Cloud Native Custom Plugin Example: envoy-extproc-method-conv-demo-go¶

Envoy-extproc-method-conv-demo-go is an example based on envoy-extproc-sdk-go, demonstrating how to use the ext_proc feature provided by Envoy in Go.

Functionality¶

Its main function is to convert GET/POST requests initiated by the downstream into POST/GET requests before sending them to the upstream, thereby achieving the purpose of request method conversion.

Prerequisites¶

• Install Envoy (Version >= v1.29)
• Install Go (Version >= v1.21), this step can be skipped if you just want to run it

• A target service supporting HTTP Method: GET/POST (hereinafter referred to as Upstream), assuming it supports the following routes:

  • /*
  • /no-extproc

Compilation¶

Navigate to the project root directory (this step can be skipped if you just want to run it).

go build . -o extproc

Running¶

• Envoy:

  envoy -c ./envoy.yaml # (1)!
  

  1. This file is located in the project root directory

• Caching:

  • Bare Metal:

    ./extproc method-conv --log-stream --log-phases
    

  • k8s:

    kubectl apply -f ./deployment.yaml # (1)!
    

    1. This file is located in the project root directory

• Curl

  curl 127.0.0.1:8000/no-extproc  # (1)!
  curl 127.0.0.1:8000/foo  # (2)!
  curl -XPOST 127.0.0.1:8000/bar  # (3)!
  

  1. Method-conv will not act on this route, each request will be routed to the upstream as is
  2. This GET request will be converted to a POST by Method-conv and then routed to the upstream
  3. This POST request will be converted to a GET by Method-conv and then routed to the upstream

Parameter Description¶

• log-stream: Whether to output logs about the request/response stream
• log-phases: Whether to output logs for each processing phase
• update-extproc-header: Whether to add the name of this plugin in the response header
• update-duration-header: Add the total processing time in the response header when the stream ends

All of the above parameters default to false.

Notes¶

1. This example only supports conversion between HTTP Methods: GET and POST.

2. The allow_all_routing in mutation_rules must be set to true , as shown in the red box in the image below:

   

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