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.

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Prerequisites

deno --version

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Install

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Step 1: Import dependencies

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

import { serve } from "https://deno.land/std@0.120.0/http/server.ts";
import { track, httpTracer, info, warn, error, debug } from "https://deno.land/x/middlewareio@v1.0.7/mod.ts";

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Step 2: Configure Tracing

Trace network requests with the following track() function:

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

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Step 3: Define Request Handler

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

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

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Step 4: Start Your Server

Start an HTTP server with the serve function:

await serve(httpTracer(handler));

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Step 5: Logging [Optional]

Add additional logging information with the following functions:

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