How to insert previous month of data into database Nifi? - apache-nifi

Question

I have data in which i need to compare month of data if it is previous month then it should be insert otherwise not.
Example:
23.12.2016 12:02:23,Koji,24
22.01.2016 01:21:22,Mahi,24
Now i need to get first column of data (23.12.2016 12:02:23) and then get month (12) on it.
Compared that with before of current month like.,
If current month is 'JAN_2017',then get before of 'JAN_2017' it should be 'Dec_2016'
For First row,
compare this 'Dec_2016'[month before] with month of data 'Dec_2016' [23.12.2016].
It matched then insert into database.
EDIT 1:
i have already tried with your suggestions.
"UpdateAttribute to add a new attribute with the previous month value, and then RouteOnAttribute to determine if the flowfile should be inserted "
i have used below expression language in RouteOnAttribute,
${literal('Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec'):getDelimitedField(${csv.1:toDate('dd.MM.yyyy hh:mm:ss'):format('MM')}):equals(${literal('Dec,Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov'):getDelimitedField(${now():toDate(' Z MM dd HH:mm:ss.SSS yyyy'):format('MM'):toNumber()})})}
it could be failed in below data.,
23.12.2015,Andy,21
23.12.2017,Present,32
My data may contains some past years and future years
It matches with my expression it also inserted.
I need to check month with year in data.
How can i check it?

Answer 1

The easiest answer is to use the ExecuteScript processor with simple date logic (this will allow you to use the Groovy/Java date framework to correctly handle things like leap years, time zones, etc.).
If you really don't want to do that, you could probably use a regex and Expression Language in UpdateAttribute to add a new attribute with the previous month value, and then RouteOnAttribute to determine if the flowfile should be inserted into the database.
Here's a simple Groovy test demonstrating the logic. You'll need to add the code to process the session, flowfile, etc.
#Test
public void textScriptShouldFindPreviousMonth() throws Exception {
// Arrange
def input = ["23.12.2016 12:02:23,Koji,24", "22.01.2016 01:21:22,Mahi,24"]
def EXPECTED = ["NOV_2016", "DEC_2015"]
// Act
input.eachWithIndex { String data, int i ->
Calendar calendar = Date.parse("dd.MM.yyyy", data.tokenize(" ")[0]).toCalendar()
calendar.add(Calendar.MONTH, -1)
String result = calendar.format("MMM_yyyy").toUpperCase()
// Assert
assert result == EXPECTED[i]
}
}