Generate and analyse esbuild bundle metadata

.gitignore

@@ -11,3 +11,5 @@ build/
 eslint.sarif
 # for local incremental compilation
 tsconfig.tsbuildinfo
+# esbuild metadata file
+meta.json

build.mjs

@@ -1,4 +1,4 @@
-import { copyFile, rm } from "node:fs/promises";
+import { copyFile, rm, writeFile } from "node:fs/promises";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 
@@ -64,7 +64,11 @@ const onEndPlugin = {
 
 const context = await esbuild.context({
   // Include upload-lib.ts as an entry point for use in testing environments.
-  entryPoints: globSync([`${SRC_DIR}/*-action.ts`, `${SRC_DIR}/*-action-post.ts`, "src/upload-lib.ts"]),
+  entryPoints: globSync([
+    `${SRC_DIR}/*-action.ts`,
+    `${SRC_DIR}/*-action-post.ts`,
+    "src/upload-lib.ts",
+  ]),
   bundle: true,
   format: "cjs",
   outdir: OUT_DIR,
@@ -74,7 +78,10 @@ const context = await esbuild.context({
   define: {
     __CODEQL_ACTION_VERSION__: JSON.stringify(pkg.version),
   },
+  metafile: true,
 });
 
-await context.rebuild();
+const result = await context.rebuild();
+await writeFile(join(__dirname, "meta.json"), JSON.stringify(result.metafile));
+
 await context.dispose();

package.json

@@ -5,7 +5,7 @@
   "description": "CodeQL action",
   "scripts": {
     "_build_comment": "echo 'Run the full build so we typecheck the project and can reuse the transpiled files in npm test'",
-    "build": "./scripts/check-node-modules.sh && npm run transpile && node build.mjs",
+    "build": "./scripts/check-node-modules.sh && npm run transpile && node build.mjs && npx tsx ./pr-checks/bundle-metadata.ts",
     "lint": "eslint --report-unused-disable-directives --max-warnings=0 .",
     "lint-ci": "SARIF_ESLINT_IGNORE_SUPPRESSED=true eslint --report-unused-disable-directives --max-warnings=0 . --format @microsoft/eslint-formatter-sarif --output-file=eslint.sarif",
     "lint-fix": "eslint --report-unused-disable-directives --max-warnings=0 . --fix",

pr-checks/api-client.ts

@@ -0,0 +1,13 @@
+import * as githubUtils from "@actions/github/lib/utils";
+import { type Octokit } from "@octokit/core";
+import { type PaginateInterface } from "@octokit/plugin-paginate-rest";
+import { type Api } from "@octokit/plugin-rest-endpoint-methods";
+
+/** The type of the Octokit client. */
+export type ApiClient = Octokit & Api & { paginate: PaginateInterface };
+
+/** Constructs an `ApiClient` using `token` for authentication. */
+export function getApiClient(token: string): ApiClient {
+  const opts = githubUtils.getOctokitOptions(token);
+  return new githubUtils.GitHub(opts);
+}

pr-checks/bundle-metadata.ts

@@ -0,0 +1,48 @@
+#!/usr/bin/env npx tsx
+
+import * as fs from "node:fs/promises";
+
+import { BUNDLE_METADATA_FILE } from "./config";
+
+interface InputInfo {
+  bytesInOutput: number;
+}
+
+type Inputs = Record<string, InputInfo>;
+
+interface Output {
+  bytes: number;
+  inputs: Inputs;
+}
+
+interface Metadata {
+  outputs: Record<string, Output>;
+}
+
+function toMB(bytes: number): string {
+  return `${(bytes / (1024 * 1024)).toFixed(2)}MB`;
+}
+
+async function main() {
+  const fileContents = await fs.readFile(BUNDLE_METADATA_FILE);
+  const metadata = JSON.parse(String(fileContents)) as Metadata;
+
+  for (const [outputFile, outputData] of Object.entries(
+    metadata.outputs,
+  ).reverse()) {
+    console.info(`${outputFile}: ${toMB(outputData.bytes)}`);
+
+    for (const [inputName, inputData] of Object.entries(outputData.inputs)) {
+      // Ignore any inputs that make up less than 5% of the output.
+      const percentage = (inputData.bytesInOutput / outputData.bytes) * 100.0;
+      if (percentage < 5.0) continue;
+
+      console.info(`  ${inputName}: ${toMB(inputData.bytesInOutput)}`);
+    }
+  }
+}
+
+// Only call `main` if this script was run directly.
+if (require.main === module) {
+  void main();
+}

pr-checks/config.ts

@@ -8,3 +8,6 @@ export const PR_CHECKS_DIR = __dirname;
 
 /** The path of the file configuring which checks shouldn't be required. */
 export const PR_CHECK_EXCLUDED_FILE = path.join(PR_CHECKS_DIR, "excluded.yml");
+
+/** The path to the esbuild metadata file. */
+export const BUNDLE_METADATA_FILE = path.join(PR_CHECKS_DIR, "..", "meta.json");

pr-checks/sync-checks.ts

@@ -5,12 +5,9 @@
 import * as fs from "fs";
 import { parseArgs } from "node:util";
 
-import * as githubUtils from "@actions/github/lib/utils";
-import { type Octokit } from "@octokit/core";
-import { type PaginateInterface } from "@octokit/plugin-paginate-rest";
-import { type Api } from "@octokit/plugin-rest-endpoint-methods";
 import * as yaml from "yaml";
 
+import { type ApiClient, getApiClient } from "./api-client";
 import {
   OLDEST_SUPPORTED_MAJOR_VERSION,
   PR_CHECK_EXCLUDED_FILE,
@@ -49,15 +46,6 @@ function loadExclusions(): Exclusions {
   ) as Exclusions;
 }
 
-/** The type of the Octokit client. */
-type ApiClient = Octokit & Api & { paginate: PaginateInterface };
-
-/** Constructs an `ApiClient` using `token` for authentication. */
-function getApiClient(token: string): ApiClient {
-  const opts = githubUtils.getOctokitOptions(token);
-  return new githubUtils.GitHub(opts);
-}
-
 /**
  * Represents information about a check run. We track the `app_id` that generated the check,
  * because the API will require it in addition to the name in the future.