Edit the Wasm file

1. SDK for developing Higress’ Wasm plugin in Go language
2. Example of plug-in development

Build the Wasm image

You can also choose to build the wasm locally first, and then copy it to the Docker image. This requires you to build the build environment locally first.

The compilation environment requirements are as follows:

• Go version: >= 1.18 (need to support generic features)

• TinyGo version: 0.28.1 (0.28.1 recommended)

The following is an example of local steps to build the request-block plugin.

step1. Compile wasm

tinygo build -o main.wasm -scheduler=none -target=wasi -gc=custom -tags=’custommalloc nottinygc_finalizer’ ./main.go

step2. Build and push the docker image of the plugin

Use this simple Dockerfile

FROM scratch
COPY main.wasm plugin.wasm

docker build -t <your_registry_hub>/request-block:1.0.0 -f <your_dockerfile> .
docker push <your_registry_hub>/request-block:1.0.0

Enable Wasm plugin

Using the Higress console

Click the Create button to create a custom plug-in in the plug-in market, and fill in the Wasm mirror address built above in the mirror address column;

After the creation is complete, click the configuration button of the plug-in card, fill in the configuration of the plug-in (if any), and turn on the switch to take effect.

If the plug-in logic changes, you can build a new image with a different image tag, click the “Edit” button in the upper right menu of the plug-in card, and change the address of the Wasm image to the address of the new version.

Using CRDs

Write the WasmPlugin resource as follows:

apiVersion: extensions.higress.io/v1alpha1
kind: WasmPlugin
metadata:
   name: request-block
   namespace: higress-system
spec:
   defaultConfig:
     block_urls:
     - “swagger.html”
   url: oci://<your_registry_hub>/request-block:1.0.0 # The address of the image built and pushed before

Use kubectl apply -f <your-wasm-plugin-yaml> to apply the resources. After the resource takes effect, if the request url carries swagger.html, the request will be rejected, for example:

curl <your_gateway_address>/api/user/swagger.html

HTTP/1.1 403 Forbidden
date: Wed, 09 Nov 2022 12:12:32 GMT
server: istio-envoy
content-length: 0