Shim Wrapper

Note: Terraspace 0.5.0 and above requires bundler/setup earlier in its bootup process and no longer requires a shim. These docs are kept around for posterity. They will be eventually removed.

If you are seeing an annoying “warning: already initialized constant” like so:

$ terraspace up demo
/Users/me/.rbenv/versions/2.7.1/lib/ruby/2.7.0/json/version.rb:4: warning: already initialized constant JSON::VERSION
/Users/me/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/json-2.3.1/lib/json/version.rb:4: warning: previous definition of VERSION was here
/Users/me/.rbenv/versions/2.7.1/lib/ruby/2.7.0/json/version.rb:5: warning: already initialized constant JSON::VERSION_ARRAY
/Users/me/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/json-2.3.1/lib/json/common.rb:136: warning: previous definition of UnparserError was here
Building .terraspace-cache/us-west-2/dev/stacks/demo

This is due to bundler not loading until a little later. Here are the options for removing the warning:

  1. Prepend bundle exec in front of all terraspace commands
  2. Run bundle clean with your terraspace project. Note this can break other gems on your system.
  3. Use a shim wraper for terraspace

The current recommended approach #3, a wrapper shim. You only have to set up the shim once.

Shim Wrapper

Here’s a wrapper shim that will work with rbenv. We’ll create it at ~/bin/terraspace


eval "$(rbenv init -)"
if [ -f config/app.rb ]; then
  exec bundle exec terraspace "$@"
  exec terraspace "$@"

Make the file executable:

chmod a+x ~/bin/terraspace

Then add ~/bin to your PATH in your ~/.bash_profile

export PATH="~/bin:$PATH"

The wrapper shim will prepend bundle exec whenever in a Terraspace project folder with a Gemfile. It will not prepend bundle exec outside of a Terraspace project. For example, if you are using terraspace new generators.

Generating the Shim Wrapper

You can also use terraspace to generate the shim wrapper.

terraspace new shim

You’ll see something like this:

$ terraspace new shim
      create  /usr/local/bin/terraspace
       chmod  /usr/local/bin/terraspace

If you want to specify the path where you want the shim to be saved like so:

terraspace new shim --path ~/bin/terraspace

Rbenv Shim Slowness

If you are using rbenv, it can be slow on some systems. You may want to consider replacing the shim that rbenv generates with a faster one. Here’s an example:


#!/usr/bin/env bash
EXE=$(gem which terraspace | sed 's|lib/terraspace.rb|exe/terraspace|')
if [ -f config/app.rb ]; then
  exec bundle exec $EXE "$@"
  exec $EXE "$@"

More tools: