Filesystem

This runs the filesystem WASM module — a WASI P1 module that writes a file to a preopened directory, reads it back, and prints the result — through the Propeller Kubernetes operator.

Prerequisites

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

Proplet Configuration

The filesystem example needs PROPLET_DIRS=/tmp to preopen a directory for WASI access.

Known gap: PROPLET_DIRS is not yet exposed on the Proplet CRD's k8s.env block. This example cannot currently run against a k8s-type proplet without a code change. Run it against an external proplet instead, where you control the environment directly.

Alternative: Run Against an External Proplet

If you have a Docker proplet registered, start it with:

docker run -d --name filesystem-proplet \
  -e PROPLET_DIRS=/tmp \
  -e PROPLET_ENTITY_ID=... \
  -e PROPLET_API_KEY=... \
  ghcr.io/absmach/propeller/proplet:latest

Build the WASM Module

cd propeller
make filesystem

Apply the Task

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

Watch and Verify

kubectl get task filesystem-example -n propeller-workloads \
  -o jsonpath='{.status.results}'

Expected result includes "All filesystem operations succeeded".

Reference