Building testable APIs using functions & meshes

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@miciek @miciek Michał Płachta www.michalplachta.com www.michalplachta.com Building testable APIs using functions & meshes @miciek

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@miciek Reinventing the Test Pyramid ? ? ?

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@miciek New Testing Pyramid: Part I ? ? Unit?

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@miciek Unit Tests

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@miciek What we really want... Fast! Stable! Quick to read/write! Documentation

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@miciek Mocking and Stubbing... Mocking interfaces with 3, 4, 5+ functions... Mocking interfaces with 0 or 1 functions...

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@miciek Part I ? ? Fast, Stable, Real

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@miciek Pac-Man Game Server ? Engine ?

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@miciek Pac-Man Engine Domain

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@miciek Pac-Man Engine Domain

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@miciek Pac-Man Engine Domain

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@miciek Pac-Man Engine Domain

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@miciek Immutable Pac-Man Engine GameState movePacMan GameState current new GameState changeDir GameState current new

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@miciek TDDing Pac-Man Engine

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@miciek TDDing Pac-Man Engine

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@miciek TDDing Pac-Man Engine Live coding

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@miciek TDDing Pac-Man Engine

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@miciek TDDing Pac-Man Engine

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@miciek TDDing Pac-Man Engine

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@miciek TDDing Pac-Man Engine

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@miciek Pure & Immutable

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@miciek TDDing Pac-Man Engine

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@miciek New Testing Pyramid: Part II ? Service? Integration? Fast, Stable, Real

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@miciek Pac-Man Game Server Engine HTTP ?

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@miciek HTTP layer requirements POST /games { “gridName”: “msPacManLevel1” } 200 OK { “gameId”: 1 } 200 OK { "pacMan": { "position": { "x": 2, "y": 1 }, "direction": "east" } } GET /games/1

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@miciek What we always want... Fast! Stable! Quick to read/write! Documentation

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@miciek Testing HTTP layer Live coding

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@miciek Fast, Stable, Real, Documenting

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@miciek Separation of Concerns I only know what I NEED to know...

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@miciek Pac-Man Game Server State Engine HTTP

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@miciek Requirements State holds multiple games at once updates (ticks) all the games every 200ms

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@miciek Holding multiple games at once A concurrent hash-trie or TrieMap is a concurrent thread-safe lock-free implementation of a hash array mapped trie. - Scala documentation http://lampwww.epfl.ch/~prokopec/ctries-snapshot.pdf

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@miciek Holding multiple games at once

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@miciek Ticking all the games every 200ms https://monix.io/docs/2x/execution/scheduler.html#schedule-with-a-delay

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@miciek Quick integration tests Live coding

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@miciek New Testing Pyramid: Part II ? Service? Integration? Fast, Stable, Real

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@miciek New Testing Pyramid: Part II ? Fast, Stable, Real

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@miciek Only one service so far... State Engine HTTP Backend service

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@miciek Communicating Services Backend service Frontend service Service Discovery Circuit Breaking Security Scalability & Routing Telemetry

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@miciek Testing on Production Backend service PROD Frontend service PROD Service Discovery Circuit Breaking Security Scalability & Routing Telemetry App Container App Container

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@miciek Testing on Production… in Isolation? Backend service PROD Frontend service PROD Sidecar Sidecar Service Discovery Circuit Breaking Security Scalability & Routing Telemetry App Container App Container

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@miciek Service Mesh Backend service PROD Frontend service PROD Sidecar Sidecar Another Service PROD Sidecar Service Mesh Control Plane

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@miciek Testing on Production… in Isolation Backend service PROD Frontend service PROD Sidecar Sidecar Backend service v2 (test) Sidecar Routing only test traffic to v2

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@miciek Isolated tests on Production Live coding

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@miciek New Testing Pyramid Real Fast, Stable, Real No HTTP Servers Function parameters Abstracting over data Routing test traffic Isolated tests on PROD

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@miciek Summary functional programming helps with separation of concerns service meshes may help with isolated testing ...but they are new & unproven

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@miciek Next steps ➔ Play around with https://www.github.com/miciek/pacman-multiplayer-fp project ➔ Play with Kubernetes and Istio using Katakoda https://www.katacoda.com/courses/istio/deploy-istio-on-kubernetes

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@miciek @miciek www.michalplachta.com

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@miciek @miciek Michał Płachta www.michalplachta.com www.michalplachta.com Building testable APIs using functions & meshes @miciek github.com/miciek/pacman-multiplayer-fp