feat(lambda-tiler): log viewer ip address from cloudfront

packages/lambda-tiler/src/__tests__/index.test.ts

@@ -3,7 +3,7 @@ import { afterEach, describe, it } from 'node:test';
 
 import { ConfigProviderMemory } from '@basemaps/config';
 
-import { handler } from '../index.js';
+import { getClientIp, handler } from '../index.js';
 import { ConfigLoader } from '../util/config.loader.js';
 import { mockRequest } from './xyz.util.js';
 
@@ -13,6 +13,29 @@ describe('LambdaXyz index', () => {
     assert.equal(typeof foo.handler, 'function');
   });
 
+  describe('getClientIp', () => {
+    const ip = (addr?: string): string | undefined => {
+      return getClientIp(mockRequest('/v1/version', 'get', addr ? { 'cloudfront-viewer-address': addr } : {}));
+    };
+
+    it('should strip the port from ipv4', () => {
+      assert.equal(ip('203.0.113.10:46532'), '203.0.113.10');
+    });
+
+    it('should strip the port from ipv6 and keep brackets', () => {
+      assert.equal(ip('[2001:db8::1]:46532'), '[2001:db8::1]');
+    });
+
+    it('should handle missing ports', () => {
+      assert.equal(ip('203.0.113.10'), '203.0.113.10');
+      assert.equal(ip('[2001:db8::1]'), '[2001:db8::1]');
+    });
+
+    it('should return undefined when header is missing', () => {
+      assert.equal(ip(), undefined);
+    });
+  });
+
   describe('version', () => {
     afterEach(() => {
       delete process.env['GIT_VERSION'];

packages/lambda-tiler/src/index.ts

@@ -42,6 +42,21 @@ function randomTrace(req: LambdaHttpRequest): void {
   else req.log.level = 'info';
 }
 
+/**
+ * Get the viewer's IP address from the CloudFront-Viewer-Address header, removing the port
+ *
+ * @example
+ * "203.0.113.10:46532" => "203.0.113.10"
+ * "[2001:db8::1]:46532" => "[2001:db8::1]"
+ */
+export function getClientIp(req: LambdaHttpRequest): string | undefined {
+  const addr = req.header('cloudfront-viewer-address');
+  if (addr == null) return undefined;
+  const portIndex = addr.lastIndexOf(':');
+  if (portIndex === -1 || addr.endsWith(']')) return addr;
+  return addr.slice(0, portIndex);
+}
+
 handler.router.hook('request', (req) => {
   LogStorage.enterWith({ log: req.log });
   FsaLog.reset();
@@ -50,6 +65,9 @@ handler.router.hook('request', (req) => {
 
   req.set('name', 'LambdaTiler');
 
+  const clientIp = getClientIp(req);
+  if (clientIp) req.set('clientIp', clientIp);
+
   req.log.debug({ ...req.logContext }, 'Lambda:Start');
 });