scala-steward / scala-zio-example

Scala ZIO example

ScalaZioExample project

Prerequisites

• sbt
• Docker
• docker-compose v2 or higher (Note for macOS: enable Use Docker Compose V2 in Docker Preferences)
• OpenJDK 11 or above

Setting up

Scalafmt Editor support

• VS Code
• Intellij IDEA

Usage

• Start MySQL in docker container

  Note: flags and options mean:

  • use detached mode
  • wait for all containers to be healthy
  • remove volumes on exit

  docker compose up -Vd --wait mysql

• Fill db by demo data

  sbt dev "scalaZioExample/runMain org.organization.utils.DemoDb"

• Run

  sbt dev scalaZioExample/run

• Run in live reload mode

  sbt dev ~scalaZioExample/reStart

• When done, remove docker containers, networks and volumes

  docker compose down -v

• Clean build artifacts and recompile (just in case)

  sbt clean compile

• Run tests

  sbt test

• Check for dependency updates (just in case)

    sbt dependencyUpdates

Swagger-UI

Go to http://localhost:8080/docs

Scalafix

• sbt scalafix – run linter, check all files, fail on warnings

Tpolecat

There are several modes: dev, ci, release. In dev mode "fatal warnings" are disabled, so you will be able to see warnings, but they won't prevent code from compiling.

• You can change tpolecat plugin mode in sbt interactively, e.g: sbt ci or sbt dev
• You can prepend your commands with mode, e.g: sbt ci test or sbt dev test
• You can set mode via env variable, e.g: SBT_TPOLECAT_DEV=true sbt compile, SBT_TPOLECAT_CI=true sbt compile, or SBT_TPOLECAT_RELEASE=true sbt compile

Migrating to ZIO2

• Apply the Zio2Upgrade scalafix rule, as described in the migration guide
• Update dependencies
  • Bump versions on core zio dependencies (zio, zio-streams, zio-test)
  • Remove pins on dependencies which were pinned to prevent a transitive dependency on ZIO2
  • For other ZIO libraries, check their respective docs for a way to correctly add a version with ZIO2 support. Some require you to specify a different organization name or artefact ID:
    • "io.d11" % "zhttp_2.13" -> "dev.zio" %% "zio-http"
    • "com.softwaremill.sttp.tapir" %% "tapir-zio1-http-server" -> "com.softwaremill.sttp.tapir" %% "tapir-zio-http-server"
    • "io.github.scottweaver" %% "zio-testcontainers-mysql" -> "io.github.scottweaver" %% "zio-2-0-testcontainers-mysql"
• Fix the remaining compilation errors referring to the migration guide.
• See PR with all the changes listed above

Additional resources

Setting up debugger in Intellij IDEA