csw.logging.client

== Logging Service ==

This is a Actor based logging library which supports writing logs to File and StdOut Console.

=== Features ===

• Supports component specific log levels, ex. HCD1 can choose to log at info level and HCD2 can choose to log at debug level
• Supports dynamically changing component log levels
• Asynchronous thread safe logging
• Structured logging
• Supports overriding default logging properties per component viz
• Intercepting logs from pekko/slf4j
• Supports JSON logging

=== LogActor ===

LogActor is the heart of logging library. It receives messages from following classes:

• Slf4jAppender: Intercepts Slf4j logs and forwards it to LogActor via MessageHandler
• PekkoLogger: Intercepts Pekko logs and forwards it to LogActor via MessageHandler.
• LoggerImpl: Provides csw logging API for component writer to log messages which gets forwarded to LogActor via MessageHandler

=== Logging Appenders ===

This library supports two types of csw.logging.client.appenders.LogAppender:

• csw.logging.client.appenders.FileAppender: Common log messages are written in Pretty Json form. This appender is useful during development. It is recommended to disable it in production.

• csw.logging.client.appenders.StdOutAppender: Log messages are written as Json, one per line. Ordinary log messages are written to the common log files. Each log file includes a day as part of its name. Each day a new file is created.

You can specify the appender in application.conf file as shown below:

 csw-logging {
    appenders = ["csw.logging.client.appenders.StdOutAppender$", "csw.logging.client.appenders.FileAppender$"]
  }

=== Component Specific Log Levels ===

For each component, ComponentLoggingState instance gets created which maintains log levels which are enabled and disabled for this particular component. Every time message gets logged by component, LoggerImpl checks in corresponding componentLoggingState whether current log level enabled or not. If enabled, then only log message gets forwarded to LogActor via MessageHandler.

You can specify the component specific log levels in application.conf file as shown below:

 component-log-levels {
    tromboneHcd = debug
    tromboneAssembly = error
 }

̄ Detailed documentation of Logging Service is available at: https://tmtsoftware.github.io/csw/services/logging.html