[Backport 2.x] Switch OSD Optimizer to rely on file hashes instead of mtimes

changelogs/fragments/8472.yml

@@ -0,0 +1,2 @@
+infra:
+- Switch OSD build cache to rely on file hashes instead of `mtime`s ([#8472](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/8472))

packages/osd-optimizer/src/common/bundle.test.ts

@@ -55,7 +55,7 @@ it('creates cache keys', () => {
     )
   ).toMatchInlineSnapshot(`
     Object {
-      "mtimes": Object {
+      "hashes": Object {
         "/foo/bar/a": 123,
         "/foo/bar/c": 789,
       },

packages/osd-optimizer/src/common/bundle.ts

@@ -103,13 +103,13 @@ export class Bundle {
 
   /**
    * Calculate the cache key for this bundle based from current
-   * mtime values.
+   * hash values.
    */
-  createCacheKey(files: string[], mtimes: Map<string, number | undefined>): unknown {
+  createCacheKey(files: string[], hashes: Map<string, string | undefined>): unknown {
     return {
       spec: this.toSpec(),
-      mtimes: entriesToObject(
-        files.map((p) => [p, mtimes.get(p)] as const).sort(ascending((e) => e[0]))
+      hashes: entriesToObject(
+        files.map((p) => [p, hashes.get(p)] as const).sort(ascending((e) => e[0]))
       ),
     };
   }

packages/osd-optimizer/src/integration_tests/bundle_cache.test.ts

@@ -34,7 +34,7 @@ import cpy from 'cpy';
 import del from 'del';
 import { createAbsolutePathSerializer } from '@osd/dev-utils';
 
-import { getMtimes } from '../optimizer/get_mtimes';
+import { getHashes } from '../optimizer/get_hashes';
 import { OptimizerConfig } from '../optimizer/optimizer_config';
 import { allValuesFrom, Bundle } from '../common';
 import { getBundleCacheEvent$ } from '../optimizer/bundle_cache';
@@ -77,8 +77,8 @@ it('emits "bundle cached" event when everything is updated', async () => {
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/index.ts'),
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/lib.ts'),
   ];
-  const mtimes = await getMtimes(files);
-  const cacheKey = bundle.createCacheKey(files, mtimes);
+  const hashes = await getHashes(files);
+  const cacheKey = bundle.createCacheKey(files, hashes);
 
   bundle.cache.set({
     cacheKey,
@@ -116,8 +116,8 @@ it('emits "bundle not cached" event when cacheKey is up to date but caching is d
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/index.ts'),
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/lib.ts'),
   ];
-  const mtimes = await getMtimes(files);
-  const cacheKey = bundle.createCacheKey(files, mtimes);
+  const hashes = await getHashes(files);
+  const cacheKey = bundle.createCacheKey(files, hashes);
 
   bundle.cache.set({
     cacheKey,
@@ -155,8 +155,8 @@ it('emits "bundle not cached" event when optimizerCacheKey is missing', async ()
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/index.ts'),
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/lib.ts'),
   ];
-  const mtimes = await getMtimes(files);
-  const cacheKey = bundle.createCacheKey(files, mtimes);
+  const hashes = await getHashes(files);
+  const cacheKey = bundle.createCacheKey(files, hashes);
 
   bundle.cache.set({
     cacheKey,
@@ -194,8 +194,8 @@ it('emits "bundle not cached" event when optimizerCacheKey is outdated, includes
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/index.ts'),
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/lib.ts'),
   ];
-  const mtimes = await getMtimes(files);
-  const cacheKey = bundle.createCacheKey(files, mtimes);
+  const hashes = await getHashes(files);
+  const cacheKey = bundle.createCacheKey(files, hashes);
 
   bundle.cache.set({
     cacheKey,
@@ -238,8 +238,8 @@ it('emits "bundle not cached" event when bundleRefExportIds is outdated, include
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/index.ts'),
     Path.resolve(MOCK_REPO_DIR, 'plugins/foo/public/lib.ts'),
   ];
-  const mtimes = await getMtimes(files);
-  const cacheKey = bundle.createCacheKey(files, mtimes);
+  const hashes = await getHashes(files);
+  const cacheKey = bundle.createCacheKey(files, hashes);
 
   bundle.cache.set({
     cacheKey,

packages/osd-optimizer/src/node/cache.ts

@@ -47,7 +47,7 @@ const dbName = (db: LMDB.Database) =>
 export class Cache {
   private readonly codes: LMDB.RootDatabase<string, string>;
   private readonly atimes: LMDB.Database<string, string>;
-  private readonly mtimes: LMDB.Database<string, string>;
+  private readonly hashes: LMDB.Database<string, string>;
   private readonly sourceMaps: LMDB.Database<string, string>;
   private readonly pathRoots: string[];
   private readonly prefix: string;
@@ -82,8 +82,8 @@ export class Cache {
       encoding: 'string',
     });
 
-    this.mtimes = this.codes.openDB('mtimes', {
-      name: 'mtimes',
+    this.hashes = this.codes.openDB('hashes', {
+      name: 'hashes',
       encoding: 'string',
     });
 
@@ -106,8 +106,8 @@ export class Cache {
     }
   }
 
-  getMtime(path: string) {
-    return this.safeGet(this.mtimes, this.getKey(path));
+  getFileHash(path: string) {
+    return this.safeGet(this.hashes, this.getKey(path));
   }
 
   getCode(path: string) {
@@ -131,12 +131,12 @@ export class Cache {
     }
   }
 
-  async update(path: string, file: { mtime: string; code: string; map: any }) {
+  async update(path: string, file: { filehash: string; code: string; map: any }) {
     const key = this.getKey(path);
 
     await Promise.all([
       this.safePut(this.atimes, key, GLOBAL_ATIME),
-      this.safePut(this.mtimes, key, file.mtime),
+      this.safePut(this.hashes, key, file.filehash),
       this.safePut(this.codes, key, file.code),
       this.safePut(this.sourceMaps, key, JSON.stringify(file.map)),
     ]);
@@ -223,7 +223,7 @@ export class Cache {
               // if a future version starts returning independent promises so
               // this is just for some future-proofing
               promises.add(this.atimes.remove(k));
-              promises.add(this.mtimes.remove(k));
+              promises.add(this.hashes.remove(k));
               promises.add(this.codes.remove(k));
               promises.add(this.sourceMaps.remove(k));
             }

packages/osd-optimizer/src/node/node_auto_tranpilation.ts

@@ -105,8 +105,8 @@ function determineCachePrefix() {
 
 function compile(cache: Cache, source: string, path: string) {
   try {
-    const mtime = `${Fs.statSync(path).mtimeMs}`;
-    if (cache.getMtime(path) === mtime) {
+    const filehash = Crypto.createHash('sha1').update(Fs.readFileSync(path)).digest('base64');
+    if (cache.getFileHash(path) === filehash) {
       const code = cache.getCode(path);
       if (code) {
         // code *should* always be defined, but if it isn't for some reason rebuild it
@@ -122,7 +122,7 @@ function compile(cache: Cache, source: string, path: string) {
     }
 
     cache.update(path, {
-      mtime,
+      filehash,
       map: result.map,
       code: result.code,
     });

packages/osd-optimizer/src/optimizer/bundle_cache.ts

@@ -34,7 +34,7 @@ import { mergeAll } from 'rxjs/operators';
 import { Bundle, BundleRefs } from '../common';
 
 import { OptimizerConfig } from './optimizer_config';
-import { getMtimes } from './get_mtimes';
+import { getHashes } from './get_hashes';
 import { diffCacheKey } from './cache_keys';
 
 export type BundleCacheEvent = BundleNotCachedEvent | BundleCachedEvent;
@@ -136,7 +136,7 @@ export function getBundleCacheEvent$(
       eligibleBundles.push(bundle);
     }
 
-    const mtimes = await getMtimes(
+    const hashes = await getHashes(
       new Set<string>(
         eligibleBundles.reduce(
           (acc: string[], bundle) => [...acc, ...(bundle.cache.getReferencedFiles() || [])],
@@ -148,7 +148,7 @@ export function getBundleCacheEvent$(
     for (const bundle of eligibleBundles) {
       const diff = diffCacheKey(
         bundle.cache.getCacheKey(),
-        bundle.createCacheKey(bundle.cache.getReferencedFiles() || [], mtimes)
+        bundle.createCacheKey(bundle.cache.getReferencedFiles() || [], hashes)
       );
 
       if (diff) {

packages/osd-optimizer/src/optimizer/cache_keys.test.ts

@@ -45,8 +45,8 @@ jest.mock('./get_changes.ts', () => ({
     ]),
 }));
 
-jest.mock('./get_mtimes.ts', () => ({
-  getMtimes: async (paths: string[]) => new Map(paths.map((path) => [path, 12345])),
+jest.mock('./get_hashes.ts', () => ({
+  getHashes: async (paths: string[]) => new Map(paths.map((path) => [path, '<content hash>'])),
 }));
 
 jest.mock('execa');
@@ -88,11 +88,11 @@ describe('getOptimizerCacheKey()', () => {
               "deletedPaths": Array [
                 "/foo/bar/c",
               ],
-              "lastCommit": "<last commit sha>",
-              "modifiedTimes": Object {
-                "/foo/bar/a": 12345,
-                "/foo/bar/b": 12345,
+              "fileHashes": Object {
+                "/foo/bar/a": "<content hash>",
+                "/foo/bar/b": "<content hash>",
               },
+              "lastCommit": "<last commit sha>",
               "workerConfig": Object {
                 "browserslistEnv": "dev",
                 "dist": false,

packages/osd-optimizer/src/optimizer/cache_keys.ts

@@ -40,7 +40,7 @@ import { diff } from 'jest-diff';
 import jsonStable from 'json-stable-stringify';
 import { ascending, CacheableWorkerConfig } from '../common';
 
-import { getMtimes } from './get_mtimes';
+import { getHashes } from './get_hashes';
 import { getChanges } from './get_changes';
 import { OptimizerConfig } from './optimizer_config';
 
@@ -138,7 +138,7 @@ export interface OptimizerCacheKey {
   readonly bootstrap: string | undefined;
   readonly workerConfig: CacheableWorkerConfig;
   readonly deletedPaths: string[];
-  readonly modifiedTimes: Record<string, number>;
+  readonly fileHashes: Record<string, string>;
 }
 
 async function getLastCommit() {
@@ -181,14 +181,14 @@ export async function getOptimizerCacheKey(config: OptimizerConfig) {
     lastCommit,
     bootstrap,
     deletedPaths,
-    modifiedTimes: {} as Record<string, number>,
+    fileHashes: {} as Record<string, string>,
     workerConfig: config.getCacheableWorkerConfig(),
   };
 
-  const mtimes = await getMtimes(modifiedPaths);
-  for (const [path, mtime] of Array.from(mtimes.entries()).sort(ascending((e) => e[0]))) {
-    if (typeof mtime === 'number') {
-      cacheKeys.modifiedTimes[path] = mtime;
+  const hashes = await getHashes(modifiedPaths);
+  for (const [path, filehash] of Array.from(hashes.entries()).sort(ascending((e) => e[0]))) {
+    if (typeof filehash === 'string') {
+      cacheKeys.fileHashes[path] = filehash;
     }
   }
 

packages/osd-optimizer/src/optimizer/get_mtimes.test.ts → packages/osd-optimizer/src/optimizer/get_hashes.test.ts

@@ -30,28 +30,36 @@
 
 jest.mock('fs');
 
-import { getMtimes } from './get_mtimes';
+import { getHashes } from './get_hashes';
 
-const { stat }: { stat: jest.Mock } = jest.requireMock('fs');
+const { stat, readFile }: { stat: jest.Mock; readFile: jest.Mock } = jest.requireMock('fs');
 
-it('returns mtimes Map', async () => {
+it('returns hashes Map', async () => {
   stat.mockImplementation((path, cb) => {
     if (path.includes('missing')) {
       const error = new Error('file not found');
       (error as any).code = 'ENOENT';
       cb(error);
     } else {
-      cb(null, {
-        mtimeMs: 1234,
-      });
+      cb(null, {});
     }
   });
 
-  await expect(getMtimes(['/foo/bar', '/foo/missing', '/foo/baz', '/foo/bar'])).resolves
+  readFile.mockImplementation((path, cb) => {
+    if (path.includes('missing')) {
+      const error = new Error('file not found');
+      (error as any).code = 'ENOENT';
+      cb(error);
+    } else {
+      cb(null, `Content of ${path}`);
+    }
+  });
+
+  await expect(getHashes(['/foo/bar', '/foo/missing', '/foo/baz', '/foo/bar'])).resolves
     .toMatchInlineSnapshot(`
     Map {
-      "/foo/bar" => 1234,
-      "/foo/baz" => 1234,
+      "/foo/bar" => "OwCtruddjWkB6ROdbLRM0NnWOhs=",
+      "/foo/baz" => "mb6SFQi4VuH8jbwW3h6YoolklXc=",
     }
   `);
 });

packages/osd-optimizer/src/optimizer/get_mtimes.ts → packages/osd-optimizer/src/optimizer/get_hashes.ts

@@ -32,23 +32,28 @@ import Fs from 'fs';
 
 import * as Rx from 'rxjs';
 import { mergeMap, map, catchError } from 'rxjs/operators';
+import Crypto from 'crypto';
 import { allValuesFrom } from '../common';
 
-const stat$ = Rx.bindNodeCallback<Fs.PathLike, Fs.Stats>(Fs.stat);
+// const stat$ = Rx.bindNodeCallback<Fs.PathLike, Fs.Stats>(Fs.stat);
+const readFile$ = Rx.bindNodeCallback<Fs.PathLike, Buffer>(Fs.readFile);
 
 /**
- * get mtimes of referenced paths concurrently, limit concurrency to 100
+ * Get content hashes of referenced paths concurrently, with at most 100 concurrent files
  */
-export async function getMtimes(paths: Iterable<string>) {
+export async function getHashes(paths: Iterable<string>): Promise<Map<string, string>> {
   return new Map(
     await allValuesFrom(
       Rx.from(paths).pipe(
-        // map paths to [path, mtimeMs] entries with concurrency of
+        // map paths to [path, sha1Hash] entries with concurrency of
         // 100 at a time, ignoring missing paths
         mergeMap(
           (path) =>
-            stat$(path).pipe(
-              map((stat) => [path, stat.mtimeMs] as const),
+            readFile$(path).pipe(
+              map(
+                (buffer) =>
+                  [path, Crypto.createHash('sha1').update(buffer).digest('base64')] as const
+              ),
               catchError((error: any) =>
                 error?.code === 'ENOENT' ? Rx.EMPTY : Rx.throwError(error)
               )

packages/osd-optimizer/src/worker/run_compilers.ts

@@ -58,6 +58,7 @@ import {
   isConcatenatedModule,
   getModulePath,
 } from './webpack_helpers';
+import { getHashes } from '../optimizer/get_hashes';
 
 const PLUGIN_NAME = '@osd/optimizer';
 
@@ -178,28 +179,21 @@ const observeCompiler = (
       }
 
       const files = Array.from(referencedFiles).sort(ascending((p) => p));
-      const mtimes = new Map(
-        files.map((path): [string, number | undefined] => {
-          try {
-            return [path, compiler.inputFileSystem.statSync(path)?.mtimeMs];
-          } catch (error) {
-            if (error?.code === 'ENOENT') {
-              return [path, undefined];
-            }
 
-            throw error;
-          }
+      getHashes(files)
+        .then((hashes) => {
+          bundle.cache.set({
+            bundleRefExportIds,
+            optimizerCacheKey: workerConfig.optimizerCacheKey,
+            cacheKey: bundle.createCacheKey(files, hashes),
+            moduleCount,
+            workUnits,
+            files,
+          });
         })
-      );
-
-      bundle.cache.set({
-        bundleRefExportIds,
-        optimizerCacheKey: workerConfig.optimizerCacheKey,
-        cacheKey: bundle.createCacheKey(files, mtimes),
-        moduleCount,
-        workUnits,
-        files,
-      });
+        .catch((_err) => {
+          // If cache fails to write, it's alright to ignore and reattempt next build
+        });
 
       return compilerMsgs.compilerSuccess({
         moduleCount,