Fix session.create to catch any exceptions, patch host name, plus better log messages (#17)

* Fix session.create to catch any exceptions, plus better log messages

* Updates based on code review feedback

samples/gateway_config.json

@@ -23,8 +23,8 @@
                         "Id": "<DeviceID>",
                         "SharedAccessKey": "<SharedAccessKey>",
                         "ServerUrl": "opc.tcp://<hostname>:51210/UA/SampleServer",
-						"MinimumSecurityLevel": 0,
-						"MinimumSecurityMode": "SignAndEncrypt",
+                        "MinimumSecurityLevel": 0,
+                        "MinimumSecurityMode": "SignAndEncrypt",
                         "PublishingInterval": 400,
                         "MonitoredItems": [
                             {

src/Opc.Ua.Client.Module/Module.cs

@@ -344,6 +344,10 @@ namespace Opc.Ua.Client
                     endpoint.SecurityLevel >= MinimumSecurityLevel &&
                     endpoint.SecurityMode >= MinimumSecurityMode)
                 {
+                    // patch endpoint to set the original host name we want to connect to.
+                    var url = new UriBuilder(endpoint.EndpointUrl);
+                    url.Host = ServerUrl.Host;
+                    endpoint.EndpointUrl = url.ToString();
                     selectedEndpoints.Add(endpoint);
                 }
             }
@@ -361,36 +365,46 @@ namespace Opc.Ua.Client
                 ConfiguredEndpoint configuredEndpoint = new ConfiguredEndpoint(
                     endpoint.Server, EndpointConfiguration.Create(Module.Configuration));
                 configuredEndpoint.Update(endpoint);
-
-                _session = await Session.Create(
-                    Module.Configuration,
-                    configuredEndpoint,
-                    true,
-                    false,
-                    Module.Configuration.ApplicationName,
-                    60000,
-                    new UserIdentity(new AnonymousIdentityToken()),
-                    null);
-
-                if (_session != null)
+                try 
                 {
-                    var subscription = new Subscription(_session.DefaultSubscription);
-                    subscription.PublishingInterval = PublishingInterval;
+                    Console.WriteLine($"Opc.Ua.Client.SampleModule: Establishing session with mode: {endpoint.SecurityMode}, level:{endpoint.SecurityLevel} to {configuredEndpoint.EndpointUrl}...");
+                    _session = await Session.Create(
+                        Module.Configuration,
+                        configuredEndpoint,
+                        true,
+                        false,
+                        Module.Configuration.ApplicationName,
+                        60000,
+                        // TODO: Make user identity configurable, plus add dedicated security policy
+                        new UserIdentity(new AnonymousIdentityToken()),
+                        null);
 
-                    // TODO: Make other subscription settings configurable...
+                    if (_session != null) 
+                    {
+                        var subscription = new Subscription(_session.DefaultSubscription);
+                        subscription.PublishingInterval = PublishingInterval;
 
-                    subscription.AddItems(MonitoredItems);
-                    _session.AddSubscription(subscription);
-                    subscription.Create();
+                        // TODO: Make other subscription settings configurable...
+                        subscription.AddItems(MonitoredItems);
+                        _session.AddSubscription(subscription);
+                        subscription.Create();
 
-                    Console.WriteLine($"Opc.Ua.Client.SampleModule: Created session with updated endpoint {configuredEndpoint.EndpointUrl} from server!");
-                    _session.KeepAlive += new KeepAliveEventHandler(StandardClient_KeepAlive);
+                        Console.WriteLine($"Opc.Ua.Client.SampleModule: Session with server endpoint {configuredEndpoint.EndpointUrl} established!");
+                        _session.KeepAlive += new KeepAliveEventHandler(StandardClient_KeepAlive);
 
-                    // Done
-                    return;
+                        // Done
+                        return;
+                    }
+                    else 
+                    {
+                        Console.WriteLine($"Opc.Ua.Client.SampleModule: WARNING Could not create session to endpoint {endpoint.ToString()}...");
+                    }
+                }
+                catch (Exception ex) 
+                {
+                    Console.WriteLine($"Opc.Ua.Client.SampleModule: ERROR Exception creating session to endpoint {endpoint.ToString()}...");
+                    Console.WriteLine($"Opc.Ua.Client.SampleModule: {ex.ToString()}");
                 }
-
-                Console.WriteLine($"Opc.Ua.Client.SampleModule: WARNING Could not create session to endpoint {endpoint.ToString()}...");
                 //  ... try another endpoint until we do not have any more...
             }