/zio-graphql-stack

Primary LanguageScala

General

PoC for a GraphQL microservice. Explore Scala 3, particularly braceless syntax.

Following capabilities:

  • Scala 3 (braceless)
  • Federation support
  • Handle n+1 queries problem
  • Query ClickHouse
    • Custom decoders for CH datatypes
    • Automatic decoding to Scala types
  • Maybe distributed tracing
  • Maybe caching with Redis
  • Maybe GraalVM native image compilation
  • Maybe runnable image using GraalVM native image

Stack:

  • zio
  • zio-prelude (newtypes)
  • zio-config
  • jedis (redis client, gave up on zio-redis due to missing multi support)
  • zio-telemetry with opentelemtry sdk (distributed tracing)
  • caliban (GraphQL+federation support)
  • zquery (n+1 problem)
  • tranzactio with anorm (zio wrapper for anorm)
  • anorm (Query ClickHouse with nice decoding)
  • sbt-tpolecat for scalac configuration

Run locally

Local JVM

  • Start ch docker container (cd docker && docker-compose start)
    • Init test data once when ch is up, run init script docker/insert-ch-data.sh
  • Run sbt run

Native image

  • Publish app native image sbt docker:publishLocal
  • Start ch docker container and app native image container (cd docker && docker-compose --profile app start)
    • Init test data once when ch is up, run init script docker/insert-ch-data.sh

Example request

curl --location 'http://localhost:8080/api/graphql' \
--header 'Content-Type: application/json' \
--data '{"query":"query {\n    persons {\n        persons {\n            name\n            address {\n                street\n            }\n        }\n    }\n}","variables":{}}'

Native image

sbt-native-packager docker plugin can be used to create a runnable image ´sbt docker:publishLocal`.

Compile using a container

Compile native image in a container sbt graalvm-native-image:packageBin.

Compile locally

  • Remove graalVMNativeImageGraalVersion := Some("22.3.2") from build.sbt
  • Provide correct path -H:ConfigurationFileDirectories in build.sbt
  • Provide native-image in PATH
  • Run sbt graalvm-native-image:packageBin

Above tested with graalvm-ce-java17-22.3.2.

Endpoints

Http server @ localhost:8080

Endpoint Description
/api/graphql GraphQL api
/graphiql GraphiQL
/metrics Prometheus metrics
/health/liveness Liveness
/health/readiness Readiness