1.
Microservices in Spray
Łukasz Sowa @luksow
Jacek Głodek @jacekglodek

2.
Spray
● Client- & server-side REST/HTTP libs
● Multiple layers – low-level to DSL
● Really fast (check out benchmarks!)
● „Acquired” by Typesafe
● Spray => akka-http
– Reactive streams
– New building block for Play
● Well-suited for REST microservices

3.
Spray
● HttpRequest => HttpResponse
● Different levels of abstraction, focus: DSL
● Key concepts
– Routing directives
– Marshalling

4.
Spray - routing
● Directives
– Transform, extract, filter, side-effecting
– Composable
– Concatanable

5.
Spray - routing
● Useful directives
– path, pathPrefix
– get, post, put, delete, patch
– parameters
– formFields
– entity
– logRequestResponse
– complete (!)

6.
Coding!
● Try out at least following combinations:
1) pathPrefix + path (with extracting)
2) get + parameters
3) post + formFields

7.
Spray - marshalling
● Return anything that is marshalable
● String (OK(value))
● HttpEntity
● Option[T] (OK(T) vs. NotFound(T))
● Either[A, B] (OK(A) vs. OK(B))
● Future[T] (OK(T) – success vs. InternalServerError)
● Loads of predefined stuff, ex. JSON
● You can write your own!

8.
Coding!
1) Try Option & Future marshallers
2) Use JSON marshaller to return JSON
3) Combine 1) & 2)
4) Use entity directive
5) Add validation
6) Time to create real microservices, yay!

9.
Registration microservice
● POST /auth/account
● JSON { login: l, password: p, passwordConfirmation: pC }
● OK + { login: l, authToken: aT }
● BadRequest
● POST /auth/session
● Form login: l, password: p
● OK + { login: l, authToken: aT }
● Forbidden
● GET /auth/account (H: AuthToken: aT)
● OK + { login: l, authToken: aT, … }
● Forbidden

10.
Links microservice
● Authenticate all the things! (Forbidden)
● POST /links/
● JSON { url: u, description: d }
● Save: ^ + date + author
● GET /links/:id
● JSON { url: u, description: d, date: dt, author: a }
● GET /links?limit=N&offset=M
● JSON { links: [url] }