Handle network connectivity outage

[HowardvanRooijen]

The Receiver encountered a transient error whereby Azure Storage could not be reached. The following exception was thrown:

Unhandled Exception: Microsoft.Azure.Storage.StorageException: No such host is known —> System.Net.Http.HttpRequestException: No such host is known —> System.Net.Sockets.SocketException: No such host is known
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
	 End of inner exception stack trace 	
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken) at System.Threading.Tasks.ValueTask 1.get_Result()
at System.Net.Http.HttpConnectionPool.CreateConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Threading.Tasks.ValueTask 1.get_Result()
at System.Net.Http.HttpConnectionPool.WaitForCreatedConnectionAsync(ValueTask 1 creationTask) at System.Threading.Tasks.ValueTask 1.get_Result()
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, Cancellat ionToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 senaTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
at Microsoft.Azure.Storage.Core.Executor.Executor.ExecuteAsync[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext, CancellationToken token)
	 End of inner exception stack trace 	
at Microsoft.Azure.Storage.Blob.BlobWriteStreamBase.ThrowLastExceptionlfExists() at Microsoft.Azure.Storage.Blob.BlobWriteStream.FlushAsync(Cancel1ationToken token) at Microsoft.Azure.Storage.Blob.BlobWriteStream.CommitAsync() at Microsoft.Azure.Storage.Blob.BlobWriteStream.Dispose Boolean disposing) at System`10.Stream.Close()
at Microsoft.Azure.Storage.Blob.CloudAppendBlob.UploadFromStreamHelper(Stream source, Nullable`1 length, Boolean createNew, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
at Microsoft.Azure.Storage.Blob.CloudAppendBlob.AppendFromStream(Stream source, AccessCondition accessCondition, Blob RequestOptions options, OperationContext operationContext)
at Microsoft.Azure.Storage.Blob.CloudAppendBlob.AppendFromByteArray(Byte[] buffer, Int32 index, Int32 count, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
at Microsoft.Azure.Storage.Blob.CloudAppendBlob.AppendText(String content, Encoding encoding, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
at Endjin.Ai s.Receiver.StorageClient.AppendMessages(IList`1 messages) in C:\Ais.Net.Receiver\Solutions\Ais.Net.Receiver\StorageClient.cs :1ine 43
at Endjin.Ais.Receiver.Program.OnMessageReceived(IList`1 messages) in C:\Ais.Net.Receiver\Solutions\Ais.Net.Receiver\Program.cs:line 51
at System.Reactive.AnonymousSafeObserver`1.OnNext(T value) in D:\a\l\s\Rx.NET\Source\src\System.Reactive\AnonymousSafeObserver.cs:line 44
at System.Reactive.Subjects.Subject`1.OnNext(T value) in D:\a\l\s\Rx.NET\Source\src\System.Reactive\Subjects\Subject.cs:line 148
at Endjin.Ais.Receiver.NmeaReceiver.RecieveAsync() in C:\Ais.Net.Receiver\Solutions\Ais.Net.Receiver\NmeaReceiver.cs:line 61
at Endiin.Ais.Receiver.Program.Main(String[] args) in C:\Ais.Net.Receiver\Solutions\Ais.Net.Receiver\Program.es:line 31
at Endjin.Ais.Receiver.Program.<Main>(String[] args)

Consider refactoring the code to use TPL Dataflow and either using a BufferBlock to hold incoming messages while trying to re-establish a connection with Azure Storage, or write messages to a local repository, which are then transmitted, in order, when the connection is re-established.