AuditThroughputCollectorHostedService can throw a null reference exception

[andreasohlund]

Describe the bug

Description

Spotted this in a customer logfile

2025-02-20 12:28:42.5872|30|Error|Particular.LicensingComponent.AuditThroughput.AuditThroughputCollectorHostedService|Failed to gather throughput from audit|System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Linq.Enumerable.SelectManySingleSelectorIterator`2.MoveNext()
   at System.Linq.Lookup`2.Create(IEnumerable`1 source, Func`2 keySelector, IEqualityComparer`1 comparer)
   at System.Linq.GroupedEnumerable`2.GetEnumerator()
   at System.Linq.Enumerable.SelectEnumerableIterator`2.ToArray()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.OrderedEnumerable`1.ToList()
   at ServiceControl.CompositeViews.MessageCounting.GetAuditCountsForEndpointApi.ProcessResults(AuditCountsForEndpointContext input, QueryResult`1[] results) in /_/src/ServiceControl/CompositeViews/AuditCounts/GetAuditCountsForEndpointApi.cs:line 34
   at ServiceControl.CompositeViews.Messages.ScatterGatherApi`3.AggregateResults(TIn input, QueryResult`1[] results) in /_/src/ServiceControl/CompositeViews/Messages/ScatterGatherApi.cs:line 77
   at ServiceControl.CompositeViews.Messages.ScatterGatherApi`3.Execute(TIn input, String pathAndQuery) in /_/src/ServiceControl/CompositeViews/Messages/ScatterGatherApi.cs:line 63
   at ServiceControl.Infrastructure.Api.AuditCountApi.GetEndpointAuditCounts(String endpoint, CancellationToken token) in /_/src/ServiceControl/Infrastructure/Api/AuditCountApi.cs:line 14
   at Particular.LicensingComponent.AuditThroughput.AuditQuery.GetAuditCountForEndpoint(String endpointUrlName, CancellationToken cancellationToken) in /_/src/Particular.LicensingComponent/AuditThroughput/AuditQuery.cs:line 39
   at Particular.LicensingComponent.AuditThroughput.AuditThroughputCollectorHostedService.GatherThroughput(CancellationToken cancellationToken) in /_/src/Particular.LicensingComponent/AuditThroughput/AuditThroughputCollectorHostedService.cs:line 75
   at Particular.LicensingComponent.AuditThroughput.AuditThroughputCollectorHostedService.ExecuteAsync(CancellationToken cancellationToken) in /_/src/Particular.LicensingComponent/AuditThroughput/AuditThroughputCollectorHostedService.cs:line 35

Expected behavior

Actual behavior

Versions

• Latest 6.3

Steps to reproduce

Not sure at this stage

Relevant log output

Additional Information

Workarounds

Possible solutions

Additional information