Customizing Log Output

Overview

This page describes Appian logging configuration settings and what changes you can make to capture more detailed information about application behavior.

• Timestamps listed in the Appian log files are recorded in Greenwich Mean Time (GMT).

• For more information about Log4j, see the Apache Log4j2 documentation.

Application logging

To configure logging for the Appian application, do one of the following:

• Make your desired setting changes in the following file:

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    <APPIAN_HOME>/deployment/web.war/WEB-INF/resources/appian_log4j.properties
  

• Create or update a custom log.properties file.

See also: Custom Logging Configuration Files.

Custom settings set in the appian_log4j.properties file are reset to Appian defaults when you patch or upgrade your installation. Keep a backup of your appian_log4j.properties file so you can restore your custom settings after upgrading. Custom log.properties files are retained during upgrades.

Search server logging

To configure search server logging for the Appian application:

• Make your desired setting changes in the following file:

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   <APPIAN_HOME>/search-server/conf/log4j2.properties`.
  

Custom settings set in the log4j2.properties file are reset to Appian defaults when you patch or upgrade your installation. Keep a backup of your log4j2.properties file so you can restore your custom settings after upgrading.

Log file location

The directory where log files are written is controlled by the following property, in custom.properties:

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conf.suite.AE_LOGS=<install_dir>/logs/

See also: Custom Configurations

Changing logging levels

The following table provides a list of the different logging levels that you can specify for each component and their descriptions.

When a logger is configured to output log entries at a certain level, it also writes any log entries of greater importance, as defined above. For instance, if it is set to WARN, the logger also outputs ERROR and FATAL log entries. If it is set to DEBUG, the logger writes all entries.

During development, we recommend that you raise the logging level to INFO or WARN. In production increased logging can negatively impact system performance, so we recommend that you lower the logging level to ERROR once in production.

Common logging changes

HTML filtering

Certain HTML tags and tag attributes are forbidden as inputs and are filtered out at runtime. When a forbidden input is encountered, a message like the following is logged.

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com.appiancorp.security.util.StringSecurityUtils - The HTML tag contained an attribute that we could not process. The request attribute has been filtered out, but the tag is still in place. The value of the attribute was ...

These messages are logged when the following logger in appian_log4j.properties is set to the WARN level. By default, it is set to ERROR.

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log4j.logger.com.appiancorp.security.util.StringSecurityUtils=ERROR

Performance logging

• Engine Performance is automatically logged at the INFO level, as listed in log.properties.

• You can enable database performance logging and in log4j.properties, including Tempo database performance logging.

See also: Performance Monitoring Log Files.

Database integration details

To log the details of the Write to Data Store smart services and Query Rules, add the following loggers:

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 # Output SQL statements
 log4j.logger.org.hibernate.SQL=DEBUG
 # Output param values within SQL statements
 log4j.logger.org.hibernate.type=TRACE

To view the calls made by the Query Database Node, add the following logger:

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log4j.logger.com.appiancorp.process.runtime.activities.QueryRdbmsActivity=DEBUG

Debugging CDTs created by plug-ins

When creating custom data types using a Java object in a plug-in, you can review the XSD being generated by the Java object by adding the following logger to log4j.properties:

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log4j.logger.com.appiancorp.common.xml.JaxbXsdGenerator=DEBUG

See also: Custom Data Types from Java Object

Customizing logging

The appian_log4j.properties file allows administrators to set up customized logging for different components of Appian.

Creating a custom logger

You can create customized loggers in the appian_log4j.properties file by entering the package you want logged using the following pattern:

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log4j.logger.<package_name>=<logging_level>

For example, to add a custom logger at the DEBUG level for the portal component only, type the following statement in the appian_log4j.properties file:

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log4j.logger.com.appiancorp.ap2=DEBUG

For each logger, you can configure the logging level. (The output formats, or appenders, vary according to property file used.) You can also configure groups of loggers using parent packages. For instance, if you configure com.appiancorp.common, then its log level applies to any classes in that package and any of its subpackages (recursively). log4j uses the most specific configuration available for a particular logger, so if both com.appiancorp.common and com.appiancorp.common.struts.BaseAction are configured, it uses the latter's configuration because it is more specific.

Appenders

In the appian_log4j.properties file, appenders are used to define the output formats of the log file messages. The appenders are listed in the root logger, which uses the following convention:

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log4j.rootLogger=<LOGGING_LEVEL>, <APPENDER_NAME_1>, <APPENDER_NAME_2>

In the following example, the root logger statement writes ERROR level messages (and above) using two appenders (console for and a named text file appender for ):

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log4j.rootLogger=ERROR, CONSOLE, WORK_POLLER

This sample appender (named the WORK_POLLER appender) writes messages to a text file named work-poller.log.

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###### WORK_POLLER appender
log4j.appender.WORK_POLLER.layout=org.apache.log4j.PatternLayout
log4j.appender.WORK_POLLER.layout.ConversionPattern=%d{ABSOLUTE} %-5p [%c{1}] %m%n
log4j.appender.WORK_POLLER=org.apache.log4j.RollingFileAppender
log4j.appender.WORK_POLLER.File=${AE_LOGS}/work-poller.log
log4j.appender.WORK_POLLER.MaxFileSize=10MB
log4j.appender.WORK_POLLER.MaxBackupIndex=<b>1000</b>

Changing the logging directory or filename

The log file name and path is determined by the log4j.appender.<APPENDER_NAME>.File property (in <APPIAN_HOME>/deployment/web.war/WEB-INF/resources/appian_log4j.properties). In the prior example, the log4j.appender.WORK_POLLER.File property is set to write to the work-poller.log file in the <APPIAN_HOME>/logs/ directory. You can modify this property to write to a different directory and or filename.

Changing log syntax

The pattern of the log message is defined in the log4j.appender.<APPENDER_NAME>.layout.ConversionPattern property. You can modify this property based on various options defined in the Log4j documentation.

See also: Log4j Documentation.

Backup and remove log files

Appian stores its log files in the <APPIAN_HOME>/logs/ directory. The maximum size for any log file is determined by the log4j.appender.<APPENDER_NAME>.MaxFileSize property, which has been set to 10MB. Modify this property to increase or decrease the maximum size of the file.

Each time the size of the file exceeds what is allowed, a new file is created. The number of files that are created are limited by the log4j.appender.<APPENDER_NAME>.MaxBackupIndex property. The default value of this property is 1000.

Log file maintenance is handled by the cleanup script: <APPIAN_HOME>/server/_scripts/cleanup.bat (.sh).

See also: Data Maintenance

Application engine logging

The log.properties file is used to configure logging for the Appian Real-time database processes in Appian. It is located within the <APPIAN_HOME>/server/_conf/logging/ directory. This properties file uses the same configuration settings and conventions as the appian_log4j.properties file - and is configured in the same manner. The log entries are written to the <APPIAN_HOME>/logs/ directory.

Custom logging configuration files

To customize logging for a specific engine:

1. Create a complete duplicate of the appian_log.properties configuration file, in the same directory.

2. Name the file log_db_YY.properties according to the below table.

3. Edit the log file settings as needed.

The following table describes the logging property file names that can be used to customize logging for an individual application engine.

Custom log files generated

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