racing

Example: Racing

This example shows how to use the X-Ray plugin for httpx, in racing mode, in an executable running on a host.

Outcome

This example provides an executable program demonstrating how the httpx plugin (httpxxray) produces X-Ray traces when run on an ordinary host computer, and parallel request racing is enabled.

When you run the example program, it starts a "local" HTTPS server executes a simple GET request to the server using an httpx.Client with the X-Ray plugin installed. The first 4 attempts cause various errors necessitating retry; the fifth attempt succeeds. The final X-Ray trace thus shows one execution with 5 attempts as shown below.

Because racing is enabled, the third request attempt starts while the second request attempt is still blocked waiting on the request headers; similarly, the fifth request attempt starts while the fourth attempt is still reading the response body.

Steps

1. Install and start the X-Ray daemon.
2. Build the example program.
3. Run the example program.
4. View the generated trace in the AWS X-Ray console.

1. Install and start the X-Ray daemon

This example requires that you have the AWS X-Ray daemon installed and running on the host on default port (2000).

For instructions on installing and running the daemon, please see the official AWS X-Ray daemon documentation.

2. Build the example program

Build the example program using the below commands:

$ go get github.com/gogama/aws-xray-httpx/example/racing
$ go install github.com/gogama/aws-xray-httpx/example/racing

The above will download the example source code and build an executable program named racing (or racing.exe on Windows) in the directory GOBIN. (If your $ go env GOBIN is empty then it will be built to the directory $(go env GOPATH)/bin.)

3. Run the example program

Run the example program!

It should print output similar to:

2021-03-31T15:46:13Z [INFO] X-Ray proxy using address : 127.0.0.1:2000
2021-03-31T15:46:13Z [INFO] Successfully fetched sampling rules
Status: 200
Body:   Success!
2021-03-31T15:46:13Z [INFO] Emitter using address: 127.0.0.1:2000

4. View trace in X-Ray console

In the AWS console, navigate to AWS X-Ray.

Select Traces and view the most recent trace.