jdwolk / chenv

chenv (CHange ENVironment) is a CLI tool for managing config changes to multiple codebases simultaneously. Sort of a meta-config tool.

chenv

chenv (CHange ENV) is a CLI tool for managing config changes to multiple codebases simultaneously. Sort of a meta-config tool.

Imagine you have 3 codebases for a project called foobar:

• Foobar API
• Foobar App
• Foobar web frontend

Each codebase uses its own text-based config format, or (WORSE) uses hardcoded config variables.

Now imagine you want to switch your entire stack to point to a staging environment.

Don't trip. chenv got you:

$ chenv foobar staging

BAM!!! Just like that, configs for all of your codebases now point to staging.

How do you know?

$ whichenv foobar // => staging

Awwwww yeah.

Install

Copy the appropriate binaries in /bin to somewhere on your $PATH, i.e. for mac:

$ cp ./bin/chenv-macos /usr/local/bin/chenv && cp ./bin/whichenv-macos /usr/local/bin/whichenv

Or build it yourself:

$ npx pkg ./chenv.js && npx pkg ./whichenv.js

Then move the built binaries wherever you need them.

Project Setup

To set up a new project, make a new project directory under ~/.chenv:

$ mkdir ~/.chenv/foobar

Then, for each env, create an executable script named <NAME OF ENV>.sh, i.e.:

# in ~/.chenv/foobar/staging.sh:

SCRIPT_DIR="$HOME/.chenv/foobar"

##############
# Foobar API #
##############
API_CONFIG="~/projects/foobar/api/.env"

cp "$SCRIPT_DIR/.staging.env" $API_CONFIG

##############
# Foobar App #
##############
APP_DIR="~/projects/foobar/app"
APP_CONFIG="$APP_DIR/app.config.js"

cd $APP_DIR && git checkout -- $APP_CONFIG && cd -;

sed -i '' "s/.*var apiUrl=.*$/    var apiUrl = \'http:\/\/foobar.staging.com/api\';/" $APP_CONFIG

#######################
# Foobar Web Frontend #
#######################
WEB_DIR="~/projects/foobar/web"
WEB_CONFIG="$APP_DIR/config.json"

cp "$SCRIPT_DIR/config.staging.json" $WEB_CONFIG

Now when you run chenv foobar staging the above shell script will be run.

FAQ

• Q: is chenv a build tool (like make, scons etc)?

  A: No. Eh, well, not really. Not unless use it like a build tool. It's more of a meta-config tool. If you use it like a build tool then yes, it's a build tool.

• Q: What does chenv actually do?

  A: I'm gonna let you in on a little secret. chenv is stupidly simple — SO RIDICULOUSLY simple. It just runs shell scripts in a prespecified location (~/.chenv).

• Q: You know the name chenv has been used before right?

  A: Yeah. But a.) none of those tools do what I want and b.) it's SUCH a great name for this util!

Caveats

• It probably goes without saying, but chenv is a band-aid. Ideally your codebases don't hardcode config vars and/or they all read configs from the same places. You should probably fix that. When you can't, chenv is your friend.

• chenv doesn't know anything about the shell scripts for the env you're switching to. It just runs them. So be careful.

• The scripts for each env should probably git checkout the config file you're munging for each codebase so you have a clean starting point to munge. Otherwise you won't be able to cleanly switch between multiple envs.

• Since your env scripts probably munge your configs, you probably shouldn't check those configs back into source control. Like I said above, chenv is a band-aid.

• When possible, you should probably just copy over example config files to their destinations instead of munging via sed but it's not always possible.

• To make copying files easy, you probably want to adopt a naming convention of <NAME OF FILE>.<ENV>.<EXTENSIONS>. Then you just copy files for the correct env.

• You probably want to check your chenv configs into source control since it's a bit of work to write those configs for each env. If you do this, make sure you check into a PRIVATE REPO (for obvious reasons...)

TODO

• Use a proper CLI framework
• Add a config option or tool to generate new skeleton project