Sharing code and schema between microservices

Question

If you go for a microservices architecture in your organization, they can share configuration via zookeeper or its equivalent. However, how should the vario

Answer 1

The "purest" approach, i.e. the one that gives you the least amount of coupling, is to not share any code.

If you find that two services (call them A and B) need the same functionality, your options are:

• split if off as a separate service C, so A and B can use C
• bite the bullet and duplicate the code

While this may sound awkward, you avoid the (not uncommon) problem of creating a "utility" or "common" or "infrastructure" library which everyone depends on, and which is then really hard to upgrade and change (i.e. which indirectly couples the services).

In practice, as usual, it's a tradeoff.

• If the shared functionality is substantial, I'd go for a seperate service.
• If it's just constants, a shared library might be the best solution. You need to be very careful about backwards compatibility, though.
• For configuration data, you could also implement a specific service, possibly using some existing technology such as LDAP.
• Finally, for simple code that is likely to evolve independently, just duplicating might be the best solution.

However, what's best will depend on your specific situation and problem.