HTTP Client

This runs the HTTP client WASM module through the Propeller Kubernetes operator. The module makes GET and POST requests using wasi:http/outgoing-handler.

Prerequisites

The operator must be deployed and a Proplet registered. Follow the end-to-end example first.

Proplet Configuration

The HTTP client needs the WASI HTTP proxy enabled on the proplet. Patch your Proplet:

kubectl patch proplet k8s-proplet --type=merge -p '{"spec":{"k8s":{"env":{"httpEnabled":true}}}}'

Wait for the proplet pod to roll:

kubectl get pods -n propeller-workloads -w | grep proplet

Build the WASM Module

cd propeller
make http-client

Apply the Task

WASM_B64=$(base64 -w0 propeller/build/http-client.wasm)
kubectl apply -n propeller-workloads -f - <<EOF
apiVersion: propeller.propeller.absmach.eu/v1
kind: Task
metadata:
  name: http-client-example
spec:
  name: http-client-example
  functionName: _start
  file: "${WASM_B64}"
  propletSelector:
    propletId: "k8s-proplet"
EOF

Watch and Verify

kubectl get task http-client-example -n propeller-workloads -w

Expected result shows HTTP response bodies from httpbin.org GET and POST requests.

Note: http-client.wasm is ~298KB. If the task stays in running without completing, the inline base64 may exceed your MQTT broker's message size. Use imageUrl instead (see Large Modules).

Reference