/// <summary>
/// Data node in the server which registers ourselves with IoT Hub when this node is written.
/// </summary>
public ServiceResult OnConnectionStringWrite(ISystemContext context, NodeState node, NumericRange indexRange, QualifiedName dataEncoding, ref object value, ref StatusCode statusCode, ref DateTime timestamp)
{
var connectionString = value as string;
if (string.IsNullOrEmpty(connectionString))
{
Trace("ConnectionStringWrite: Invalid Argument!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments as strings!"));
}
statusCode = StatusCodes.Bad;
timestamp = DateTime.Now;
// read current connection string and compare to the one passed in
string currentConnectionString = SecureIoTHubToken.Read(OpcConfiguration.ApplicationName, IotDeviceCertStoreType, IotDeviceCertStorePath);
if (string.Equals(connectionString, currentConnectionString, StringComparison.OrdinalIgnoreCase))
{
Trace("ConnectionStringWrite: Connection string up to date!");
return(ServiceResult.Create(StatusCodes.Bad, "Connection string already up-to-date!"));
}
Trace($"ConnectionStringWrite: Attempting to configure publisher with connection string: {connectionString}");
// configure publisher and write connection string
try
{
IotHubCommunication.ConnectionStringWrite(connectionString);
}
catch (Exception e)
{
statusCode = StatusCodes.Bad;
Trace(e, $"ConnectionStringWrite: Exception while trying to create IoTHub client and store device connection string in cert store");
return(ServiceResult.Create(StatusCodes.Bad, "Publisher registration failed: " + e.Message));
}
statusCode = StatusCodes.Good;
Trace("ConnectionStringWrite: Success!");
return(statusCode);
}
/// <summary>
/// Initializes the communication with secrets and details for (batched) send process.
/// </summary>
/// <returns></returns>
public bool Init(string iotHubOwnerConnectionString, uint maxSizeOfIoTHubMessageBytes, int defaultSendIntervalSeconds)
{
_maxSizeOfIoTHubMessageBytes = maxSizeOfIoTHubMessageBytes;
_defaultSendIntervalSeconds = defaultSendIntervalSeconds;
try
{
// check if we also received an owner connection string
if (string.IsNullOrEmpty(iotHubOwnerConnectionString))
{
Trace("IoT Hub owner connection string not passed as argument.");
// check if we have an environment variable to register ourselves with IoT Hub
if (!string.IsNullOrEmpty(Environment.GetEnvironmentVariable("_HUB_CS")))
{
iotHubOwnerConnectionString = Environment.GetEnvironmentVariable("_HUB_CS");
Trace("IoT Hub owner connection string read from environment.");
}
}
// register ourselves with IoT Hub
string deviceConnectionString;
Trace($"IoTHub device cert store type is: {IotDeviceCertStoreType}");
Trace($"IoTHub device cert path is: {IotDeviceCertStorePath}");
if (string.IsNullOrEmpty(iotHubOwnerConnectionString))
{
Trace("IoT Hub owner connection string not specified. Assume device connection string already in cert store.");
}
else
{
Trace($"Attempting to register ourselves with IoT Hub using owner connection string: {iotHubOwnerConnectionString}");
RegistryManager manager = RegistryManager.CreateFromConnectionString(iotHubOwnerConnectionString);
// remove any existing device
Device existingDevice = manager.GetDeviceAsync(ApplicationName).Result;
if (existingDevice != null)
{
Trace($"Device '{ApplicationName}' found in IoTHub registry. Remove it.");
manager.RemoveDeviceAsync(ApplicationName).Wait();
}
Trace($"Adding device '{ApplicationName}' to IoTHub registry.");
Device newDevice = manager.AddDeviceAsync(new Device(ApplicationName)).Result;
if (newDevice != null)
{
string hostname = iotHubOwnerConnectionString.Substring(0, iotHubOwnerConnectionString.IndexOf(";"));
deviceConnectionString = hostname + ";DeviceId=" + ApplicationName + ";SharedAccessKey=" + newDevice.Authentication.SymmetricKey.PrimaryKey;
Trace($"Device connection string is: {deviceConnectionString}");
Trace($"Adding it to device cert store.");
SecureIoTHubToken.Write(ApplicationName, deviceConnectionString, IotDeviceCertStoreType, IotDeviceCertStorePath);
}
else
{
Trace($"Could not register ourselves with IoT Hub using owner connection string: {iotHubOwnerConnectionString}");
Trace("exiting...");
return(false);
}
}
// try to read connection string from secure store and open IoTHub client
Trace($"Attempting to read device connection string from cert store using subject name: {ApplicationName}");
deviceConnectionString = SecureIoTHubToken.Read(ApplicationName, IotDeviceCertStoreType, IotDeviceCertStorePath);
if (!string.IsNullOrEmpty(deviceConnectionString))
{
Trace($"Create Publisher IoTHub client with device connection string: '{deviceConnectionString}' using '{IotHubProtocol}' for communication.");
_iotHubClient = DeviceClient.CreateFromConnectionString(deviceConnectionString, IotHubProtocol);
_iotHubClient.RetryPolicy = RetryPolicyType.Exponential_Backoff_With_Jitter;
_iotHubClient.OpenAsync().Wait();
}
else
{
Trace("Device connection string not found in secure store. Could not connect to IoTHub.");
Trace("exiting...");
return(false);
}
// start up task to send telemetry to IoTHub.
_dequeueAndSendTask = null;
_tokenSource = new CancellationTokenSource();
Trace("Creating task to send OPC UA messages in batches to IoT Hub...");
_dequeueAndSendTask = Task.Run(() => DeQueueMessagesAsync(_tokenSource.Token), _tokenSource.Token);
}
catch (Exception e)
{
Trace(e, "Error during IoTHub messaging initialization.");
return(false);
}
return(true);
}