Boot Hooks
If you need to hook into the Terraspace boot process super-early on, Terraspace boot hooks are designed for that.
- They run very early in the Terraspace boot process even before plugins are loaded.
- They are useful for setting shared global values like env vars.
- Boot hooks are ruby files that get required. It’s nice and simple. There’s no interface to learn.
Hooks
Terraspace will searches 2 files in the config folder. If the files exist, they will be ran in this order.
- config/boot.rb: Always runs.
- config/boot/TS_ENV.rb: Runs based on the env. IE:
TS_ENV=dev=>config/boot/dev.rb
Both files are required and ran if they both exists. Since the TS_ENV one runs second, it can be used to override previously set values.
Example: Default TS_ENV
If you prefer a different default than TS_ENV=dev.
config/boot.rb
ENV['TS_ENV'] ||= 'development'
This changes the default for everyone using the project, but still allows them to control the default by adding export TS_ENV=development to their ~/.bash_profile.
Example: Auto-Switch AWS_PROFILE
One useful example is switching AWS_PROFILE based on the TS_ENV. Example:
config/boot/dev.rb
ENV['AWS_PROFILE'] = 'dev'
This example is for AWS, but you can can do similiar switch logic with GOOGLE_APPLICATION_CREDENTIALS, etc.
Other Examples
Users have done interesting things with the boot hook. Here’s are some community examples:
Boot Ordering
This config/boot.rb hooks run the earliest. Here’s an overview of the boot ordering:
- config/boot.rb
- dotenv files
- plugins: IE: aws, azure, google
- app/inits: Initializers
Please refer to the source code for more details on boot ordering: terraspace/booter.rb
