Logging

Format

The log entries are structured as follows:

[DATE, format: JJJJ-MM-TT][Time, format: HH-MM-SS][Log level]{Process}[Component][Log message]

The following log levels are available:

Example:

2020-04-02 09:21:36.653 INFO {http-nio-0.0.0.0-8080-exec-49} [N.A] [GLOBAL] [ComponentContainerImpl] Starting component 'events-aggregator

If an error occurs, additional hints are displayed in the form of runtime exceptions which must be checked by the development partner, e.g.:

2020-04-02 04:40:31.685 ERROR {http-nio-0.0.0.0-8080-exec-2} [N.A] [GLOBAL] [ComponentContainerImpl] Can't start component [id=kafka-events-consumer, descriptor=[metadata=[metadata={Manifest-Version=1.0, Implementation-Title=Event Service - Kafka Connector, Implementation-Vendor=GK Software SE, GK-Package-Revision=8e603b31782fc89b70cc19de172f61cf075519a7, Specification-Version=5.15, Specification-Title=Event Service - Kafka Connector, Implementation-Vendor-Id=com.gk-software.gkr.event-service.server, Created-By=Apache Maven 3.3.9, X-Compile-Source-JDK=1.8, Implementation-Version=5.15.0-b04-SNAPSHOT, Specification-Vendor=GK Software SE, Built-By=hagent, Build-Jdk=1.8.0_111, X-Compile-Target-JDK=1.8, Implementation-URL=scm:git:ssh://git@gitlab.gk.gk-software.com/retail-services/event-service.git/event-service-server-parent/mod-kafka-connector}]], config=[configEntries=[[fileName=event-service], [fileName=event-service-firmware], [fileName=kafka-firmware], [key=event-service.kafka.consumer.topics, value=${event-service.kafka.consumer.topics.events},${event-service.kafka.consumer.topics.commands},${event-service.kafka.consumer.topics.states}], [key=event-service.kafka.consumer.id, value=${event-service.kafka.consumer.id}]]], mapping=[importBeanAliases={stompMessageDelegator=messageDelegator, deviceStatusRegistry=deviceStatusRegistry, eventsAggregator=eventsAggregator, deviceStatusProcessor=deviceStatusProcessor}], if=${event-service.broker.type}, containsToken=kafka]
org.springframework.context.ApplicationContextException: Failed to start bean 'org.springframework.kafka.config.internalKafkaListenerEndpointRegistry'; nested exception is org.apache.kafka.common.KafkaException: Failed to construct kafka consumer
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:185) ~[org.springframework.spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:53) ~[org.springframework.spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:360) ~[org.springframework.spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:158) ~[org.springframework.spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:122) ~[org.springframework.spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:894) ~[org.springframework.spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553) ~[org.springframework.spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]

Log files are permanently written. As soon as a defined file size is reached, the log files are packed and later deleted.

Activation

Configuration file:

<EVENT_SERVICE_ROOT>/config/parameter/log4j-logging.properties:

appender.root-local.enabled=true
appender.root-error-local.enabled=true
appender.root-info-local.enabled=true
appender.cloud.enabled=false

Location for Outputs

An application directory will be defined during installation. This application directory includes a /log directory which is used to store the log files.

In Apache Tomcat environments, it is possible to view or change this directory:

The default value for the storage location of the log file is, for example, on Linux:

Configuration File Name, Max. File Size, etc.

The following log file is written:

• /log/ event-service-[node.id].log

File name:

• An unpacked log file has the following format: event-service-[node.id].log
• Packed log files have the following format: event-service-[node.id].log-[JJJJMMDD].zip

There are several parameters to influence the storage duration, file size, etc.:

• size: Max. file size. If it is exceeded, the file is packed and a new file is created.
• max, exceeds: Max. number of files. If it is exceeded, the files are deleted.
• age: Max. age of files. If it is exceeded, the corresponding files are deleted.

Configuration file

<EVENT_SERVICE_ROOT>/config/parameter/log4j2.xml:

<Policies>
<SizeBasedTriggeringPolicy size="20MB" />
</Policies>
<DefaultRolloverStrategy max="100">
<Delete basePath="${log.dir}">
<IfFileName glob="event-service-${node.id}*.log.zip">
<IfAny>
<IfLastModified age="10d" />
<IfAccumulatedFileCount exceeds="100" />
</IfAny>
</IfFileName>
</Delete>
</DefaultRolloverStrategy

Configuration of Outputted Log Levels

The log level can be set differently for the individual components. Therefore, it can be defined whether outputs of a particular category (=level) are written or not.

The following log levels are available:

• TRACE
• DEBUG
• INFO
• WARNING
• ERROR
• FATAL

If INFO is set, all messages of the level INFO and higher are outputted.

OFF disables the logging completely.

Configuration file

<EVENT_SERVICE_ROOT>/config/parameter/log4j-logging.properties, e.g.:

# Base log level definition
log.level.com.gk_software=DEBUG
# Data source tracer
 log.level.com.gk_software.core.server.datasource.internal.tracing.PrintConnectionsOnErrorDataSourceExtension=TRACE
# ClassLoader cleanup TRACE for better memory leak detection
 log.level.com.gk_software.core.server.resource.internal.cleaners=TRACE
# Too noisy with load-balancer (health check)
 log.level.com.gk_software.core.common.security.server.internal.spring_security.common.filter.wrapper.SpringSecurityFilterWrapper=INFO
# Filter ERROR in TenantContextSwitchSetupFilter (when used with single tenant context)
 log.level.com.gk_software.core.common.security.server.internal.spring_security.common.filter.TenantContextSwitchSetupFilter=FATAL
log.level.gk=DEBUG
# Spring AbstractBeanFactory is too noisy on default DEBUG level
 log.level.gk.spring_ext.component.internal.ComponentBeanFactoryImpl=WARN

Log Output on the Console

In the configuration file <EVENT_SERVICE_ROOT>/config/parameter/log4j-logging.properties, it is possible to set which messages are displayed on the console.

In Tomcat, these messages are written to the Tomcat log. Messages are not redirected to this log, by default. The values for the setting are:

• false = Output suppressed
• true = Output allowed

Configuration file

<EVENT_SERVICE_ROOT>/config/parameter/log4j-logging.properties:

appender.system-out.enabled=false
appender.system-err.enabled=false