singleton

[hollow marten]

I have a singleton analytics client that I use for logging. I initialize it within each HTTP action, then shut it down when before the http action is done. I notice it's not available within another action. Is this expected? Each action has its own context, and my action is actually running in a Node environment instead of the default Convex environment, so maybe that plays a part. right?

Does this mean I should avoid using Singleton?

[paper beacon]

Hi @hollow marten. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

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You're correct in your understanding. The behavior you're experiencing with your singleton analytics client is expected in Convex, especially considering you're using Node.js actions. Let me explain why:

1. Isolated Contexts: Each action in Convex runs in its own isolated context. This means that state or objects initialized in one action are not automatically available in another action Functions > Actions > The action constructor (https://docs.convex.dev/functions/actions#action-context).

2. Node.js Runtime: You mentioned that your action is running in the Node.js environment. This is significant because Node.js actions in Convex have additional isolation. As stated in the documentation, "Use of the Node.js environment is restricted to action functions only" Functions > Runtimes > Node.js runtime (https://docs.convex.dev/functions/runtimes#nodejs-runtime).

3. Lifecycle of Actions: Actions are designed to be self-contained units of work. When an action completes, its context is cleaned up, which includes any objects or state initialized within it Functions > Actions > Dangling promises (https://docs.convex.dev/functions/actions#dangling-promises).

Regarding the use of singletons, it's generally advisable to avoid relying on them in Convex actions, especially across different actions. Instead, consider these approaches:

1. Initialize the client within each action where it's needed. This ensures each action has its own fresh instance.

2. If you need to share data or state between actions, use Convex's built-in mechanisms like the database or scheduled functions Functions > Actions > Action context (https://docs.convex.dev/functions/actions#action-context).

3. For logging specifically, Convex provides built-in logging capabilities that you might want to leverage instead of a custom analytics client Auth > Debugging (https://labs.convex.dev/auth/debugging).

Remember, the Convex architecture is designed to promote scalability and reliability by keeping functions isolated. While this might require adjusting how you structure your code, it ultimately leads to more predictable and maintainable applications.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: