feat: add worker process with bounded concurrency and per-job timeout

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/worker.js

@@ -0,0 +1,78 @@
+import { loadConfig } from './config.js';
+import { getPool } from './db.js';
+import { ensureStorageDirs, uploadPath, outputPath, deleteIfExists } from './storage.js';
+import { outputMimeType } from './mime.js';
+import { resolve as resolveConverter } from './converters/registry.js';
+import { registerImageConverters } from './converters/image.js';
+import { registerImageToPdfConverter } from './converters/imageToPdf.js';
+import { registerDocumentConverters } from './converters/document.js';
+import { findPendingJobs, markProcessing, markDone, markFailed } from './jobs/jobRepository.js';
+
+const JOB_TIMEOUT_MS = 60000;
+
+function withTimeout(promise, ms) {
+  let timeoutId;
+  const timeout = new Promise((_, reject) => {
+    timeoutId = setTimeout(() => reject(new Error(`Conversion timed out after ${ms}ms`)), ms);
+  });
+  return Promise.race([promise, timeout]).finally(() => clearTimeout(timeoutId));
+}
+
+async function processJob(pool, config, job) {
+  await markProcessing(pool, job.id);
+
+  const inputFilePath = uploadPath(config, job.id, job.sourceFormat);
+  const outputFilePath = outputPath(config, job.id, job.targetFormat);
+
+  try {
+    const entry = resolveConverter(job.sourceFormat, job.targetFormat);
+    if (!entry) {
+      throw new Error(`No converter registered for ${job.sourceFormat} -> ${job.targetFormat}`);
+    }
+
+    await withTimeout(entry.convert(inputFilePath, outputFilePath), JOB_TIMEOUT_MS);
+
+    await markDone(pool, job.id, {
+      outputPath: `${job.id}.${job.targetFormat}`,
+      outputMimeType: outputMimeType(job.targetFormat),
+    });
+  } catch (error) {
+    await deleteIfExists(outputFilePath);
+    await markFailed(pool, job.id, {
+      errorMessage: 'Conversion failed, please try again.',
+      errorLog: error.stack ?? String(error),
+    });
+  }
+}
+
+export async function processPendingJobs(pool, config) {
+  const jobs = await findPendingJobs(pool, config.workerConcurrency);
+  await Promise.all(jobs.map((job) => processJob(pool, config, job)));
+  return jobs.length;
+}
+
+export function startWorker(pool, config) {
+  const interval = setInterval(() => {
+    processPendingJobs(pool, config).catch((error) => {
+      console.error('Error while processing pending jobs:', error);
+    });
+  }, config.workerPollIntervalMs);
+  return () => clearInterval(interval);
+}
+
+async function main() {
+  const config = loadConfig();
+  await ensureStorageDirs(config);
+  const pool = getPool(config);
+
+  registerImageConverters();
+  registerImageToPdfConverter();
+  registerDocumentConverters();
+
+  startWorker(pool, config);
+  console.log(`Worker started, polling every ${config.workerPollIntervalMs}ms`);
+}
+
+if (import.meta.url === `file://${process.argv[1]}`) {
+  main();
+}