Joseph Doherty
fd80aeab57
The first mutation (instance deploy) to a site pair whose sticky node was down
returned OUTCOME_UNKNOWN: SitePairChannelProvider.ExecuteAsync treated every
Unavailable on a non-retry-safe command as possibly-applied unless the server
sent the not-dispatched trailer, flipped stickiness, and threw. The retry then
succeeded on the live peer.
A connect-phase failure provably never sent the request, so it is now treated
like the pre-dispatch rejection: GrpcRetrySafety.WasNeverSent recognises
Grpc.Net.Client's subchannel connect failure ("Error connecting to subchannel."
with a SocketException cause) and an HttpRequestException name-resolution /
connection error with a connect-only socket error. Anything that may have been
delivered (reset, premature end, GOAWAY, server Unavailable) stays
OUTCOME_UNKNOWN and is not replayed. The site->central reconcile path uses the
same ProvablyNotApplied rule.
Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
74 lines
3.8 KiB
C#
74 lines
3.8 KiB
C#
using System.Net.Http;
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using System.Net.Sockets;
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using Grpc.Core;
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using ZB.MOM.WW.ScadaBridge.Communication.Grpc;
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namespace ZB.MOM.WW.ScadaBridge.Communication.Tests.Grpc;
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/// <summary>
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/// ScadaBridge#136: <see cref="GrpcRetrySafety.WasNeverSent"/> admits only connect-phase failures
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/// (the request provably never left the client) and rejects every shape that may have delivered it.
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/// </summary>
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public sealed class GrpcRetrySafetyNeverSentTests
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{
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private static RpcException Rpc(StatusCode code, string detail, Exception? debug)
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=> new(new Status(code, detail, debug));
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private static SocketException Sock(SocketError error) => new((int)error);
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/// <summary>The balancer's subchannel connect failure is pre-send, whatever the socket error.</summary>
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/// <param name="error">The socket error the subchannel connect saw.</param>
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[Theory]
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[InlineData(SocketError.ConnectionRefused)]
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[InlineData(SocketError.HostNotFound)]
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[InlineData(SocketError.TryAgain)]
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[InlineData(SocketError.HostUnreachable)]
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[InlineData(SocketError.TimedOut)]
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public void SubchannelConnectFailure_IsNeverSent(SocketError error)
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{
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var ex = Rpc(StatusCode.Unavailable, GrpcRetrySafety.SubchannelConnectFailureDetail, Sock(error));
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Assert.True(GrpcRetrySafety.WasNeverSent(ex));
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Assert.True(GrpcRetrySafety.ProvablyNotApplied(ex));
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}
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/// <summary>An HttpRequestException connect error with a connect-only socket error is pre-send.</summary>
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/// <param name="kind">The HTTP request error classification.</param>
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/// <param name="error">The socket error.</param>
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[Theory]
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[InlineData(HttpRequestError.ConnectionError, SocketError.ConnectionRefused)]
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[InlineData(HttpRequestError.NameResolutionError, SocketError.HostNotFound)]
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[InlineData(HttpRequestError.NameResolutionError, SocketError.TryAgain)]
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public void HttpConnectError_WithConnectOnlySocketError_IsNeverSent(HttpRequestError kind, SocketError error)
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{
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var ex = Rpc(StatusCode.Unavailable, "Error starting gRPC call.",
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new HttpRequestException(kind, "connect failed", Sock(error)));
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Assert.True(GrpcRetrySafety.WasNeverSent(ex));
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}
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/// <summary>Shapes that may follow delivery stay ambiguous.</summary>
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[Fact]
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public void FailuresThatMayFollowDelivery_AreNotNeverSent()
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{
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// Premature end / reset on an established connection.
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Assert.False(GrpcRetrySafety.WasNeverSent(Rpc(StatusCode.Unavailable, "Error starting gRPC call.",
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new HttpRequestException(HttpRequestError.ResponseEnded, "ended",
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new IOException("reset", Sock(SocketError.ConnectionReset))))));
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// A ConnectionError classification with a post-connect socket error.
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Assert.False(GrpcRetrySafety.WasNeverSent(Rpc(StatusCode.Unavailable, "Error starting gRPC call.",
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new HttpRequestException(HttpRequestError.ConnectionError, "x", Sock(SocketError.ConnectionReset)))));
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// A server-sent Unavailable (no transport exception at all).
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Assert.False(GrpcRetrySafety.WasNeverSent(Rpc(StatusCode.Unavailable, "modelled fault", null)));
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// A bare socket error outside the subchannel-pick path.
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Assert.False(GrpcRetrySafety.WasNeverSent(Rpc(StatusCode.Unavailable, "Error starting gRPC call.",
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Sock(SocketError.ConnectionRefused))));
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// Subchannel detail without a socket cause.
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Assert.False(GrpcRetrySafety.WasNeverSent(Rpc(StatusCode.Unavailable,
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GrpcRetrySafety.SubchannelConnectFailureDetail, new InvalidOperationException())));
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// Not Unavailable.
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Assert.False(GrpcRetrySafety.WasNeverSent(Rpc(StatusCode.DeadlineExceeded,
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GrpcRetrySafety.SubchannelConnectFailureDetail, Sock(SocketError.ConnectionRefused))));
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}
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}
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