ClientRetryPolicy: Fixes failover handling of 503 HTTP errors (#3479)

* Added Expected Behavior and Tests * Suggested changes + ported over tests from v2 Co-authored-by: Nalu Tripician <ntripician@microsoft.com>
Azure · Sep 30, 2022 · dfe1fac · dfe1fac
1 parent 01d56ab
commit dfe1fac
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diff --git a/Microsoft.Azure.Cosmos/src/ClientRetryPolicy.cs b/Microsoft.Azure.Cosmos/src/ClientRetryPolicy.cs
@@ -216,7 +216,7 @@ private async Task<ShouldRetryResult> ShouldRetryInternalAsync(
 
  // Received 503.0 due to client connect timeout or Gateway
  if (statusCode == HttpStatusCode.ServiceUnavailable
- && subStatusCode == SubStatusCodes.Unknown)
+ && ClientRetryPolicy.IsRetriableServiceUnavailable(subStatusCode))
  {
  DefaultTrace.TraceWarning("ClientRetryPolicy: ServiceUnavailable. Refresh cache and retry. Failed Location: {0}; ResourceAddress: {1}",
  this.documentServiceRequest?.RequestContext?.LocationEndpointToRoute?.ToString() ?? string.Empty,
@@ -233,6 +233,12 @@ private async Task<ShouldRetryResult> ShouldRetryInternalAsync(
  return null;
  }
 
+ private static bool IsRetriableServiceUnavailable(SubStatusCodes? subStatusCode)
+ {
+ return subStatusCode == SubStatusCodes.Unknown ||
+ (subStatusCode.HasValue && subStatusCode.Value.IsSDKGeneratedSubStatus());
+ }
+
  private async Task<ShouldRetryResult> ShouldRetryOnEndpointFailureAsync(
  bool isReadRequest,
  bool markBothReadAndWriteAsUnavailable,