Zenn
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Cloud CDNでキャッシュヒット時のログを観察する

KanonKanon

バックエンドのバケットを作り、LBを作成。バケットはEUに作ってる。
このコマンドでリクエストを送る。

for i in {1..3};do curl -s -w "%{time_total}\n" -o /dev/null http://$LB_IP_ADDRESS/cdn.png; done

結果、こう

2.299874
0.006055
0.005619

最初のリクエストに時間かかってるけど、2回目以降は早いのでCloudCDNのキャッシュヒットしたっぽいのがわかる

KanonKanon

ログを出す。

違いは、httpRequestのcacheLookup, cacheHit, jsonPayloadのstatusDetailsがresponse_sent_by_backendとresponse_from_cacheになっていることがわかる。これをもとに、キャッシュが効いてるor効いてないを判断できる。

一回目はこっち。

{
  "insertId": "973zgwf2db5o5",
  "jsonPayload": {
    "backendTargetProjectNumber": "projects/770540151631",
    "statusDetails": "response_sent_by_backend",
    "@type": "type.googleapis.com/google.cloud.loadbalancing.type.LoadBalancerLogEntry",
    "cacheDecision": [
      "RESPONSE_HAS_CACHE_CONTROL",
      "RESPONSE_CACHE_CONTROL_PUBLIC",
      "RESPONSE_HAS_ETAG",
      "RESPONSE_HAS_LAST_MODIFIED",
      "RESPONSE_HAS_EXPIRES",
      "RESPONSE_HAS_CONTENT_TYPE",
      "CACHE_MODE_CACHE_ALL_STATIC"
    ],
    "cacheId": "TPE",
    "remoteIp": "35.221.243.134"
  },
  "httpRequest": {
    "requestMethod": "GET",
    "requestUrl": "http://34.8.204.145/cdn.png",
    "requestSize": "82",
    "status": 200,
    "responseSize": "308310",
    "userAgent": "curl/8.5.0",
    "remoteIp": "35.221.243.134",
    "cacheLookup": true,
    "cacheFillBytes": "308310",
    "serverIp": "2002:a05:66aa:349::",
    "latency": "2.296103s"
  },
  "resource": {
    "type": "http_load_balancer",
    "labels": {
      "url_map_name": "cdn-lb",
      "project_id": "qwiklabs-gcp-04-d815591cff5f",
      "backend_service_name": "",
      "target_proxy_name": "cdn-lb-target-proxy",
      "zone": "global",
      "forwarding_rule_name": "cdn-lb-forwarding-rule"
    }
  },
  "timestamp": "2024-11-10T02:33:53.628526Z",
  "severity": "INFO",
  "logName": "projects/qwiklabs-gcp-04-d815591cff5f/logs/requests",
  "trace": "projects/qwiklabs-gcp-04-d815591cff5f/traces/27ee809e2dd82359bb7dea6216d09e71",
  "receiveTimestamp": "2024-11-10T02:33:56.533734175Z",
  "spanId": "b45d29eb6d2c4d8a"
}

二回目はこっち。

{
  "insertId": "10yaxgbfaoutsi",
  "jsonPayload": {
    "remoteIp": "35.221.243.134",
    "@type": "type.googleapis.com/google.cloud.loadbalancing.type.LoadBalancerLogEntry",
    "cacheDecision": [
      "RESPONSE_HAS_CACHE_CONTROL",
      "RESPONSE_CACHE_CONTROL_PUBLIC",
      "RESPONSE_HAS_ETAG",
      "RESPONSE_HAS_LAST_MODIFIED",
      "RESPONSE_HAS_EXPIRES",
      "RESPONSE_HAS_CONTENT_TYPE",
      "CACHE_MODE_CACHE_ALL_STATIC"
    ],
    "statusDetails": "response_from_cache",
    "backendTargetProjectNumber": "projects/770540151631",
    "cacheId": "TPE"
  },
  "httpRequest": {
    "requestMethod": "GET",
    "requestUrl": "http://34.8.204.145/cdn.png",
    "requestSize": "82",
    "status": 200,
    "responseSize": "308318",
    "userAgent": "curl/8.5.0",
    "remoteIp": "35.221.243.134",
    "cacheHit": true,
    "cacheLookup": true,
    "latency": "0.004081s"
  },
  "resource": {
    "type": "http_load_balancer",
    "labels": {
      "target_proxy_name": "cdn-lb-target-proxy",
      "backend_service_name": "",
      "zone": "global",
      "url_map_name": "cdn-lb",
      "forwarding_rule_name": "cdn-lb-forwarding-rule",
      "project_id": "qwiklabs-gcp-04-d815591cff5f"
    }
  },
  "timestamp": "2024-11-10T02:33:55.935335Z",
  "severity": "INFO",
  "logName": "projects/qwiklabs-gcp-04-d815591cff5f/logs/requests",
  "trace": "projects/qwiklabs-gcp-04-d815591cff5f/traces/79b3ae5b1f06327dbe9398c7c152990d",
  "receiveTimestamp": "2024-11-10T02:33:59.199281030Z",
  "spanId": "8c20fdb741895b08"
}
このスクラップは16日前にクローズされました