Server Log

Overview

The log functionality of the Servoy Application Server is based on Log4j of the Apache Logging Services project.

The logging mechanism is highly configurable and enables control over:

• the level of logging per area

• the format of the log file

• log file rollover/location/size settings

Servoy 8.4 and later: all log settings are stored in a separate file: log4j.xml located in the <servoy>/application_server. In case of WAR deployment, the export as war wizard will allow you to specify the log4j.xml/servoy.properties that you want the war deployment to use.

Besides the log4j properties, administrators can also configure the servoy.client.report.max.valuelist.items property on the Servoy admin page, or directly in the servoy.properties file. This property is used to disable/enable the logging of messages that not all records can be loaded into the valuelist, i.e. when the valuelist contains more than 500 records. It is not recommended to set this property to false when running from the Servoy developer, otherwise the developers will not be aware of these warnings at all.

Changing the Log Level

There are 6 levels of logging (in order of severity):

1. FATAL: The FATAL level designates very severe error events that will presumably lead the application to abort.

2. ERROR: The ERROR level designates error events that might still allow the application to continue running.

3. WARN: The WARN level designates potentially harmful situations.

4. INFO: The INFO level designates informational messages that highlight the progress of the application at coarse-grained level.

5. DEBUG: The DEBUG Level designates fine-grained informational events that are most useful to debug an application.

6. TRACE: The TRACE Level designates finer-grained informational events than the DEBUG.

By default, the log level is set to WARN. This means that all WARN, ERROR and FATAL messages will be logged. Here are some of the entries we have there:

The same log level settings as configured in log4j.xml (>= 8.4) :

<Loggers>
    <Logger name="com.servoy.j2db.util.Debug" level="WARN" />
    <Logger name="org.sablo.websocket" level="WARN" />
    <Root level="WARN">
        <AppenderRef ref="asyncfile" />
        <AppenderRef ref="configservlet" />
        <AppenderRef ref="debugconsole" />
        <!-- <AppenderRef ref="stdout" /> -->
    </Root>
</Loggers>

The first logger entry sets the log level for the internal Servoy Java class used for most of the application server logging done by Servoy.

The second entry sets the log level for websocket logger(s) which are used in Servoy NGClient. The third entry sets the overall log level and specifies the output channels for the log.

Check the actual configuration file contents to see more logger entries and other configuration options that are used by default (and can be altered to suit your needs).

To change the the log level for various loggers, replace 'WARN' in the corresponding entry with, for example 'TRACE' - to get the most logging information. The overall log level could also be set, but this would generate a lot of log data. You can also target a subset of loggers by using the common prefix in the logger name for example, but you can look at log4j documentation for more details.

Here is an example of a log entry; the pattern it uses is defined via PatternLayout in the configuration:

Log entry:

2019-03-25 10:48:52,965 ERROR [Executor,uuid:3f0bccdb-0dec-42fd-8c06-81b67fad3bce] com.servoy.j2db.util.Debug - error getting data from global method valuelist

It starts with date, log level (Error in this case), thread that logged this error, logger name then message. In this case, this message is logged under: com.servoy.j2db.util.Debug logger. So, in order to hide/show/customize this message you have to use that logger name in log4j.xml.

Some of the loggers that Servoy registers:

com.servoy.j2db.util.Debug

persistence.Server

ClientManager

com.servoy.j2db.persistence.XMLExporter

com.servoy.j2db.persistence.XMLImportHandlerVersions1to10

com.servoy.j2db.persistence.XMLInMemoryImportHandlerVersions11AndHigher

com.servoy.j2db.dataprocessing.editedRecords

WebServer

datasource.TransactionConnection

com.servoy.event.tracing

com.servoy.performance.timing.methods

com.servoy.performance.timing.sql

ResourceProvider

loggers related to jsunit tests:

com.servoy.automation.jsunit.runner.ImportClient

com.servoy.automation.jsunit.SolutionJSTestSuite

com.servoy.automation.jsunit.mobile.ServoyMobileJSUnitTestRunner

com.servoy.eclipse.jsunit.runner.JSUnitToJavaRunner

com.servoy.mobile.test.server.service.TestSuiteController

sablo (part of NGClient impl) related loggers :

org.sablo.BrowserConsole

org.sablo.eventthread.Event

org.sablo.eventthread.EventDispatcher

org.sablo.services.server.FormServiceHandler

sablo property type related loggers (start with org.sablo.specification.property):

org.sablo.specification.property.types.TypesRegistry

org.sablo.specification.property.types.DoublePropertyType

org.sablo.specification.property.types.EnabledSabloValue

org.sablo.specification.property.types.FloatPropertyType

org.sablo.specification.property.types.IntPropertyType

org.sablo.specification.property.types.LongPropertyType

org.sablo.specification.property.CustomJSONPropertyType

org.sablo.specification.property.CustomPropertyTypeResolver

org.sablo.specification.property.BrowserConverterContext

loggers related to sablo packages and specification (start with org.sablo.specification):

org.sablo.specification.Package

org.sablo.specification.WebObjectSpecification

org.sablo.specification.WebLayoutSpecification

org.sablo.specification.WebComponentSpecProvider

org.sablo.specification.WebServiceSpecProvider

org.sablo.specification.WebSpecReader

loggers related to classes close to web socket communication (start with org.sablo.websocket):

org.sablo.websocket.impl.ClientService

org.sablo.websocket.utils.JSONUtils

org.sablo.websocket.utils.PropertyUtils

org.sablo.websocket.BaseWebsocketSession

org.sablo.websocket.BaseWindow

org.sablo.websocket.WebsocketEndpoint

org.sablo.websocket.WebsocketSessionManager

org.sablo.BaseWebObject

org.sablo.CustomObjectContext

org.sablo.IndexPageEnhancer

ngclient related loggers:

com.servoy.less.Compiler

ngclient property type related loggers:

com.servoy.j2db.server.ngclient.property.types.FormatPropertyType

com.servoy.j2db.server.ngclient.property.ComponentTypeSabloValue

com.servoy.j2db.server.ngclient.startup.resourceprovider.ResourceProvider

com.servoy.j2db.server.ngclient.MessageLogger

com.servoy.j2db.server.ngclient.api

com.servoy.extensions.plugins.rest_ws.RestWSPlugin

com.servoy.j2db.server.main.Activator

com.servoy.j2db.server.headlessclient.ServoyModificationWatcher

com.servoy.j2db.util.ImageLoader

com.servoy.PersistIndexCache

plugin.oauth

The logging level can be set independently of for subsets of all these loggers, by adding extra 'log4j.logger' entries in the log4j.xml file; for example:

Set the loglevel to the most finegrained level for the ClientManager class (in log4j.xml, so for Servoy >=8.4):

<Logger name="ClientManager" level="TRACE" />
<Logger name="org.sablo.websocket" level="TRACE" />

Setting the log level to DEBUG or TRACE will generate a lot of logging data. This is not recommended in a production environment, unless absolutely necessary. Make sure enough disk space is available for the log file(s).

Logging Pattern

The pattern in the log4j.xml defines what information is logged. Log4j supports a number of lookups, Servoy has added servoy-lookup (starting from release 2021.06) that can be used to print Servoy-specific data in the logfile.

The lookup is called servoy and can be used like in this example. Note that the double dollar-sign is needed to ensure that the value is looked up for each message, otherwise Log4j may cache the value.

<PatternLayout
         pattern="%d %p [%t] %c - %m [$${servoy:clientid:-(NO CLIENT)} $${servoy:solution:-(NO SOLUTION)}]%n" />

The supported lookup keys are:

• clientid

• solution

• username

• useruuid

• clienttype

• hostname

• hostaddress

• sessionkey (ng client only)

More information on Log4J For more information on log4j, visit the Log4j site (Frequently Asked Log4j Questions section can help with some questions).