Add embedded driver support for Aeron

Author: cuihairu

docs/guide/transport-aeron.md

@@ -16,7 +16,7 @@
 1. 外置 Media Driver（推荐生产）
 2. Embedded Media Driver（开发/单机）
 
-当前实现默认使用外置 Media Driver。
+当前实现默认使用外置 Media Driver，Java 支持 embedded 模式（仅开发/单机）。
 
 ## 配置建议
 - `channel`: Aeron channel（ipc/udp）
@@ -30,6 +30,8 @@
 - `fragmentLimit`: 单次 poll 最大片段数（Java 默认 64）
 - `offerMaxAttempts`: offer 重试上限（Java 默认 10）
 - `idleStrategy`: 空转策略（Java 默认 BusySpin）
+- `embeddedDriver`: 是否启用 embedded driver（Java）
+- `dirDeleteOnStart/Shutdown`: embedded 模式是否清理目录（Java）
 
 ## 消息帧格式（v1）
 固定长度 56 bytes，偏移如下：

java/scripts/fetch-aeron.sh

@@ -8,6 +8,7 @@ AERON_VERSION="1.49.3"
 AGRGONA_VERSION="2.3.2"
 
 CLIENT_JAR="$CACHE_DIR/aeron-client-${AERON_VERSION}.jar"
+DRIVER_JAR="$CACHE_DIR/aeron-driver-${AERON_VERSION}.jar"
 AGRGONA_JAR="$CACHE_DIR/agrona-${AGRGONA_VERSION}.jar"
 
 mkdir -p "$CACHE_DIR"
@@ -16,8 +17,12 @@ if [ ! -f "$CLIENT_JAR" ]; then
   curl -sSL "https://repo1.maven.org/maven2/io/aeron/aeron-client/${AERON_VERSION}/aeron-client-${AERON_VERSION}.jar" -o "$CLIENT_JAR"
 fi
 
+if [ ! -f "$DRIVER_JAR" ]; then
+  curl -sSL "https://repo1.maven.org/maven2/io/aeron/aeron-driver/${AERON_VERSION}/aeron-driver-${AERON_VERSION}.jar" -o "$DRIVER_JAR"
+fi
+
 if [ ! -f "$AGRGONA_JAR" ]; then
   curl -sSL "https://repo1.maven.org/maven2/org/agrona/agrona/${AGRGONA_VERSION}/agrona-${AGRGONA_VERSION}.jar" -o "$AGRGONA_JAR"
 fi
 
-echo "${CLIENT_JAR}:${AGRGONA_JAR}"
+echo "${CLIENT_JAR}:${DRIVER_JAR}:${AGRGONA_JAR}"

java/src/main/java/io/epoch/AeronTransport.java

@@ -3,6 +3,7 @@
 import io.aeron.Aeron;
 import io.aeron.Publication;
 import io.aeron.Subscription;
+import io.aeron.driver.MediaDriver;
 import io.aeron.logbuffer.Header;
 import java.util.ArrayList;
 import java.util.List;
@@ -19,7 +20,10 @@ public record AeronConfig(
         String aeronDirectory,
         int fragmentLimit,
         int offerMaxAttempts,
-        IdleStrategy idleStrategy
+        IdleStrategy idleStrategy,
+        boolean embeddedDriver,
+        boolean dirDeleteOnStart,
+        boolean dirDeleteOnShutdown
     ) {
         public AeronConfig {
             if (fragmentLimit <= 0) {
@@ -34,27 +38,46 @@ public record AeronConfig(
         }
 
         public static AeronConfig defaults(String channel, int streamId, String aeronDirectory) {
-            return new AeronConfig(channel, streamId, aeronDirectory, 64, 10, new BusySpinIdleStrategy());
+            return new AeronConfig(channel, streamId, aeronDirectory, 64, 10, new BusySpinIdleStrategy(), false, false, false);
+        }
+
+        public static AeronConfig embeddedDefaults(String channel, int streamId, String aeronDirectory) {
+            return new AeronConfig(channel, streamId, aeronDirectory, 64, 10, new BusySpinIdleStrategy(), true, true, true);
         }
     }
 
     private final AeronConfig config;
     private final Aeron aeron;
     private final Publication publication;
     private final Subscription subscription;
+    private final MediaDriver mediaDriver;
     private final UnsafeBuffer sendBuffer;
     private final IdleStrategy idleStrategy;
     private final AeronStats stats = new AeronStats();
 
     public AeronTransport(AeronConfig config) {
         this.config = config;
+        MediaDriver driver = null;
+        String aeronDir = config.aeronDirectory();
+        if (config.embeddedDriver()) {
+            MediaDriver.Context driverContext = new MediaDriver.Context();
+            if (aeronDir != null && !aeronDir.isBlank()) {
+                driverContext.aeronDirectoryName(aeronDir);
+            }
+            driverContext.dirDeleteOnStart(config.dirDeleteOnStart());
+            driverContext.dirDeleteOnShutdown(config.dirDeleteOnShutdown());
+            driver = MediaDriver.launch(driverContext);
+            aeronDir = driverContext.aeronDirectoryName();
+        }
+
         Aeron.Context context = new Aeron.Context();
-        if (config.aeronDirectory() != null && !config.aeronDirectory().isBlank()) {
-            context.aeronDirectoryName(config.aeronDirectory());
+        if (aeronDir != null && !aeronDir.isBlank()) {
+            context.aeronDirectoryName(aeronDir);
         }
         this.aeron = Aeron.connect(context);
         this.publication = aeron.addPublication(config.channel(), config.streamId());
         this.subscription = aeron.addSubscription(config.channel(), config.streamId());
+        this.mediaDriver = driver;
         this.sendBuffer = new UnsafeBuffer(new ExpandableArrayBuffer(AeronMessageCodec.FRAME_LENGTH));
         this.idleStrategy = config.idleStrategy();
     }
@@ -100,6 +123,9 @@ public void close() {
         publication.close();
         subscription.close();
         aeron.close();
+        if (mediaDriver != null) {
+            mediaDriver.close();
+        }
     }
 
     public AeronConfig config() {