feat(agent): implement Agent HTTP recording retrieval

src/main/java/io/cryostat/net/AgentClient.java

@@ -46,6 +46,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ForkJoinPool;
+import java.io.InputStream;
 
 import javax.script.ScriptException;
 
@@ -152,6 +153,25 @@ Future<IRecordingDescriptor> startRecording(StartRecordingRequest req) {
                 });
     }
 
+    Future<Buffer> openStream(long id) {
+        Future<HttpResponse<Buffer>> f =
+                invoke(
+                        HttpMethod.GET,
+                        "/recordings/" + id,
+                        BodyCodec.buffer());
+        return f.map(
+                resp -> {
+                    int statusCode = resp.statusCode();
+                    if (HttpStatusCodeIdentifier.isSuccessCode(statusCode)) {
+                        return resp.body();
+                    } else if (statusCode == 403) {
+                        throw new UnsupportedOperationException();
+                    } else {
+                        throw new RuntimeException("Unknown failure");
+                    }
+                });
+    }
+
     Future<Void> stopRecording(long id) {
         Future<HttpResponse<Void>> f =
                 invoke(

src/main/java/io/cryostat/net/AgentJFRService.java

@@ -37,6 +37,8 @@
  */
 package io.cryostat.net;
 
+import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.text.ParseException;
@@ -72,6 +74,8 @@
 import io.cryostat.core.templates.MergedTemplateService;
 import io.cryostat.core.templates.Template;
 import io.cryostat.core.templates.TemplateType;
+import io.vertx.core.Future;
+import io.vertx.core.buffer.Buffer;
 
 import org.jsoup.nodes.Document;
 
@@ -208,20 +212,29 @@ public boolean isEnabled() {
     }
 
     @Override
-    public InputStream openStream(IRecordingDescriptor arg0, boolean arg1)
+    public InputStream openStream(IRecordingDescriptor descriptor, boolean removeOnClose)
             throws FlightRecorderException {
-        throw new UnimplementedException();
+        Future<Buffer> f = client.openStream(descriptor.getId());
+        try {
+            Buffer b = f.toCompletionStage().toCompletableFuture().get();
+            return new BufferedInputStream(
+                    new ByteArrayInputStream(b.getBytes())
+                    );
+        } catch (ExecutionException | InterruptedException e) {
+            logger.warn(e);
+            throw new FlightRecorderException("Failed to open remote recording stream", e);
+        }
     }
 
     @Override
-    public InputStream openStream(IRecordingDescriptor arg0, IQuantity arg1, boolean arg2)
+    public InputStream openStream(IRecordingDescriptor descriptor, IQuantity lastPartDuration, boolean removeOnClose)
             throws FlightRecorderException {
         throw new UnimplementedException();
     }
 
     @Override
     public InputStream openStream(
-            IRecordingDescriptor arg0, IQuantity arg1, IQuantity arg2, boolean arg3)
+            IRecordingDescriptor descriptor, IQuantity startTime, IQuantity endTime, boolean removeOnClose)
             throws FlightRecorderException {
         throw new UnimplementedException();
     }

src/main/java/io/cryostat/net/web/WebServer.java

@@ -72,6 +72,7 @@
 import io.cryostat.net.web.http.api.ApiVersion;
 import io.cryostat.net.web.http.api.v2.ApiException;
 import io.cryostat.util.HttpStatusCodeIdentifier;
+import io.cryostat.util.URIUtil;
 
 import com.google.gson.Gson;
 import io.vertx.core.AbstractVerticle;
@@ -318,13 +319,7 @@ public String getAssetDownloadURL(ApiVersion apiVersion, String... pathSegments)
     }
 
     private String getTargetId(JFRConnection conn) throws IOException {
-        // TODO this is a hack, the JFRConnection interface should be refactored to expose a more
-        // general connection URL / targetId method since the JMX implementation is now only one
-        // possible implementation
-        if (conn instanceof AgentConnection) {
-            return ((AgentConnection) conn).getUri().toString();
-        }
-        return conn.getJMXURL().toString();
+        return URIUtil.getConnectionUri(conn).toString();
     }
 
     public FileUpload getTempFileUpload(

src/main/java/io/cryostat/recordings/RecordingArchiveHelper.java

@@ -938,7 +938,7 @@ private void validateRecordingPath(
 
     Path writeRecordingToDestination(JFRConnection connection, IRecordingDescriptor descriptor)
             throws IOException, URISyntaxException, FlightRecorderException, Exception {
-        URI serviceUri = URIUtil.convert(connection.getJMXURL());
+        URI serviceUri = URIUtil.getConnectionUri(connection);
         String jvmId = jvmIdHelper.getJvmId(serviceUri.toString());
         Path specificRecordingsPath = getRecordingSubdirectoryPath(jvmId);
         if (!fs.exists(specificRecordingsPath)) {

src/main/java/io/cryostat/util/URIUtil.java

@@ -37,11 +37,15 @@
  */
 package io.cryostat.util;
 
+import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
 
 import javax.management.remote.JMXServiceURL;
 
+import io.cryostat.core.net.JFRConnection;
+import io.cryostat.net.AgentConnection;
+
 public class URIUtil {
     private URIUtil() {}
 
@@ -70,4 +74,14 @@ public static URI getRmiTarget(JMXServiceURL serviceUrl) throws URISyntaxExcepti
         }
         return new URI(pathPart.substring("/jndi/".length(), pathPart.length()));
     }
+
+    public static URI getConnectionUri(JFRConnection connection) throws IOException {
+        // TODO this is a hack, the JFRConnection interface should be refactored to expose a more
+        // general connection URL / targetId method since the JMX implementation is now only one
+        // possible implementation
+        if (connection instanceof AgentConnection) {
+            return ((AgentConnection) connection).getUri();
+        }
+        return URI.create(connection.getJMXURL().toString());
+    }
 }