Accessing data from industrial control devices can be made easier and safer by utilizing an OPC Server. OPC Servers provide protocol proxy services by translating requests for data from a standardized protocol like OPC to the native protocol of the industrial control device. Since the typical OPC Server can proxy many requests into many different protocols each for a different family of data sources they also make ideal aggregation points for control system data. Centralized data access also has advantages in security that should not be overlooked. The OPC Sever and Nifi can work together to provide certificate based authentication and role based data access to devices in process control networks. Nifi's unique pedigree is capable of complying with the stringent network ingress and regress rules. Get started fast with Kepware and Apache Nifi Out of the box tools available in KepServer Ex can make data available via HTTP and MQTT. ----|Kepware|---HTTP REST API-----|NIFI| or ----|Kepware|-----------MQTT-----------|NIFI| Data can also be acquired via OPC UA but this requires you to build the Nifi processor available at https://github.com/wadesalazar/NIFI-OPCUA First Get Kepware Download and install a copy of Kepware's Kepserver on a Windows VM host. You can download the application at at https://my.kepware.com/download/demo/ex/ The installation is straightforward but be sure to install select the optional IoT Gateway Plug-in. Start KepServer Configuration from the Windows Start menu. After being started a unlicensed demo will run for 2 hours before “timing out”. Restarting the server will restore it. Open the KepServerEX Configuration tool and select IoT Gateway Right click on the default agent and select New IoT Item Select Sin1 from the simulation functions and apply this tag. Selecting a scan rate and ok applies this tag configuration to this agent. From here you can export a CSV file that can be used for batch imports of IoT Item configurations Again right click on the Agent but select Properties this time. On the Endpoint tab of the dialogue box you will find the port configuration and option to enable HTTPS. Here you can also find a test link for the server which will bring you to a docs page that explains the available queries and JSON response format Now the data has been exposed over HTTP you may make REST requests to KepServer for data. Configure Get HTTP processor The URL is something of the form: http://YOUR.KEPSERVER.ADDRESS:39320/iotgateway/read?ids=Simulation%20Examples.Functions.Sine1 Review the acquired data in the data providence section of Nifi FYI the default JSON from Kepware puts [] around the inner document like this: {"readResults":[{"id":"Simulation Examples.Functions.Sine1","s":true,"r":"","v":33.705616,"t":1462251936055}]} Using MQTT or OPC UA is a very similar process requiring only changes in the Nifi processors used. Enjoy! ... View more

To post random data to Azure Event hubs using HTTP, use a generate flowfile processor to first generate the random data. Connect this to an UpdateAttribute processor to add your SAS (Share Access Signature) as a new attribute called "Authorization" to the flow file's attributes. Finally use PostHTTP to submit the data to Event Hubs Place the following processors on the pallet and set the run schedule of the generate flowfile processor to something reasonable like 10 seconds. Configure Update Attribute, adding the "Authorized" property with a SAS token. For more information on creating a SAS token see https://community.hortonworks.com/articles/69823/creating-shared-access-signature-sas-for-posting-d.html Configure the PostHTTP to post the URL https://eventhub-nifi.servicebus.windows.net/hub-nifi/messages Note: I set the content type to text/plain you should set this to suit your use case. Only the truststore needs to be configured for this example as we only need to trust the server certificates presented to us by the Azure servers. For simplicity I use Java's default keystore. See this post for finding and configuring the SSL service to use this keystore. Otherwise you will need to import trust certificates into your keystore manually Start all processors and verify successful submissions to the Event Hub Service in the Azure Portal Background on the security mechanisms of Event Hubs https://docs.microsoft.com/en-us/azure/service-bus-messaging/service-bus-shared-access-signature-authentication Background on Shard Access Signatures and how to generate them https://docs.microsoft.com/en-us/azure/service-bus-messaging/service-bus-sas-overview ... View more