
541 | 3 | import org.slf4j.Marker; |
543 | 4 | import org.slf4j.MarkerFactory; |
547 | 6 | final Logger logger = LoggerFactory.getLogger(this.getClass()); |
549 | 7 | final Marker marker = MarkerFactory.getMarker("MY\_MARKER"); |
551 | 8 | logger.warn(marker, "This warning has a 'MY\_MARKER' annotation."); |
552 +-----+-----------------------------------------------------------------------+
554 EELF does not allow Markers to be set directly. See notes on
555 the \ **InvocationID** MDC.
559 Marker names also need to be escaped, though they're much less likely to
560 contain problematic characters than MDC values.
562 Escaping in Logback configuration can be achieved with:
564 +-----+---------------------------------------------------------------------+
565 | 1 | %replace(%replace(%marker){'\\t','\\\\\\\\t'}){'\\n','\\\\\\\\n'} |
566 +-----+---------------------------------------------------------------------+
570 This should be reported as early in invocation as possible, immediately
571 after setting the \ **RequestID** and **InvocationID** MDCs.
573 It can be automatically set by EELF, and written to the AUDIT log.
575 It must be manually set otherwise.
589 +-----+------------------------------------------------------------------------+
590 | 1 | public static final Marker ENTRY = MarkerFactory.getMarker("ENTRY"); |
594 | 3 | final Logger logger = LoggerFactory.getLogger(this.getClass()); |
596 | 4 | logger.debug(ENTRY, "Entering."); |
597 +-----+------------------------------------------------------------------------+
601 This should be reported as late in invocation as possible, immediately
602 before unsetting the \ **RequestID** and **InvocationID** MDCs.
604 It can be automatically reported by EELF, and written to the METRIC
607 It must be manually set otherwise.
621 +-----+----------------------------------------------------------------------+
622 | 1 | public static final Marker EXIT = MarkerFactory.getMarker("EXIT"); |
626 | 3 | final Logger logger = LoggerFactory.getLogger(this.getClass()); |
628 | 4 | logger.debug(EXIT, "Exiting."); |
629 +-----+----------------------------------------------------------------------+
633 This should be reported by the caller of another ONAP component via
634 REST, including a newly allocated \ **InvocationID**, which will be
635 passed to the caller.
641 +------+--------------------------------------------------------------------------+
642 | 1 | public static final Marker INVOKE = MarkerFactory.getMarker("INVOKE"); |
648 | 4 | // Generate and report invocation ID. |
652 | 6 | final String invocationID = UUID.randomUUID().toString(); |
654 | 7 | MDC.put(MDC\_INVOCATION\_ID, invocationID); |
658 | 9 | logger.debug(INVOKE\_SYNCHRONOUS, "Invoking synchronously ... "); |
664 | 12 | MDC.remove(MDC\_INVOCATION\_ID); |
670 | 15 | // Pass invocationID as HTTP X-InvocationID header. |
674 | 17 | callDownstreamSystem(invocationID, ... ); |
675 +------+--------------------------------------------------------------------------+
677 **TODO: EELF, without changing published APIs.**
679 **Marker - SYNCHRONOUS**
681 This should accompany \ **INVOKE** when the invocation is synchronous.
687 +------+-------------------------------------------------------------------------+
688 | 1 | public static final Marker INVOKE\_SYNCHRONOUS; |
692 | 3 | INVOKE\_SYNCHRONOUS = MarkerFactory.getMarker("INVOKE"); |
694 | 4 | INVOKE\_SYNCHRONOUS.add(MarkerFactory.getMarker("SYNCHRONOUS")); |
702 | 8 | // Generate and report invocation ID. |
706 | 10 | final String invocationID = UUID.randomUUID().toString(); |
708 | 11 | MDC.put(MDC\_INVOCATION\_ID, invocationID); |
712 | 13 | logger.debug(INVOKE\_SYNCHRONOUS, "Invoking synchronously ... "); |
718 | 16 | MDC.remove(MDC\_INVOCATION\_ID); |
724 | 19 | // Pass invocationID as HTTP X-InvocationID header. |
728 | 21 | callDownstreamSystem(invocationID, ... ); |
729 +------+-------------------------------------------------------------------------+
731 **TODO: EELF, without changing published APIs. **
735 Errorcodes are reported as MDCs.
737 Exceptions should be accompanied by an errrorcode. Typically this is
738 achieved by incorporating errorcodes into your exception hierarchy and
739 error handling. ONAP components generally do not share this kind of
740 code, though EELF defines a marker interface (meaning it has no
741 methods) \ **EELFResolvableErrorEnum**.
743 A common convention is for errorcodes to have two components:
745 1. A \ **prefix**, which identifies the origin of the error.
747 2. A \ **suffix**, which identifies the kind of error.
749 Suffixes may be numeric or text. They may also be common to more than
754 +-----+-------------------------------+
755 | 1 | COMPONENT\_X.STORAGE\_ERROR |
756 +-----+-------------------------------+
760 Several considerations:
762 1. Logs should be human-readable (within reason).
764 2. Shipper and indexing performance and durability depends on logs that
765 can be parsed quickly and reliably.
767 3. Consistency means fewer shipping and indexing rules are required.
771 ONAP needs to strike a balance between human-readable and
772 machine-readable logs. This means:
774 - The use of tab (**\\t**) as a delimiter.
776 - Escaping all messages, exceptions, MDC values, Markers, etc. to
777 replace tabs in their content.
779 - Escaping all newlines with \ **\\n** so that each entry is on one
782 In logback, this looks like:
784 +-----+-------------------------------------------------------------------------------+
785 | 1 | <property name="defaultPattern" value="%nopexception%logger |
787 | 2 | \\t%date{yyyy-MM-dd'T'HH:mm:ss.SSSXXX,UTC} |
791 | 4 | \\t%replace(%replace(%message){'\\t','\\\\\\\\t'}){'\\n','\\\\\\\\n'} |
793 | 5 | \\t%replace(%replace(%mdc){'\\t','\\\\\\\\t'}){'\\n','\\\\\\\\n'} |
795 | 6 | \\t%replace(%replace(%rootException){'\\t','\\\\\\\\t'}){'\\n','\\\\\\\\n'} |
797 | 7 | \\t%replace(%replace(%marker){'\\t','\\\\\\\\t'}){'\\n','\\\\\\\\n'} |
802 +-----+-------------------------------------------------------------------------------+
804 The output of which, with MDCs, a Marker and a nested exception, with
805 newlines added for readability looks like:
807 TODO: remove tab below
809 +------+-----------------------------------------------------------------------------------------------------------------------------+
810 | 1 | org.onap.example.component1.subcomponent1.LogbackTest |
812 | 2 | \\t2017-08-06T16:09:03.594Z |
816 | 4 | \\tHere's an error, that's usually bad |
818 | 5 | \\tkey1=value1, key2=value2 with space, key5=value5"with"quotes, key3=value3\\nwith\\nnewlines, key4=value4\\twith\\ttabs |
820 | 6 | \\tjava.lang.RuntimeException: Here's Johnny |
822 | 7 | \\n\\tat org.onap.example.component1.subcomponent1.LogbackTest.main(LogbackTest.java:24) |
824 | 8 | \\nWrapped by: java.lang.RuntimeException: Little pigs, little pigs, let me come in |
826 | 9 | \\n\\tat org.onap.example.component1.subcomponent1.LogbackTest.main(LogbackTest.java:27) |
831 +------+-----------------------------------------------------------------------------------------------------------------------------+
833 Default Logstash indexing rules understand output in this format.
837 For Log4j 1.X output, since escaping is not supported, the best
838 alternative is to emit logs in XML format.
840 There may be other instances where XML (or JSON) output may be
841 desirable. Default indexing rules support
843 Default Logstash indexing rules understand the XML output of \ `*Log4J's
844 XMLLayout* <https://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/xml/XMLLayout.html>`__.
848 Standardization of output locations makes logs easier to locate and ship
851 Logfiles should default to beneath \ **/var/log**, and
852 beneath \ **/var/log/ONAP** in the case of core ONAP components:
854 +-----+-----------------------------------------------------+
855 | 1 | /var/log/ONAP/<component>[/<subcomponent>]/\*.log |
856 +-----+-----------------------------------------------------+
860 Logging providers should be configured by file. Files should be at a
861 predictable, static location, so that they can be written by deployment
862 automation. Ideally this should be under \ **/etc/ONAP**, but compliance
867 All logger provider configuration document locations namespaced by
868 component and (if applicable) subcomponent by default:
870 +-----+---------------------------------------------------------+
871 | 1 | /etc/onap/<component>[/<subcomponent>]/<provider>.xml |
872 +-----+---------------------------------------------------------+
874 Where \ **<provider>.xml**, will typically be one of:
884 Logger providers should reconfigure themselves automatically when their
885 configuration file is rewritten. All major providers should support
888 The default interval is 10s.
892 The location of the configuration file MAY be overrideable, for example
893 by an environment variable, but this is left for individual components
898 Configuration archetypes can be found in the ONAP codebase. Choose
899 according to your provider, and whether you're logging via EELF. Efforts
900 to standardize them are underway, so the ones you should be looking for
901 are where pipe (\|) is used as a separator. (Previously it was "\|").
905 Logfiles are often large. Logging providers allow retention policies to
908 Retention has to balance:
910 - The need to index logs before they're removed.
912 - The need to retain logs for other (including regulatory) purposes.
914 Defaults are subject to change. Currently they are:
916 1. Files <= 50MB before rollover.
918 2. Files retain for 30 days.
920 3. Total files capped at 10GB.
922 In Logback configuration XML:
924 +------+-------------------------------------------------------------------------------------------------------------+
925 | 1 | <appender name="file" class="ch.qos.logback.core.rolling.RollingFileAppender"> |
927 | 2 | <file>${outputDirectory}/${outputFilename}.log</file> |
929 | 3 | <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy"> |
931 | 4 | <fileNamePattern>${outputDirectory}/${outputFilename}.%d{yyyy-MM-dd}.%i.log.zip</fileNamePattern> |
933 | 5 | <maxFileSize>50MB</maxFileSize> |
935 | 6 | <maxHistory>30</maxHistory> |
937 | 7 | <totalSizeCap>10GB</totalSizeCap> |
939 | 8 | </rollingPolicy> |
943 | 10 | <!-- ... --> |
948 +------+-------------------------------------------------------------------------------------------------------------+
952 EELF guidelines stipulate that an application should output log records
953 to four separate files:
963 This applies only to EELF logging. Components which log directly to a
964 provider may choose to emit the same set of logs, but most do not.
968 An audit log is required for EELF-enabled components, and provides a
969 summary view of the processing of a (e.g., transaction) request within
970 an application. It captures activity requests that are received by an
971 ONAP component, and includes such information as the time the activity
972 is initiated, then it finishes, and the API that is invoked at the
975 Audit log records are intended to capture the high level view of
976 activity within an ONAP component. Specifically, an API request handled
977 by an ONAP component is reflected in a single Audit log record that
978 captures the time the request was received, the time that processing was
979 completed, as well as other information about the API request (e.g., API
980 name, on whose behalf it was invoked, etc).
984 A metric log is required for EELF-enabled components, and provides a
985 more detailed view into the processing of a transaction within an
986 application. It captures the beginning and ending of activities needed
987 to complete it. These can include calls to or interactions with other
988 ONAP or non-ONAP entities.
990 Suboperations invoked as part of the processing of the API request are
991 logged in the Metrics log. For example, when a call is made to another
992 ONAP component or external (i.e., non-ONAP) entity, a Metrics log record
993 captures that call. In such a case, the Metrics log record indicates
994 (among other things) the time the call is made, when it returns, the
995 entity that is called, and the API invoked on that entity. The Metrics
996 log record contain the same RequestID as the Audit log record so the two
999 Note that a single request may result in multiple Audit log records at
1000 an ONAP component and may result in multiple Metrics log records
1001 generated by the component when multiple suboperations are required to
1002 satisfy the API request captured in the Audit log record.
1006 An error log is required for EELF-enabled components, and is intended to
1007 capture info, warn, error and fatal conditions sensed (“exception
1008 handled”) by the software components.
1012 A debug log is optional for EELF-enabled components, and is intended to
1013 capture whatever data may be needed to debug and correct abnormal
1014 conditions of the application.
1018 Console logging may also be present, and is intended to capture
1019 “system/infrastructure” records. That is stdout and stderr assigned to a
1020 single “engine.out” file in a directory configurable (e.g. as an
1021 environment/shell variable) by operations personnel.
1023 New ONAP Component Checklist
1025 By following a few simple rules:
1027 - Your component's output will be indexed automatically.
1029 - Analytics will be able to trace invocation through your component.
1031 Obligations fall into two categories:
1033 1. Conventions regarding configuration, line format and output.
1035 2. Ensuring the propagation of contextual information.
1039 1. Choose a Logging provider and/or EELF. Decisions, decisions.
1041 2. Create a configuration file based on an existing
1042 archetype. See \ `*Configuration* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-Configuration>`__.
1044 3. Read your configuration file when your components initialize logging.
1046 4. Write logs to a standard location so that they can be shipped by
1047 Filebeat for indexing. See \ `*Output
1048 Location* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-OutputLocation>`__.
1050 5. Report transaction state:
1052 a. Retrieve, default and propagate \ **RequestID**. See \ `*MDC -
1053 RequestID* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-MDC-RequestID>`__.
1055 b. At each invocation of one ONAP component by another:
1057 i. Initialize and propagate \ **InvocationID**. See \ `*MDC -
1059 ID* <https://wiki.onap.org/display/DW/ONAP+Application+Logging+Guidelines+v1.1#ONAPApplicationLoggingGuidelinesv1.1-MDC-InvocationID>`__.
1061 ii. Report \ **INVOKE** and **SYNCHRONOUS** markers in caller.
1063 iii. Report \ **ENTRY** and **EXIT** markers in recipient.
1065 6. Write useful logs!
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