keep

The keep proc is used to keep only the field names specified from every point in the stream.

...  | keep(*fieldnames) | ...

Argument	Description	Required?
*fieldnames	list of field names to keep in each point	No, default: None

keep just the count field

from flume import *

(
    emit(limit=5)
    | put(count=count())
    | keep('count'
    | write('stdio')
).execute()

The above would produce the output:

{"count": 1}
{"count": 2}
{"count": 3}
{"count": 4}
{"count": 5}