Slight demo application: Latest commits in GitHub repos

This sample application displays the five most recent commits from a set of GitHub repositories. The application gets the set of repositories from a table in a Postgresql database.

The application is written using Slight and uses the SQL and HTTP Client capabilities released in version 0.3.

PicoCSS is used for styling the HTML.

IMPORTANT This application is a demo app and is not intended to be run in a production environment. It is intended for demonstrating the features and capabilities of Slight only. Use at your own risk.

Before you begin

To run this sample application, at minimum you'll need:

• Slight installed
• Access to a postgresql database

If you don't have access to a postgresql database, you can run one locally using Docker Desktop and the postgres image. The README for the image has instructions for running the image, but does not expose the port to the host by default. Use the -p flag to expose the port to the host, for example:

docker run --name some-postgres -e POSTGRES_PASSWORD=mysecretpassword -d -p 5432:5432 postgres

You can also use a hosted database service, such as Azure Database for PostgreSQL.

IMPORTANT At this time, the demo application can't connect to a database that requires SSL. Make sure your database is configured to not prefer, but not require SSL.

Run the application on your development computer

You can run the Slight demo application directly on your development computer.

Clone the sample repo and navigate to the root directory:

git clone https://github.com/deislabs/spiderlightning-gh-latest-commits-demo.git
cd spiderlightning-gh-latest-commits-demo

Set the DB_URL environment variable to your postgresql database connection string, then build and run the application:

export DB_URL="YOUR_CONNECTION_STRING"
cargo build --target wasm32-wasi 
slight -c slightfile.toml run target/wasm32-wasi/debug/gh-latest-commits-demo.wasm

Navigate to localhost:3000/init_db to initialize the database for the sample application.

Navigate to localhost:3000/show_feeds to show the latest commits for the default sample repos added during database initialization.

Add or remove entries in the repos table and refresh localhost:3000/show_feeds to see your changes. The newest entries in repos should be at the top.

NOTE: When adding entries to the repo table, use the format gh-user/repo. For example, the repository at https://github.com/deislabs/containerd-wasm-shims would have the entry deislabs/containerd-wasm-shims.

Run the application in Kubernetes

You can run the Slight demo application in a Kubernetes cluster.

In addition to Slight and a postgresql database, you'll need:

• Docker Desktop installed
• Access to a Kubernetes cluster that can run WebAssembly modules, such as k3d
• Access to a container registry, such as Dockerhub, ORAS registry, or Azure Container Registry

Clone the sample repo and navigate to the root directory:

git clone URL
cd gh-latest-commits-demo

Build an image for the sample and push it to your registry:

docker buildx build --platform=wasi/wasm -t REGISTRY_URL/gh-latest-commits-demo .
docker push REGISTRY_URL/gh-latest-commits-demo:latest

Update gh-latest-commits-demo.yaml with registry URL:

    spec:
      runtimeClassName: wasmtime-slight
      containers:
        - name: gh-latest-commits-demo
          image: REGISTRY_URL/gh-latest-commits-demo:latest

Create a secret with your database connection URL:

kubectl create secret generic gh-latest-commits-demo-database --from-literal=connection-url='YOUR_CONNECTION_STRING'

Run the application in Kubernetes using gh-latest-commits-demo.yaml:

kubectl apply -f gh-latest-commits-demo.yaml

Navigate to DEMO_APP_IP/init_db to initialize the database for the sample application.

Navigate to DEMO_APP_IP/show_feeds to show the latest commits for the default sample repos added during database initialization.

Add or remove entries in the repos table and refresh DEMO_APP_IP/show_feeds to see your changes. The newest entries in repos should be at the top.

NOTE: When adding entries to the repo table, use the format gh-user/repo. For example, the repository at https://github.com/deislabs/containerd-wasm-shims would have the entry deislabs/containerd-wasm-shims.