RabbitMQ cluster default uses SSL configured in ConnectionFactory

[litiansum]

When using dotnetcore/CAP with a RabbitMQ cluster that has SSL enabled, the connection cannot be established.

After investigating the source code, it seems that when multiple hosts are configured (comma-separated), the generated Endpoint objects are created without assigning the corresponding SSL configuration. As a result:

The default port and protocol are used instead of the SSL configuration.

Connections fail because the client attempts a non-SSL connection to an SSL-enabled cluster.

Error message

DotNetCore.CAP.Internal.ConsumerRegister[0] Broker Unreachable DotNetCore.CAP.BrokerConnectionException: Broker Unreachable ---> RabbitMQ.Client.Exceptions.BrokerUnreachableException: None of the specified endpoints were reachable ---> System.AggregateException: One or more errors occurred. (Connection failed, host 192.168.2.17:5672) (Connection failed, host 192.168.2.22:5672) (Connection failed, host 192.168.2.19:5672) ---> RabbitMQ.Client.Exceptions.ConnectFailureException: Connection failed, host 192.168.2.17:5672

Root cause：
`

    if (options.HostName.Contains(","))
    {
        options.ConnectionFactoryOptions?.Invoke(factory);
        return () => factory.CreateConnectionAsync(AmqpTcpEndpoint.ParseMultiple(options.HostName));
    }

`

The AmqpTcpEndpoint.ParseMultiple(options.HostName) method generates Endpoint objects without applying the SslOptions configuration, which leads to incorrect connections.

When creating endpoints from multiple hosts, explicitly apply the SslOptions configuration from the factory. For example:

`

    if (options.HostName.Contains(","))
    {
        options.ConnectionFactoryOptions?.Invoke(factory);

        var endpoints = AmqpTcpEndpoint.ParseMultiple(options.HostName);
        foreach (var endpoint in endpoints)
        {
            // Ensure SSL options are applied
            endpoint.Ssl = factory.Ssl;
        }

        return () => factory.CreateConnectionAsync(endpoints);
    }

`

[yang-xiaodong]

I Think this treatment is not correct, and it cannot be ensured that every Endpoint in the cluster uses the same SSL configuration.

[litiansum]

I Think this treatment is not correct, and it cannot be ensured that every Endpoint in the cluster uses the same SSL configuration.

I think that in most production environments, the cluster will use the same SSL configuration (CA root certificate and server certificate policy).

I checked and found that in another overload method provided by RabbitMQ.Client, the same SSL configuration is also used.

`

    public Task<IConnection> CreateConnectionAsync(IEnumerable<string> hostnames, string? clientProvidedName,
        CancellationToken cancellationToken = default)
    {
        IEnumerable<AmqpTcpEndpoint> endpoints = hostnames.Select(h => new AmqpTcpEndpoint(h, Port, Ssl, MaxInboundMessageBodySize));
        return CreateConnectionAsync(EndpointResolverFactory(endpoints), clientProvidedName, cancellationToken);
    }

`

[yang-xiaodong]

Are you willing to submit a PR? I think we can keep most scenes as you said first. 😄

[litiansum]

Are you willing to submit a PR? I think we can keep most scenes as you said first. 😄

I have created a PR, please review it, thank you.