Deno

This guide walks you through setting up Application Performance Monitoring (APM) on a Deno application. These instructions can also be found on the Installation page in your Middleware Account. View example code here.

Prerequisites

1 MW Host Agent

Middleware Host Agent (MW Agent). To install the MW Agent, see our Installation Guide.

2 Deno Version

Deno version 1.41.2 or above. Check your Deno version with the following command:

Shell

shell

deno --version

Install

Step 1: Import dependencies

Import necessary packages into your Deno project from the Deno standard library and middlewareio library:

index.ts

TypeScript

import { serve } from "https://deno.land/[email protected]/http/server.ts";
import { track, httpTracer, info, warn, error, debug } from "https://deno.land/x/[email protected]/mod.ts";

Step 2: Configure Tracing

Trace network requests with the following track() function:

track({
serviceName: '{SERVICE_NAME}',
target: 'https://{ACCOUNT-UID}.middleware.io:443',
accessToken: "<MW_API_KEY>",
})

Step 3: Define Request Handler

Define how your server responds to incoming HTTP requests with the following function:

index.ts

TypeScript

function handler(_req: Request): Response {
   const data = {
       message: `Hello world!`,
   };
   return new Response(JSON.stringify(data), { headers: { 'Content-Type': 'application/json' } });
}

Step 4: Start Your Server

Start an HTTP server with the serve function:

index.ts

TypeScript

await serve(httpTracer(handler));

Step 5: Logging [Optional]

Add additional logging information with the following functions:

index.ts

TypeScript

info("info");
warn("warn");
error("error");
debug("debug");

Hono Framework

To use Middleware with the Hono framework, follow the example below:

import { Hono } from "https://deno.land/x/[email protected]/mod.ts";
import {
  debug,
  error,
  httpTracer,
  info,
  track,
  warn,
} from "https://deno.land/x/[email protected]/mod.ts";