EnvPatcher

A generic rule-driven environment variables injector.

Overview

EnvPatcher is a simple application which aids problem with sharing common variables among several applications configured with standard .config files. Now settings may be shared with no great work among applications. Thus you could avoid forbidden settings problem as a developer and downgrade the overall size of .configs or gather critical settings in the single place as a maintainer.

The rules are located in rules.config by default and are very self-descriptive:

[
    {inets, [
        {some_value, {ref, env_patcher, [some_value]}}
    ]},

    {sasl, [
        {some_value, {ref, env_patcher, [error_logger]}}
    ]}
].

Given the first rule you declare that the application inets will be told that its enviroment variable some_value should be equal to one under application env_patcher at {some_value, Value}. The same story with the second rule but for the application sasl.

You may specify fixed values too:

[
    {inets, [
        {some_value, {value, 42}}
    ]}
].

And from now you may specify conditional clauses in the form:

{some_value, {clause, {some_app, [flag]}, {value, 42}}},
{some_value, {clause, {some_app, [complex_var], {0, any, [complex, value]}}, {ref, some_app, [another]}}}

They mean exactly what they say. Given the first one it says: set some value to 42 when flag environment variable upon application some_app is set to true. Given the second one: let some value be equal to variable another under application some_app when complex_var environment variable upon application some_app is set to {0, any, [complex, value]}.

Consult sample configuration files in the repository for the details you are intrested in.

Building and configuring

In order to build a project you should execute something like that:

git clone git://github.com/keynslug/envpatcher.git
cd envpatcher
make compile

Then consider consulting sample configuration files in the repository.