Move systemd notification into cli

distribution/build.gradle

@@ -231,7 +231,7 @@ xpack.subprojects.findAll { it.parent == xpack }.each { Project xpackModule ->
   }
 }
 
-distro.copyModule(processSystemdOutputsTaskProvider, project(':modules:systemd'))
+//distro.copyModule(processSystemdOutputsTaskProvider, project(':modules:systemd'))
 
 project(':test:external-modules').subprojects.each { Project testModule ->
   distro.copyModule(processExternalTestOutputsTaskProvider, testModule)
@@ -372,9 +372,9 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
         if (BuildParams.isSnapshotBuild()) {
           from(buildExternalTestModulesTaskProvider)
         }
-        if (project.path.startsWith(':distribution:packages')) {
+        /*if (project.path.startsWith(':distribution:packages')) {
           from(systemdModuleFiles)
-        }
+        }*/
       }
     }
 

distribution/tools/server-cli/build.gradle

@@ -12,10 +12,17 @@ apply plugin: 'elasticsearch.build'
 dependencies {
   compileOnly project(":server")
   compileOnly project(":libs:elasticsearch-cli")
+  compileOnly project(":libs:elasticsearch-native")
 
   testImplementation project(":test:framework")
 }
 
+tasks.named("compileJava").configure {
+  // nativeaccess only has qualified exports. Even though the cli is not run modular, compilation is done with the module path
+  // so nativeaccess needs to be exported here, just at compile time
+  options.compilerArgs << '--add-exports' << 'org.elasticsearch.nativeaccess/org.elasticsearch.nativeaccess=ALL-UNNAMED'
+}
+
 tasks.named("test").configure {
   systemProperty "tests.security.manager", "false"
 }

distribution/tools/server-cli/src/main/java/org/elasticsearch/server/cli/ServerCli.java

@@ -24,12 +24,14 @@
 import org.elasticsearch.common.cli.EnvironmentAwareCommand;
 import org.elasticsearch.common.settings.SecureSettings;
 import org.elasticsearch.common.settings.SecureString;
+import org.elasticsearch.core.Booleans;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.monitor.jvm.JvmInfo;
 
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -48,6 +50,7 @@ class ServerCli extends EnvironmentAwareCommand {
     // flag for indicating shutdown has begun. we use an AtomicBoolean to double as a synchronization object
     private final AtomicBoolean shuttingDown = new AtomicBoolean(false);
     private volatile ServerProcess server;
+    private volatile SystemdNotifier notifier;
 
     // visible for testing
     ServerCli() {
@@ -249,6 +252,9 @@ public void close() throws IOException {
                 server.stop();
             }
         }
+        if (notifier != null) {
+            notifier.close();
+        }
     }
 
     // allow subclasses to access the started process
@@ -270,9 +276,21 @@ protected ServerProcess startServer(Terminal terminal, ProcessInfo processInfo,
             .withServerArgs(args)
             .withTempDir(tempDir)
             .withJvmOptions(jvmOptions);
+        this.notifier = maybeStartSystemdNotifier(processInfo);
+        if (notifier != null) {
+            serverProcessBuilder.withListener(notifier);
+        }
         return serverProcessBuilder.start();
     }
 
+    private static SystemdNotifier maybeStartSystemdNotifier(ProcessInfo processInfo) {
+        String notifyFlag = processInfo.envVars().get("ES_SD_NOTIFY");
+        if (Booleans.parseBoolean(notifyFlag, false)) {
+            return new SystemdNotifier();
+        }
+        return null;
+    }
+
     // protected to allow tests to override
     protected SecureSettingsLoader secureSettingsLoader(Environment env) {
         // TODO: Use the environment configuration to decide what kind of secrets store to load

distribution/tools/server-cli/src/main/java/org/elasticsearch/server/cli/ServerProcessBuilder.java

@@ -43,6 +43,7 @@ public class ServerProcessBuilder {
     private ProcessInfo processInfo;
     private List<String> jvmOptions;
     private Terminal terminal;
+    private ServerProcessListener listener;
 
     // this allows mocking the process building by tests
     interface ProcessStarter {
@@ -89,6 +90,11 @@ public ServerProcessBuilder withTerminal(Terminal terminal) {
         return this;
     }
 
+    public ServerProcessBuilder withListener(ServerProcessListener listener) {
+        this.listener = listener;
+        return this;
+    }
+
     private Map<String, String> getEnvironment() {
         Map<String, String> envVars = new HashMap<>(processInfo.envVars());
 
@@ -175,6 +181,10 @@ ServerProcess start(ProcessStarter processStarter) throws UserException {
             }
         }
 
+        if (listener != null) {
+            listener.onReady();
+        }
+
         return new ServerProcess(jvmProcess, errorPump);
     }
 

distribution/tools/server-cli/src/main/java/org/elasticsearch/server/cli/ServerProcessListener.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.server.cli;
+
+/**
+ * A listener for Elasticsearch process events.
+ */
+public interface ServerProcessListener {
+
+    /**
+     * Called when the server process has successfully started and is ready.
+     */
+    void onReady();
+}

distribution/tools/server-cli/src/main/java/org/elasticsearch/server/cli/SystemdNotifier.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.server.cli;
+
+import org.elasticsearch.core.TimeValue;
+import org.elasticsearch.logging.LogManager;
+import org.elasticsearch.logging.Logger;
+import org.elasticsearch.nativeaccess.NativeAccess;
+import org.elasticsearch.nativeaccess.Systemd;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Timer;
+import java.util.TimerTask;
+
+class SystemdNotifier implements ServerProcessListener, Closeable {
+
+    private static final Logger logger = LogManager.getLogger(SystemdNotifier.class);
+    private static final Systemd systemd = NativeAccess.instance().systemd();
+    private final Timer timer;
+
+    SystemdNotifier() {
+        this.timer = new Timer("systemd-notifier", true);
+        long timeBetweenExtend = TimeValue.timeValueSeconds(15).millis();
+        TimerTask extendTask = new TimerTask() {
+            @Override
+            public void run() {
+                systemd.notify_extend_timeout(30);
+            }
+        };
+        timer.scheduleAtFixedRate(extendTask, timeBetweenExtend, timeBetweenExtend);
+    }
+
+    @Override
+    public void onReady() {
+        timer.cancel();
+        systemd.notify_ready();
+    }
+
+    @Override
+    public void close() throws IOException {
+        timer.cancel();
+        systemd.notify_stopping();
+    }
+}