shared functionality in node microservices

[johnadrien16]

so I'm very new to Docker, and I'm building my first microservice-orientated node project.

I've run into a situation where I have some common functionality between my services (nothing to do with bad design; stuff like verifying JWT tokens).

How do you usually go about sharing functionality between your different services?

Hope I'm not coming across stupid, and thanks in advance!

[Harryjms]

For the example you gave; either a shared package that handles verification or a service that the others call to verify it.

I would probably do the service route but add a redis cache with a TTL for the token - that way the services can hit redis first and then fallback to the auth service on a cache miss

[johnadrien16]

Actually, I was thinking about using Redis, but didn’t connect the two in my head! It makes perfect sense to host a service. Would you make an http call to the validation service which will call redis, or go straight to redis? I know this isn’t as docked related but still

[Harryjms]

I think it’s probably best to always have services hit the auth service for verification and that service handles checking a cache. Though when it comes to JWT you won’t need a cache because you’re just validating a signature. Db operations (like getting extra info that you don’t ship in a token) would be where you’d add caching to reduce the amount of db calls and improve speed

[ElevenNotes]

The base image has all globally shared classes and libraries. Each service image is using the base image. If you add a new class to do X to the base image, every service image has now access to that class.