Building Great APIs With gRPC - GoLab 2018

It generally takes lots of time and decisions to create an HTTP API, but when you want to get productive fast, you want to skip as many steps as possible. I’ve been working with gRPC for almost a year and I can guide you from first lines of the code up to request tracking or exposing it via HTTP.

When you want to build a usable API these days, you immediately think about creating an HTTP server and you start from there. You may want to use a standard library or a handful of popular libraries that help you with that. What if I told you that there is an alternative? With gRPC you can build fast, elegant and reliable solutions which, in the end, could also be exposed via standard HTTP server. I would like to guide you from the first steps, through various levels of compexity, to request tracking while mainaining an elegant, readable and testable codebase.

Transcript

1. Building great 
 APIs
 with gRPC Paweł Słomka
2. @pawel_slomka ABOUT ME • Blogger at mycodesmells.com • Go developer at Ingrid • Co-organizer of GoWroc meetup • Runner ! • Millenial @pawel_slomka
3. @pawel_slomka WHAT IS gRPC?
4. @pawel_slomka gRPC stands for… gRPC Remote Procedure Call
5. @pawel_slomka Building Blocks protocol buffers HTTP/2
6. @pawel_slomka What do we need?
7. @pawel_slomka fromProto()
8. @pawel_slomka Protocol Buffers It all starts with service and message definitions…
9. @pawel_slomka Protocol Buffers …then we generate code with protoc command…
10. @pawel_slomka Protocol Buffers …finally, the messages are ready…
11. @pawel_slomka Protocol Buffers …and so are the server and client stubs!
12. @pawel_slomka serveGRPC()
13. @pawel_slomka Serving gRPC Implementing handlers
14. @pawel_slomka Serving gRPC Starting gRPC server
15. @pawel_slomka runClient()
16. @pawel_slomka Calling gRPC Client implementation is autogenerated, you just need to establish a connection:
17. @pawel_slomka securityOn()
18. @pawel_slomka HTTP/2 & TLS HTTP/2 does not enforce TLS, but all major browsers decided not to support it for insecure connections. Go automatically upgrades to HTTP/2 if you run your servers with TLS. gRPC does not require TLS, but it’s better be safe than sorry, we’ll use it anyway!
19. @pawel_slomka Making it secure We start by generating certificate files…
20. @pawel_slomka Secured server …which we use to start a server…
21. @pawel_slomka Secured client call …and to call it from the client.
22. @pawel_slomka test()
23. @pawel_slomka Testing gRPC handler Handlers are functions that are easy to test
24. @pawel_slomka Integration tests With generated clients, integration tests are simple, too
25. @pawel_slomka serveHTTP()
26. @pawel_slomka Why HTTP? • While gRPC is cool, it’s not that popular (yet?) • Clients still prefer HTTP API • Need for automatic translation • github.com/grpc-ecosystem/grpc-gateway
27. @pawel_slomka HTTP-aware proto • First, we need to tweak proto a bit…
28. @pawel_slomka Generating *.pb.gw.go • …add flag to protoc command…
29. @pawel_slomka Serving the Gateway • …start HTTP server in a goroutine…
30. @pawel_slomka HTTP-aware proto • …and see the results!
31. @pawel_slomka serveDocs()
32. @pawel_slomka Need for docs • Having an API is not enough • Generating Swagger (JSON) • Swagger UI
33. @pawel_slomka HTTP-aware proto • One more tweak to protoc…
34. @pawel_slomka Serving Swagger JSON • …then we can serve generated Swagger JSON…
35. @pawel_slomka Swagger JSON • …and see our API documentation:
36. @pawel_slomka Serving Swagger UI • But that’s not all! We can serve Swagger UI template…
37. @pawel_slomka HTTP-aware proto • …and see this!
38. @pawel_slomka go runPython()
39. @pawel_slomka Next steps • Not everyone is using Go • Make life easier for the QA • Generate client code eg. in Python?
40. @pawel_slomka Extras with Postman Importing collection from Swagger URL…
41. @pawel_slomka Code generation …see lots of choices…
42. @pawel_slomka Code generation …choose eg. Python and copy that into a file…
43. @pawel_slomka Testing out It cannot be THAT simple!
44. @pawel_slomka SUMMARY
45. @pawel_slomka What we did (1/3) • Started with simple protobuf declarations and • Generated Go code • Server stubs • Working client code
46. @pawel_slomka What we did (2/3) • With grpc-gateway • Generate HTTP API • Swagger docs
47. @pawel_slomka What we did (3/3) • With Postman • Allow QA use our API • Generated client in Python
48. @pawel_slomka THANK YOU!