zenoh-flat transition (integration branch)

.github/workflows/ci.yml

@@ -22,7 +22,34 @@ jobs:
         os: [ubuntu-latest, macos-latest]
 
     steps:
-      - uses: actions/checkout@v4
+      - name: Check out zenoh-java
+        uses: actions/checkout@v4
+        with:
+          path: zenoh-java
+
+      - name: Check out zenoh-flat-jni
+        uses: actions/checkout@v4
+        with:
+          repository: ZettaScaleLabs/zenoh-flat-jni
+          ref: 9bc155b3272c8c905bf95614cb7eb7e6d656c72f
+          path: zenoh-flat-jni
+
+      - name: Check out zenoh-flat
+        uses: actions/checkout@v4
+        with:
+          repository: ZettaScaleLabs/zenoh-flat
+          ref: 6d22091d75912be1c14330b0f78fa1d4bf258ea3
+          path: zenoh-flat
+
+      - name: Use prebindgen from GitHub main
+        shell: bash
+        working-directory: zenoh-flat-jni
+        run: |
+          sed -i.bak \
+            -e 's|prebindgen = { path = "../prebindgen/prebindgen" }|prebindgen = { git = "https://github.com/milyin/prebindgen.git", branch = "main" }|g' \
+            -e 's|prebindgen-proc-macro = { path = "../prebindgen/prebindgen-proc-macro",|prebindgen-proc-macro = { git = "https://github.com/milyin/prebindgen.git", branch = "main",|g' \
+            Cargo.toml ../zenoh-flat/Cargo.toml
+          rm Cargo.toml.bak ../zenoh-flat/Cargo.toml.bak
 
       - uses: actions/setup-java@v4
         with:
@@ -32,31 +59,29 @@ jobs:
       - name: Install Rust toolchain
         run: |
           rustup show
-          rustup component add rustfmt clippy
+          rustup component add rustfmt clippy --toolchain 1.93.0
 
       - name: Cargo Format
-        working-directory: zenoh-jni
-        run: cargo fmt --all --check
+        working-directory: zenoh-flat-jni
+        run: cargo fmt --check
 
-      - name: Clippy Check without Cargo.lock
-        working-directory: zenoh-jni
-        run: |
-          rm Cargo.lock
-          cargo clippy --all-targets --all-features -- -D warnings
-          git restore Cargo.lock
+      - name: Clippy Check
+        working-directory: zenoh-flat-jni
+        run: cargo clippy --all-targets --all-features -- -D warnings
 
       - name: Check for feature leaks
-        working-directory: zenoh-jni
+        working-directory: zenoh-flat-jni
         run: cargo test --no-default-features
 
-      - name: Build Zenoh-JNI
-        working-directory: zenoh-jni
+      - name: Build zenoh-flat-jni
+        working-directory: zenoh-flat-jni
         run: cargo build
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
 
       - name: Gradle Test
+        working-directory: zenoh-java
         run: ./gradlew jvmTest --info
 
   markdown_lint:

ZENOH_FLAT_TRANSITION.md

@@ -0,0 +1,39 @@
+# zenoh-flat transition
+
+This branch (`zenoh-flat-transition`) is the **integration branch** for rebuilding
+zenoh-java on top of the generated JNI/Kotlin bindings, replacing the hand-written
+`zenoh-jni` layer. It exists so the transition can land as a series of reviewable
+PRs targeting this branch instead of `main`; when the transition is complete, this
+branch merges to `main` as a whole (and this file is removed).
+
+## Architecture
+
+```
+zenoh (Rust)
+  └─ zenoh-flat            flat #[prebindgen]-annotated Rust API
+       └─ zenoh-flat-jni   generated JNI externs + Kotlin classes (prebindgen lang::JniGen)
+            └─ zenoh-java  Kotlin SDK wrapper (this repo)
+```
+
+- **prebindgen** — <https://github.com/milyin/prebindgen> (generator)
+- **zenoh-flat** — <https://github.com/ZettaScaleLabs/zenoh-flat> (flat Rust API)
+- **zenoh-flat-jni** — <https://github.com/ZettaScaleLabs/zenoh-flat-jni> (generated bindings,
+  consumed as a sibling checkout in CI and via Gradle composite build locally;
+  as a Maven artifact once published)
+
+## Constituent PRs
+
+| PR | Scope | Status |
+| --- | --- | --- |
+| [#481](https://github.com/eclipse-zenoh/zenoh-java/pull/481) | Use receiver-style zenoh-flat-jni bindings (generated Session/Query/Publisher methods, split key-expr overloads, de-prefixed callback names); +61–83% subscriber throughput | merged |
+| [#484](https://github.com/eclipse-zenoh/zenoh-java/pull/484) | `Encoding`/`ZenohId.toString` become pure JVM values (fixes a per-message native leak); the conversion logic lives in the **shared tier** (`EncodingCodec`/`zidString` in zenoh-flat-jni, correspondence-tested against native, reusable by zenoh-kotlin) with only a thin facade here; publisher **default encoding set natively at declare** (plain puts cross no encoding data). Pairs with [zenoh-flat-jni#4](https://github.com/ZettaScaleLabs/zenoh-flat-jni/pull/4), [zenoh-flat#3](https://github.com/ZettaScaleLabs/zenoh-flat/pull/3) (merged), [prebindgen#80](https://github.com/milyin/prebindgen/pull/80) (merged) | in progress |
+
+Companion PRs in the upstream repos are coordinated per constituent PR (e.g.
+[ZettaScaleLabs/zenoh-flat-jni#3](https://github.com/ZettaScaleLabs/zenoh-flat-jni/pull/3)
+pairs with #481 and merges first; CI here pins the exact upstream commits).
+
+## CI pinning
+
+`.github/workflows/ci.yml` on the constituent branches pins the exact
+`zenoh-flat-jni` / `zenoh-flat` commits the code was written against, while
+`prebindgen` resolves from its `main`. Pins are bumped as the upstream PRs land.

examples/build.gradle.kts

@@ -78,19 +78,13 @@ tasks {
 
     examples.forEach { example ->
         register(example, JavaExec::class) {
-            dependsOn("CompileZenohJNI")
+            dependsOn(":zenoh-java:buildZenohFlatJni")
             description = "Run the $example example"
             mainClass.set("io.zenoh.$example")
             classpath(sourceSets["main"].runtimeClasspath)
-            val zenohPaths = "../zenoh-jni/target/release"
+            val zenohPaths = "../zenoh-flat-jni/target/release"
             val defaultJvmArgs = arrayListOf("-Djava.library.path=$zenohPaths")
             jvmArgs(defaultJvmArgs)
         }
     }
 }
-
-tasks.register("CompileZenohJNI") {
-    project.exec {
-        commandLine("cargo", "build", "--release", "--manifest-path", "../zenoh-jni/Cargo.toml")
-    }
-}

examples/src/main/java/io/zenoh/ZSubThr.java

@@ -17,6 +17,7 @@
 import io.zenoh.exceptions.ZError;
 import io.zenoh.keyexpr.KeyExpr;
 import io.zenoh.pubsub.Subscriber;
+import io.zenoh.sample.Sample;
 import picocli.CommandLine;
 
 import java.util.List;
@@ -40,7 +41,7 @@ public Integer call() throws Exception {
         System.out.println("Opening Session");
         try (Session session = Zenoh.open(config)) {
             try (KeyExpr keyExpr = KeyExpr.tryFrom("test/thr")) {
-                subscriber = session.declareSubscriber(keyExpr, sample -> listener(number));
+                subscriber = session.declareSubscriber(keyExpr, sample -> listener(sample, number));
                 System.out.println("Press CTRL-C to quit...");
 
                 while (subscriber.isValid()) {
@@ -51,7 +52,12 @@ public Integer call() throws Exception {
         return 0;
     }
 
-    private void listener(long number) {
+    private void listener(Sample sample, long number) {
+        // Touch the delivered data so it actually reaches the Java surface
+        // (payload bytes + key-expression string): keeps lazy bindings honest
+        // and prevents either side from skipping materialization costs.
+        dataSink += sample.getPayload().toBytes().length
+                + sample.getKeyExpr().toString().length();
         if (batchCount > samples) {
             closeSubscriber();
             report();
@@ -86,8 +92,8 @@ private void report() {
         double elapsedTimeSecs = (double) (end - globalStartTimestampNs) / NANOS_TO_SEC;
         double averageMessagesPerSec = totalMessages / elapsedTimeSecs;
 
-        System.out.printf("Received %d messages in %.2f seconds: averaged %.2f msgs/sec%n",
-                totalMessages, elapsedTimeSecs, averageMessagesPerSec);
+        System.out.printf("Received %d messages in %.2f seconds: averaged %.2f msgs/sec (sink %d)%n",
+                totalMessages, elapsedTimeSecs, averageMessagesPerSec, dataSink);
     }
 
     private void closeSubscriber() {
@@ -114,6 +120,7 @@ private void closeSubscriber() {
     private static final long NANOS_TO_SEC = 1_000_000_000L;
     private long batchCount = 0;
     private long count = 0;
+    private long dataSink = 0;
     private long startTimestampNs = 0;
     private long globalStartTimestampNs = 0;
 

settings.gradle.kts

@@ -23,7 +23,11 @@ rootProject.name = "zenoh-java"
 
 include(":zenoh-java")
 include(":examples")
-include(":zenoh-jni")
+
+// zenoh-flat-jni is now a separate repository (https://github.com/ZettaScaleLabs/zenoh-flat-jni)
+// and is consumed as a Maven artifact: org.eclipse.zenoh:zenoh-flat-jni:VERSION
+// For local development with coordinated changes, use Gradle composite build:
+includeBuild("../zenoh-flat-jni")
 
 plugins {
     id("org.gradle.toolchains.foojay-resolver-convention") version("0.4.0")

zenoh-java/build.gradle.kts

@@ -12,8 +12,6 @@
 //   ZettaScale Zenoh Team, <zenoh@zettascale.tech>
 //
 
-import com.nishtahir.CargoExtension
-
 plugins {
     kotlin("multiplatform")
     kotlin("plugin.serialization")
@@ -30,26 +28,21 @@ val release = project.findProperty("release")?.toString()?.toBoolean() == true
 // Modifying this property will affect the release workflows!
 val isRemotePublication = project.findProperty("remotePublication")?.toString()?.toBoolean() == true
 
-var buildMode = if (release) BuildMode.RELEASE else BuildMode.DEBUG
+// zenoh-flat-jni is now consumed as a Maven artifact: org.eclipse.zenoh:zenoh-flat-jni:VERSION
+// Native libraries are bundled in the JAR by the zenoh-flat-jni module
 
 if (androidEnabled) {
     apply(plugin = "com.android.library")
-    apply(plugin = "org.mozilla.rust-android-gradle.rust-android")
-
-    configureCargo()
     configureAndroid()
 }
 
+
 kotlin {
     jvmToolchain(11)
     jvm {
         compilations.all {
             kotlinOptions.jvmTarget = "11"
         }
-        testRuns["test"].executionTask.configure {
-            val zenohPaths = "../zenoh-jni/target/$buildMode"
-            jvmArgs("-Djava.library.path=$zenohPaths")
-        }
         if (!androidEnabled) {
             withJava() // Adding java to a kotlin lib targeting android is incompatible
                        // The java code is only meant for testing and is non-critical for the android publication.
@@ -66,6 +59,8 @@ kotlin {
     sourceSets {
         val commonMain by getting {
             dependencies {
+                // Zenoh Flat JNI - includes Kotlin sources and native libraries
+                implementation("org.eclipse.zenoh:zenoh-flat-jni:1.9.0")
                 implementation("commons-net:commons-net:3.9.0")
                 implementation("com.google.guava:guava:33.3.1-jre")
             }
@@ -82,18 +77,6 @@ kotlin {
                 }
             }
         }
-        val jvmMain by getting {
-            if (isRemotePublication) {
-                // The line below is intended to load the native libraries that are crosscompiled on GitHub actions when publishing a JVM package.
-                resources.srcDir("../jni-libs").include("*/**")
-            } else {
-                resources.srcDir("../zenoh-jni/target/$buildMode").include(arrayListOf("*.dylib", "*.so", "*.dll"))
-            }
-        }
-
-        val jvmTest by getting {
-            resources.srcDir("../zenoh-jni/target/$buildMode").include(arrayListOf("*.dylib", "*.so", "*.dll"))
-        }
     }
 
     val javadocJar by tasks.registering(Jar::class) {
@@ -153,65 +136,6 @@ tasks.withType<PublishToMavenRepository>().configureEach {
     dependsOn(tasks.withType<Sign>())
 }
 
-tasks.withType<Test> {
-    doFirst {
-        // The line below is added for the Android Unit tests which are equivalent to the JVM tests.
-        // For them to work we need to specify the path to the native library as a system property and not as a jvmArg.
-        systemProperty("java.library.path", "../zenoh-jni/target/$buildMode")
-    }
-}
-
-tasks.whenObjectAdded {
-    if ((this.name == "mergeDebugJniLibFolders" || this.name == "mergeReleaseJniLibFolders")) {
-        this.dependsOn("cargoBuild")
-    }
-}
-
-tasks.named("compileKotlinJvm") {
-    dependsOn("buildZenohJni")
-}
-
-tasks.register("buildZenohJni") {
-    doLast {
-        if (!isRemotePublication) {
-            // This is intended for local publications. For publications done through GitHub workflows,
-            // the zenoh-jni build is achieved and loaded differently from the CI
-            buildZenohJNI(buildMode)
-        }
-    }
-}
-
-fun buildZenohJNI(mode: BuildMode = BuildMode.DEBUG) {
-    val cargoCommand = mutableListOf("cargo", "build")
-
-    if (mode == BuildMode.RELEASE) {
-        cargoCommand.add("--release")
-    }
-
-    val result = project.exec {
-        commandLine(*(cargoCommand.toTypedArray()), "--manifest-path", "../zenoh-jni/Cargo.toml")
-    }
-
-    if (result.exitValue != 0) {
-        throw GradleException("Failed to build Zenoh-JNI.")
-    }
-
-    Thread.sleep(1000)
-}
-
-enum class BuildMode {
-    DEBUG {
-        override fun toString(): String {
-            return "debug"
-        }
-    },
-    RELEASE {
-        override fun toString(): String {
-            return "release"
-        }
-    }
-}
-
 fun Project.configureAndroid() {
     extensions.configure<com.android.build.gradle.LibraryExtension>("android") {
         namespace = "io.zenoh"
@@ -249,20 +173,3 @@ fun Project.configureAndroid() {
         }
     }
 }
-
-fun Project.configureCargo() {
-    extensions.configure<CargoExtension>("cargo") {
-        pythonCommand = "python3"
-        module = "../zenoh-jni"
-        libname = "zenoh-jni"
-        targetIncludes = arrayOf("libzenoh_jni.so")
-        targetDirectory = "../zenoh-jni/target/"
-        profile = "release"
-        targets = arrayListOf(
-            "arm",
-            "arm64",
-            "x86",
-            "x86_64",
-        )
-    }
-}