Problem with add_tag

Elastic Stack Logstash
1

Hello, I would like to change the tags field to a lowercase field.

My original message like this:
{ "@timestamp": "2019-08-08T13:33:38.86", "appid": "bla", "tags": [ "SUCC:AUTHEN"] }

My filter:
mutate {
rename => { "[tags]" => "[tags_tmp]" }
}

	if "SUCC" in [tags_tmp] {
		add_tag = ["succ"]
	}

OR
if [tags_tmp] =~ /SUCC/ {
add_tag = ["succ"]
}

My result:
"tags_tmp": ["SUCC:AUTHEN"],
"tags": ,

Why the tags field is empty??

2

Have you tried the mutate filter lowercase option instead?

3

no, tags must look like this :tags: ["succ","authen"]and not like this: tags: ["succ:authen"]

4

But if you followed Benny's suggestion and combined it with a split filter, you'd get what you want.

5

The first one, using "in", fails because there is no member of the tags array that is exactly equal to "SUCC". For the second you would have to test against a member of the array

if [tags_tmp][0] =~ /SUCC/ { mutate { add_tag => ["succ"] } }
7

ok almost works.

"tags_tmp": [ "SUCC:AUTHEN" ]

My filter:
if [tags_tmp][0] =~/SUCC/ {
mutate { add_tag => ["succ"] }
}
else if [tags_tmp][0] =~/FAIL/ {
mutate { add_tag => ["fail"] }
}
else if [tags_tmp][0] =~/AUTHEN/ {
mutate { add_tag => ["authen"] }
}
if [tags_tmp][1] =~/SUCC/ {
mutate { add_tag => ["succ"] }
}
else if [tags_tmp][1] =~/FAIL/ {
mutate { add_tag => ["fail"] }
}
else if [tags_tmp][1] =~/AUTHEN/ {
mutate { add_tag => ["authen"] }
}

My result: "tags": ["succ"], but why not "tags": ["succ","authen"] ??

8

There is no [tags_tmp][1] because there is only one entry (which is a string with multiple words).

if [tags_tmp][0] =~/SUCC/ {
mutate { add_tag => ["succ"] }
}
if [tags_tmp][0] =~/FAIL/ {
mutate { add_tag => ["fail"] }
}
if [tags_tmp][0] =~/AUTHEN/ {
mutate { add_tag => ["authen"] }
}
9

Great !
It's works:
if [tags_tmp][0] =~/SUCC/ {
mutate { add_tag => ["succ"] }
}
if [tags_tmp][0] =~/FAIL/ {
mutate { add_tag => ["fail"] }
}
if [tags_tmp][0] =~/AUTHEN/ {
mutate { add_tag => ["authen"] }
}

10

This is all going to be really fragile, because it can break if the initial message has more than one tags. That said, I would do it using

    mutate { copy => { "[tags][0]" => "[tags_tmp]" } }
    mutate { split => { "[tags_tmp]" => ":" } }
    mutate { lowercase => [ "tags_tmp" ] }

which gets you

  "tags_tmp" => [
    [0] "succ",
    [1] "authen"
],
2 Likes
11

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