ppikula/journerl

An Erlang shell available via web interface which can be easily recorded to a file

Journerl

NOTICE: right now project is in its early stage AKA: nothing works

It is an Erlang shell available via web browser.

Why

First of all I wanted to have a frictionless way to record my debugging/troubleshooting sessions on productions system. I found it quite useful, where it comes to writing summary of your investigation or teaching other developers how to do such things.

Why not iPython/jupyter kernel?

I've tried to play with these tool, but in my opinion it requires a lot of hassle to get it working, especially installing jupyter deps, which might be not so easy on production environments. My goal here is to reduce this hassle to one simple step: add journerl dependecy to the rebar.config file. Moreover, I want to fix all stanard shell's quirks, for instance I want to be able to call the following command: erlang:process_info(<0.27.0>). (no longer need to call either pid/3 or list_to_pid/1 to be able to use values returned by shell using copy-paste techinque;) ).

Features

• [in-progress] add plain text comments between shell calls
• [in-progress] fold/unfold big results and returned data structures
• [in-progress] inspect values such as pids or ports
• [in-progress] ability to display some results in visual form(ex. present erlang:memory result on a chart)
• [in-progress] export report to the pdf format

How to use

The only thing you need to do is add the joernerl repository to list of your dependencies and just start the journerl application. Alternatively you can tak a look at the For Developers section. By default the web UI listens on the loopback interface on port 8080. This can be changed using proper application config. For example to change it to 10.0.0.1:9090 set the following values in your sys.config:

[
...
{journerl,[
           {listen_ip, {10,0,0,1}},
           {listen_port, 9090}
          ]},
...

Under the hood

TODO

For Developers

For those who want to develop journerl, it can be run in stand-alone mode. Development environment requires node.js. When you have node.js installed in your system, you need to install 2 node's dependencies webpack and bower globally. They are used for transpiling and packing assets.

$ npm install --global bower webpack

Having all required dependencies you can run:

$ make run

This command is going to download all required JS libraries, transpile them, convert assets and place the results in the priv/build directory. Right after preparing JS the command will start Erlang node with journerl running and listening on previously set port(by default 127.0.0.1:8080). More over this command will start the sync application(github.com/rustyio/sync), so all erlang source code changes will be reloaded on the fly - no need to re-run make run each time you change a source file.

To achieve the same functionality as above, but for jsx files, you have to run the following command:

cd priv; webpack -w