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.

cpanm Log::Any::Adapter::DERIV

perl -MCPAN -e shell
install Log::Any::Adapter::DERIV