Configure logging

Web3Signer provides multiple methods to configure logging:

• Basic - Change the log level or structured logging format.
• Advanced - Configure the output and format of the logs.

Basic log level setting

Use the --logging command line option to specify logging verbosity. This option changes the volume of events displayed in the log. Valid log levels are OFF, FATAL, ERROR, WARN, INFO, DEBUG, TRACE, ALL. The default level is INFO.

Use the --logging-format option to specify the logging format. You can select a structured logging format, which emits each log record as a JSON object in a well-defined format, making logs consistent and machine-readable. Valid formats are PLAIN, ECS, GCP, LOGSTASH, GELF. The default format is PLAIN, which specifies traditional pattern-based text logging.

Advanced custom logging

You can provide your own logging configuration using the standard Log4J2 configuration mechanisms.

Web3Signer includes the Log4J JSON Template Layout library, which enables production-ready templates for each structured logging format. Specify JsonTemplateLayout in your configuration file to use the Log4J templates.

The following is an example of a custom configuration file, a configuration file using the default Elastic Common Schema (ECS) template, and a configuration file using the Google Cloud Platform (GCP) template. For more information, see the Log4j configuration file and event templates documentation.

Custom configuration

<?xml version="1.0" encoding="UTF-8"?>
<Configuration level="INFO">
  <Properties>
    <Property name="root.log.level">INFO</Property>
    <Property name="dependency.log.level">INFO</Property>
  </Properties>

  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSSZZZ} | %t | %-5level | %c{1} | %msg%n"/>
    </Console>
  </Appenders>
  <Loggers>
    <Logger name="com.azure.security.keyvault.secrets.SecretAsyncClient"
      level="${dependency.log.level}" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="com.networknt.schema" level="${env:dependency.log.level}" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="org.jdbi.v3.core" level="${env:dependency.log.level}" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="com.zaxxer.hikari" level="${env:dependency.log.level}" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="io.swagger.v3" level="${env:dependency.log.level}"
      additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="io.netty" level="${env:dependency.log.level}" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Root level="${sys:root.log.level}">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

With default ECS template

<?xml version="1.0" encoding="UTF-8"?>
<Configuration level="INFO">
  <Properties>
    <Property name="root.log.level">INFO</Property>
  </Properties>

  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <JsonTemplateLayout/>
    </Console>
  </Appenders>
  <Loggers>
    <Root level="${sys:root.log.level}">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

With GCP template

<?xml version="1.0" encoding="UTF-8"?>
<Configuration level="INFO">
  <Properties>
    <Property name="root.log.level">INFO</Property>
  </Properties>

  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <JsonTemplateLayout eventTemplateUri="classpath:GcpLayout.json"/>
    </Console>
  </Appenders>
  <Loggers>
    <Root level="${sys:root.log.level}">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

To use your custom configuration, set the environment variable JAVA_OPTS to the location of your configuration file.

export JAVA_OPTS="-Dlog4j.configurationFile=<path_to_file>"

For Bash-based executions, you can set the variable for only the scope of the program execution by setting it before starting Web3Signer.

Set the custom logging and start Web3Signer

JAVA_OPTS="-Dlog4j.configurationFile=/Users/me/debug.xml" web3signer --key-store-path=/Users/me/keyFiles/ eth2

Note

When a custom Log4j2 configuration file is provided, it takes precedence over the logging command line options.