Tracing calls to downstream HTTP web services using the X-Ray SDK for Python

When your application makes calls to microservices or public HTTP APIs, you can use the X-Ray SDK for Python to instrument those calls and add the API to the service graph as a downstream service.

To instrument HTTP clients, patch the library that you use to make outgoing calls. If you use requests or Python's built in HTTP client, that's all you need to do. For aiohttp, also configure the recorder with an async context.

If you use aiohttp 3's client API, you also need to configure the ClientSession's with an instance of the tracing configuration provided by the SDK.

Example aiohttp 3 client API

from aws_xray_sdk.ext.aiohttp.client import aws_xray_trace_config

async def foo():
    trace_config = aws_xray_trace_config()
    async with ClientSession(loop=loop, trace_configs=[trace_config]) as session:
        async with session.get(url) as resp
            await resp.read()

When you instrument a call to a downstream web API, the X-Ray SDK for Python records a subsegment that contains information about the HTTP request and response. X-Ray uses the subsegment to generate an inferred segment for the remote API.

Example Subsegment for a downstream HTTP call

{
  "id": "004f72be19cddc2a",
  "start_time": 1484786387.131,
  "end_time": 1484786387.501,
  "name": "names.example.com",
  "namespace": "remote",
  "http": {
    "request": {
      "method": "GET",
      "url": "https://names.example.com/"
    },
    "response": {
      "content_length": -1,
      "status": 200
    }
  }
}

Example Inferred segment for a downstream HTTP call

{
  "id": "168416dc2ea97781",
  "name": "names.example.com",
  "trace_id": "1-62be1272-1b71c4274f39f122afa64eab",
  "start_time": 1484786387.131,
  "end_time": 1484786387.501,
  "parent_id": "004f72be19cddc2a",
  "http": {
    "request": {
      "method": "GET",
      "url": "https://names.example.com/"
    },
    "response": {
      "content_length": -1,
      "status": 200
    }
  },
  "inferred": true
}