Hi @sally sally, You can do that by using invokeHTTP processor, once you make first service call then keep Response relationship to trigger next service. This way we can only triggers next service once we get response from previous service. Example:- In my below flow service 1 is triggered by GenerateFlowFile processor then i connected response relationship to trigger service2 InvokeHTTP processor. This service2 processor only triggers when it got response from service1 processor and keep in mind the response from service1 will be overwritten by response of service2. ... View more

Hi @sally sally, List Hdfs processor are developed as store the last state.. i.e when you configure ListHDFS processor you are going to specify directory name in properties. once the processor lists all the files existed in that directory at the time it will stores the state as maximum file time when it got stored into HDFS. you can view the state info by clicking on view state button. if you want to clear the state then you need to get into view state and click on clear the state. 2. so once it saves the state in listhdfs processor, if you are running the processor by scheduling as cron(or)timer driven it will only checks for the new files after the state timestamp. Note:- as we are running ListHDFS on primary node only, but this state value will be stored across all the nodes of NiFi cluster as primary node got changed, there won't be any issues regarding duplicates. Example:- hadoop fs -ls /user/yashu/test/ Found 1 items -rw-r--r-- 3 yash hdfs 3 2017-09-15 16:16 /user/yashu/test/part1.txt when i configure ListHDFS processor to list all the files in the above directory if you see the state of ListHDFS processor that should be same as when part1.txt got stored in HDFS in our case that should be 2017-09-15 16:16 it would be unix time in milliseconds when we convert the state time to date time format that should be Unixtime in milliseconds:- 1505506613479 Timestamp :- 2017-09-15 16:16:53 so the processor has stored the state, when it will run again it will lists only the new files that got stored after the state timestamp in to the directory and updates the state with new state time (i.e maximum file created in hadoop directory). ... View more

Using your browser's Developer Tools window, use the UI to clear a queue while monitoring the network tab. Everything the Apache NiFi UI does is performed via the REST API. You will be able to see exactly what requests are sent to the server to clear the connection queue and can recreate that programmatically. The specific API endpoint you want in this case is POST /flowfile-queues/{id}/drop-requests where {id} is the connection ID. ... View more

From my answer to this question on Stack Overflow: To extract the desired value, use the XPath expression //ErrorCode . This will return a String value -7. By selecting Destination flowfile-attribute, you can keep the flowfile content constant and put this new value in a flowfile attribute (i.e. named attribute ). You can chain the matched relationship to an UpdateAttribute processor which has the expression ${attribute:toNumber()} to convert it to a numerical representation, i.e. ${attribute:toNumber():plus(10)} would return 3. ... View more