Spring-Boot Liveness 和 Readness 接口使用

Dear 丶 2022-10-22 04:28 58阅读 0赞

# Spring Boot Liveness 和 Readness 接口使用 #

在 Spring Boot 2.3+ 中，提供了单独的 liveness 和 readness，用于为 Kubernetes 提供相应检查接口

*  liveness  
    用于检查应用是否存活，当应用组件因故障不健康时，可以通过这个接口的结果，配置相应策略，重启应用或重新调度 Pod
 *  readness  
    用于检查应用是否就绪，是否可以提供服务，如当流量太大超过应用的承载范围时，可以将这个接口的状态改为不健康，这样可以停止接收流量，当处理完后再次检查时变为健康，继续处理请求

## 配置 ##

*  build.gradle 添加依赖

plugins { 
        id 'org.springframework.boot' version '2.3.2.RELEASE'
        id 'io.spring.dependency-management' version '1.0.9.RELEASE'
        id 'java'
    }
    dependencies { 
        implementation 'org.springframework.boot:spring-boot-starter-actuator'
        implementation 'org.springframework.boot:spring-boot-starter-web'
    }

*  application.properties 添加配置

从 2.3.2 开始，`/actuator/health` 接口添加了分组的概念，默认分为 liveness 和 readness 两个组，需要显式指定后才可以使用，否则会返回 404；`/actuator/health` 接口包含所有的指标

当前应用支持的指标，可以设置 `management.endpoint.health.show-details=always`后从 `/actuator/health` 接口获取

先指定 readness 指标，之后可以将剩余的所有指标设置为 liveness 的指标

management.endpoint.health.show-details=always
    management.endpoint.health.group.readiness.include=ping
    management.endpoint.health.group.liveness.include=*
    management.endpoint.health.group.liveness.exclude=${management.endpoint.health.group.readiness.include}

## 测试 ##

*  启动应用

### 请求相应的接口 ###

*  health

curl http://localhost:8080/actuator/health

{ 
        "status": "UP",
        "components": { 
            "diskSpace": { 
                "status": "UP",
                "details": { 
                    "total": 499963174912,
                    "free": 380364800000,
                    "threshold": 10485760,
                    "exists": true
                }
            },
            "livenessStateProbeIndicator": { 
                "status": "UP"
            },
            "ping": { 
                "status": "UP"
            },
            "readinessStateProbeIndicator": { 
                "status": "UP"
            }
        },
        "groups": [
            "liveness",
            "readiness"
        ]
    }

*  readiness

curl http://localhost:8080/actuator/health/readiness

{ 
        "components": { 
            "ping": { 
                "status": "UP"
            }
        },
        "status": "UP"
    }

*  liveness

curl http://localhost:8080/actuator/health/liveness

{ 
        "components": { 
            "custom": { 
                "details": { 
                    "Status": "Health"
                },
                "status": "UP"
            },
            "diskSpace": { 
                "details": { 
                    "exists": true,
                    "free": 380286464000,
                    "threshold": 10485760,
                    "total": 499963174912
                },
                "status": "UP"
            }
        },
        "status": "UP"
    }

## 自定义检查项 ##

和自定义健康检查项一样，添加一个新的 `HealthIndicator`，添加到相应的分组即可

*  CustomHealthIndicator.java

@Component
    public class CustomHealthIndicator implements HealthIndicator {
    
        private boolean health = true;
    
        @Override
        public Health health() {
            if (health) {
                return Health.up().withDetail("Status", "Health").build();
            }
            return Health.down().withDetail("Status", "Not Health").build();
        }
    
        public void setHealth(boolean health) {
            this.health = health;
        }
    }

*  applicaiton.properties

management.endpoint.health.group.readiness.include=ping,custom

### 测试 ###

*  readiness

curl http://localhost:8080/actuator/health/readiness

{ 
        "components": { 
            "custom": { 
                "details": { 
                    "Status": "Health"
                },
                "status": "UP"
            },
            "ping": { 
                "status": "UP"
            }
        },
        "status": "UP"
    }