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Version: 1.x

Go HTTP Client

This repository contains a WebAssembly Component compiled using TinyGo, which:

  • Implements a wasi:http-compliant HTTP handler
  • Uses the httpserver provider to serve requests
  • Calls a random number generator service to get random numbers using wasi:http
  • Can be declaratively provisioned with wadm

Dependencies

Before starting, ensure that you have the following installed in addition to the Go toolchain:

Quickstart

To get started developing this repository quickly, clone the repo and run wash dev:

console
wash dev

wash dev does many things for you:

  • Starts the wasmCloud host that can run your WebAssembly component
  • Builds this project
  • Builds a declarative WADM manifest consisting of:
    • Your locally built component
    • A HTTP server provider which will receive requests from the outside world (on port 8000 by default)
    • A HTTP client provider which will call a random number generator service
    • Necessary links between providers and your component so your component can handle web traffic
  • Deploys the built manifest (i.e all dependencies to run this application) locally
  • Watches your code for changes and re-deploys when necessary.

Send a request to the running component​

Once wash dev is serving your component, to send a request to the running component (via the HTTP server provider). It will call an upstream API and return a list of random numbers:

console
curl localhost:8000
[438,424,166,260,681]

Issues/ FAQ

curl produces a "failed to invoke" error​

If curling produces

curl localhost:8000
failed to invoke `wrpc:http/incoming-handler.handle`: failed to invoke `wrpc:http/incoming-handler@0.1.0.handle`: failed to shutdown synchronous parameter channel: not connected%

You may need to just wait a little bit -- the HTTP server takes a second or two to start up.

If the issue persists, you may have a lingering HTTP server provider running on your system. You can use pgrep to find it:

console
❯ pgrep -la ghcr_io
4007604 /tmp/wasmcloudcache/NBCBQOZPJXTJEZDV2VNY32KGEMTLFVP2XJRZJ5FWEJJOXESJXXR2RO46/ghcr_io_wasmcloud_http_server_0_23_1