logstash output not showing the desired timestamp - logstash

Question

I am trying to get the desired time stamp format from logstash output. I can''t get that if I use this format in syslog
Please share your thoughts about convert to the other format that’s in the _source field like Yyyy-mm-ddThh:mm:ss.sssZ format?
filter {
grok {
match => [ "logdate", "Yyyy-mm-ddThh:mm:ss.sssZ" ]
overwrite => ["host", "message"]
}
_source: {
message: "activity_log: {"created_at":1421114642210,"actor_ip":"192.168.1.1","note":"From system","user":"4561c9d7aaa9705a25f66d","user_id":null,"actor":"4561c9d7aaa9705a25f66d","actor_id":null,"org_id":null,"action":"user.failed_login","data":{"transaction_id":"d6768c473e366594","name":"user.failed_login","timing":{"start":1422127860691,"end":14288720480691,"duration":0.00257},"actor_locatio
I am using this code in syslog file
filter {
if [message] =~ /^activity_log: / {
grok {
match => ["message", "^activity_log: %{GREEDYDATA:json_message}"]
}
json {
source => "json_message"
remove_field => "json_message"
}
date {
match => ["created_at", "UNIX_MS"]
}
mutate {
rename => ["[json][repo]", "repo"]
remove_field => "json"
}
}
}
output {
elasticsearch { host => localhost }
stdout { codec => rubydebug }
}
thanks
"message" => "<134>feb 1 20:06:12 {\"created_at\":1422765535789, pid=5450 tid=28643 version=b0b45ac proto=http ip=192.168.1.1 duration_ms=0.165809 fs_sent=0 fs_recv=0 client_recv=386 client_sent=0 log_level=INFO msg=\"http op done: (401)\" code=401" }
"#version" => "1",
"#timestamp" => "2015-02-01T20:06:12.726Z",
"type" => "activity_log",
"host" => "192.168.1.1"

Answer 1

The pattern in your grok filter doesn't make sense. You're using a Joda-Time pattern (normally used for the date filter) and not a grok pattern.
It seems your message field contains a JSON object. That's good, because it makes it easy to parse. Extract the part that comes after "activity_log: " to a temporary json_message field,
grok {
match => ["message", "^activity_log: %{GREEDYDATA:json_message}"]
}
and parse that field as JSON with the json filter (removing the temporary field if the operation was successful):
json {
source => "json_message"
remove_field => ["json_message"]
}
Now you should have the fields from the original message field at the top level of your message, including the created_at field with the timestamp you want to extract. That number is the number of milliseconds since the epoch so you can use the UNIX_MS pattern in a date filter to extract it into #timestamp:
date {
match => ["created_at", "UNIX_MS"]
}