Mobile Stack Hooks Platform
Developing a hook
Developers must implement hooks in TypeScript and integrate them with one of the existing per-hook type GitHub repositories.
We hope to make hooks easy to develop but also want to easily iterate on the Mobile Stack Hooks Platform for developing and deploying hooks. For now we require all deployed hook code to be located in Mobile Stack GitHub repositories so we can help improve and maintain them (e.g., when we implement breaking changes to the platform), but in the future we expect to impose fewer requirements on how hooks are developed.
Execution environment
Each hook executes in a Node.js 20 environment. Currently we implement this as a Google Cloud Function, which has several important implications:
- statelessness: your hook cannot store data locally (e.g., in memory)
- timeout: the app will timeout waiting for a hook to execute
- background: the app destroys the hook environment after it returns so it's not possible to continue computation in the hook after returning a result
Eventually every hook will execute in a sandboxed JavaScript
environment (like Secure ECMAScript
(SES), which
MetaMask Snaps use) and we encourage hook developers to have that
high-level model in mind when developing their hooks and avoid
depending on Google Cloud Function specific attributes (e.g., reading
the reserved environment variable K_SERVICE)
Deploying a hook to a Mobile Stack app
To deploy your hook you must:
- submit a PR to the appropriate GitHub repository and work with a Valora engineer to merge your PR; and
- confirm with a Valora engineer that they added your hook to the list of enabled hooks.