Rocket Prometheus监控插件使用指南

基本用法

首先在Cargo.toml中添加依赖：

[dependencies]
rocket = "0.5.0"
rocket_prometheus = "0.10.1"

然后在Rocket应用中添加并挂载PrometheusMetrics实例：

use rocket_prometheus::PrometheusMetrics;

#[rocket::launch]
fn launch() -> _ {
    let prometheus = PrometheusMetrics::new();
    rocket::build()
        .attach(prometheus.clone())
        .mount("/metrics", prometheus)
}

这样会在应用的/metrics端点暴露如下指标：

$ curl localhost:8000/metrics
# HELP rocket_http_requests_duration_seconds HTTP request duration in seconds for all requests
# TYPE rocket_http_requests_duration_seconds histogram
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="0.005"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="0.01"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="0.025"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="0.05"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="0.1"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/ metrics",method="GET",status="200",le="0.25"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="0.5"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="1"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="2.5"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="5"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="10"} 2
rocket_http_requests_duration_seconds_bucket{endpoint="/metrics",method="GET",status="200",le="+Inf"} 2
rocket_http_requests_duration_seconds_sum{endpoint="/metrics",method="GET",status="200"} 0.0011045669999999999
rocket_http_requests_duration_seconds_count{endpoint="/metrics",method="GET",status="200"} 2
# HELP rocket_http_requests_total Total number of HTTP requests
# TYPE rocket_http_requests_total counter
rocket_http_requests_total{endpoint="/metrics",method="GET",status="200"} 2

默认指标

该插件默认跟踪两个指标：

• rocket_http_requests_total (标签: endpoint, method, status): Rocket处理的HTTP请求总数
• rocket_http_requests_duration_seconds (标签: endpoint, method, status): Rocket处理的所有HTTP请求的请求持续时间

可以通过设置ROCKET_PROMETHEUS_NAMESPACE环境变量来更改这些指标的"rocket"前缀。

自定义指标

可以通过向PrometheusMetrics实例的注册表注册新指标来跟踪更多指标：

#[macro_use]
use once_cell::sync::Lazy;
use rocket::{get, launch, routes};
use rocket_prometheus::{
    prometheus::{opts, IntCounterVec},
    PrometheusMetrics,
};

static NAME_COUNTER: Lazy<IntCounterVec> = Lazy::new(|| {
    IntCounterVec::new(opts!("name_counter", "Count of names"), &["name"])
        .expect("Could not create NAME_COUNTER")
});

#[get("/hello/<name>")]
pub fn hello(name: &str) -> String {
    NAME_COUNTER.with_label_values(&[name]).inc();
    format!("Hello, {}!", name)
}

#[launch]
fn launch() -> _ {
    let prometheus = PrometheusMetrics::new();
    prometheus
        .registry()
        .register(Box::new(NAME_COUNTER.clone()))
        .unwrap();
    rocket::build()
        .attach(prometheus.clone())
        .mount("/", routes![hello])
        .mount("/metrics", prometheus)
}

完整示例代码

use once_cell::sync::Lazy;
use rocket::{get, launch, routes};
use rocket_p极地us::{
    prometheus::{opts, IntCounterVec, HistogramOpts, Histogram},
    PrometheusMetrics,
};

// 定义自定义计数器
static NAME_COUNTER: Lazy<IntCounterVec> = Lazy::new(|| {
    IntCounterVec::new(opts!("name_counter", "Count of names"), &["name"])
        .expect("Could not create NAME_COUNTER")
});

// 定义自定义直方图
static RESPONSE_TIME: Lazy<Histogram> = Lazy::new(|| {
    Histogram::with_opts(HistogramOpts::new(
        "response_time_seconds",
        "Response time in seconds",
    ))
    .expect("Could not create RESPONSE_TIME")
});

#[get("/hello/<name>")]
pub fn hello(name: &str) -> String {
    // 记录名称访问次数
    NAME_COUNTER.with_label_values(&[name]).inc();
    
    // 计时器开始
    let timer = RESPONSE_TIME.start_timer();
    
    // 模拟处理时间
    std::thread::sleep(std::time::Duration::from_millis(100));
    
    // 计时器结束并记录
    timer.observe_duration();
    
    format!("Hello, {}!", name)
}

#[launch]
fn launch() -> _ {
    let prometheus = PrometheusMetrics::new();
    
    // 注册自定义指标
    prometheus
        .registry()
        .register(Box::new(NAME_COUNTER.clone()))
        .unwrap();
    prometheus
        .registry()
        .register(Box::new(RESPONSE_TIME.clone()))
        .unwrap();
        
    rocket::build()
        .attach(prometheus.clone())
        .mount("/", routes![hello])
        .mount("/metrics", prometheus)
}

这个完整示例展示了如何：

1. 创建一个基本的Rocket应用
2. 集成Prometheus监控
3. 添加自定义计数器指标(NAME_COUNTER)
4. 添加自定义直方图指标(RESPONSE_TIME)
5. 在路由处理程序中记录指标数据

应用启动后，访问/metrics端点可以看到所有默认和自定义的指标数据。