Add documentation for Docker+Wasm

_data/toc.yaml

@@ -1379,6 +1379,8 @@ manuals:
                   path: /desktop/extensions-sdk/dev/api/reference/README/
     - path: /desktop/containerd/
       title: Containerd Image Store (Beta)
+    - path: /desktop/wasm/
+      title: Wasm (Beta)
     - sectiontitle: FAQs
       section:
       - path: /desktop/faqs/general/

desktop/wasm/index.md

@@ -0,0 +1,169 @@
+---
+title: Docker+Wasm (Beta)
+description: How to use the Wasm integration in Docker Desktop
+keywords: Docker, WebAssembly, wasm, containerd, engine
+toc_max: 3
+---
+
+This page provides information about the new ability to run Wasm applications alongside your Linux containers in Docker.
+
+To learn more about the launch and how it works, read [the launch blog post here](https://www.docker.com/blog/docker-wasm-technical-preview/).
+
+> **Beta**
+>
+> The Docker+Wasm feature is currently in [Beta](../../release-lifecycle.md/#beta). We recommend that you do not use this feature in production environments as this feature may change or be removed from future releases.
+
+
+## Enabling the Docker+Wasm integration
+
+The Docker+Wasm integration currently requires a special build of Docker Desktop.
+
+- **Important note #1:** This is a technical preview build of Docker Desktop and things might not work as expected. Be sure to back up your containers and images before proceeding.
+- **Important note #2:** This preview has the containerd image store enabled and cannot be disabled. If you’re not currently using the containerd image store, then pre-existing images and containers will be inaccessible.
+
+You can download the technical preview build of Docker Desktop here:
+
+- [macOS Apple Silicon](https://dockr.ly/3sf56vH)
+- [macOS Intel](https://dockr.ly/3VF6uFB)
+- [Windows AMD64](https://dockr.ly/3ShlsP0)
+- Linux Arm64 ([deb](https://dockr.ly/3TDcjRV))
+- Linux AMD64 ([deb](https://dockr.ly/3TgpWH8), [rpm](https://dockr.ly/3eG6Mvp), [tar](https://dockr.ly/3yUhdCk))
+
+
+## Usage examples
+
+### Running a Wasm application with docker run
+
+```
+$ docker run -dp 8080:8080 \
+  --name=wasm-example \
+  --runtime=io.containerd.wasmedge.v1 \
+  --platform=wasi/wasm32 \
+  michaelirwin244/wasm-example
+```
+
+Note the addition of two additional flags to the run command:
+
+- **--runtime=io.containerd.wasmedge.v1** - This informs the Docker engine that we want to use the Wasm containerd shim instead of the standard Linux container runtime
+- **--platform=wasi/wasm32** - This specifies the architecture of the image we want to use. By leveraging a Wasm architecture, we don’t need to build separate images for the different machine architectures. The Wasm runtime will do the final step of converting the Wasm binary to machine instructions.
+
+### Running a Wasm application with Docker Compose
+
+The same application can be run using the following Docker Compose file:
+
+```yaml
+services:
+  app:
+    image: michaelirwin244/wasm-example
+    platform: wasi/wasm32
+    runtime: io.container.wasmedge.v1
+    ports:
+      - 8080:8080
+```
+
+Then start the application using the normal Docker Compose commands:
+
+```
+docker compose up
+```
+
+
+### Running a multi-service application with Wasm
+
+Networking works the same as you expect with Linux containers, giving you the flexibility to combine Wasm applications with other containerized workloads (such as a database) in a single application stack.
+
+In this example, the Wasm application will leverage a MariaDB database running in a container.
+
+1. Start by cloning the repository.
+
+    ```
+    $ git clone https://github.com/second-state/microservice-rust-mysql.git
+    Cloning into 'microservice-rust-mysql'...
+    remote: Enumerating objects: 75, done.
+    remote: Counting objects: 100% (75/75), done.
+    remote: Compressing objects: 100% (42/42), done.
+    remote: Total 75 (delta 29), reused 48 (delta 14), pack-reused 0
+    Receiving objects: 100% (75/75), 19.09 KiB | 1.74 MiB/s, done.
+    Resolving deltas: 100% (29/29), done.
+    ```
+
+2. Navigate into the cloned project and start the project using Docker Compose.
+
+    ```
+    $ cd microservice-rust-mysql
+    $ docker compose up
+    [+] Running 0/1
+    ⠿ server Warning                                                                                                  0.4s
+    [+] Building 4.8s (13/15)
+    ...
+    microservice-rust-mysql-db-1      | 2022-10-19 19:54:45 0 [Note] mariadbd: ready for connections.
+    microservice-rust-mysql-db-1      | Version: '10.9.3-MariaDB-1:10.9.3+maria~ubu2204'  socket: '/run/mysqld/mysqld.sock'  port: 3306  mariadb.org binary distribution
+    ```
+
+3. In another terminal, we can see the Wasm image that was created.
+
+    ```
+    $ docker images
+    REPOSITORY   TAG       IMAGE ID       CREATED         SIZE
+    server       latest    2c798ddecfa1   2 minutes ago   3MB
+    ```
+
+4. Inspecting the image will show the image has a `wasi/wasm32` platform (combination of Os and Architecture).
+
+    ```
+    $ docker image inspect server | grep -A 3 "Architecture"
+            "Architecture": "wasm32",
+            "Os": "wasi",
+            "Size": 3001146,
+            "VirtualSize": 3001146,
+    ```
+
+5. Open the website at http://localhost:8090 and create a few sample orders. All of these are interacting with the Wasm server.
+
+6. When you're all done, tear everything down by hitting Ctrl+C in the terminal you launched the application.
+
+
+### Building and pushing a Wasm module
+
+1. Create a Dockerfile that will build your Wasm application. This will vary depending on the language you are using.
+
+2. In a separate stage in your `Dockerfile`, extract the module and set it as the `ENTRYPOINT`.
+
+    ```
+    FROM scratch
+    COPY --from=build /build/hello_world.wasm /hello_world.wasm
+    ENTRYPOINT [ "hello_world.wasm" ]
+    ```
+
+3. Build and push the image specifying the `wasi/wasm32` architecture. Buildx makes this easy to do in a single command.
+
+    ```
+    $ docker buildx build --platform wasi/wasm32 -t username/hello-world .
+    ...
+    => exporting to image                                                                             0.0s
+    => => exporting layers                                                                            0.0s
+    => => exporting manifest sha256:2ca02b5be86607511da8dc688234a5a00ab4d58294ab9f6beaba48ab3ba8de56  0.0s
+    => => exporting config sha256:a45b465c3b6760a1a9fd2eda9112bc7e3169c9722bf9e77cf8c20b37295f954b    0.0s
+    => => naming to docker.io/username/hello-world:latest                                            0.0s
+    => => unpacking to docker.io/username/hello-world:latest                                         0.0s
+    $ docker push username/hello-world
+    ```
+
+
+## Docker+Wasm Release Notes
+
+(2022-10-24)  
+Initial release
+
+### New
+- Initial implementation of Wasm integration
+
+### Known issues
+- Docker Compose may not exit cleanly when interrupted
+    - Workaround: Clean up `docker-compose` processes by sending them a SIGKILL (`killall -9 docker-compose`).
+- Pushes to Hub might give an error stating `server message: insufficient_scope: authorization failed`, even after logging in using Docker Desktop
+    - Workaround: Run `docker login` in the CLI
+
+## Feedback
+
+Thanks for trying the new Docker+Wasm integration. We’d love to hear from you! Please feel free to give feedback or report any bugs you may find through the issues tracker on the [public roadmap item](https://github.com/docker/roadmap/issues/426){: target="_blank" rel="noopener" class="_"}.