Explicitly declare and isolate dependencies
Most programming languages have their designated platforms for sharing and posting system packages. For instance, Ruby utilizes Rubygems.
Each library can be installed through what we refer to as "site-packages," which serve system-wide, or by explicitly declaring them within our app's scope, a practice known as "vendoring."
The Twelve-Factor methodology does not rely on the implicit existence of system-wide packages. Instead, dependencies should be declared within our application via a declaration manifest. Additionally, it employs dependency isolation tools during execution to prevent any implicit dependencies from seeping in from the surrounding system. For instance, Ruby employs the Gemfile manifest format for dependency declaration and bundle exec for dependency isolation.
Explicitly declaring dependencies brings the benefit of simplifying setup for new developers joining the app. A new developer can clone the app's codebase onto their local machine, needing only the language runtime and the installed dependency manager as prerequisites. Consequently, they can set up everything required with a single command, such as bundle install for Ruby/Bundler.
The Twelve-Factor methodology also does not rely on the implicit existence of system tools like curl or ImageMagick, for example. Even though these tools may be prevalent in many systems, there's no assurance that they will exist on all systems where the app may run in the future, or that they will be compatible with the app. All of those should be "vendored" into the app.
This Twelve-Factor App post series is a means for me to consolidate the knowledge I've gained while studying these rules. Please feel free to visit [the site (https://12factor.net/) for more detailed explanations. That's all folks!
Top comments (0)