Node.js 18读取S3 JSON文件时触发TypeError: Converting circular structure to JSON错误

错误详情 #

TypeError: Converting circular structure to JSON
--> starting at object with constructor 'TLSSocket'
| property 'parser' -> object with constructor 'HTTPParser'
--- property 'socket' closes the circle
at JSON.stringify (<anonymous>)
at responseHook (/opt/wrapper.js:147:24)
at /opt/nodejs/node_modules/@opentelemetry/instrumentation-aws-sdk/build/src/aws-sdk.js:149:61
at safeExecuteInTheMiddle (/opt/nodejs/node_modules/@opentelemetry/instrumentation/build/src/utils.js:28:18)
at AwsInstrumentation._callUserResponseHook (/opt/nodejs/node_modules/@opentelemetry/instrumentation-aws-sdk/build/src/aws-sdk.js:149:54)
at /opt/nodejs/node_modules/@opentelemetry/instrumentation-aws-sdk/build/src/aws-sdk.js:269:34
at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

场景与代码片段 #

在Node.js 18环境下，使用@aws-sdk/client-s3的S3Client和GetObjectCommand读取S3中的JSON文件，调用.transformToString('utf-8')将返回内容转为字符串时触发了上述错误，相关代码如下：

const client = new S3Client({
    region
});
const params = {
    Bucket: bucket,
    Key: key
};
const response = await client.send(new GetObjectCommand(params));
const body = await response.Body.transformToString('utf-8');

解决方案 #

这个错误和transformToString本身无关，是OpenTelemetry的AWS SDK instrumentation插件在序列化响应对象时，试图处理包含循环引用的TLSSocket等底层网络对象导致的。可通过以下方式解决：

• 禁用OpenTelemetry对AWS SDK的自动 instrumentation
  如果不需要追踪AWS SDK调用，可直接在代码中关闭该插件，或在部署配置中移除相关依赖。示例代码：

  const { NodeTracerProvider } = require('@opentelemetry/sdk-trace-node');
  const { registerInstrumentations } = require('@opentelemetry/instrumentation');
  const { AwsInstrumentation } = require('@opentelemetry/instrumentation-aws-sdk');
  
  registerInstrumentations({
      instrumentations: [
          // 移除或注释掉AWS SDK instrumentation的初始化代码
          // new AwsInstrumentation(),
      ],
  });
  

• 修改responseHook逻辑，避免序列化整个响应对象
  如果必须保留追踪，需调整/opt/wrapper.js第147行的responseHook实现，只序列化业务所需字段（比如响应体内容），不要直接序列化包含底层网络连接的完整response对象。

• 临时替换响应体读取方式
  可以绕开transformToString，改用流读取方式临时规避错误：

  const { Readable } = require('stream');
  const response = await client.send(new GetObjectCommand(params));
  const body = await new Promise((resolve, reject) => {
      const chunks = [];
      Readable.from(response.Body)
          .on('data', chunk => chunks.push(chunk))
          .on('end', () => resolve(Buffer.concat(chunks).toString('utf-8')))
          .on('error', reject);
  });
  

内容的提问来源于stack exchange，提问作者shakya-abhi