@Umakanth    The API is exposed out of the box, it is not something you need to enable. Every action you take while performing actions within the UI makes a call to the NiFi rest-api. When learning how to use the rest-api calls, you may find using the developer tools in your browser helpful. Open the developer tools  while you are accessing your NiFi UI.  Then perform some action and you will see those requests being made by your browser to NiFi.  In the below example (Using Chrome browser developer tools), I opened NiFi's summary UI from the global menu in the upper right corner of the UI: You'll notice that several requests were made.  I can write click on any one of those request and select "Copy as cURL" to copy the full request to the system clipboard. I can then paste the request in a terminal window and see what the rest-api call returns.  You will notice that the curl command that is copied will have numerous additional headers (-H) that are not always necessary depending on the rest-api endpoint being used.  Example: curl 'http://<nifi-hostname>:<nifi-port>/nifi-api/flow/process-groups/root/status?recursive=true' Of course you will need to parse the rest-api returns yourself to extract in many cases the specific details/stats you want to monitor. Hope this helps, Matt ... View more

@Alexandros  Securing NiFi and NiFi-registry will always require TLS certificates.  There are then numerous options for authentication in to those secured sevices. Both NiFi and NiFi Registry both offer: 1. User based certificate authentication.  You would need to create a user certificate for each user who will access NiFi or NiFi-registry 2. Spnego - This requires that you have a KDC and your users have Spnego enabled in their browser 3. LDAP/AD user authentication.  You would need to have your own LDAP/AD setup which you can use to authenticate your users. 4. kerberos login provider.  This would require you to setup your own KDC as well. NiFi also supports OpenID connect compatible service based authentication; however, the same is not offered in NiFi-Registry.  The jira for adding OpenID connect capability to NiFi-Registry is still open here: https://issues.apache.org/jira/browse/NIFIREG-313 So based on options above and depending on the number of users you want to give access to, your best options are either by issuing each of your users a user/client certificate or setting up a simple LDAP server or KDC server.   Hope this helps, Matt ... View more

@TVGanesh    The following statement is not accurate: "I read that typically the number of concurrent tasks is roughly equal to  2 or 4 times the cores"   The general recommendation is that the "Max Timer Driven Thread Count" is set to 2 to 4 times the number of cores.  This setting is all relative to the other process running on your server (or you mac in this case). The "Max Timer Driven Thread Count" setting establishes the max number of threads that can be handed out to requesting components that want to execute. (This is a soft limit, there are some scenarios where a thread can be obtained even when active threads executing has reached this configured max count). The "Max Timer Driven Thread Count" is configured under the NiFi Global Menu --> Controller Settings --> General (tab).  When you adjust this value, monitor your cpu usage and adjust accordingly. Keep in mind that adding additional concurrent tasks to your processor will not improve the processing of a single FlowFile.  The concurrency allows the processor to work on different FlowFiles pulled from the inbound connection queue concurrently.  In the case of the ExecuteStreamCommand processor, the ability to execute the same command concurrently also is dependent of the command you are executing.    A small number will be displayed in the upper right corner of the processor illustrating the number of currently active threads in use by that processor at time of last browser refresh (NiFi browser auto refresh default is every 30 seconds). Hope this helps, Matt ... View more

@maryem    Any action you can do through the NiFi UI, you can also do via interacting directly with the NiFi rest-api. This will not animate the action of actually dragging and dropping a processor on the canvas, but you can make a rest-api call that would add new processor of type ABC at coordinates x,y on the canvas.   NiFi's rest-api documentation can be found here: https://nifi.apache.org/docs/nifi-docs/rest-api/index.html Some users find it easier to learn the rest-api call through examples.  If you open the developer tools in your browser, you can perform the action via the UI and see the rest-api call that was made.  Most browser developer tools even let you save the rest-api call as a curl command that you could then execute yourself via command line. Matt ... View more

@nishank_paras    You can use the invokeHTTP processor to fetch your file.  Here is an example: The above example fetches the Apache nifi-toolkit-1.11.3-bin.tar.gz file. You can then construct a dataflow using other processors to manipulate as you want or simply just connect to another invokeHTTP processor that instead of "GET" uses "PUT" to put your file "nn.csv" at the new http endpoint.   Hope this helps you, Matt   ... View more