please supply documentation for Kotlin-DSL of Gradle

[louie-wh]

Is your feature request related to a problem?

Describe the solution you'd like

I want to use grpc-java in my android project with kotlin DSL but no java file generate.

I hava read those doc https://github.com/grpc/grpc-java/pull/5202 https://github.com/google/protobuf-gradle-plugin/blob/master/examples/exampleKotlinDslProject/build.gradle.kts no work!

can supply kotlin dsl example ?

[louie-wh]

this is build.gradle.kts

import com.google.protobuf.gradle.id
import com.google.protobuf.gradle.proto

plugins {
    id("com.android.library")
    id("com.google.protobuf")
}

android {
    namespace = "com.example.car.grpc.proto"
    compileSdk = 33

    defaultConfig {
        minSdk = 16

        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
        consumerProguardFiles("consumer-rules.pro")
    }

    buildTypes {
        release {
            isMinifyEnabled = false
            proguardFiles(
                getDefaultProguardFile("proguard-android-optimize.txt"),
                "proguard-rules.pro"
            )
        }
    }
    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }

    sourceSets {
        getByName("main") {
            proto {
                srcDir("src/main/proto")
            }
        }
    }
}

protobuf {
    protoc {
        // The artifact spec for the Protobuf Compiler
        artifact = "com.google.protobuf:protoc:3.22.3"
    }
    plugins {
        // Optional: an artifact spec for a protoc plugin, with "grpc" as
        // the identifier, which can be referred to in the "plugins"
        // container of the "generateProtoTasks" closure.
        id("grpc") {
            artifact = "io.grpc:protoc-gen-grpc-java:1.57.1"
        }
        id("javalite") {
            artifact = "com.google.protobuf:protoc-gen-javalite:3.0.0"
        }
    }

    generateProtoTasks {
        ofSourceSet("src/main/proto").forEach {
            it.plugins {
                // Apply the "grpc" plugin whose spec is defined above, without
                // options. Note the braces cannot be omitted, otherwise the
                // plugin will not be added. This is because of the implicit way
                // NamedDomainObjectContainer binds the methods.
                // id("grpc") { option("lite") }
                // id("java") { option("lite") }
                id("grpc")
                id("javalite") { }
            }
        }
    }
}

dependencies {

    implementation("androidx.appcompat:appcompat:1.6.1")
    implementation("com.google.android.material:material:1.9.0")
    testImplementation("junit:junit:4.13.2")
    androidTestImplementation("androidx.test.ext:junit:1.1.5")
    androidTestImplementation("androidx.test.espresso:espresso-core:3.5.1")
}

[ejona86]

no work!

What error did you experience?

Remove this:

    sourceSets {
        getByName("main") {
            proto {
                srcDir("src/main/proto")
            }
        }
    }

Use all(), not ofSourceSet().

    generateProtoTasks {
        ofSourceSet("src/main/proto").forEach {

Don't use the ancient protoc. This will cause problems:

            artifact = "com.google.protobuf:protoc-gen-javalite:3.0.0"

You're going to need those uncommented:

                // id("grpc") { option("lite") }
                // id("java") { option("lite") }

I suggest you take a look at our main README again. It seems you already have enough here to see the difference in syntax.

[louie-wh]

this is my build.gradle.ksl . no error , no java file generated. this is my project url

https://github.com/louie-wh/GrpcProto/tree/master

import com.google.protobuf.gradle.id

plugins {
    id("com.android.library")
    id("org.jetbrains.kotlin.android")
    id("com.google.protobuf")
}

android {
    namespace = "com.example.kotlindsl"
    compileSdk = 34

    defaultConfig {
        minSdk = 24

        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
        consumerProguardFiles("consumer-rules.pro")
    }

    buildTypes {
        release {
            isMinifyEnabled = false
            proguardFiles(
                getDefaultProguardFile("proguard-android-optimize.txt"),
                "proguard-rules.pro"
            )
        }
    }
    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
}

protobuf {
    protoc {
        // The artifact spec for the Protobuf Compiler
        artifact = "com.google.protobuf:protoc:3.6.1"
    }
    plugins {
        // Optional: an artifact spec for a protoc plugin, with "grpc" as
        // the identifier, which can be referred to in the "plugins"
        // container of the "generateProtoTasks" closure.
        id("grpc") {
            artifact = "io.grpc:protoc-gen-grpc-java:1.15.1"
        }
    }
    generateProtoTasks {
        ofSourceSet("main").forEach {
            it.plugins {
                // Apply the "grpc" plugin whose spec is defined above, without
                // options. Note the braces cannot be omitted, otherwise the
                // plugin will not be added. This is because of the implicit way
                // NamedDomainObjectContainer binds the methods.
                id("grpc") { }
            }
        }
    }
}

dependencies {

    implementation("androidx.core:core-ktx:1.9.0")
    implementation("androidx.appcompat:appcompat:1.6.1")
    implementation("com.google.android.material:material:1.9.0")
    testImplementation("junit:junit:4.13.2")
    androidTestImplementation("androidx.test.ext:junit:1.1.5")
    androidTestImplementation("androidx.test.espresso:espresso-core:3.5.1")
}

[ejona86]

this is my build.gradle.ksl . no error , no java file generated.

Are you sure? I tried it and I get lots of compilation errors because protobuf and grpc aren't dependencies.

The main components missing I see it need are:

                id("grpc") { option("lite") }
                id("java") { option("lite") }

and:

dependencies {
    implementation("io.grpc:grpc-protobuf-lite:1.57.2")
    implementation("io.grpc:grpc-stub:1.57.2")
    compileOnly("org.apache.tomcat:annotations-api:6.0.53")

}

Although at that point you realize that your protoc was ancient. This worked without issue:

import com.google.protobuf.gradle.id

plugins {
    ...
    id("com.google.protobuf")
}
...

protobuf {
    protoc {
        artifact = "com.google.protobuf:protoc:3.22.3"
    }
    plugins {
        id("grpc") {
            artifact = "io.grpc:protoc-gen-grpc-java:1.57.2"
        }
    }
    generateProtoTasks {
        all().forEach {
            it.plugins {
                id("grpc") { option("lite") }
                id("java") { option("lite") }

            }
        }
    }
}

dependencies {
    ...
    implementation("io.grpc:grpc-protobuf-lite:1.57.2")
    implementation("io.grpc:grpc-stub:1.57.2")
    compileOnly("org.apache.tomcat:annotations-api:6.0.53")
}

[louie-wh]

Thanks you tips . now it can work .

But sometimes I need invalid cache and restart It can work make project no work.

[ejona86]

Feel free to file an issue at https://github.com/google/protobuf-gradle-plugin for that. But you'd need to report the actual error messages, and ideally steps to reproduce. I'm aware of a history of issues where the cache is unable to be used, especially when sharing a cache across machines, but none where the cache is broken.