Add support for WASM plugins (with examples)

.github/workflows/release.yml

@@ -84,6 +84,16 @@ jobs:
         env:
           NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
 
+      - name: Publish assemblyscript-plugin-sdk
+        run: |
+          LOCAL_VERSION=$(awk '/"version":/{gsub(/("|",)/,"",$2);print $2}' packages/assemblyscript-plugin-sdk/package.json)
+          if ! npm view @signalk/assemblyscript-plugin-sdk@$LOCAL_VERSION version &>/dev/null; then
+            cd packages/assemblyscript-plugin-sdk
+            npm publish --access public
+          fi
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+
       - name: Set tag variable
         id: vars
         run: echo "tag=${GITHUB_REF#refs/*/}" >> $GITHUB_OUTPUT

.gitignore

@@ -30,3 +30,21 @@ test/server-test-config/ssl-key.pem
 test/server-test-config/plugin-config-data/
 
 docs/built
+
+# WASM build artifacts
+*.wasm  
+
+# .net builds
+jco-output/
+obj/
+bin/
+Debug/
+Release/
+*.ps1
+nul
+
+# wasmtime build artifacts
+*.wasm
+
+# debug artefacts
+*.sln

.npmignore

@@ -44,6 +44,8 @@ compilation-stats.json
 .babelrc
 public/*.hot-update.js
 public/*.hot-update.json
+**/stats.json
+**/*.js.map
 
 plugin-config-data/
 
@@ -77,3 +79,20 @@ fly_io
 
 /docs/*
 !/docs/dist
+
+
+# .net builds
+jco-output/
+obj/
+bin/
+Debug/
+Release/
+*.ps1
+nul
+
+# wasmtime build artifacts
+*.wasm
+
+# debug artefacts
+*.sln
+

.prettierignore

@@ -3,3 +3,8 @@ public
 
 **/*.mbtiles
 **/*.pmtiles
+# AssemblyScript files use decorators that prettier doesn't understand
+examples/wasm-plugins/*/assembly
+packages/assemblyscript-plugin-sdk/assembly
+# AssemblyScript build outputs
+packages/assemblyscript-plugin-sdk/build

README.md

@@ -221,10 +221,10 @@ To enable debugging without going through the Admin UI, see the file `~/.signalk
 
 ## Development
 
-The documents provide more details about developing Webapps or Plugings for Signal K Server, as well as working on the server itself:
+The documents provide more details about developing Webapps or Plugins for Signal K Server, as well as working on the server itself:
 
-- [Contributing to this repo](./contributing.md)
-- [Server Plugins](docs/develop/plugins/README.md)
+- [Contributing to this repo](docs/develop/contributing.md)
+- [WASM Plugins](docs/develop/plugins/wasm/README.md) (Rust, AssemblyScript, Go)
 - [Webapps](docs/develop/webapps.md)
 - [Working with the Course API](docs/develop/rest-api/course_api.md)
 - [Working with the Resources API](docs/develop/rest-api/resources_api.md)

docs/develop/plugins/README.md

@@ -2,6 +2,7 @@
 title: Plugins
 children:
   - ../webapps.md
+  - wasm/README.md
   - deltas.md
   - configuration.md
   - backpressure.md
@@ -20,6 +21,17 @@ They are installed via the AppStore and configured via the Admin UI.
 
 Signal K server exposes an interface for plugins to use in order to interact with the full data model, emit delta messages and process requests.
 
+## Plugin Types
+
+Signal K supports two types of plugins:
+
+- **JavaScript Plugins** - Traditional JavaScript/TypeScript plugins (documented below)
+- **[WASM Plugins](./wasm/README.md)** - Plugins written in Rust, AssemblyScript, Go, or other WASM-compatible languages
+
+[WASM](https://en.wikipedia.org/wiki/WebAssembly) is short for WebAssembly. WASM is a runtime for executing portable code in near native speeds and in isolation. WASM plugins offer sandbox isolation, memory safety, and the ability to use languages other than JavaScript. See the [WASM Plugins documentation](./wasm/README.md) for details.
+
+## Node.js Plugin Capabilities
+
 Plugins can:
 
 - Expose _[REST APIs](../rest-api/README.md)_ to provide consumers/clients a way to perform operations offered by your plugin. The APIs will be published under `http://{skserver}:3000/plugins/{pluginId}`.

docs/develop/plugins/wasm/README.md

@@ -0,0 +1,155 @@
+---
+title: WASM Plugins
+children:
+  - assemblyscript.md
+  - rust.md
+  - go.md
+  - dotnet.md
+  - http_endpoints.md
+  - deltas.md
+  - capabilities.md
+  - best_practices.md
+  - integration_guide.md
+---
+
+# WASM Plugin Development Guide
+
+## Overview
+
+This guide covers how to develop WASM/WASIX plugins for Signal K Server 3.0. WASM plugins run in a secure sandbox with isolated storage and capability-based permissions.
+
+## What Makes a WASM Plugin?
+
+A WASM plugin is an npm package that contains the WASM code for the plugin instead of the traditional JavaScript code. A WASM plugin is identified by the `signalk-wasm-plugin` keyword in package.json and the **`wasmManifest`** field in `package.json`:
+
+```json
+{
+  "name": "my-plugin-name",
+  "wasmManifest": "plugin.wasm",
+  "wasmCapabilities": { ... }
+}
+```
+
+**Key points:**
+
+- **`wasmManifest`** (required): Path to the compiled `.wasm` file. This field tells Signal K to load this as a WASM plugin instead of a Node.js plugin.
+- **`wasmCapabilities`** (required): Declares what permissions the plugin needs (network, storage, etc.)
+- **Package name** (flexible): Can be anything - `my-plugin`, `@myorg/my-plugin`, etc. There is **no requirement** to use `@signalk/` scope.
+- **Keywords**: Include `signalk-wasm-plugin` for discovery (do **not** use `signalk-node-server-plugin` - that's for Node.js plugins only)
+
+## Language Options
+
+Signal K Server supports multiple languages for WASM plugin development:
+
+- **AssemblyScript** - TypeScript-like syntax, easiest for JS/TS developers, smallest binaries (3-10 KB)
+- **Rust** - Best performance and tooling, medium binaries (50-200 KB)
+- **Go/TinyGo** - Go via TinyGo compiler, medium binaries (50-150 KB)
+- **C#/.NET** - **NOT WORKING** - .NET 10 with componentize-dotnet produces WASI Component Model (P2/P3) format. Currently incompatible with Node.js/jco runtime. See [Creating C#/.NET Plugins](./dotnet.md) for details.
+
+## Why WASM Plugins?
+
+### Benefits
+
+- **Security**: Sandboxed execution with no access to host system
+- **Hot-reload**: Update plugins without server restart
+- **Multi-language**: Write plugins in Rust, AssemblyScript, and more
+- **Crash isolation**: Plugin crashes don't affect server
+- **Performance**: Near-native performance with WASM
+- **Self contained**: WASM plugins do not install any additional dependencies
+- **Small binaries (compared to native options)**: 3-200 KB depending on language
+
+### Current Capabilities
+
+- **Delta Emission**: Send SignalK deltas to update vessel data
+- **Status & Error Reporting**: Set plugin status and error messages
+- **Configuration**: The same JSON schema-based configuration as JS plugins
+- **Data Storage**: VFS-isolated file storage
+- **HTTP Endpoints**: Register custom REST API endpoints
+- **Static Files**: Serve web UI from `public/` directory
+- **Network Access**: HTTP requests via as-fetch (AssemblyScript)
+- **Resource Providers**: Serve SignalK resources
+- **Weather Providers**: Integrate with Signal K Weather API
+- **Radar Providers**: Integrate with Signal K Radar API
+
+## Choose Your Language
+
+### AssemblyScript - Recommended for JS/TS Developers
+
+**Best for:**
+
+- Quick prototypes
+- Simple data processing
+- Migrating existing Node.js plugins
+- Developers familiar with TypeScript
+
+**Pros:**
+
+- TypeScript-like syntax
+- Fast development
+- Smallest binaries (3-10 KB)
+- Familiar tooling (npm)
+
+**Cons:**
+
+- Smaller ecosystem than Rust
+- Some TypeScript features unavailable
+- Manual memory management
+
+**[Jump to AssemblyScript Guide](./assemblyscript.md)**
+
+### Rust - Recommended for Performance-Critical Plugins
+
+**Best for:**
+
+- Performance-critical plugins
+- Complex algorithms
+- Low-level operations
+- Production plugins
+
+**Pros:**
+
+- Best performance
+- Memory safety
+- Rich ecosystem
+- Strong typing
+
+**Cons:**
+
+- Steeper learning curve
+- Longer compile times
+- Larger binaries (50-200 KB)
+
+**[Jump to Rust Guide](./rust.md)**
+
+### Go/TinyGo - For Go Developers
+
+**Best for:**
+
+- Go developers wanting to write plugins
+- Medium complexity plugins
+- Resource providers with hybrid patterns
+
+**Pros:**
+
+- Familiar Go syntax
+- Good standard library support
+- Medium binaries (50-150 KB)
+- Strong typing
+
+**Cons:**
+
+- Requires TinyGo (not standard Go)
+- Some Go features unavailable
+- Slower than Rust
+
+**[Jump to Go/TinyGo Guide](./go.md)**
+
+### C#/.NET - NOT CURRENTLY WORKING
+
+> **Status: Non-functional** - See [jco issue #1173](https://github.com/bytecodealliance/jco/issues/1173) for details and updates.
+
+componentize-dotnet produces WASI Component Model format which is currently incompatible with the Node.js/jco runtime used by Signal K.
+
+**Recommendation:** Use AssemblyScript or Rust instead.
+
+**[Jump to C#/.NET Guide](./dotnet.md)** (reference only)