Failure to convert epoch number in scientific format to date

[jlevym (Jeffrey)]

my input json file (coming from mongoexport) is showing the time in scientific notation, for example:

"lastUpdate":1.575882773525e+12

When I try and convert this to date format using "UNIX_MX" I get the following

lastUpdate 1,575,882,773,525

and the system @timestamp is incorrect:

@timestamp Dec 9, 2019 @ 11:12:53.525 (the correct timestamp is Dec 14 2019 and works fine when I don't us the date filter)

Please suggest how I can fix this issue.

This is my input and filter code:

input {
	file   {
		path => "/usr/share/logstash/mydata/mongodb.json"  
		start_position => "beginning"
		sincedb_path => "/dev/null"
		codec => json
        }
}

## Add your filters / logstash plugins configuration here

filter {

   date {
	   match => [ "lastUpdate" => "UNIX_MS" ]
	}

   mutate {  remove_field => [ "_id", "path", "host", "userId", "lessonId", "tags", "classreportId", "data.lesson.image", "answers.checkAnswer"] }
}

[Badger]

I don't understand the issue. A date filter is used to modify @timestamp by default. If you want it to modify another field then use the target option. And specify the timezone too, since 1,575,882,773,525 is 2019/12/09 9:12:53.525 (9 AM, not 11 AM).

[jlevym (Jeffrey)]

Thank you so much for pointing this out to me. I had a basic misunderstanding of how this plugin works and this cleared it up and now it runs perfectly!