feat(management): avoid self-referencing JMX operations

src/main/java/io/cryostat/agent/FlightRecorderHelper.java

@@ -15,10 +15,14 @@
  */
 package io.cryostat.agent;
 
+import java.io.IOException;
+import java.io.StringReader;
+import java.text.ParseException;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
@@ -32,7 +36,25 @@ public class FlightRecorderHelper {
 
     private final Logger log = LoggerFactory.getLogger(getClass());
 
-    public Optional<TemplatedRecording> createRecording(String templateNameOrLabel) {
+    public Optional<Recording> createSnapshot() {
+        Recording snapshot = FlightRecorder.getFlightRecorder().takeSnapshot();
+        if (snapshot.getSize() == 0) {
+            log.warn("No active recordings");
+            snapshot.close();
+            return Optional.empty();
+        }
+        return Optional.of(snapshot);
+    }
+
+    public Recording createRecordingWithCustomTemplate(String template)
+            throws IOException, ParseException {
+        Recording recording = new Recording(Configuration.create(new StringReader(template)));
+        recording.setToDisk(true);
+        return recording;
+    }
+
+    public Optional<TemplatedRecording> createRecordingWithPredefinedTemplate(
+            String templateNameOrLabel) {
         Optional<Configuration> opt = getTemplate(templateNameOrLabel);
         if (opt.isEmpty()) {
             log.error(
@@ -58,16 +80,24 @@ public boolean isValidTemplate(String nameOrLabel) {
         return getTemplate(nameOrLabel).isPresent();
     }
 
-    public List<RecordingInfo> getRecordings() {
+    public List<Recording> getRecordings() {
+        return getRecordings(r -> true);
+    }
+
+    public List<Recording> getRecordings(Predicate<Recording> predicate) {
         if (!FlightRecorder.isAvailable()) {
             log.error("FlightRecorder is unavailable");
             return List.of();
         }
         return FlightRecorder.getFlightRecorder().getRecordings().stream()
-                .map(RecordingInfo::new)
+                .filter(predicate)
                 .collect(Collectors.toList());
     }
 
+    public Optional<Recording> getRecording(long id) {
+        return getRecordings(r -> r.getId() == id).stream().findFirst();
+    }
+
     @SuppressFBWarnings(value = {"EI_EXPOSE_REP", "EI_EXPOSE_REP2"})
     public static class TemplatedRecording {
         private final Configuration configuration;

src/main/java/io/cryostat/agent/MainModule.java

@@ -15,9 +15,7 @@
  */
 package io.cryostat.agent;
 
-import java.io.IOException;
 import java.net.URI;
-import java.nio.file.Path;
 import java.security.KeyManagementException;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
@@ -38,12 +36,8 @@
 import io.cryostat.agent.remote.RemoteContext;
 import io.cryostat.agent.remote.RemoteModule;
 import io.cryostat.agent.triggers.TriggerModule;
-import io.cryostat.core.net.JFRConnection;
-import io.cryostat.core.net.JFRConnectionToolkit;
-import io.cryostat.core.sys.Environment;
-import io.cryostat.core.sys.FileSystem;
-import io.cryostat.core.templates.LocalStorageTemplateService;
-import io.cryostat.core.tui.ClientWriter;
+import io.cryostat.core.JvmIdentifier;
+import io.cryostat.core.net.IDException;
 
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
@@ -71,7 +65,6 @@ public abstract class MainModule {
     // one for outbound HTTP requests, one for incoming HTTP requests, and one as a general worker
     private static final int NUM_WORKER_THREADS = 3;
     private static final String JVM_ID = "JVM_ID";
-    private static final String TEMPLATES_PATH = "TEMPLATES_PATH";
 
     @Provides
     @Singleton
@@ -242,76 +235,14 @@ public static FlightRecorderHelper provideFlightRecorderHelper() {
         return new FlightRecorderHelper();
     }
 
-    @Provides
-    @Singleton
-    public static FileSystem provideFileSystem() {
-        return new FileSystem();
-    }
-
-    @Provides
-    @Singleton
-    @Named(TEMPLATES_PATH)
-    public static Path provideTemplatesTmpPath(FileSystem fs) {
-        try {
-            return fs.createTempDirectory(null);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
-    @Provides
-    @Singleton
-    public static Environment provideEnvironment(@Named(TEMPLATES_PATH) Path templatesTmp) {
-        return new Environment() {
-            @Override
-            public String getEnv(String key) {
-                if (LocalStorageTemplateService.TEMPLATE_PATH.equals(key)) {
-                    return templatesTmp.toString();
-                }
-                return super.getEnv(key);
-            }
-        };
-    }
-
-    @Provides
-    @Singleton
-    public static ClientWriter provideClientWriter() {
-        Logger log = LoggerFactory.getLogger(JFRConnectionToolkit.class);
-        return new ClientWriter() {
-            @Override
-            public void print(String msg) {
-                log.info(msg);
-            }
-        };
-    }
-
-    @Provides
-    @Singleton
-    public static JFRConnectionToolkit provideJfrConnectionToolkit(
-            ClientWriter cw, FileSystem fs, Environment env) {
-        return new JFRConnectionToolkit(cw, fs, env);
-    }
-
     @Provides
     @Singleton
     @Named(JVM_ID)
-    public static String provideJvmId(JFRConnectionToolkit tk) {
-        Logger log = LoggerFactory.getLogger(JFRConnectionToolkit.class);
+    public static String provideJvmId() {
         try {
-            try (JFRConnection connection = tk.connect(tk.createServiceURL("localhost", 0))) {
-                String id = connection.getJvmId();
-                log.info("Computed self JVM ID: {}", id);
-                return id;
-            }
-        } catch (Exception e) {
+            return JvmIdentifier.getLocal().getHash();
+        } catch (IDException e) {
             throw new RuntimeException(e);
         }
     }
-
-    @Provides
-    @Singleton
-    public static LocalStorageTemplateService provideLocalStorageTemplateService(
-            FileSystem fs, Environment env) {
-        return new LocalStorageTemplateService(fs, env);
-    }
 }

src/main/java/io/cryostat/agent/harvest/Harvester.java

@@ -304,7 +304,7 @@ private void startRecording(boolean restart) {
                         return;
                     }
                     flightRecorderHelper
-                            .createRecording(template)
+                            .createRecordingWithPredefinedTemplate(template)
                             .ifPresent(
                                     recording -> {
                                         recording

src/main/java/io/cryostat/agent/remote/EventTemplatesContext.java

@@ -17,16 +17,14 @@
 
 import java.io.IOException;
 import java.io.OutputStream;
-import java.lang.management.ManagementFactory;
 import java.util.List;
 import java.util.stream.Collectors;
 
 import javax.inject.Inject;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.sun.net.httpserver.HttpExchange;
-import jdk.management.jfr.ConfigurationInfo;
-import jdk.management.jfr.FlightRecorderMXBean;
+import jdk.jfr.Configuration;
 import org.apache.http.HttpStatus;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -53,11 +51,9 @@ public void handle(HttpExchange exchange) throws IOException {
             switch (mtd) {
                 case "GET":
                     try {
-                        FlightRecorderMXBean bean =
-                                ManagementFactory.getPlatformMXBean(FlightRecorderMXBean.class);
                         List<String> xmlTexts =
-                                bean.getConfigurations().stream()
-                                        .map(ConfigurationInfo::getContents)
+                                Configuration.getConfigurations().stream()
+                                        .map(Configuration::getContents)
                                         .collect(Collectors.toList());
                         exchange.sendResponseHeaders(HttpStatus.SC_OK, BODY_LENGTH_UNKNOWN);
                         try (OutputStream response = exchange.getResponseBody()) {