NAME

    Log::Any::Adapter::DERIV - standardised logging to STDERR and JSON file

SYNOPSIS

        use Log::Any;
        # print text log to STDERR, json format when inside docker container , colored text format when STDERR is a tty, non-colored text format when STDERR is redirected.
        use Log::Any::Adapter ('DERIV');
    
        #specify STDERR directly
        use Log::Any::Adapter ('DERIV', stderr => 1)
    
        #specify STDERR's format
        use Log::Any::Adapter ('DERIV', stderr => 'json')
    
        #specify the json log name
        use Log::Any::Adapter ('DERIV', json_log_file => '/var/log/program.json.log');

DESCRIPTION

    Applies some opinionated log handling rules for Log::Any.

    This is extremely invasive. It does the following, affecting global
    state in various ways:

      * applies UTF-8 encoding to STDERR

      * writes to a .json.log file.

      * overrides the default Log::Any::Proxy formatter to provide data as
      JSON

      * when stringifying, may replace some problematic objects with
      simplified versions

    An example of the string-replacement approach would be the event loop
    in asynchronous code: it's likely to have many components attached to
    it, and dumping that would effectively end up dumping the entire tree
    of useful objects in the process. This is a planned future extension,
    not currently implemented.

 Why

    This is provided as a CPAN module as an example for dealing with
    multiple outputs and formatting. The existing Log::Any::Adapter modules
    tend to cover one thing, and it's not immediately obvious how to extend
    formatting, or send data to multiple logging mechanisms at once.

    Although the module may not be directly useful, it is hoped that other
    teams may find parts of the code useful for their own logging
    requirements.

    There is a public repository on Github, anyone is welcome to fork that
    and implement their own version or make feature/bugfix suggestions if
    they seem generally useful:

    https://github.com/binary-com/perl-Log-Any-Adapter-DERIV

 PARAMETERS

      * json_log_file

      Specify a file name that the json format log file will be printed
      into. If not given, then a default file 'program_name.json.log' will
      be used.

      * STDERR

      If it is true, then print logs to STDERR

      If the value is json or text, then print logs with that format

      If the value is just a true value other than `json` or `text`, then
      if it is running in a container, then the logs is `json` format. Else
      if STDERR is a tty will be `colored text` format. Else if will be a
      non-color text format.

    If no any parameter, then default `stderr => 1`;

 _process_data

    Process the data before printing out.

    Takes the following arguments as named parameters:

      * $self

      * data

      The log data.

    Return: processed data

 _filter_stack

    In some cases we don't want to print stack info. This function is used
    to filter out the stack info.

    Takes the following arguments as named parameters:

      * $self

      * data

      The log data.

    Return: processed data

 _collapse_future_stack

    The future frames are too much and too tedious. This method will keep
    only one frame if there are many continuously future frames. Parameter:
    log data Return: log data

 _linux_flock_data

    Param: lock type. It can be F_WRLCK or F_UNLCK

    return: A FLOCK structure

 _flock

    call fcntl to lock or unlock a file handle

    Param:

    fh - file handle

    type - lock type, either F_WRLCK or F_UNLCK

    Return : true or false

 _lock

    Lock a file handler with fcntl.

    Param: fh - File handle

    Return: true or false

 _unlock

    Unlock a file handler locked by fcntl

    Param: fh - File handle Return: true or false

 level

    return the current log level name

AUTHOR

    Deriv Group Services Ltd. DERIV@cpan.org

LICENSE

    Copyright Deriv Group Services Ltd 2020-2021. Licensed under the same
    terms as Perl itself.

