Viewing Logs

Each Google Cloud CDN request is logged in Stackdriver Logging. Logging is automatic and does not need to be enabled.

Viewing logs

To view Cloud CDN logs, go to the Logs Viewer in the Cloud Platform Console.

Cloud CDN logs are indexed first by forwarding rule, then by URL map.

  • To see all logs, in the first pull-down menu select Load Balancing > All forwarding rules.
  • To see logs for just one forwarding rule, select a single forwarding rule name from the list.
  • To see logs for just one URL map used by a forwarding rule, select Load Balancing and choose the forwarding rule and URL map of interest.

What is logged

In addition to general information contained in most logs, such as severity, project ID, project number, and timestamp, HTTP(S) load balancing logs contain HttpRequest log fields, which can indicate the following cache hit/miss status:

  1. Cache Hit
    httpRequest.cacheHit=true
    httpRequest.cacheValidatedWithOriginServer!=true

  2. Cache Hit Validated With Origin Server
    httpRequest.cacheHit=true
    httpRequest.cacheValidatedWithOriginServer=true

  3. Cache Miss
    httpRequest.cacheHit!=true
    httpRequest.cacheLookup=true

Log fields of type boolean typically only appear if they have a value of true. If a boolean field has a value of false, that field is omitted from the log.

UTF-8 encoding is enforced for these fields. Characters that are not UTF-8 characters are replaced with question marks.

When Cloud CDN serves a client request by initiating validation requests and/or byte range requests, it omits the serverIp field from the Stackdriver Logging log entry for the client request. This is because Cloud CDN can send requests to multiple server IP addresses in reaction to a single client request.

Each request initiated by Cloud CDN creates a Stackdriver Logging log entry. The resulting log entry contains a parentInsertId field inside the jsonPayload. You can use this field to identify the insertId of the log entry for the single client request that prompted Cloud CDN to initiate the validation request or byte range request. Furthermore, the log entry identifies Cloud CDN as the user agent.

What's next

Refer to the Stackdriver Logging documentation for more information, including how to export logs and how to use logs-based metrics for monitoring and alerting.

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Cloud CDN Documentation