plaflamme / sbt-protoc

SBT plugin for generating code from Protocol Buffer using protoc

sbt-protoc

This plugin uses protoc to generate code from proto files. This SBT plugin is meant to supersede sbt-protobuf and sbt-scalapb.

Highlights

1. Uses protoc-jar by default (no need to install protoc)
2. Generates source code directly under src_managed by default (works better with IntelliJ)
3. Supports compiling protos in both test and compile configuration.
4. Supports JVM-based code generators. Write your own custom code generator.
5. Straightforward: No PB.protobufSettings, packaged as auto-plugin.

Installation

Step 1: create project/protoc.sbt with:

addSbtPlugin("com.thesamet" % "sbt-protoc" % "0.99.25")

libraryDependencies += "com.thesamet.scalapb" %% "compilerplugin" % "0.9.0"

Step 2: add to build.sbt:

If you only want to generate Java code:

PB.targets in Compile := Seq(
  PB.gens.java -> (sourceManaged in Compile).value
)

A version of protobuf-java is going to get added to the runtime dependencies. To explicitly set this version you can write:

PB.targets in Compile := Seq(
  PB.gens.java("3.7.0") -> (sourceManaged in Compile).value
)

For ScalaPB:

PB.targets in Compile := Seq(
  scalapb.gen() -> (sourceManaged in Compile).value
)

To generate Java + Scala with Java conversions:

PB.targets in Compile := Seq(
  PB.gens.java -> (sourceManaged in Compile).value,
  scalapb.gen(javaConversions = true) -> (sourceManaged in Compile).value
)

Download plugins that are available on maven repository

To download an artifact and use it as a code generator plugin:

libraryDependencies += "io.grpc" % "protoc-gen-grpc-java" % "1.23.0" asProtocPlugin()

PB.targets in Compile := Seq(
  PB.gens.plugin("grpc-java") -> (sourceManaged in Compile).value,
)

Note the asProtocPlugin provided to the dependency, this is equivalent to:

libraryDependencies += "io.grpc" % "protoc-gen-grpc-java" % "1.23.0" % "protobuf" artifacts(
  Artifact("protoc-gen-grpc-java", PB.ProtocPlugin, "exe", "linux-x86_64"))

with the operating system replaced accordingly to the system you are running on. You can use the full syntax in case the code generator you are trying to download follows a different pattern.

To invoke a plugin that is already locally installed

PB.targets in Compile := Seq(
  PB.gens.plugin(name="myplugin", path="/path/to/plugin") -> (sourceManaged in Compile).value / "js"
)

If you need to pass parameters to the plugin, it can be done as follows:

val grpcWebGen = PB.gens.plugin(
  name="grpc-web",
  path="/usr/local/bin/protoc-gen-grpc-web-1.0.7-linux-x86_64"
)

PB.targets in Compile := Seq(
  (grpcWebGen, Seq("mode=grpcwebtext")) -> (sourceManaged in Compile).value / "js"
)

Step 3: Put some protos in src/main/protobuf and compile

Additional options

The options below need to be scoped to either Compile or Test (if unsure, you probably want Compile)

Example settings:

// Additional directories to search for imports:
PB.includePaths in Compile ++= Seq(file("/some/other/path"))

// Make protos from some Jar available to import.
libraryDependencies ++= Seq(
  "com.google.protobuf" % "protobuf-java" % "3.7.0" % "protobuf"
)

// Compile protos from some Jar (and make them available to import). Without
// the intrasitive() directory, `protobuf-src` would also unpack and compile
// all transitive dependencies of the package. This could lead to having
// duplicate class files, if another library is already providing compiled
// classes for your dependencies.
libraryDependencies ++= Seq(
  "com.google.api.grpc" % "proto-google-common-protos" % "1.17.0" % "protobuf-src" intransitive()
)

// Changing where to look for protos to compile (default src/main/protobuf):
PB.protoSources in Compile := Seq(sourceDirectory.value / "somewhere")

// Additional options to pass to protoc:
PB.protocOptions in Compile := Seq("-xyz")

// Excluding some proto files:
excludeFilter in PB.generate := "test-*.proto"

// Rarely needed: override where proto files from library dependencies are
// extracted to:
PB.externalIncludePath := file("/tmp/foo")

// By default we generate into target/src_managed. To customize:
PB.targets in Compile := Seq(
  scalapb.gen() -> file("/some/other/dir")
)

// Use a locally provided protoc (in 1.x):
PB.protocExecutable := file("/path/to/protoc")
// In <1.0:
PB.runProtoc in Compile := (args => Process("/path/to/protoc", args)!)

// Prevents the plugin from adding libraryDependencies to your project
PB.additionalDependencies := Nil

// Before version 0.99.15, when compiling in Windows, Python was used to bridge
// protoc and this JVM. To set the path for Python.exe:
// Note that this must be Python2 and not Python3.
// Since version 0.99.15 this option has no effect, and will be removed in a
// future version.
PB.pythonExe := "/path/to/python.exe"

Protos in other configs

This plugin supports generating protos in the Test config. That means, that you can put protos under src/test/protobuf and have it generated and compiled under the Test configuration, so the generated code is only available to your tests, but not to your main code.

To do that, add:

PB.targets in Test := Seq(
    PB.gens.java("3.11.4") -> (sourceManaged in Test).value
)

If you want to have protos in some other configuration (not Compile or Test), for example IntegrationTest you need to manually add the plugin default settings in that configuration:

configs(IntegrationTest)

inConfig(IntegrationTest)(sbtprotoc.ProtocPlugin.protobufConfigSettings)

PB.targets in IntegrationTest := Seq(
    PB.gens.java("3.11.4") -> (sourceManaged in IntegrationTest).value
)

Debugging

Show proto files extracted and where there are comming from:

sbt> set logLevel := Level.Debug
sbt> protocUnpackDependencies