WatcherのIndex Actionで、Index名を可変にする方法がないか

Watcherの実行時にAction句でIndexを作成しているのですが、
この時、作成される日付に応じて、Index名を変える(=Watcherが実行されるたびに新しいIndexを作成する)ことができないでしょうか。

具体的にやりたいこととしては、
毎月月初にWatcherを実行し、実行日の前月の年月がIndex名の末尾に付記されるようにしたいです。
例: 6月1日にWatcherが実行され、watcher_201905というIndexが作成される

{
"trigger": {
"schedule": {
"monthly": {"on":1,"at":"midnight"} //毎月月初に実行
}
},
"input": {
・・・
},
"condition": {
・・・
},
"actions": {
"index_payload": {
"index": {
"index": "watcher", //Indexの末尾に、”YYYYMM”という形で、実行日の前月の年月を付記したい
"doc_type": "doc"
}
...
}

Hey,

see https://www.elastic.co/guide/en/elasticsearch/reference/current/date-math-index-names.html

You can use date math in index names, and just always go one month back with, see this example from the above link

<logstash-{now/M-1M{yyyy.MM}}>

--Alex

Hello,

Thank you for your replay.
Sorry that my description was not enough. The above code I posted is not for config file (like logstash.conf) or the part of API but the script for the watcher. So in my understand, it cannot contain such characters.
In case, I executed and I got following message.

message": "[watch_{now/M-1M{yyyy.MM}}] InvalidIndexNameException[Invalid index name [watch_{now/M-1M{yyyy.MM}}], must not contain the following characters [ , ", *, \, <, |, ,, >, /, ?]]",

Best regards.

this is supposed to be the index name so it can go straight into your watch. Judging from the error message the <> brackets are missing. Can you share the whole watch again including your changes, so one can try to reproduce locally? Thanks!

Finally worked! As you told me, the problem was just lacking of <>.
Thank you for your swift and helpful advice.

My latest code is like below.

"actions" : {
   "index_payload" : {
       "transform" : { ... },
       "index" : {
            "index" : "<logstash-{now/M-1M{yyyy.MM}}>",
            "doc_type" : "doc"
        }
    }
 }