photoncloud-monorepo/nightlight/crates/nightlight-server/examples/query_metrics.rs

//! Example: Query metrics from Nightlight using PromQL
//!
//! This example demonstrates how to query metrics from a running Nightlight
//! server using the Prometheus-compatible HTTP API.
//!
//! # Usage
//!
//! 1. Start a Nightlight server:
//!    ```bash
//!    cargo run --bin nightlight-server
//!    ```
//!
//! 2. Run this example:
//!    ```bash
//!    cargo run --example query_metrics
//!    ```
//!
//! # Prerequisites
//!
//! The server should have some data ingested via the push_metrics example first.

use serde::{Deserialize, Serialize};

#[derive(Debug, Deserialize, Serialize)]
struct QueryResponse {
    status: String,
    data: Option<serde_json::Value>,
    error: Option<String>,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("Nightlight Query Client Example");
    println!("================================\n");

    let client = reqwest::Client::new();
    let base_url = "http://127.0.0.1:9101";

    // Example 1: Instant Query
    println!("1. Instant Query: up");
    println!("   GET /api/v1/query?query=up");
    let response = client
        .get(format!("{}/api/v1/query", base_url))
        .query(&[("query", "up")])
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    // Example 2: Instant Query with Time
    println!("2. Instant Query with Timestamp");
    println!("   GET /api/v1/query?query=http_requests_total&time=1234567890000");
    let response = client
        .get(format!("{}/api/v1/query", base_url))
        .query(&[("query", "http_requests_total"), ("time", "1234567890000")])
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    // Example 3: Label Selector
    println!("3. Query with Label Selector");
    println!("   GET /api/v1/query?query=http_requests_total{{method=\"GET\"}}");
    let response = client
        .get(format!("{}/api/v1/query", base_url))
        .query(&[("query", "http_requests_total{method=\"GET\"}")])
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    // Example 4: Aggregation
    println!("4. Aggregation Query");
    println!("   GET /api/v1/query?query=sum(http_requests_total)");
    let response = client
        .get(format!("{}/api/v1/query", base_url))
        .query(&[("query", "sum(http_requests_total)")])
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    // Example 5: Range Query
    let now = chrono::Utc::now().timestamp_millis();
    let one_hour_ago = now - 3600 * 1000;
    println!("5. Range Query");
    println!(
        "   GET /api/v1/query_range?query=http_requests_total&start={}&end={}&step=60000",
        one_hour_ago, now
    );
    let response = client
        .get(format!("{}/api/v1/query_range", base_url))
        .query(&[
            ("query", "http_requests_total"),
            ("start", &one_hour_ago.to_string()),
            ("end", &now.to_string()),
            ("step", "60000"), // 1 minute step
        ])
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    // Example 6: Rate Function
    println!("6. Rate Function");
    println!("   GET /api/v1/query?query=rate(http_requests_total[5m])");
    let response = client
        .get(format!("{}/api/v1/query", base_url))
        .query(&[("query", "rate(http_requests_total[5m])")])
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    // Example 7: Label Values
    println!("7. Label Values Query");
    println!("   GET /api/v1/label/method/values");
    let response = client
        .get(format!("{}/api/v1/label/method/values", base_url))
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    // Example 8: Series Metadata
    println!("8. Series Metadata Query");
    println!("   GET /api/v1/series");
    let response = client
        .get(format!("{}/api/v1/series", base_url))
        .send()
        .await?;

    println!("   Status: {}", response.status());
    let data: QueryResponse = response.json().await?;
    println!("   Response: {}\n", serde_json::to_string_pretty(&data)?);

    println!("\n================================");
    println!("Query examples completed!");
    println!("\nTip: You can use these query patterns in Grafana by configuring");
    println!("     a Prometheus data source pointing to http://localhost:9101");

    Ok(())
}