benschw / di-duck-types-clean-code-ex

Example repo to walk through layering in dependency injection and duck typing for cleaner, more testable code

default

• Shows straight forward way to discover an address
• To test, you have to build and run against an instance of Consul

di

• Refactored to have a Discover function into which you can inject your dns resolver
• Makes testing easier, but you still can't test Discover without also running Consul and resolving a real SRV record

duck

• Adds AddressGetter interface so that tests can use a stub implementation
• We don't want to test dns-clb-go, only our implementation. This facilitates that
• Didn't have to include unnecessary interface in core library
• Allows implementation to only depend on the parts of the library we are using (cleaner code reuse)

server

• Example client/server implementation where client discovers server's address
• AddressGetter interface allows different load balancer implementations to be injected
• We can component test our web service locally without running Consul