As my reader will know (Hey Mom!), I’ve been noodling around with WASM and waPC. I’ve been exploring ways to pass structured messages across the host:guest boundary.

Protobufs was my first choice. @KevinHoffman created waPC and waSCC and he explained to me and that wSCC uses Message Pack.

It’s slightly surprising to me (still) that technologies like this exist with everyone else seemingly using them and I’ve not heard of them. I don’t expect to know everything but I’m surprised I’ve not stumbled upon msgpack until now.

A digression thanks to Sal Rashid who’s exploring WASM filters w/ Envoy.

The documentation is sparse but:

• How to write WASM filters for Envoy…

There is a Rust SDK but it’s not documented:

• proxy-wasm-rust-sdk

I found two useful posts by Rustaceans who were able to make use of it:

• Extending Envoy with WASM and Rust
• Extending Istio with Rust and WebAssembly

Here’s my simple use of the SDK’s examples.

wasme

curl -sL https://run.solo.io/wasme/install | sh
PATH=${PATH}:${HOME}/.wasme/bin
wasme --version

It may be possible to avoid creating an account on WebAssemblyHub if you’re staying local.

Following on from waPC & Protobufs, I can now remotely invoke (arbitrary) WASM functions:

Client:

The logging isn’t perfectly clear but, the client gets (a previously added) WASM binary from the server (using the SHA-256 of the WASM binary as a unique identifier). The result includes metadata that includes a protobuf descriptor of the WASM binary’s functions. The descriptor defines gRPC services (that represent the WASM functions) with input (parameters) and output (results) messages.

Google has a new Golang Protobuf API, APIv2 (google.golang.org/protobuf) superseding APIv1 (github.com/golang/protobuf). If your code is importing github.com/golang/protobuf, you’re using APIv2. Otherwise, you should consult with the docs because Google reimplemented APIv1 atop APIv2. One challenge this caused me, as someone who does not use protobufs and gRPC on a daily basis, is that gRPC (code-generation) is being removed from the (Golang) protoc-gen-go, the Golang plugin that generates gRPC service bindings.

Following on from waPC & Protobufs and a question on Stack Overflow about Cloud Functions, I was compelled to try running WASM on Cloud Functions no JavaScript.

I wanted to reuse the WASM waPC functions that I’d written in Rust as described in the other post. Cloud Functions does not (yet!?) provide a Rust runtime and so I’m using the waPC Host for Go in this example.

It works!

PARAMS=$(printf '{"a":{"real":39,"imag":3},"b":{"real":39,"imag":3}}' | base64)
TOKEN=$(gcloud auth print-identity-token)

echo "{
	\"filename\":\"complex.wasm\",
	\"function\":\"c:mul\",
	\"params\":\"${PARAMS}\"
}" |\
curl \
--silent \
--request POST \
--header "Content-Type: application/json" \
--header "Authorization: Bearer ${TOKEN}" \
--data @- \
https://${REGION}-${PROJECT}.cloudfunctions.net/invoker

yields (correctly):

I’m hacking around with a solution that combines WASM and Google Trillian.

Ultimately, I’d like to be able to ship WASM (binaries) to a Trillian personality and then invoke (exported) functions on them. Some this was borne from the interesting exploration of Krustlet and its application of wascc.

I’m still booting into WASM but it’s a very interesting technology that has most interesting potential outside the browser. Some folks have been trailblazing the technology and I have been reading Kevin Hoffman’s medium and wascc (nee waxosuit) work. From this, I stumbled upon Kevin’s waPC and I’m using waPC in this prototyping as a way to exchange data between clients and servers running WASM binaries.

I’ve been spending some time this week with Krustlet.

I’m working on documenting how to run Krustlet(s) alongside GKE. I’ve been running a Krustlet with MicroK8s.

The Krustlet demos reference WASM assemblines stored in Azure Container Registry as OCI containers. Google Container Registry supports OCI format and so I tried (successfully) using GCR instead of AZR.

There may be an easier approach but this is how I got this working.

Krustlet uses wasm-to-oci. I was challenged by wasm-to-oci authentication. wasm-to-oci uses ORAS. It turns out that, after authenticating using ORAS, I’m able to use wasm-to-oci to authenticate to a GCR registry!

I’ve been hacking on a Rust-based transparent application for Google Trillian. As appears to be my fixation, this personality is for another package manager. This time, Rust’s Crates often found in crates.io which is Rust’s Package Registry. I discussed this project earlier this month Rust Crate Transparency && Rust SDK for Google Trillian and and earlier approach for Python’s packages with pypi-transparency.

This time, of course, I’m using Rust. And, by way of a first for me, for the gRPC server implementation (aka “personality”). I’ve been lazy thanks to the excellent gRPCurl and have been using it way of a client. Because I’m more familiar with Golang and because I’ve written (most) other Trillian personalities in Golang, I resorted to quickly implementing Crate Transparency in Golang too in order to uncover bugs with the Rust implementation. I’ll write a follow-up post on the complexity I seem to struggle with when using protobufs and gRPC [in Golang].

Well, this became more of an adventure that I’d originally wanted but, after learning some BLE and, with the help of others (Thanks Jonatha, JsBergbau), I’ve sample code that connects to 4 Xiaomi 2nd gen. Thermometers, subscribes to readings and publishes the data to MQTT. From there, I’m scraping it using Inuits MQTTGateway into Prometheus.

Repo: https://github.com/DazWilkin/gomijia2

Thanks|Credit:

• Jonathan McDowell for gomijia and help
• JsBergbau for help

Background

I’ve been playing around with ESPHome and blogged around my very positive experience ESPHome, MQTT, Prometheus and almost Cloud IoT. I’ve ordered a couple of ESP32-DevKitC and hope this will enable me to connect to Google Cloud IoT.

I’m noodling the utility of a Transparency solution for Rust Crates. When developers push crates to Cargo, a bunch of metadata is associated with the crate. E.g. protobuf. As with Golang Modules, Python packages on PyPi etc., there appears to be utility in making tamperproof recordings of these publications. Then, other developers may confirm that a crate pulled from cates.io is highly unlikely to have been changed.

On Linux, Cargo stores downloaded crates under ${HOME}/.crates/registry. In the case of the latest version (2.12.0) of protobuf, on my machine, I have: