add s2a java client.

MODULE.bazel

@@ -41,7 +41,9 @@ IO_GRPC_GRPC_JAVA_ARTIFACTS = [
     "io.perfmark:perfmark-api:0.26.0",
     "junit:junit:4.13.2",
     "org.apache.tomcat:annotations-api:6.0.53",
+    "org.checkerframework:checker-qual:3.12.0",
     "org.codehaus.mojo:animal-sniffer-annotations:1.23",
+    "org.jcommander:jcommander:1.83",
 ]
 # GRPC_DEPS_END
 

repositories.bzl

@@ -45,7 +45,9 @@ IO_GRPC_GRPC_JAVA_ARTIFACTS = [
     "io.perfmark:perfmark-api:0.26.0",
     "junit:junit:4.13.2",
     "org.apache.tomcat:annotations-api:6.0.53",
+    "org.checkerframework:checker-qual:3.12.0",
     "org.codehaus.mojo:animal-sniffer-annotations:1.23",
+    "org.jcommander:jcommander:1.83",
 ]
 # GRPC_DEPS_END
 
@@ -80,6 +82,7 @@ IO_GRPC_GRPC_JAVA_OVERRIDE_TARGETS = {
     "io.grpc:grpc-rls": "@io_grpc_grpc_java//rls",
     "io.grpc:grpc-services": "@io_grpc_grpc_java//services:services_maven",
     "io.grpc:grpc-stub": "@io_grpc_grpc_java//stub",
+    "io.grpc:grpc-s2a": "@io_grpc_grpc_java//s2a",
     "io.grpc:grpc-testing": "@io_grpc_grpc_java//testing",
     "io.grpc:grpc-xds": "@io_grpc_grpc_java//xds:xds_maven",
     "io.grpc:grpc-util": "@io_grpc_grpc_java//util",

s2a/BUILD.bazel

@@ -0,0 +1,194 @@
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("//:java_grpc_library.bzl", "java_grpc_library")
+load("@rules_jvm_external//:defs.bzl", "artifact")
+
+java_library(
+    name = "s2a_channel_pool",
+    srcs = glob([
+        "src/main/java/io/grpc/s2a/channel/*.java",
+    ]),
+    deps = [
+        "//api",
+        "//core",
+        "//core:internal",
+        "//netty",
+        artifact("com.google.code.findbugs:jsr305"),
+        artifact("com.google.errorprone:error_prone_annotations"),
+        artifact("com.google.guava:guava"),
+        artifact("org.checkerframework:checker-qual"),
+        artifact("io.netty:netty-common"),
+        artifact("io.netty:netty-transport"),
+    ],
+)
+
+java_library(
+    name = "s2a_identity",
+    srcs = ["src/main/java/io/grpc/s2a/handshaker/S2AIdentity.java"],
+    deps = [
+        ":common_java_proto",
+        artifact("com.google.errorprone:error_prone_annotations"),
+        artifact("com.google.guava:guava"),
+    ],
+)
+
+java_library(
+    name = "token_fetcher",
+    srcs = ["src/main/java/io/grpc/s2a/handshaker/tokenmanager/TokenFetcher.java"],
+    deps = [
+        ":s2a_identity",
+    ],
+)
+
+java_library(
+    name = "access_token_manager",
+    srcs = [
+        "src/main/java/io/grpc/s2a/handshaker/tokenmanager/AccessTokenManager.java",
+    ],
+    deps = [
+        ":s2a_identity",
+        ":token_fetcher",
+        artifact("com.google.code.findbugs:jsr305"),
+    ],
+)
+
+java_library(
+    name = "single_token_fetcher",
+    srcs = [
+        "src/main/java/io/grpc/s2a/handshaker/tokenmanager/SingleTokenFetcher.java",
+    ],
+    deps = [
+        ":s2a_identity",
+        ":token_fetcher",
+        artifact("org.jcommander:jcommander"),
+    ],
+)
+
+java_library(
+    name = "s2a_handshaker",
+    srcs = [
+        "src/main/java/io/grpc/s2a/handshaker/ConnectionIsClosedException.java",
+        "src/main/java/io/grpc/s2a/handshaker/GetAuthenticationMechanisms.java",
+        "src/main/java/io/grpc/s2a/handshaker/ProtoUtil.java",
+        "src/main/java/io/grpc/s2a/handshaker/S2AConnectionException.java",
+        "src/main/java/io/grpc/s2a/handshaker/S2APrivateKeyMethod.java",
+        "src/main/java/io/grpc/s2a/handshaker/S2AProtocolNegotiatorFactory.java",
+        "src/main/java/io/grpc/s2a/handshaker/S2AStub.java",
+        "src/main/java/io/grpc/s2a/handshaker/S2ATrustManager.java",
+        "src/main/java/io/grpc/s2a/handshaker/SslContextFactory.java",
+    ],
+    deps = [
+        ":access_token_manager",
+        ":common_java_proto",
+        ":s2a_channel_pool",
+        ":s2a_identity",
+        ":s2a_java_proto",
+        ":s2a_java_grpc_proto",
+        ":single_token_fetcher",
+        "//api",
+        "//core:internal",
+        "//netty",
+        "//stub",
+        artifact("com.google.code.findbugs:jsr305"),
+        artifact("com.google.errorprone:error_prone_annotations"),
+        artifact("com.google.guava:guava"),
+        artifact("org.checkerframework:checker-qual"),
+        "@com_google_protobuf//:protobuf_java",
+        artifact("io.netty:netty-common"),
+        artifact("io.netty:netty-handler"),
+        artifact("io.netty:netty-transport"),
+    ],
+)
+
+java_library(
+    name = "s2av2_credentials",
+    srcs = ["src/main/java/io/grpc/s2a/S2AChannelCredentials.java"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":s2a_channel_pool",
+        ":s2a_handshaker",
+        ":s2a_identity",
+        "//api",
+        "//core:internal",
+        "//netty",
+        artifact("com.google.code.findbugs:jsr305"),
+        artifact("com.google.errorprone:error_prone_annotations"),
+        artifact("com.google.guava:guava"), 
+        artifact("org.checkerframework:checker-qual"), 
+    ],
+)
+
+java_library(
+    name = "mtls_to_s2av2_credentials",
+    srcs = ["src/main/java/io/grpc/s2a/MtlsToS2AChannelCredentials.java"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":s2a_channel_pool",
+        ":s2av2_credentials",
+        "//api",
+        "//util",
+        artifact("com.google.guava:guava"),
+    ],
+)
+
+# bazel only accepts proto import with absolute path.
+genrule(
+    name = "protobuf_imports",
+    srcs = glob(["src/main/proto/grpc/gcp/*.proto"]),
+    outs = [
+        "protobuf_out/grpc/gcp/s2a.proto",
+        "protobuf_out/grpc/gcp/s2a_context.proto",
+        "protobuf_out/grpc/gcp/common.proto",
+    ],
+    cmd = "for fname in $(SRCS); do " +
+          "sed 's,import \",import \"s2a/protobuf_out/,g' $$fname > " +
+          "$(@D)/protobuf_out/grpc/gcp/$$(basename $$fname); done",
+)
+
+proto_library(
+    name = "common_proto",
+    srcs = [
+        "protobuf_out/grpc/gcp/common.proto",
+    ],
+)
+
+proto_library(
+    name = "s2a_context_proto",
+    srcs = [
+        "protobuf_out/grpc/gcp/s2a_context.proto",
+    ],
+    deps = [
+        ":common_proto",
+    ],
+)
+
+proto_library(
+    name = "s2a_proto",
+    srcs = [
+        "protobuf_out/grpc/gcp/s2a.proto",
+    ],
+    deps = [
+        ":common_proto",
+        ":s2a_context_proto",
+    ],
+)
+
+java_proto_library(
+    name = "s2a_java_proto",
+    deps = [":s2a_proto"],
+)
+
+java_proto_library(
+    name = "s2a_context_java_proto",
+    deps = [":s2a_context_proto"],
+)
+
+java_proto_library(
+    name = "common_java_proto",
+    deps = [":common_proto"],
+)
+
+java_grpc_library(
+    name = "s2a_java_grpc_proto",
+    srcs = [":s2a_proto"],
+    deps = [":s2a_java_proto"],
+)

s2a/build.gradle

@@ -0,0 +1,153 @@
+buildscript {
+  dependencies {
+    classpath 'com.google.gradle:osdetector-gradle-plugin:1.4.0'
+  }
+}
+
+plugins {
+    id "java-library"
+    id "maven-publish"
+
+    id "com.github.johnrengelman.shadow"
+    id "com.google.protobuf"
+    id "ru.vyarus.animalsniffer"
+}
+
+description = "gRPC: S2A"
+
+apply plugin: "com.google.osdetector"
+
+dependencies {
+
+    api project(':grpc-api')
+    implementation project(':grpc-stub'),
+            project(':grpc-protobuf'),
+            project(':grpc-core'),
+            libraries.protobuf.java,
+            libraries.conscrypt,
+            libraries.guava.jre // JRE required by protobuf-java-util from grpclb
+    compileOnly 'org.jcommander:jcommander:1.83'
+    def nettyDependency = implementation project(':grpc-netty')
+    compileOnly libraries.javax.annotation
+
+    shadow configurations.implementation.getDependencies().minus(nettyDependency)
+    shadow project(path: ':grpc-netty-shaded', configuration: 'shadow')
+
+    testImplementation project(':grpc-benchmarks'),
+            project(':grpc-testing'),
+            project(':grpc-testing-proto'),
+            testFixtures(project(':grpc-core')),
+            libraries.guava,
+            libraries.junit,
+            libraries.mockito.core,
+            libraries.truth,
+            libraries.conscrypt,
+            libraries.netty.transport.epoll
+
+    testImplementation 'org.jcommander:jcommander:1.83'
+    testImplementation 'com.google.truth:truth:1.4.2'
+    testImplementation 'com.google.truth.extensions:truth-proto-extension:1.4.2' 
+    testImplementation libraries.guava.testlib
+
+    testRuntimeOnly libraries.netty.tcnative,
+            libraries.netty.tcnative.classes
+    testRuntimeOnly (libraries.netty.tcnative) {
+        artifact {
+            classifier = "linux-x86_64"
+        }
+    }
+    testRuntimeOnly (libraries.netty.tcnative) {
+        artifact {
+            classifier = "linux-aarch_64"
+        }
+    }
+    testRuntimeOnly (libraries.netty.tcnative) {
+        artifact {
+            classifier = "osx-x86_64"
+        }
+    }
+    testRuntimeOnly (libraries.netty.tcnative) {
+        artifact {
+            classifier = "osx-aarch_64"
+        }
+    }
+    testRuntimeOnly (libraries.netty.tcnative) {
+        artifact {
+            classifier = "windows-x86_64"
+        }
+    }
+    testRuntimeOnly (libraries.netty.transport.epoll) {
+        artifact {
+            classifier = "linux-x86_64"
+        }
+    }
+
+    signature libraries.signature.java
+}
+
+tasks.named("compileJava") {
+    dependsOn(tasks.named("generateProto"))
+    //dependsOn(tasks.named("syncGeneratedSourcesmain"))
+}
+
+
+tasks.named("sourcesJar") {
+    dependsOn(tasks.named("generateProto"))
+    //dependsOn(tasks.named("syncGeneratedSourcesmain"))
+}
+
+sourceSets {
+  main {
+    //java.srcDirs += "src/generated/main/java"
+    //java.srcDirs += "src/generated/main/grpc"
+  }
+}
+//println sourceSets.main.java.srcDirs
+//println sourceSets.test.resources.srcDirs
+
+configureProtoCompilation()
+
+tasks.named("javadoc").configure {
+    exclude 'io/grpc/s2a/**'
+}
+
+tasks.named("jar").configure {
+    // Must use a different archiveClassifier to avoid conflicting with shadowJar
+    archiveClassifier = 'original'
+    manifest {
+        attributes('Automatic-Module-Name': 'io.grpc.s2a')
+    }
+}
+
+// We want to use grpc-netty-shaded instead of grpc-netty. But we also want our
+// source to work with Bazel, so we rewrite the code as part of the build.
+tasks.named("shadowJar").configure {
+    archiveClassifier = null
+    dependencies {
+        exclude(dependency {true})
+    }
+    relocate 'io.grpc.netty', 'io.grpc.netty.shaded.io.grpc.netty'
+    relocate 'io.netty', 'io.grpc.netty.shaded.io.netty'
+}
+
+publishing {
+    publications {
+        maven(MavenPublication) {
+            // We want this to throw an exception if it isn't working
+            def originalJar = artifacts.find { dep -> dep.classifier == 'original'}
+            artifacts.remove(originalJar)
+
+            pom.withXml {
+                def dependenciesNode = new Node(null, 'dependencies')
+                project.configurations.shadow.allDependencies.each { dep ->
+                    def dependencyNode = dependenciesNode.appendNode('dependency')
+                    dependencyNode.appendNode('groupId', dep.group)
+                    dependencyNode.appendNode('artifactId', dep.name)
+                    dependencyNode.appendNode('version', dep.version)
+                    dependencyNode.appendNode('scope', 'compile')
+                }
+                asNode().dependencies[0].replaceNode(dependenciesNode)
+            }
+        }
+    }
+}