Deno integration

⭐ Community Toolkit

The Aspire Deno hosting integration enables you to run Deno applications alongside your Aspire projects in the Aspire app host. Deno is a modern JavaScript and TypeScript runtime.

Hosting integration

To get started with the Aspire Deno hosting integration, install the CommunityToolkit.Aspire.Hosting.Deno NuGet package in the app host project.

Install the NuGet package

dotnet add package CommunityToolkit.Aspire.Hosting.Deno

Add Deno app

To add a Deno application to your app host, use the AddDenoApp extension method:

var builder = DistributedApplication.CreateBuilder(args);
  
var denoApp = builder.AddDenoApp(
    name: "deno-api",
    workingDirectory: "../deno-app",
    scriptPath: "main.ts",
    args: ["--allow-net", "--allow-env"])
    .WithHttpEndpoint(port: 8000, env: "PORT");
  
builder.AddProject<Projects.ExampleProject>()
       .WithReference(denoApp);
  
// After adding all resources, run the app...

The AddDenoApp method requires:

name: The name of the resource in the Aspire dashboard
workingDirectory: The path to the directory containing your Deno application
scriptPath: The path to the Deno script to run (relative to working directory)
args: Permission flags required by Deno (e.g., --allow-net, --allow-env)

Note

Deno requires explicit permissions for various operations. Common permission flags include:

--allow-net: Network access
--allow-env: Environment variables
--allow-read: File system reading
--allow-write: File system writing

Add Deno task

To run a task defined in package.json or deno.json, use the AddDenoTask extension method:

var builder = DistributedApplication.CreateBuilder(args);
  
var denoApp = builder.AddDenoTask(
    name: "deno-api",
    workingDirectory: "../deno-app",
    taskName: "start")
    .WithHttpEndpoint(port: 8000, env: "PORT");
  
// After adding all resources, run the app...

This runs deno task start in the specified working directory.

Package installation

To ensure packages are installed before running your Deno application, use the WithDenoPackageInstallation method:

var builder = DistributedApplication.CreateBuilder(args);
  
var denoApp = builder.AddDenoApp("deno-api", "../deno-app", "main.ts", ["--allow-net", "--allow-env"])
    .WithDenoPackageInstallation()
    .WithHttpEndpoint(port: 8000, env: "PORT");
  
// After adding all resources, run the app...

Note

Package installation requires a deno.lock file in your Deno project. If the file doesn't exist, run deno install in your Deno project directory to generate it.

Configure endpoints

Deno applications typically use environment variables to configure the port they listen on. Use WithHttpEndpoint to configure the port and set the PORT environment variable:

var builder = DistributedApplication.CreateBuilder(args);
  
var denoApp = builder.AddDenoApp("deno-api", "../deno-app", "main.ts", ["--allow-net", "--allow-env"])
    .WithHttpEndpoint(port: 8000, env: "PORT");
  
// After adding all resources, run the app...

Your Deno application can read the PORT environment variable:

const port = Number(Deno.env.get("PORT")) || 8000;
  
Deno.serve({ port }, () => {
  return new Response("Hello from Deno!");
});
  
console.log(`Server listening on port ${port}`);

Working directory

The workingDirectory parameter specifies where the Deno application is located. The Aspire app host will run Deno commands in this directory.