## Part 2: Scaling the Team and Deploying to Production Project Insight is a success. The team is growing, and the application needs to be deployed for real users. These new challenges require new tools that build upon the solid foundation Alex and Ben have already created. ### Chapter 3: The Polyglot Developer and the Universal Tool (`asdf`) The team hires Chloe, a talented frontend developer, to build a web interface for Project Insight. Her part of the project is written in Node.js. Now the team faces a new complexity: - The backend needs Python 3.10.13, managed by `pyenv` and a `.python-version` file. - The frontend needs Node.js 18.17.1, managed by `nvm` and a `.nvmrc` file. Having two different version managers with two different configuration files feels clunky. Alex discovers the perfect solution: **`asdf`**, a single, extendable tool for managing the versions of _all_ their languages. #### Step 1: Migrating to a Single Source of Truth The team decides to standardize on `asdf`. Alex removes the old `.python-version` file. He then creates a single, new file called `.tool-versions`. This file will now be the universal source of truth for all runtime versions in the project. ``` # .tool-versions python 3.10.13 nodejs 18.17.1 ``` #### Step 2: Chloe's Onboarding Experience Chloe's setup is now incredibly simple. She only needs to install one tool: `asdf`. After cloning the project, her workflow is seamless. ``` # Chloe clones the project and enters the directory $ git clone https://github.com/alex/project-insight.git $ cd project-insight # She tells asdf to install whatever the project needs. # asdf reads the .tool-versions file and sees it needs Python and Node.js $ asdf install Installing python 3.10.13... Installing nodejs 18.17.1... ``` With one command, `asdf` installs the exact versions of both Python and Node.js. Chloe can now run the Python backend and the Node.js frontend, confident that her runtimes match the project's requirements perfectly. The team has successfully scaled its local development workflow.