Logging API for MuranoPL


The purpose is to add an ability to log actions while developing MuranoPL applications

Problem description

It is good practice to log basic stages during application execution. Logging API should make debugging and troubleshooting processes easier.

Proposed change

Implemention key points

  1. New MuranoPL class io.murano.system.Logger

    Class Logger will be part of the MuranoPL core library.

    This class should contain basic logging functionality. Usage example in MuranoPL:

    $.log: logger('logger_name')
    $.log.info('message: {0}', 'checkpoint')

    that code should be equivalent of python code:

    from oslo_log import log as logging
    LOG = logging.getLogger('logger_name')
    LOG.info(_LI('message: {0}').format('checkpoint'))

    Others logging methods are Logger.debug, Logger.info, Logger.warning, Logger.error, Logger.critical. Each method corresponds to the oslo.log logging level.

    There is also separate method for exception stack trace output described below.

  2. Exceptions logging

    Method Logger.exception intended to log a stack trace:

    $.log.exception(exc, 'Something bad happened: {0}', 'Oops!')

    exception method uses the same log level as Logger.error.

  3. New global MuranoPL function logger()

    Call of the function logger(‘logger_name’) returns new instance of the io.murano.system.Logger. If function with the same logger_name was called previously then the same logger instance should be returned instead of building new one.

  4. Logging configuration

    Logging should use standard Murano Engine logging subsystem.

    Application itself cannot set logging settings at runtime.

    All of appenders, formatters an etc. may be configured via standard way as others loggers in Murano Engine.

    Prefix applications should be added to each logger name which created by application. As example, logger named active_directory in the MuranoPL should be identified as applications.active_directory at the python side and in the system config. This is for separation loggers used by applications and engine system loggers. Also it will allow us to specify settings for the application loggers separately from others loggers.

  5. Default configuration

    All logs written in the one file by default. Log rotation should be used, so maximum size of logs is limited.

  6. Logging naming conventions

    A note about the logging naming conventions should be added to the MuranoPL tutorial.



Data model impact


REST API impact


Versioning impact


Other end user impact


Deployer impact

Deployer will get more information about application execution stages and additional tool for more precise troubleshooting

Developer impact

Logging API will allow developer to debug application in a more effective manner getting information from logs.

Murano-dashboard / Horizon impact




Alexey Khivin

Primary assignee:

Work Items

  • Create new MuranoPL class io.murano.system.Logger
  • Create new global MuranoPL function logger()
  • Create method Logger.exception
  • Add new section for logging parameters into the Murano Engine config
  • Describe naming conventions for loggers in the Murano docs




Functional tests for MuranoPL must be updated.

Documentation Impact