fix: 大样图生成偶发失败加固(前端草图压缩1536px+后端超时5xx自动重试)

src/huamenchuang/api/ai_render.py

@@ -124,41 +124,58 @@ async def generate(body: AiRenderBody, user: CurrentUser, db: DbSession):
     base = settings.ai_base_url.rstrip("/")
     headers = {"Authorization": f"Bearer {settings.ai_api_key}"}
     timeout = httpx.Timeout(settings.ai_timeout, connect=15)
-    try:
-        async with httpx.AsyncClient(timeout=timeout) as client:
-            if body.mode == "blueprint":
-                img_bytes = base64.b64decode(body.sketch_b64.split(",")[-1])
-                mime = "image/jpeg" if img_bytes[:2] == b"\xff\xd8" else "image/png"
-                ext = "jpg" if mime == "image/jpeg" else "png"
-                resp = await client.post(
-                    f"{base}/v1/images/edits", headers=headers,
-                    data={"model": settings.ai_model, "prompt": prompt, "size": size, "n": "1"},
-                    files={"image[]": (f"drawing.{ext}", img_bytes, mime)})
-            elif body.mode == "photo":
-                img_bytes = base64.b64decode(body.photo_b64.split(",")[-1])
-                mime = "image/jpeg" if img_bytes[:2] == b"\xff\xd8" else "image/png"
-                ext = "jpg" if mime == "image/jpeg" else "png"
-                resp = await client.post(
-                    f"{base}/v1/images/edits", headers=headers,
-                    data={"model": settings.ai_model, "prompt": prompt, "size": size, "n": "1"},
-                    files={"image[]": (f"photo.{ext}", img_bytes, mime)})
-            else:
-                resp = await client.post(
-                    f"{base}/v1/images/generations", headers=headers,
-                    json={"model": settings.ai_model, "prompt": prompt, "n": 1, "size": size})
-        resp.raise_for_status()
-        data = resp.json()
-        item = (data.get("data") or [{}])[0]
-        b64 = item.get("b64_json")
-        if not b64:
-            return fail(f"生图服务返回异常: {str(data)[:200]}")
-    except httpx.TimeoutException:
-        return fail("AI 生图超时，请稍后重试")
-    except httpx.HTTPStatusError as e:
-        detail = e.response.text[:200] if e.response is not None else ""
-        return fail(f"生图服务错误({e.response.status_code if e.response else '?'}): {detail}")
-    except Exception as e:
-        return fail(f"生图失败: {str(e)[:150]}")
+
+    async def _post_image(client: httpx.AsyncClient) -> httpx.Response:
+        if body.mode == "blueprint":
+            img_bytes = base64.b64decode(body.sketch_b64.split(",")[-1])
+            mime = "image/jpeg" if img_bytes[:2] == b"\xff\xd8" else "image/png"
+            ext = "jpg" if mime == "image/jpeg" else "png"
+            return await client.post(
+                f"{base}/v1/images/edits", headers=headers,
+                data={"model": settings.ai_model, "prompt": prompt, "size": size, "n": "1"},
+                files={"image[]": (f"drawing.{ext}", img_bytes, mime)})
+        if body.mode == "photo":
+            img_bytes = base64.b64decode(body.photo_b64.split(",")[-1])
+            mime = "image/jpeg" if img_bytes[:2] == b"\xff\xd8" else "image/png"
+            ext = "jpg" if mime == "image/jpeg" else "png"
+            return await client.post(
+                f"{base}/v1/images/edits", headers=headers,
+                data={"model": settings.ai_model, "prompt": prompt, "size": size, "n": "1"},
+                files={"image[]": (f"photo.{ext}", img_bytes, mime)})
+        return await client.post(
+            f"{base}/v1/images/generations", headers=headers,
+            json={"model": settings.ai_model, "prompt": prompt, "n": 1, "size": size})
+
+    b64 = None
+    last_err = ""
+    # 中转偶发超时/5xx 自动重试一次(生图耗时长, 失败重试显著提升成功率)
+    for attempt in range(2):
+        try:
+            async with httpx.AsyncClient(timeout=timeout) as client:
+                resp = await _post_image(client)
+            resp.raise_for_status()
+            data = resp.json()
+            item = (data.get("data") or [{}])[0]
+            b64 = item.get("b64_json")
+            if b64:
+                break
+            last_err = f"生图服务返回异常: {str(data)[:200]}"
+        except httpx.TimeoutException:
+            last_err = "AI 生图超时，请稍后重试"
+        except httpx.HTTPStatusError as e:
+            detail = e.response.text[:200] if e.response is not None else ""
+            last_err = f"生图服务错误({e.response.status_code if e.response else '?'}): {detail}"
+            # 4xx(如鉴权/参数)重试无意义
+            if e.response is not None and e.response.status_code < 500:
+                break
+        except Exception as e:  # noqa: BLE001
+            last_err = f"生图失败: {str(e)[:150]}"
+        if attempt == 0 and b64 is None:
+            stage_wait = 3  # 重试前短暂等待
+            import asyncio
+            await asyncio.sleep(stage_wait)
+    if not b64:
+        return fail(last_err or "生成失败")
     return ok(data={"image_b64": b64, "prompt": prompt, "size": size,
                     "features": {"width_mm": info["width_mm"], "height_mm": info["height_mm"],
                                  "summary": info["summary"]}},