Integration Test Example Device

The integration test example device (crates/snakeway-wasm-test-device) is a small WASM device that exercises every device capability. Snakeway's integration tests load it as a fixture, and it doubles as a working reference for authoring your own device.

note

This device exists for testing and learning. Its behavior is driven by the request path and a mode config value so that tests can trigger each capability on demand. It is not meant for production traffic.

Building

cargo component build --release --target wasm32-unknown-unknown -p snakeway-wasm-test-device

Configuration Example

wasm_devices = [
  {
    name        = "test-device"
    enable      = true
    path        = "/path/to/snakeway_wasm_test_device.wasm"
    fail_policy = "open"

    config = {
      mode       = "inject"
      echo_value = "hello-from-config"
    }
  }
]

Path-Driven Behavior

The on_request hook branches on the request path, so a test can trigger a specific capability by choosing the path:

Path	Behavior
/block	Returns 403 Forbidden (an Action::Block).
/synthetic	Returns a synthetic 299 response with body synthetic-ok.
/rewrite	Rewrites the route path to /api.
/set-header	Sets the request header x-wasm-test: injected.
/append-header	Appends x-multi: a and x-multi: b.
/remove-header	Removes the request header x-to-remove.
/config-echo	Returns 200 with the value of the echo_value config key as the body.
any other path	Continues unmodified.

Mode-Driven Behavior

The remaining hooks branch on the mode config value:

Hook	mode	Behavior
on_stream_request_body	replace	Replaces each request body chunk with replaced.
on_stream_request_body	drop	Drops each request body chunk.
before_proxy	inject	Sets the request header x-before-proxy: injected.
after_proxy	set-status	Overrides the response status to 299.
after_proxy then on_response	strip-response-header	Sets x-remove-me on the response, then removes it, to exercise response-header removal.
on_response	tag-response	Sets the response header x-wasm-response: tagged.

Independent of mode, on_stream_request_body blocks any request whose body contains the bytes BLOCK_BODY.

Config Keys

Key	Description
mode	Selects the behavior for the body, before_proxy, after_proxy, and on_response hooks.
echo_value	Value returned in the body by the /config-echo path.

See Also

• Authoring WASM Devices for the full authoring guide.
• JWT Auth WASM Device for a security-focused example.