Match parameter field name of date filter doesn't support variable interpolation

[hartfordfive]

It seems that the date filter's first argument of the match parameter does not support interpolation.

I've had a use case where I've dynamically set the name of the field containing the date/time within the [@metadata][time_field] attribute (to the value timestamp in my case) but unfortunately I've had to revert back to using a simple string.

Logstash Installation details:

• Logstash version: 5.2.2
• Date filter plugin version: 3.1.3
• Operating System: Darwin

This was attempted, and didn't work:

      date {
        match => ["[@metadata][time_field]",  "yyyy/mm/dd HH:mm:ss", "dd/MMM/yyyy:HH:mm:ss Z", "UNIX", "UNIX_MS"]
        locale => "en"
        add_tag => [ "timestamp_updated" ]
        timezone => "Etc/UTC"
        tag_on_failure => ["_dpf"]
      }

Therefore modifying the field needed to be changed to a simple string:

      date {
        match => ["timestamp",  "yyyy/mm/dd HH:mm:ss", "dd/MMM/yyyy:HH:mm:ss Z", "UNIX", "UNIX_MS"]
        locale => "en"
        add_tag => [ "timestamp_updated" ]
        timezone => "Etc/UTC"
        tag_on_failure => ["_dpf"]
      }