| /* |
| * 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 SF 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.felix.hc.api; |
| |
| import org.osgi.annotation.versioning.ConsumerType; |
| |
| /** The Health Check SPI provides a means to check a certain system aspect programmatically. Health checks return a result {@link Result}, |
| * for most cases it is most convenient to use {@link FormattingResultLog} that automatically derives the correct {@link Result.Status} from |
| * the log messages. |
| * |
| * Clients should not look up health checks directly but rather use the {@link org.apache.felix.hc.api.execution.HealthCheckExecutor} |
| * service and executed checks based on tags. |
| * |
| * If the {@link #MBEAN_NAME} service registration property is set, the health check is registered as an mbean and can be invoked by getting |
| * the MBean from the JMX registry. */ |
| @ConsumerType |
| public interface HealthCheck { |
| |
| /** Optional service property: the name of a health check. This name should be unique, however there might be more than one health check |
| * service with the same value for this property. The value of this property must be of type String. */ |
| String NAME = "hc.name"; |
| |
| /** Optional service property: tags for categorizing the health check services. The value of this property must be of type String or |
| * String array. */ |
| String TAGS = "hc.tags"; |
| |
| /** Optional service property: the name of the MBean for registering the health check as an MBean. If this property is missing the |
| * health check is not registered as a JMX MBean. If there is more than one service with the same value for this property, the one with |
| * the highest service ranking is registered only. The value of this property must be of type String. */ |
| String MBEAN_NAME = "hc.mbean.name"; |
| |
| /** Optional service property: If this property is set the health check will be executed asynchronously using the cron expression |
| * provided. */ |
| String ASYNC_CRON_EXPRESSION = "hc.async.cronExpression"; |
| |
| /** Optional service property: If this property is set the health check will be executed asynchronously every n seconds */ |
| String ASYNC_INTERVAL_IN_SEC = "hc.async.intervalInSec"; |
| |
| /** Optional service property: TTL for health check {@link Result}. The value of this property must be of type {@link Long} and is |
| * specified in ms. */ |
| String RESULT_CACHE_TTL_IN_MS = "hc.resultCacheTtlInMs"; |
| |
| /** Optional service property: If given, non-ok results from past executions will be taken into account as well for the given seconds |
| * (use Long.MAX_VALUE for indefinitely). Useful for unhealthy system states that disappear but might leave the system at an |
| * inconsistent state (e.g. an event queue overflow where somebody needs to intervene manually) or for checks that should only go back |
| * to OK with a delay (can be useful for load balancers). */ |
| String KEEP_NON_OK_RESULTS_STICKY_FOR_SEC = "hc.keepNonOkResultsStickyForSec"; |
| |
| /** Execute this health check and return a {@link Result}.*/ |
| Result execute(); |
| } |