Error Reporting aggregates error events produced in your running cloudservices. Anerror event represents a single occurrence of an error in yourapplication. The data stored for each event includes information about theerror, such as the time at which it occurred, the context in which it occurred,and the error message that was returned.

Error events are either reported by theError Reporting API or are inferredby Error Reporting when it inspects log entries for commontext patterns such as stack traces. Error Reporting groupserror events that are considered to have the same root cause.

Error Reporting is automatically enabled.

Error Reporting samples up to 1,000 errors per hour.When thislimit is reached, the displayed counts are estimated. If too many events arereceived, then Error Reporting samples up to100 errors per hour and continue to extrapolate the counts.

When Error Reporting analyzes log entries

Error Reporting is a global service built onCloud Logging and can analyze log entries when all of the following are true:

• Assured workloads are disabled. For more information, seeOverview of Assured Workloads.
• Customer-managed encryption keys (CMEK) are disabled on all log buckets that store the log entry. Error Reporting can't store log entries in log buckets that have CMEK enabled. For information about how to determine the CMEK configuration for a log bucket, seeVerify key enablement.
• The log bucket satisfies one of the following:
  • The log bucket is stored in the same project where the log entries originated.
  • The log entries were routed to a project, and then that project stored those log entries in a log bucket that it owns.

How error events are grouped

When Error Reporting evaluates log entries to identifyerror events, it ignores log entries with the following conditions:

• Log entries written by App Engine standard environment that have aseverity level lower thanERROR.
• Stack frames which aren't owned by the user (for instance, thosethat belong to public libraries).

When a log entry is scanned, Error Reporting makes the followingmodifications before inferring error events:

• Replaces any repeating sequence of one or more stack frames with a singleoccurrence of that sequence.
• Removes compiler-introduced methods and symbols.

Error Reporting applies these rules, in the specified order, togroup error events:

com.google.apphosting.runtime.HardDeadlineExceededError

com.google.appengine.api.datastore.DatastoreTimeoutException

java.util.concurrent.CancellationException

runtime error: index out of rangepackage1.func1()      file1:20package2.func2()      file2:33

runtime error: index out of range    func1()

Data regionality

If you set upAssured Workloadsfor data-residency orImpact Level 4 (IL4)requirements, then Google Cloud automatically disablesError Reporting.

In Cloud Logging, you canregionalize your logs by routingthem to a specific location. On theError Groups page,Error Reporting organizes and shows error groups based on theregion of the log bucket that contains the log entries. For example,an error group listed underus-central-1 contains only error logsthat are part of a log bucket inus-central-1. Global error groups containonly error logs that are part of a log bucket in theglobal region.

To filter the region of the error groups displayed on theError Groups page,select a value from theRegion menu. This menu has a default value ofglobal.

• Collect error events by using Error Reporting
• View error groups