fix(aws-cdk): Move version check TTL file to home directory (#2774)

Originally, the version check TTL file was located alongside the CDK
node installation directory. This caused issues for people who had CDK
installed on a readonly filesystem.

This change moves this file to the user's home directory, specifically
under $HOMEDIR/.cdk/cache. This directory is already being used by
account-cache.ts.

The old logic is maintained where a repo check is run once a day against
NPM, when a CDK command is invoked, and when a new version is present
will generate a console banner notifying the user of this.

The edge case with the updated implementation is when there are 2+
active installations of CDK and they are used interchangably. When
this happens, the user will only get one notification per non-latest
installation of CDK per day.

packages/aws-cdk/.gitignore

@@ -7,7 +7,6 @@ dist
 
 # Generated by generate.sh
 build-info.json
-.LAST_VERSION_CHECK
 
 .LAST_BUILD
 .nyc_output

packages/aws-cdk/lib/version.ts

@@ -1,17 +1,16 @@
 import { exec as _exec } from 'child_process';
 import colors = require('colors/safe');
-import { close as _close, open as _open, stat as _stat } from 'fs';
+import fs = require('fs-extra');
+import os = require('os');
+import path = require('path');
 import semver = require('semver');
 import { promisify } from 'util';
-import { debug, print, warning } from '../lib/logging';
+import { debug, print } from '../lib/logging';
 import { formatAsBanner } from '../lib/util/console-formatters';
 
 const ONE_DAY_IN_SECONDS = 1 * 24 * 60 * 60;
 
-const close = promisify(_close);
 const exec = promisify(_exec);
-const open = promisify(_open);
-const stat = promisify(_stat);
 
 export const DISPLAY_VERSION = `${versionNumber()} (build ${commit()})`;
 
@@ -23,23 +22,39 @@ function commit(): string {
   return require('../build-info.json').commit;
 }
 
-export class TimestampFile {
+export class VersionCheckTTL {
+  public static timestampFilePath(): string {
+    // Get the home directory from the OS, first. Fallback to $HOME.
+    const homedir = os.userInfo().homedir || os.homedir();
+    if (!homedir || !homedir.trim()) {
+      throw new Error('Cannot determine home directory');
+    }
+    // Using the same path from account-cache.ts
+    return path.join(homedir, '.cdk', 'cache', 'repo-version-ttl');
+  }
+
   private readonly file: string;
 
-  // File modify times are accurate only till the second, hence using seconds as precision
+  // File modify times are accurate only to the second
   private readonly ttlSecs: number;
 
-  constructor(file: string, ttlSecs: number) {
-    this.file = file;
-    this.ttlSecs = ttlSecs;
+  constructor(file?: string, ttlSecs?: number) {
+    this.file = file || VersionCheckTTL.timestampFilePath();
+    try {
+      fs.mkdirsSync(path.dirname(this.file));
+      fs.accessSync(path.dirname(this.file), fs.constants.W_OK);
+    } catch {
+      throw new Error(`Directory (${path.dirname(this.file)}) is not writable.`);
+    }
+    this.ttlSecs = ttlSecs || ONE_DAY_IN_SECONDS;
   }
 
   public async hasExpired(): Promise<boolean> {
     try {
-      const lastCheckTime = (await stat(this.file)).mtimeMs;
+      const lastCheckTime = (await fs.stat(this.file)).mtimeMs;
       const today = new Date().getTime();
 
-      if ((today - lastCheckTime) / 1000 > this.ttlSecs) { // convert ms to secs
+      if ((today - lastCheckTime) / 1000 > this.ttlSecs) { // convert ms to sec
         return true;
       }
       return false;
@@ -52,15 +67,17 @@ export class TimestampFile {
     }
   }
 
-  public async update(): Promise<void> {
-    const fd = await open(this.file, 'w');
-    await close(fd);
+  public async update(latestVersion?: string): Promise<void> {
+    if (!latestVersion) {
+      latestVersion = '';
+    }
+    await fs.writeFile(this.file, latestVersion);
   }
 }
 
 // Export for unit testing only.
 // Don't use directly, use displayVersionMessage() instead.
-export async function latestVersionIfHigher(currentVersion: string, cacheFile: TimestampFile): Promise<string | null> {
+export async function latestVersionIfHigher(currentVersion: string, cacheFile: VersionCheckTTL): Promise<string|null> {
   if (!(await cacheFile.hasExpired())) {
     return null;
   }
@@ -74,7 +91,7 @@ export async function latestVersionIfHigher(currentVersion: string, cacheFile: T
     throw new Error(`npm returned an invalid semver ${latestVersion}`);
   }
   const isNewer = semver.gt(latestVersion, currentVersion);
-  await cacheFile.update();
+  await cacheFile.update(latestVersion);
 
   if (isNewer) {
     return latestVersion;
@@ -83,14 +100,13 @@ export async function latestVersionIfHigher(currentVersion: string, cacheFile: T
   }
 }
 
-const versionCheckCache = new TimestampFile(`${__dirname}/../.LAST_VERSION_CHECK`, ONE_DAY_IN_SECONDS);
-
 export async function displayVersionMessage(): Promise<void> {
   if (!process.stdout.isTTY) {
     return;
   }
 
   try {
+    const versionCheckCache = new VersionCheckTTL();
     const laterVersion = await latestVersionIfHigher(versionNumber(), versionCheckCache);
     if (laterVersion) {
       const bannerMsg = formatAsBanner([
@@ -100,6 +116,6 @@ export async function displayVersionMessage(): Promise<void> {
       bannerMsg.forEach((e) => print(e));
     }
   } catch (err) {
-    warning(`Could not run version check due to error ${err.message}`);
+    debug(`Could not run version check - ${err.message}`);
   }
-}
+}

packages/aws-cdk/test/test.version.ts

@@ -1,7 +1,11 @@
+import fs = require('fs-extra');
 import { Test } from 'nodeunit';
+import os = require('os');
+import path = require('path');
+import sinon = require('sinon');
 import { setTimeout as _setTimeout } from 'timers';
 import { promisify } from 'util';
-import { latestVersionIfHigher, TimestampFile } from '../lib/version';
+import { latestVersionIfHigher, VersionCheckTTL } from '../lib/version';
 
 const setTimeout = promisify(_setTimeout);
 
@@ -10,14 +14,29 @@ function tmpfile(): string {
 }
 
 export = {
+  'tearDown'(callback: () => void) {
+    sinon.restore();
+    callback();
+  },
+
+  'initialization fails on unwritable directory'(test: Test) {
+    test.expect(1);
+    const cacheFile = tmpfile();
+    sinon.stub(fs, 'mkdirsSync').withArgs(path.dirname(cacheFile)).throws('Cannot make directory');
+    test.throws(() => new VersionCheckTTL(cacheFile), /not writable/);
+    test.done();
+  },
+
   async 'cache file responds correctly when file is not present'(test: Test) {
-    const cache = new TimestampFile(tmpfile(), 1);
+    test.expect(1);
+    const cache = new VersionCheckTTL(tmpfile(), 1);
     test.strictEqual(await cache.hasExpired(), true);
     test.done();
   },
 
   async 'cache file honours the specified TTL'(test: Test) {
-    const cache = new TimestampFile(tmpfile(), 1);
+    test.expect(2);
+    const cache = new VersionCheckTTL(tmpfile(), 1);
     await cache.update();
     test.strictEqual(await cache.hasExpired(), false);
     await setTimeout(1001); // Just above 1 sec in ms
@@ -26,14 +45,16 @@ export = {
   },
 
   async 'Skip version check if cache has not expired'(test: Test) {
-    const cache = new TimestampFile(tmpfile(), 100);
+    test.expect(1);
+    const cache = new VersionCheckTTL(tmpfile(), 100);
     await cache.update();
     test.equal(await latestVersionIfHigher('0.0.0', cache), null);
     test.done();
   },
 
   async 'Return later version when exists & skip recent re-check'(test: Test) {
-    const cache = new TimestampFile(tmpfile(), 100);
+    test.expect(3);
+    const cache = new VersionCheckTTL(tmpfile(), 100);
     const result = await latestVersionIfHigher('0.0.0', cache);
     test.notEqual(result, null);
     test.ok((result as string).length > 0);
@@ -44,9 +65,38 @@ export = {
   },
 
   async 'Return null if version is higher than npm'(test: Test) {
-    const cache = new TimestampFile(tmpfile(), 100);
+    test.expect(1);
+    const cache = new VersionCheckTTL(tmpfile(), 100);
     const result = await latestVersionIfHigher('100.100.100', cache);
     test.equal(result, null);
     test.done();
   },
+
+  'No homedir for the given user'(test: Test) {
+    test.expect(1);
+    sinon.stub(os, 'homedir').returns('');
+    sinon.stub(os, 'userInfo').returns({ username: '', uid: 10, gid: 11, shell: null, homedir: ''});
+    test.throws(() => new VersionCheckTTL(), /Cannot determine home directory/);
+    test.done();
+  },
+
+  async 'Version specified is stored in the TTL file'(test: Test) {
+    test.expect(1);
+    const cacheFile = tmpfile();
+    const cache = new VersionCheckTTL(cacheFile, 1);
+    await cache.update('1.1.1');
+    const storedVersion = fs.readFileSync(cacheFile, 'utf8');
+    test.equal(storedVersion, '1.1.1');
+    test.done();
+  },
+
+  async 'No Version specified for storage in the TTL file'(test: Test) {
+    test.expect(1);
+    const cacheFile = tmpfile();
+    const cache = new VersionCheckTTL(cacheFile, 1);
+    await cache.update();
+    const storedVersion = fs.readFileSync(cacheFile, 'utf8');
+    test.equal(storedVersion, '');
+    test.done();
+  },
 };