Enabling per-API Logs for APIs

The advantage of having per-API log files is that it is very easy to analyze/monitor what went wrong in a particular REST API defined in the ESB profile by looking at the log files. The API log is an additional log file, which will contain a copy of the logs to a particular REST API.

Below are the configuration details to configure the logs of a REST API called TestAPI using log4j2 properties.

Open <EI_HOME>/conf/log4j2.properties file using your favorite text editor to configure log4j to log the API specific logs to a file. You can configure the logger for either INFO level logs or DEBUG level logs as follows:

Open up the log4j2.properties file found in the conf directory of the WSO2 EI installation directory using your favorite text editor and add the following log appender.

#Per API appender
appender.TestAPI_LOGGER.type = RollingFile
appender.TestAPI_LOGGER.name = TestAPI_LOGGER
appender.TestAPI_LOGGER.fileName = ${sys:carbon.home}/repository/logs/TestAPI.log
appender.TestAPI_LOGGER.filePattern = ${sys:carbon.home}/repository/logs/TestAPI-%d{MM-dd-yyyy}.log
appender.TestAPI_LOGGER.layout.type = PatternLayout
appender.TestAPI_LOGGER.layout.pattern = TID: [%tenantId] [%d] %5p {%c} - %m%ex%n
appender.TestAPI_LOGGER.policies.type = Policies
appender.TestAPI_LOGGER.policies.time.type = TimeBasedTriggeringPolicy
appender.TestAPI_LOGGER.policies.time.interval = 1
appender.TestAPI_LOGGER.policies.time.modulate = true
appender.TestAPI_LOGGER.policies.size.type = SizeBasedTriggeringPolicy
appender.TestAPI_LOGGER.policies.size.size=10MB
appender.TestAPI_LOGGER.strategy.type = DefaultRolloverStrategy
appender.TestAPI_LOGGER.strategy.max = 20
appender.TestAPI_LOGGER.filter.threshold.type = ThresholdFilter
appender.TestAPI_LOGGER.filter.threshold.level = INFO

Define a logger referring to the appender . Add the following section to the end of the file to configure the logger for log messages where the Log Category is INFO.
logger.API_LOGGER_TestAPI.name = API_LOGGER.TestAPI
Here TestAPI is the name of the API which you have created.
```
#Logger for per API
logger.API_LOGGER_TestAPI.name = API_LOGGER.TestAPI
logger.API_LOGGER_TestAPI.level = INFO
logger.API_LOGGER_TestAPI.additivity = false
logger.API_LOGGER_TestAPI.appenderRef.TestAPI_LOGGER.ref = TestAPI_LOGGER
```
The in-sequence of the REST API will need to contain a Log mediator with the Log Category defined as INFO to be able to view logs in the log file.

Add your appender name into the section called "list of all appenders" as following manner.

# list of all appenders
#add entry "syslog" to use the syslog appender
appenders = CARBON_CONSOLE, CARBON_LOGFILE, AUDIT_LOGFILE, ATOMIKOS_LOGFILE, CARBON_TRACE_LOGFILE, osgi, SERVICE_LOGFILE, ERROR_LOGFILE, TestAPI_LOGGER

Add your logger name into the section called “loggers” as following manner.

loggers = AUDIT_LOG, SERVICE_LOGGER, trace-messages, org-apache-coyote, com-hazelcast, Owasp-CsrfGuard, \
     org-apache-axis2-wsdl-codegen-writer-PrettyPrinter, org-apache-axis2-clustering, org-apache-catalina, \
     org-apache-tomcat, org-wso2-carbon-apacheds, org-apache-directory-server-ldap, \
     org-apache-directory-server-core-event, com-atomikos, org-quartz, org-apache-jackrabbit-webdav, org-apache-juddi, \
     org-apache-commons-digester-Digester, org-apache-jasper-compiler-TldLocationsCache, org-apache-jasper-servlet-TldScanner, org-apache-qpid, \
     org-apache-qpid-server-Main, qpid-message, qpid-message-broker-listening, ca-uhn-hl7v2, org-apache-tiles, \
     org-apache-commons-httpclient, org-apache-solr, me-prettyprint-cassandra-hector-TimingLogger, \
     org-apache-axis-enterprise, org-apache-directory-shared-ldap, org-apache-directory-server-ldap-handlers, \
     org-apache-directory-shared-ldap-entry-DefaultServerAttribute, org-apache-directory-server-core-DefaultDirectoryService, \
     org-apache-directory-shared-ldap-ldif-LdifReader, org-apache-directory-server-ldap-LdapProtocolHandler, \
     org-apache-directory-server-core, org-apache-directory-server-ldap-LdapSession, DataNucleus, Datastore, Datastore-Schema, \
     JPOX-Datastore, JPOX-Plugin, JPOX-MetaData, JPOX-Query, JPOX-General, JPOX-Enhancer, org-apache-hadoop-hive, hive, ExecMapper, \
     ExecReducer, net-sf-ehcache-config-ConfigurationFactory, axis2Deployment, equinox, tomcat2, StAXDialectDetector, \
     org-apache-synapse, org-apache-synapse-transport, org-apache-axis2, org-apache-axis2-transport, org-wso2-carbon, synapse-transport-http-access, API_LOGGER_TestAPI

The above configuration creates a log file names TestAPI.log in the folder <EI_HOME>/repository/logs.

The in-sequence of the REST API will need to contain a Log mediator with the Log Category defined as DEBUG to be able to view logs in the log file.