feat: 将视频转写重构为纯文字异步语音识别

lib/stt/worker.ts

@@ -0,0 +1,112 @@
+import type { TranscriptionTask } from "@prisma/client";
+import { prepareAudio } from "./audio";
+import {
+  AsrError,
+  downloadTranscript,
+  getAsrConfig,
+  queryTranscription,
+  submitTranscription,
+} from "./dashscope";
+import { claimTask, completeTask, updateOwnedTask } from "./tasks";
+
+export const defaultServices = {
+  prepareAudio,
+  submitTranscription,
+  queryTranscription,
+  downloadTranscript,
+};
+export async function processTask(
+  task: TranscriptionTask,
+  services = defaultServices,
+) {
+  let submitting = false;
+  const heartbeat = setInterval(() => {
+    void updateOwnedTask(task, {
+      leaseUntil: new Date(Date.now() + 180_000),
+    }).catch(() => {});
+  }, 30_000);
+  try {
+    getAsrConfig();
+    if (!task.providerTaskId) {
+      if (task.submittingAt)
+        throw new AsrError(
+          "上次提交结果不确定，请核对百炼任务后手动重试，避免重复计费",
+        );
+      const url = await services.prepareAudio(task.videoId);
+      if (url === null) {
+        await completeTask(task, []);
+        return;
+      }
+      await updateOwnedTask(task, { submittingAt: new Date() });
+      submitting = true;
+      const providerTaskId = await services.submitTranscription(url);
+      await updateOwnedTask(task, {
+        providerTaskId,
+        submittedAt: new Date(),
+        nextPollAt: new Date(Date.now() + 10_000),
+        leaseToken: null,
+        leaseUntil: null,
+        lastError: null,
+      });
+      return;
+    }
+    // Provider result URLs expire after 24 hours; do not poll forever.
+    if (
+      task.submittedAt &&
+      Date.now() - task.submittedAt.getTime() > 24 * 60 * 60 * 1000
+    ) {
+      throw new AsrError("ASR 任务超过 24 小时，请手动重试");
+    }
+    const result = await services.queryTranscription(task.providerTaskId);
+    if (result.status === "SUCCEEDED") {
+      const transcript = await services.downloadTranscript(result.resultURL);
+      await completeTask(task, transcript);
+    } else {
+      await updateOwnedTask(task, {
+        nextPollAt: new Date(Date.now() + 10_000),
+        leaseToken: null,
+        leaseUntil: null,
+        lastError: null,
+        attempts: 0,
+      });
+    }
+  } catch (error) {
+    // Unknown exceptions (e.g. database outage) leave the lease and submitting marker
+    // intact. Recovery can query a saved ID, but must never blindly submit again.
+    if (!(error instanceof AsrError)) throw error;
+    const retry = !submitting && !!task.providerTaskId && error.retryable;
+    await updateOwnedTask(task, {
+      status: retry ? "PROCESSING" : "FAILED",
+      lastError:
+        submitting && !error.definitiveRejection
+          ? `${error.message}；提交结果不确定，请核对百炼任务后手动重试`
+          : error.message,
+      attempts: { increment: 1 },
+      leaseToken: null,
+      leaseUntil: null,
+      nextPollAt: new Date(
+        Date.now() +
+          Math.min(300_000, 10_000 * 2 ** Math.min(task.attempts, 5)),
+      ),
+    });
+    console.warn(`[ASR] ${task.videoId}: ${retry ? "等待重试" : "失败"}`);
+  } finally {
+    clearInterval(heartbeat);
+  }
+}
+export async function workerTick(services = defaultServices) {
+  const tasks: TranscriptionTask[] = [];
+  for (let i = 0; i < 2; i++) {
+    const task = await claimTask();
+    if (task) tasks.push(task);
+  }
+  await Promise.all(
+    tasks.map(async (task) => {
+      try {
+        await processTask(task, services);
+      } catch {
+        console.error(`[ASR] ${task.videoId}: 执行中断，租约到期后恢复`);
+      }
+    }),
+  );
+}