| /* |
| * 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.cassandra.sidecar.routes; |
| |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.TimeUnit; |
| import java.util.function.Supplier; |
| import javax.annotation.Nullable; |
| 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 com.google.common.collect.ImmutableMap; |
| |
| import com.datastax.driver.core.Cluster; |
| import com.datastax.driver.core.Host; |
| import com.google.inject.Inject; |
| import com.google.inject.Singleton; |
| import io.netty.handler.codec.http.HttpResponseStatus; |
| import io.swagger.v3.oas.annotations.Operation; |
| import io.swagger.v3.oas.annotations.responses.ApiResponse; |
| import io.vertx.core.json.Json; |
| import io.vertx.core.logging.Logger; |
| import io.vertx.core.logging.LoggerFactory; |
| import org.apache.cassandra.sidecar.CQLSession; |
| import org.apache.cassandra.sidecar.Configuration; |
| |
| /** |
| * Tracks health check[s] and provides a REST response that should match that defined by api.yaml |
| */ |
| @Singleton |
| @Path("/api/v1/__health") |
| public class HealthService implements Host.StateListener |
| { |
| private static final Logger logger = LoggerFactory.getLogger(HealthService.class); |
| private final int checkPeriodMs; |
| private final Supplier<Boolean> check; |
| private volatile boolean registered = false; |
| |
| @Nullable |
| private final CQLSession session; |
| |
| private final ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor(); |
| private volatile boolean lastKnownStatus = false; |
| |
| @Inject |
| public HealthService(Configuration config, HealthCheck check, @Nullable CQLSession session) |
| { |
| this.checkPeriodMs = config.getHealthCheckFrequencyMillis(); |
| this.session = session; |
| this.check = check; |
| } |
| |
| public synchronized void start() |
| { |
| logger.info("Starting health check"); |
| maybeRegisterHostListener(); |
| executor.scheduleWithFixedDelay(this::refreshNow, 0, checkPeriodMs, TimeUnit.MILLISECONDS); |
| } |
| |
| public synchronized void refreshNow() |
| { |
| try |
| { |
| lastKnownStatus = this.check.get(); |
| maybeRegisterHostListener(); |
| } |
| catch (Exception e) |
| { |
| logger.error("Error while performing health check", e); |
| } |
| } |
| |
| private synchronized void maybeRegisterHostListener() |
| { |
| if (!registered) |
| { |
| if (session != null && session.getLocalCql() != null) |
| { |
| session.getLocalCql().getCluster().register(this); |
| registered = true; |
| } |
| } |
| } |
| |
| public synchronized void stop() |
| { |
| logger.info("Stopping health check"); |
| executor.shutdown(); |
| } |
| |
| @Operation(summary = "Health Check for Cassandra's status", |
| description = "Returns HTTP 200 if Cassandra is available, 503 otherwise", |
| responses = { |
| @ApiResponse(responseCode = "200", description = "Cassandra is available"), |
| @ApiResponse(responseCode = "503", description = "Cassandra is not available") |
| }) |
| @Produces(MediaType.APPLICATION_JSON) |
| @GET |
| public Response doGet() |
| { |
| int status = lastKnownStatus ? HttpResponseStatus.OK.code() : HttpResponseStatus.SERVICE_UNAVAILABLE.code(); |
| return Response.status(status).entity(Json.encode(ImmutableMap.of("status", lastKnownStatus ? |
| "OK" : "NOT_OK"))).build(); |
| } |
| |
| public void onAdd(Host host) |
| { |
| refreshNow(); |
| } |
| |
| public void onUp(Host host) |
| { |
| refreshNow(); |
| } |
| |
| public void onDown(Host host) |
| { |
| refreshNow(); |
| } |
| |
| public void onRemove(Host host) |
| { |
| refreshNow(); |
| } |
| |
| public void onRegister(Cluster cluster) |
| { |
| } |
| |
| public void onUnregister(Cluster cluster) |
| { |
| } |
| } |