Add cloudflare worker to collect API key usage inside Influx DB

.env.example

@@ -1,3 +1,5 @@
-INFLUX_HOST=http://localhost:8086
-INFLUX_TOKEN=example
-INFLUX_DATABASE=example
+REQUEST_URL="https://example.com"
+INFLUX_METRIC="example"
+INFLUX_URL="http://localhost:8086"
+INFLUX_TOKEN="example"
+INFLUX_DATABASE="example"

.gitignore

@@ -2,7 +2,6 @@
 /dist
 **/*.rs.bk
 Cargo.lock
-bin/
 pkg/
 wasm-pack.log
 worker/

README.md

@@ -2,20 +2,12 @@
 
 Send your page views from [Cloudflare worker](https://developers.cloudflare.com/workers/) to InfluxDB.
 
-![Dashboard views](static/dashboard.png)
+## Get started
 
-## Requirements
-
-1. Your site need to be setup behind Cloudflare CDN.
-2. You need to setup InfluxDB with external access (make sure you have set [authentication](https://docs.influxdata.com/influxdb/v1.7/administration/authentication_and_authorization/#set-up-authentication))
-   1. Make sure InfluxDB is hosted under [supported port](https://blog.cloudflare.com/cloudflare-now-supporting-more-ports/) for Workers. Best option is 80 or 443.
-
-## How to use
-
-1. Install wrangler package
+1. Install dependencies
 
 ```
-npm i @cloudflare/wrangler -g
+npm install
 ```
 
 2. Copy example files
@@ -25,10 +17,8 @@ cp .env.example .env
 cp wrangler.toml.example wrangler.toml
 ```
 
-3. Deploy your worker to a site with wrangler
+3. Deploy your worker
 
 ```
-wrangler publish --env production
-```
-
-4. (Optional) If you're using Grafana with InfluxDB, then you can import [example Dashboard](static/dashboard.json) from first screen.
+npm run deploy
+```

bin/worker.js

@@ -0,0 +1,16 @@
+import { reportMetric } from "../lib/metrics";
+
+export const handleRequest = async (request, env) => {
+  const url = new URL(request.url);
+  const newRequest = new Request(`${env.REQUEST_URL}${url.pathname}${url.search}`, request);
+
+  return await fetch(newRequest);
+}
+
+export default {
+  async fetch(request, env, ctx) {
+    const response = await handleRequest(request, env);
+    ctx.waitUntil(reportMetric(request, response, env));
+    return response;
+  }
+}

lib/metrics.js

@@ -0,0 +1,25 @@
+import zlib from 'node:zlib';
+import { promisify } from 'node:util';
+import { formatRequestData } from './request.js';
+
+export const reportMetric = async (request, response, env) => {
+  const compress = promisify(zlib.gzip);
+  const requestData = formatRequestData(request, response, env);
+
+  // Define API endpoint and headers
+  const url = `${env.INFLUX_URL}/api/v2/write?&bucket=${env.INFLUX_DATABASE}&precision=ms`;
+
+  // Compress the string using gzip
+  const compressedData = await compress(requestData);
+
+  // Make the POST request
+  return fetch(url, {
+    method: 'POST',
+    headers: {
+      'Authorization': `Token ${env.INFLUX_TOKEN}`,
+      'Content-Encoding': 'gzip',
+      'Content-Type': 'text/plain; charset=utf-8',
+    },
+    body: compressedData,
+  })
+}

lib/request.js

@@ -0,0 +1,11 @@
+export const formatRequestData = (request, response, env) => {
+  const url = new URL(request.url);
+  const timestamp = Date.now();
+  const originResponse = response || {};
+  const apiKey = request.headers.get('api-key') || url.searchParams.get('api-key') || (request.headers.get('Authorization')?.startsWith('Bearer ') ? request.headers.get('Authorization').substring(7) : 'unknown');
+  const cfCache = (originResponse) ? (response.headers.get('CF-Cache-Status') || 'miss') : 'miss'
+  const formattedUrl = url.toString().replaceAll('=', '\\=');
+
+  // We're setting field value to 1 to count the number of requests
+  return `${env.INFLUX_METRIC},status_code=${originResponse.status},url=${formattedUrl},hostname=${url.hostname},pathname="${url.pathname}",method=${request.method},cf_cache=${cfCache},api_key=${apiKey} value=1 ${timestamp}`
+}