feat: 诊断过程实时进度展示 (SSE流式推送)

- 新增 GET /api/diagnose/stream SSE接口, 每完成一项检查实时推送
- 前端: 诊断中显示步骤进度条+每项检查状态(运行中/完成/问题数)
- 解决诊断过程'卡着'无反馈的体验问题
- 保留 POST /api/diagnose 兼容旧接口

backend/main.py

@@ -1,14 +1,22 @@
 """K8S 智能诊断平台 - FastAPI 主应用"""
 import os
+import json
+import asyncio
 from datetime import datetime
 from fastapi import FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.staticfiles import StaticFiles
+from fastapi.responses import StreamingResponse
 from pydantic import BaseModel
 from typing import Optional
 
 from backend.config import PORT
-from backend.diagnosis import run_full_diagnosis, build_diagnosis_report, ALL_CHECKS
+from backend.diagnosis import (
+    run_full_diagnosis, build_diagnosis_report, ALL_CHECKS,
+    check_cluster_info, check_pods, check_nodes, check_events,
+    check_deployments, check_services, check_pvc, check_resource_usage,
+    check_network_policies,
+)
 from backend.ai_agent import analyze_with_ai, chat_with_ai
 
 app = FastAPI(title="K8S 智能诊断平台", version="1.0.0")
@@ -24,6 +32,19 @@ app.add_middleware(
 _last_diagnosis: Optional[dict] = None
 _last_report: str = ""
 
+# 诊断项执行顺序 (带中文标题)
+CHECK_ORDER = [
+    ("cluster_info", "集群信息", check_cluster_info),
+    ("nodes", "Node 状态检查", check_nodes),
+    ("pods", "Pod 状态检查", check_pods),
+    ("deployments", "Deployment 状态检查", check_deployments),
+    ("services", "Service/Endpoint 检查", check_services),
+    ("events", "异常事件检查", check_events),
+    ("pvc", "PVC 存储检查", check_pvc),
+    ("resource_usage", "资源使用率", check_resource_usage),
+    ("network", "网络策略检查", check_network_policies),
+]
+
 
 class DiagnoseRequest(BaseModel):
     namespace: str = ""
@@ -48,15 +69,79 @@ async def list_checks():
     """列出所有可用诊断项"""
     return {
         "checks": [
-            {"name": name, "title": fn.__doc__ or name}
-            for name, fn in ALL_CHECKS.items()
+            {"name": name, "title": title}
+            for name, title, _ in CHECK_ORDER
         ]
     }
 
 
+@app.get("/api/diagnose/stream")
+async def diagnose_stream(namespace: str = ""):
+    """SSE 流式诊断 - 实时推送每一步进度"""
+    global _last_diagnosis, _last_report
+
+    async def event_generator():
+        start = datetime.now()
+        results = {}
+        all_issues = []
+        total = len(CHECK_ORDER)
+
+        for idx, (name, title, fn) in enumerate(CHECK_ORDER, 1):
+            # 推送: 开始检查
+            yield f"data: {json.dumps({'type': 'progress', 'step': idx, 'total': total, 'name': name, 'title': title, 'status': 'running'}, ensure_ascii=False)}\n\n"
+
+            try:
+                if name in ("pods", "events", "deployments", "services", "pvc", "network"):
+                    result = await fn(namespace)
+                else:
+                    result = await fn()
+                results[name] = result
+                issue_count = len(result.get("issues", []))
+                for issue in result.get("issues", []):
+                    issue["check"] = title
+                    all_issues.append(issue)
+            except Exception as e:
+                results[name] = {"name": name, "title": title, "error": str(e), "issues": []}
+                issue_count = -1
+
+            # 推送: 完成检查
+            yield f"data: {json.dumps({'type': 'progress', 'step': idx, 'total': total, 'name': name, 'title': title, 'status': 'done', 'issues': issue_count}, ensure_ascii=False)}\n\n"
+
+        # 汇总
+        critical = [i for i in all_issues if i["level"] == "critical"]
+        warning = [i for i in all_issues if i["level"] == "warning"]
+        elapsed = (datetime.now() - start).total_seconds()
+        score = max(0, 100 - len(critical) * 15 - len(warning) * 5)
+        status = "healthy" if score >= 90 else ("warning" if score >= 60 else "critical")
+
+        diagnosis = {
+            "timestamp": start.isoformat(),
+            "elapsed_seconds": round(elapsed, 2),
+            "namespace": namespace or "all",
+            "score": score,
+            "status": status,
+            "critical_count": len(critical),
+            "warning_count": len(warning),
+            "issues": all_issues,
+            "checks": results,
+        }
+
+        _last_diagnosis = diagnosis
+        _last_report = build_diagnosis_report(diagnosis)
+
+        # 推送: 最终结果
+        yield f"data: {json.dumps({'type': 'complete', 'diagnosis': diagnosis}, ensure_ascii=False)}\n\n"
+
+    return StreamingResponse(
+        event_generator(),
+        media_type="text/event-stream",
+        headers={"Cache-Control": "no-cache", "X-Accel-Buffering": "no"},
+    )
+
+
 @app.post("/api/diagnose")
 async def diagnose(req: DiagnoseRequest):
-    """执行一键诊断"""
+    """执行一键诊断 (非流式，兼容旧接口)"""
     global _last_diagnosis, _last_report
     _last_diagnosis = await run_full_diagnosis(namespace=req.namespace, checks=req.checks)
     _last_report = build_diagnosis_report(_last_diagnosis)