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Elasticsearch.Net and NEST: the .NET clients [2.x] » Client Concepts - Elasticsearch.Net » Unrecoverable exceptions
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Unrecoverable exceptionsedit

Unrecoverable exceptions are excepted exceptions that are grounds to exit the client pipeline immediately. By default, the client won’t throw on any ElasticsearchClientException but instead return an invalid response which can be detected by checking .IsValid on the response You can configure the client to throw using ThrowExceptions() on ConnectionSettings. The following test both a client that throws and one that returns an invalid response with an .OriginalException exposed

The following are recoverable exceptions

var recoverablExceptions = new[]
{
    new PipelineException(PipelineFailure.BadResponse),
    new PipelineException(PipelineFailure.PingFailure),
};

recoverablExceptions.Should().OnlyContain(e => e.Recoverable);

and the unrecoverable exceptions

var unrecoverableExceptions = new[]
{
    new PipelineException(PipelineFailure.CouldNotStartSniffOnStartup),
    new PipelineException(PipelineFailure.SniffFailure),
    new PipelineException(PipelineFailure.Unexpected),
    new PipelineException(PipelineFailure.BadAuthentication),
    new PipelineException(PipelineFailure.MaxRetriesReached),
    new PipelineException(PipelineFailure.MaxTimeoutReached)
};

unrecoverableExceptions.Should().OnlyContain(e => !e.Recoverable);

As an example, let’s set up a 10 node cluster that will always succeed when pinged but will fail with a 401 response when making client calls

var audit = new Auditor(() => Framework.Cluster
    .Nodes(10)
    .Ping(r => r.SucceedAlways())
    .ClientCalls(r => r.FailAlways(401))
    .StaticConnectionPool()
    .AllDefaults()
);

Here we make a client call and determine that the first audit event was a successful ping, followed by a bad response as a result of a bad authentication response

audit = await audit.TraceElasticsearchException(
    new ClientCall {
        { AuditEvent.PingSuccess, 9200 },
        { AuditEvent.BadResponse, 9200 },
    },
    (e) =>
    {
        e.FailureReason.Should().Be(PipelineFailure.BadAuthentication);
    }
);
var audit = new Auditor(() => Framework.Cluster
    .Nodes(10)
    .Ping(r => r.SucceedAlways())
    .ClientCalls(r => r.FailAlways(401).ReturnResponse(ResponseHtml))
    .StaticConnectionPool()
    .AllDefaults()
);

audit = await audit.TraceElasticsearchException(
    new ClientCall {
        { AuditEvent.PingSuccess, 9200 },
        { AuditEvent.BadResponse, 9200 },
    },
    (e) =>
    {
        e.FailureReason.Should().Be(PipelineFailure.BadAuthentication);
        e.Response.HttpStatusCode.Should().Be(401);
        e.Response.ResponseBodyInBytes.Should().BeNull();
    }
);

e.FailureReason.Should().Be(PipelineFailure.BadAuthentication);

e.Response.HttpStatusCode.Should().Be(401);

e.Response.ResponseBodyInBytes.Should().BeNull();
var audit = new Auditor(() => Framework.Cluster
    .Nodes(10)
    .Ping(r => r.SucceedAlways())
    .ClientCalls(r => r.FailAlways(401).ReturnResponse(ResponseHtml))
    .StaticConnectionPool()
    .Settings(s=>s.DisableDirectStreaming())
);

audit = await audit.TraceElasticsearchException(
    new ClientCall {
        { AuditEvent.PingSuccess, 9200 },
        { AuditEvent.BadResponse, 9200 },
    },
    (e) =>
    {
        e.FailureReason.Should().Be(PipelineFailure.BadAuthentication);
        e.Response.HttpStatusCode.Should().Be(401);
        e.Response.ResponseBodyInBytes.Should().NotBeNull();
        var responseString = Encoding.UTF8.GetString(e.Response.ResponseBodyInBytes);
        responseString.Should().Contain("nginx/");
        e.DebugInformation.Should().Contain("nginx/");
    }
);

e.FailureReason.Should().Be(PipelineFailure.BadAuthentication);

e.Response.HttpStatusCode.Should().Be(401);

e.Response.ResponseBodyInBytes.Should().NotBeNull();

var responseString = Encoding.UTF8.GetString(e.Response.ResponseBodyInBytes);

responseString.Should().Contain("nginx/");

e.DebugInformation.Should().Contain("nginx/");
var audit = new Auditor(() => Framework.Cluster
    .Nodes(10)
    .Ping(r => r.SucceedAlways())
    .ClientCalls(r => r.FailAlways(401).ReturnResponse(ResponseHtml))
    .StaticConnectionPool()
    .Settings(s=>s.DisableDirectStreaming().DefaultIndex("default-index"))
    .ClientProxiesTo(
        (c, r) => c.Get<Project>("1", s=>s.RequestConfiguration(r)),
        async (c, r) => await c.GetAsync<Project>("1", s=>s.RequestConfiguration(r)) as IResponse
    )
);

audit = await audit.TraceElasticsearchException(
    new ClientCall {
        { AuditEvent.PingSuccess, 9200 },
        { AuditEvent.BadResponse, 9200 },
    },
    (e) =>
    {
        e.FailureReason.Should().Be(PipelineFailure.BadAuthentication);
        e.Response.HttpStatusCode.Should().Be(401);
        e.Response.ResponseBodyInBytes.Should().NotBeNull();
        var responseString = Encoding.UTF8.GetString(e.Response.ResponseBodyInBytes);
        responseString.Should().Contain("nginx/");
        e.DebugInformation.Should().Contain("nginx/");
    }
);

e.FailureReason.Should().Be(PipelineFailure.BadAuthentication);

e.Response.HttpStatusCode.Should().Be(401);

e.Response.ResponseBodyInBytes.Should().NotBeNull();

var responseString = Encoding.UTF8.GetString(e.Response.ResponseBodyInBytes);

responseString.Should().Contain("nginx/");

e.DebugInformation.Should().Contain("nginx/");
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