Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.pulsar.functions.worker.rest.api; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufAllocator; import org.apache.pulsar.common.util.SimpleTextOutputStream; import org.apache.pulsar.functions.worker.FunctionsStatsGenerator; import org.apache.pulsar.functions.worker.WorkerService; import org.apache.pulsar.functions.worker.rest.FunctionApiResource; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.Response; import javax.ws.rs.core.StreamingOutput; @Path("/") public class FunctionsMetricsResource extends FunctionApiResource { @Path("metrics") @GET @Produces(MediaType.TEXT_PLAIN) public Response getMetrics() { WorkerService workerService = get(); ByteBuf buf = ByteBufAllocator.DEFAULT.heapBuffer(); try { SimpleTextOutputStream stream = new SimpleTextOutputStream(buf); FunctionsStatsGenerator.generate(workerService, "default", stream); byte[] payload = buf.array(); int arrayOffset = buf.arrayOffset(); int readableBytes = buf.readableBytes(); StreamingOutput streamOut = out -> { out.write(payload, arrayOffset, readableBytes); out.flush(); }; return Response.ok(streamOut).type(MediaType.TEXT_PLAIN_TYPE).build(); } finally { buf.release(); } } }