如何用Java/Python/Postman调用带Snappy压缩的Prometheus remote_write API

当调用Prometheus的/api/v1/write接口写入数据时出现「snappy: corrupt input」错误，本质是远程接收器要求请求体必须经过Snappy压缩，直接发送明文文本不符合要求。以下是Python、Java和Postman的实现方案：

Python 示例 #

依赖python-snappy处理压缩，requests发送HTTP请求：

1. 先安装依赖包：

pip install requests python-snappy

2. 代码实现：

import requests
import snappy

# 待写入的Prometheus指标内容
metric_content = 'metrics_app_20221201091829_0000_driver_BlockManager_memory_diskSpaceUsed_MB_Number{type="gauges"} 0\n'

# 对文本进行Snappy压缩
compressed_data = snappy.compress(metric_content.encode('utf-8'))

# 发送POST请求
request_url = 'http://<prometheus-host>/api/v1/write'
headers = {
    'Content-Type': 'application/x-protobuf',
    'Content-Encoding': 'snappy'
}

response = requests.post(request_url, headers=headers, data=compressed_data)
print(f"响应状态码: {response.status_code}")
print(f"响应内容: {response.text}")

Java 示例 #

使用org.xerial.snappy做Snappy压缩，OkHttp处理HTTP请求：

1. Maven依赖配置：

<dependencies>
    <dependency>
        <groupId>com.squareup.okhttp3</groupId>
        <artifactId>okhttp</artifactId>
        <version>4.10.0</version>
    </dependency>
    <dependency>
        <groupId>org.xerial.snappy</groupId>
        <artifactId>snappy-java</artifactId>
        <version>1.1.10.1</version>
    </dependency>
</dependencies>

2. 代码实现：

import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;
import org.xerial.snappy.Snappy;
import java.io.IOException;

public class PrometheusRemoteWriter {
    public static void main(String[] args) throws IOException {
        // 指标文本内容
        String metricText = "metrics_app_20221201091829_0000_driver_BlockManager_memory_diskSpaceUsed_MB_Number{type=\"gauges\"} 0\n";
        byte[] rawBytes = metricText.getBytes("UTF-8");
        
        // 执行Snappy压缩
        byte[] compressedBytes = Snappy.compress(rawBytes);
        
        // 构建并发送请求
        OkHttpClient client = new OkHttpClient();
        MediaType mediaType = MediaType.parse("application/x-protobuf");
        RequestBody body = RequestBody.create(compressedBytes, mediaType);
        
        Request request = new Request.Builder()
                .url("http://<prometheus-host>/api/v1/write")
                .post(body)
                .addHeader("Content-Encoding", "snappy")
                .build();
        
        try (Response response = client.newCall(request).execute()) {
            System.out.println("响应状态码: " + response.code());
            System.out.println("响应内容: " + response.body().string());
        }
    }
}

Postman 操作步骤 #

1. 新建POST请求，填入目标URL：http://<prometheus-host>/api/v1/write
2. 在Headers标签页添加两个请求头：
   • Content-Type: application/x-protobuf
   • Content-Encoding: snappy
3. 切换到Body标签页，选择binary类型，点击Select File
4. 提前将明文指标文本通过Snappy压缩为二进制文件（可借助Python脚本生成：读取文本文件后用snappy.compress()处理，再写入新文件）
5. 选择压缩后的二进制文件，点击「发送」即可

注意事项 #

• 必须设置Content-Encoding: snappy请求头，明确告知服务器请求体的压缩方式
• 部分远程接收器要求Content-Type为application/x-protobuf，而非原始的text/plain，需根据实际配置调整

内容的提问来源于stack exchange，提问作者Shane