Move noProxy handling to separate module

Signed-off-by: Christina Ying Wang <christina@balena.io>

src/host-config.ts

@@ -3,7 +3,12 @@ import _ from 'lodash';
 import path from 'path';
 
 import * as applicationManager from './compose/application-manager';
-import { readHostname, setHostname } from './host-config/index';
+import {
+	readHostname,
+	setHostname,
+	readNoProxy,
+	setNoProxy,
+} from './host-config/index';
 import * as dbus from './lib/dbus';
 import { isENOENT } from './lib/errors';
 import { mkdirp, unlinkAll } from './lib/fs-utils';
@@ -30,7 +35,6 @@ const proxyFields = ['type', 'ip', 'port', 'login', 'password'];
 
 const proxyBasePath = pathOnBoot('system-proxy');
 const redsocksConfPath = path.join(proxyBasePath, 'redsocks.conf');
-const noProxyPath = path.join(proxyBasePath, 'no_proxy');
 
 interface ProxyConfig {
 	[key: string]: string | string[] | number;
@@ -83,18 +87,9 @@ async function readProxy(): Promise<ProxyConfig | undefined> {
 		}
 	}
 
-	try {
-		const noProxy = await readFromBoot(noProxyPath, 'utf-8')
-			// Prevent empty newline from being reported as a noProxy address
-			.then((addrs) => addrs.split('\n').filter((addr) => addr !== ''));
-
-		if (noProxy.length) {
-			conf.noProxy = noProxy;
-		}
-	} catch (e: unknown) {
-		if (!isENOENT(e)) {
-			throw e;
-		}
+	const noProxy = await readNoProxy();
+	if (noProxy.length) {
+		conf.noProxy = noProxy;
 	}
 
 	// Convert port to number per API doc spec
@@ -121,14 +116,15 @@ function generateRedsocksConfEntries(conf: ProxyConfig): string {
 
 async function setProxy(maybeConf: ProxyConfig | null): Promise<void> {
 	if (_.isEmpty(maybeConf)) {
-		await unlinkAll(redsocksConfPath, noProxyPath);
+		await unlinkAll(redsocksConfPath);
+		await setNoProxy([]);
 	} else {
 		// We know that maybeConf is not null due to the _.isEmpty check above,
 		// but the compiler doesn't
 		const conf = maybeConf as ProxyConfig;
 		await mkdirp(proxyBasePath);
 		if (Array.isArray(conf.noProxy)) {
-			await writeToBoot(noProxyPath, conf.noProxy.join('\n'));
+			await setNoProxy(conf.noProxy);
 		}
 
 		let currentConf: ProxyConfig | undefined;

src/host-config/index.ts

@@ -3,6 +3,8 @@ import { promises as fs } from 'fs';
 import * as config from '../config';
 import { pathOnRoot } from '../lib/host-utils';
 
+export * from './proxy';
+
 const hostnamePath = pathOnRoot('/etc/hostname');
 
 export async function readHostname() {

src/host-config/proxy.ts

@@ -0,0 +1,36 @@
+import { promises as fs } from 'fs';
+import path from 'path';
+
+import { pathOnBoot, readFromBoot } from '../lib/host-utils';
+import { unlinkAll } from '../lib/fs-utils';
+import { isENOENT } from '../lib/errors';
+
+const proxyBasePath = pathOnBoot('system-proxy');
+const noProxyPath = path.join(proxyBasePath, 'no_proxy');
+
+export async function readNoProxy(): Promise<string[]> {
+	try {
+		const noProxy = await readFromBoot(noProxyPath, 'utf-8')
+			// Prevent empty newline from being reported as a noProxy address
+			.then((addrs) => addrs.split('\n').filter((addr) => addr !== ''));
+
+		if (noProxy.length) {
+			return noProxy;
+		} else {
+			return [];
+		}
+	} catch (e: unknown) {
+		if (!isENOENT(e)) {
+			throw e;
+		}
+		return [];
+	}
+}
+
+export async function setNoProxy(list: string[]) {
+	if (!list || !Array.isArray(list) || !list.length) {
+		await unlinkAll(noProxyPath);
+	} else {
+		await fs.writeFile(noProxyPath, list.join('\n'));
+	}
+}

test/integration/host-config.spec.ts

@@ -98,6 +98,42 @@ describe('host-config', () => {
 		});
 	});
 
+	describe('noProxy', () => {
+		it('reads IPs to exclude from proxy', async () => {
+			expect(await hostConfig.readNoProxy()).to.deep.equal([
+				'152.10.30.4',
+				'253.1.1.0/16',
+			]);
+		});
+
+		it('sets IPs to exclude from proxy', async () => {
+			await hostConfig.setNoProxy(['balena.io', '1.1.1.1']);
+			expect(await fs.readFile(noProxy, 'utf-8')).to.equal(
+				'balena.io\n1.1.1.1',
+			);
+		});
+
+		it('removes no_proxy file if empty or invalid', async () => {
+			// Set initial no_proxy
+			await hostConfig.setNoProxy(['2.2.2.2']);
+			expect(await hostConfig.readNoProxy()).to.deep.equal(['2.2.2.2']);
+
+			// Set to empty array
+			await hostConfig.setNoProxy([]);
+			expect(await hostConfig.readNoProxy()).to.deep.equal([]);
+			expect(await fs.readdir(proxyBase)).to.not.have.members(['no_proxy']);
+
+			// Reset initial no_proxy
+			await hostConfig.setNoProxy(['2.2.2.2']);
+			expect(await hostConfig.readNoProxy()).to.deep.equal(['2.2.2.2']);
+
+			// Set to invalid value
+			await hostConfig.setNoProxy(null as any);
+			expect(await hostConfig.readNoProxy()).to.deep.equal([]);
+			expect(await fs.readdir(proxyBase)).to.not.have.members(['no_proxy']);
+		});
+	});
+
 	it('reads proxy configs and hostname', async () => {
 		const { network } = await get();
 		expect(network).to.have.property('hostname', 'deadbeef');