fix: write logs under the home cache directory and await artifact upload

Instruments opened its log files at the relative path cache-apt-pkgs/
before that directory existed, so the action crashed at startup with
ENOENT. It also pointed artifact uploads there while Cache uses
~/cache-apt-pkgs. Resolve both with a shared resolveCacheDir helper and
create the directory before opening the logs.

The artifact upload was also never awaited, so a failed upload became an
unhandled rejection. Await it and report failures as a warning.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/cache.ts

@@ -12,6 +12,18 @@ import { CommandRunner, PackageName } from "ts-apt";
 export const CACHE_DEFAULT_DIRNAME = "cache-apt-pkgs";
 export const CACHE_KEY_FILENAME = "cache_key.md5";
 
+/**
+ * Resolves the absolute cache directory path for a cache directory name.
+ *
+ * @param cacheDir Directory name under the user's home directory.
+ * @returns Absolute path to the cache directory.
+ */
+export function resolveCacheDir(
+  cacheDir: string = CACHE_DEFAULT_DIRNAME,
+): string {
+  return path.join(os.homedir(), cacheDir);
+}
+
 export const MANIFEST_MAIN_FILENAME = "manifest_main.json";
 export const MANIFEST_ALL_FILENAME = "manifest_all.json";
 
@@ -106,7 +118,7 @@ export class Cache {
     logger: winston.Logger,
     cacheDir: string = CACHE_DEFAULT_DIRNAME,
   ) {
-    this.path = path.join(os.homedir(), cacheDir);
+    this.path = resolveCacheDir(cacheDir);
     this.commandRunner = commandRunner;
     this.logger = logger;
   }

src/index.ts

@@ -70,7 +70,11 @@ async function main(): Promise<void> {
     const message = error instanceof Error ? error.message : String(error);
     core.setFailed(message);
   } finally {
-    instruments.artifacts.upload();
+    // Logs are diagnostics, so a failed upload shouldn't fail the action.
+    await instruments.artifacts.upload().catch((error: unknown) => {
+      const message = error instanceof Error ? error.message : String(error);
+      core.warning(`Failed to upload diagnostic artifacts: ${message}`);
+    });
   }
 }
 

src/instrumentation.ts

@@ -8,6 +8,7 @@ import {
   CACHE_KEY_FILENAME,
   MANIFEST_ALL_FILENAME,
   MANIFEST_MAIN_FILENAME,
+  resolveCacheDir,
 } from "./cache.js";
 
 const APP_LOG_FILENAME = "capa_app.log";
@@ -40,9 +41,9 @@ export class Artifacts {
   ) {}
 
   /** Upload artifacts to GitHub Actions via [@actions/artifact]. */
-  upload(): string {
+  async upload(): Promise<string> {
     const client = new DefaultArtifactClient();
-    client.uploadArtifact(
+    await client.uploadArtifact(
       "capa_artifacts-" + this.runId,
       this.artifactFilenames
         .map((filename) => path.join(this.dir, filename))
@@ -99,8 +100,10 @@ function createGitHubLogger(debug: boolean, filepath: string): winston.Logger {
 
 /** Container for all instrumentation: telemetry, logging, and artifacts generated */
 export class Instruments {
-  /** Cache directory where all artifacts are stored, including cached packages. */
+  /** Cache directory name where all artifacts are stored, including cached packages. */
   readonly cacheDir: string;
+  /** Absolute path of the cache directory (i.e. under the home directory). */
+  readonly cacheDirPath: string;
   /** Whether debug is enabled which affects artifacts otherwise not. */
   readonly debug: boolean;
   /** Manages artifact creation and upload.  */
@@ -112,11 +115,14 @@ export class Instruments {
 
   constructor(cacheDir: string, debug: boolean, artifacts?: Artifacts) {
     this.cacheDir = cacheDir;
+    this.cacheDirPath = resolveCacheDir(cacheDir);
     this.debug = debug;
+    // The log streams open their files right away, so the directory must exist.
+    fs.mkdirSync(this.cacheDirPath, { recursive: true });
 
     this.artifacts =
       artifacts ??
-      new Artifacts(cacheDir, [
+      new Artifacts(this.cacheDirPath, [
         APP_LOG_FILENAME,
         EXEC_LOG_FILENAME,
         CACHE_KEY_FILENAME,
@@ -125,11 +131,11 @@ export class Instruments {
       ]);
     this.appLogger = createGitHubLogger(
       debug,
-      path.join(cacheDir, APP_LOG_FILENAME),
+      path.join(this.cacheDirPath, APP_LOG_FILENAME),
     );
     this.execLogger = createExecLogger(
       debug,
-      path.join(cacheDir, EXEC_LOG_FILENAME),
+      path.join(this.cacheDirPath, EXEC_LOG_FILENAME),
     );
   }
 }

test/instrumentation.test.ts

@@ -1,3 +1,6 @@
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
 import { Artifacts, Instruments } from "../src/instrumentation.ts";
 import { afterEach, describe, expect, it, vi } from "vitest";
 
@@ -41,6 +44,29 @@ describe("instrumentation", () => {
     });
   });
 
+  describe("Instruments", () => {
+    const CACHE_DIRNAME = "cache-apt-pkgs";
+
+    it("constructor cache dir missing creates it under home with the logs", async () => {
+      const home = fs.mkdtempSync(path.join(os.tmpdir(), "instruments-test-"));
+      vi.stubEnv("HOME", home);
+      const expectedDir = path.join(home, CACHE_DIRNAME);
+
+      const instruments = new Instruments(CACHE_DIRNAME, false);
+      instruments.appLogger.info("app message");
+      await new Promise((resolve) => instruments.appLogger.end(resolve));
+
+      expect(instruments.cacheDirPath).toBe(expectedDir);
+      expect(instruments.artifacts.dir).toBe(expectedDir);
+      await vi.waitFor(() =>
+        expect(
+          fs.readFileSync(path.join(expectedDir, "capa_app.log"), "utf8"),
+        ).toContain("app message"),
+      );
+      fs.rmSync(home, { recursive: true, force: true });
+    });
+  });
+
   // describe("Instruments", () => {
   //   it("constructor initializes properties correctly", () => {
   //     const cacheDir = "/path/to/cache";