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Monitoring Number of Of Flow Files Queued in Apache NiFi via PyPortal

When I am developing in NiFi it is sometimes helpful to have an information radiator to tell me some things of immediate interest without going into the NiFi Summary screen.   So I made a quick information radiator with Adafruit's awesome PyPortal.   This device with screen connects to the WiFi network shared with my Apache NiFi node and will read the REST API to ingest the current number of total flow files queued in the system.

I saw mine was almost 300,000 flow files waiting, so I went into queues and emptied out ones I did not need to process.   There was nothing broken, but a few sinks no longer valid so I emptied those out.

NiFi Summary

System Statistics

When I first checked the Flow Files in the Queue, there were a lot of them.  

 As a Typical Business User, You Will Know Immediately Queue Count


Every Minute Let's Grab the NiFi Flow Files in Queue via REST API

grab data from Apache NiFi REST API
If you can find something that spits out JSON data, we can display it!
import time
import board
from adafruit_pyportal import PyPortal
# Set up where we'll be fetching data from
DATA_SOURCE = "http://hw13125.local:8080/nifi-api/flow/status"
DATA_LOCATION = ["controllerStatus", "flowFilesQueued"]
def text_transform(val):
format_str = "FlowFilesQueued in NiFi = {:d}"
return format_str.format(val)
# the current working directory (where this file is)
cwd = ("/"+__file__).rsplit('/', 1)[0]
pyportal = PyPortal(url=DATA_SOURCE, json_path=DATA_LOCATION,
text_position=(20, 20),
pyportal.preload_font(b'$012345789') # preload numbers
while True:
value = pyportal.fetch()
print("Response is", value)
except (ValueError, RuntimeError) as e:
print("Some error occured, retrying! -", e)
time.sleep(60) #

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