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Lumberjack::Application cpan:JSTOWE last updated on 2021-02-06

Lumberjack::Application

A web facility for the Lumberjack logging framework

Synopsis

# In some shell start the lumberjack standalone application
# on port 8898 and mirroring log messages to the console

lumberjack-application --port=8898 --console

Meanwhile in some other application:

use Lumberjack;
use Lumberjack::Dispatcher::Proxy;

# Add the proxy dispatcher
Lumberjack.dispatchers.append: Lumberjack::Dispatcher::Proxy.new(url => 'http://localhost:8898/log');

# Now all logging messages will be sent to the server application as well
# as any other dispatchers that may be configured. The logs will be displayed
# at a Websocket application that you can point your browser at.

Or you can arrange components as you see fit:

# This is almost  identical to what Lumberjack::Application does
use Lumberjack;
use Lumberjack::Dispatcher::Supply;
use Lumberjack::Application::PSGI;
use Lumberjack::Application::WebSocket;
use Lumberjack::Application::Index;

use Crust::Builder;

# The supply dispatcher is used to transfer the messages
# between the lumberjack dispatch mechanism and the
# connected websocket clients.
my $supply  = Lumberjack::Dispatcher::Supply.new;
Lumberjack.dispatchers.append: $supply;

# The application classes are PSGI applications in their own right
my &ws-app  = Lumberjack::Application::WebSocket.new(supply => $supply.Supply);
my &log-app = Lumberjack::Application::PSGI.new;
my &ind-app = Lumberjack::Application::Index.new(ws-url => 'socket');

# Use Crust::Builder to map the applications to locations on the server
# you can of course any other mechanism that you choose.
my &app = builder {
    mount '/socket', &ws-app;
   mount '/log', &log-app;
   mount '/', &ind-app;
};

# Then pass &app to your P6SGI container.

Description

This is actually more a collection of related modules than a single module. It comprises a Lumberjack dispatcher that sends the logging messages encoded as JSON to a web server, A P6SGI application module that handles the JSON messages, deserialising them back to the appropriate objects and re-transmitting them to the local Lumberjack object, and a Websocket app module that will re-transmit the messages as JSON to one or more connected websockets. There are one or two convenience helpers to tie all this together.

These components together can be combined in various ways to make for example, a log aggregator for a larger system, a web log monitoring tool, or simply perform logging to a service which is not on the local machine.

This should probably be considered more as a proof of concept, experiment or demonstration than a polished application. Please feel free to take the parts you need and do what you want with them.

Installation

Assuming you have a working installation of Rakudo with "zef" then you can simply do:

zef install Lumberjack::Application

Or if you have a local copy of this distribution:

zef install .

Though I haven't tested it I can see no reason why this shouldn't work equally well with some similarly capable package manager that may come along in the future.

Support

This is quite experimental and depends on things that are themselves probably fairly experimental, but it it works and I hope you find it useful in some way, that said I'll be interested in enhancements, fixes and suggestions at github

Licence and Copyright

This free software, please see the LICENCE file in the distribution directory.

© Jonathan Stowe, 2016 - 2021