tunnel: add gRPC over unix domain socket to the go backend

With gRPC it will be easier to extend the go backend API.
In this commit the Version function is reimplemented in gRPC.

Gitignore generated protobuf files.

1 files changed, 53 insertions, 0 deletions

diff --git a/tunnel/build.gradle b/tunnel/build.gradle
index e1742f4c..6cca87b1 100644
--- a/tunnel/build.gradle
+++ b/tunnel/build.gradle
@@ -1,5 +1,12 @@
+buildscript {
+    dependencies {
+        classpath "com.google.protobuf:protobuf-gradle-plugin:$protobufGradleVersion"
+    }
+}
+
 plugins {
     id 'com.android.library'
+    id 'com.google.protobuf' version "$protobufGradleVersion"
 }
 
 version wireguardVersionName
@@ -54,8 +61,54 @@ android {
 dependencies {
     implementation "androidx.annotation:annotation:$annotationsVersion"
     implementation "androidx.collection:collection:$collectionVersion"
+    implementation "io.grpc:grpc-okhttp:$grpcVersion"
+    implementation "io.grpc:grpc-protobuf-lite:$grpcVersion"
+    implementation "io.grpc:grpc-stub:$grpcVersion"
     compileOnly "com.google.code.findbugs:jsr305:$jsr305Version"
+    compileOnly "javax.annotation:javax.annotation-api:1.2"
     testImplementation "junit:junit:$junitVersion"
 }
 
+protobuf {
+    protoc {
+        // You still need protoc like in the non-Android case
+        artifact = "com.google.protobuf:protoc:$protocVersion"
+    }
+    plugins {
+        grpc {
+            artifact = "io.grpc:protoc-gen-grpc-java:$grpcVersion"
+        }
+    }
+    generateProtoTasks {
+        all().each { task ->
+            task.builtins {
+                java {
+                    option 'lite'
+                }
+            }
+            task.plugins {
+                grpc {
+                    option 'lite'
+                }
+            }
+        }
+    }
+}
+
+afterEvaluate({ project ->
+    // All custom configurations created by the protobuf plugin,
+    // are only available at this point.
+    def protoc = configurations.getByName('protobufToolsLocator_protoc')
+
+    task copyProtoc(type: Copy) {
+        // Used by tunnel/tools/libwg-go/Makefile run in tools/CMakeLists.txt
+        from protoc
+        into "${gradle.gradleUserHomeDir}/caches/protoc-${protocVersion}"
+        rename 'protoc-.*', 'protoc'
+        fileMode 0775
+    }
+
+    preBuild.dependsOn copyProtoc
+})
+
 apply from: "publish.gradle"