feat(diagnostics): Add endpoint for triggering heap dumps

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

@@ -374,6 +374,60 @@ public CompletableFuture<Void> update(
         }
     }
 
+    public CompletableFuture<Void> pushHeapDump(int maxFiles, String fileName, Path heapDump)
+            throws IOException {
+        Instant start = Instant.now();
+
+        HttpPost req =
+                new HttpPost(baseUri.resolve("/api/beta/diagnostics/heapdump/upload/" + jvmId));
+
+        CountingInputStream is = getRecordingInputStream(heapDump);
+
+        MultipartEntityBuilder entityBuilder =
+                MultipartEntityBuilder.create()
+                        .addPart(
+                                FormBodyPartBuilder.create(
+                                                "heapDump",
+                                                new InputStreamBody(
+                                                        is,
+                                                        ContentType.APPLICATION_OCTET_STREAM,
+                                                        fileName))
+                                        .build())
+                        .addPart(
+                                FormBodyPartBuilder.create(
+                                                "maxFiles",
+                                                new StringBody(
+                                                        Integer.toString(maxFiles),
+                                                        ContentType.TEXT_PLAIN))
+                                        .build());
+        req.setEntity(entityBuilder.build());
+        return supply(
+                        req,
+                        (res) -> {
+                            Instant finish = Instant.now();
+                            log.trace(
+                                    "{} {} ({} -> {}): {}/{}",
+                                    req.getMethod(),
+                                    res.getStatusLine().getStatusCode(),
+                                    fileName,
+                                    req.getURI(),
+                                    FileUtils.byteCountToDisplaySize(is.getByteCount()),
+                                    Duration.between(start, finish));
+                            assertOkStatus(req, res);
+                            return (Void) null;
+                        })
+                .whenComplete(
+                        (v, t) -> {
+                            // Heap dump files tend to be very large, clean up after uploading
+                            try {
+                                Files.delete(heapDump);
+                            } catch (IOException ioe) {
+                                log.warn("Failed to delete heap dump: ", heapDump.toString());
+                            }
+                            req.reset();
+                        });
+    }
+
     public CompletableFuture<Void> upload(
             Harvester.PushType pushType,
             Optional<TemplatedRecording> opt,

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

@@ -19,12 +19,16 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.lang.management.ManagementFactory;
+import java.nio.file.Paths;
+import java.util.Arrays;
 import java.util.Objects;
 
 import javax.inject.Inject;
 import javax.management.MBeanServer;
 import javax.management.ObjectName;
 
+import io.cryostat.agent.CryostatClient;
+
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.sun.net.httpserver.HttpExchange;
 import org.apache.http.HttpStatus;
@@ -40,10 +44,13 @@ class InvokeContext extends MutatingRemoteContext {
     private final Logger log = LoggerFactory.getLogger(getClass());
     private final ObjectMapper mapper;
 
+    private CryostatClient client;
+
     @Inject
-    InvokeContext(ObjectMapper mapper, Config config) {
+    InvokeContext(ObjectMapper mapper, Config config, CryostatClient client) {
         super(config);
         this.mapper = mapper;
+        this.client = client;
     }
 
     @Override
@@ -64,6 +71,9 @@ public void handle(HttpExchange exchange) throws IOException {
                             exchange.sendResponseHeaders(
                                     HttpStatus.SC_BAD_REQUEST, BODY_LENGTH_NONE);
                         }
+                        log.warn(
+                                "Dumping heap with parameters: "
+                                        + Arrays.asList(req.parameters).toString());
                         MBeanServer server = ManagementFactory.getPlatformMBeanServer();
                         Object response =
                                 server.invoke(
@@ -72,6 +82,14 @@ public void handle(HttpExchange exchange) throws IOException {
                                         req.parameters,
                                         req.signature);
 
+                        // TODO: Verify if dumpHeap is blocking, if so we should split the
+                        // invocation
+                        // into a separate thread and listen for when it finishes
+                        if (req.getOperation().equals("dumpHeap")) {
+                            String fileName = req.getParameters()[0].toString();
+                            client.pushHeapDump(1, fileName, Paths.get(fileName));
+                        }
+
                         if (Objects.nonNull(response)) {
                             exchange.sendResponseHeaders(HttpStatus.SC_OK, BODY_LENGTH_UNKNOWN);
                             try (OutputStream responseStream = exchange.getResponseBody()) {
@@ -103,8 +121,12 @@ static class MBeanInvocationRequest<T> {
         public Object[] parameters;
         public String[] signature;
 
+        private static final String HOTSPOT_DIAGNOSTIC_BEAN_NAME =
+                "com.sun.management:type=HotSpotDiagnostic";
+
         public boolean isValid() {
-            if (this.beanName.equals(ManagementFactory.MEMORY_MXBEAN_NAME)) {
+            if (this.beanName.equals(ManagementFactory.MEMORY_MXBEAN_NAME)
+                    || this.beanName.equals(HOTSPOT_DIAGNOSTIC_BEAN_NAME)) {
                 return true;
             } else if (this.beanName.equals(DIAGNOSTIC_BEAN_NAME)
                     && (this.operation.equals(DUMP_THREADS)
@@ -114,6 +136,14 @@ public boolean isValid() {
             return false;
         }
 
+        public Object[] getParameters() {
+            return parameters;
+        }
+
+        public void setParameters(Object[] parameters) {
+            this.parameters = parameters;
+        }
+
         public String getBeanName() {
             return beanName;
         }