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Installing ScalaPB

To automatically generate Scala case classes for your messages add ScalaPB's sbt plugin to your project. Create a file named project/scalapb.sbt containing the following lines:

addSbtPlugin("com.thesamet" % "sbt-protoc" % "1.0.6")

libraryDependencies += "com.thesamet.scalapb" %% "compilerplugin" % "0.11.21"

Add the following settings to your build.sbt:

Compile / PB.targets := Seq(
  scalapb.gen(
    scala3Sources = scalaBinaryVersion.value == "3"
  ) -> (Compile / sourceManaged).value / "scalapb"
)

// (optional) If you need scalapb/scalapb.proto or anything from
// google/protobuf/*.proto
libraryDependencies ++= Seq(
    "com.thesamet.scalapb" %% "scalapb-runtime" % scalapb.compiler.Version.scalapbVersion % "protobuf"
)

The scala3Sources setting selects Scala 3 syntax when the project uses Scala 3, and Scala 2 syntax otherwise, including when cross-building. It ensures that generated wildcard types use ? on Scala 3, which is required with underscore kind-projector compiler settings such as those enabled by sbt-typelevel.

ScalaPB will look for protocol buffer (.proto) files under src/main/protobuf, which can be customized. Running the compile command in sbt will generate Scala sources for your protos and compile them.

For additional configuration options, see ScalaPB SBT Settings.

Running Standalone Using scalapbc​

If you would like to compile protocol buffers into Scala outside SBT, you can use scalapbc (ScalaPB compiler).

See ScalaPBC.

Running from Maven​

Use protoc-jar-maven-plugin with the protoc-gen-scala plugin artifact to generate Scala code in your Maven build. Check out the ScalaPB Maven example.

Next:​

Read about the Generated Code.