Add 'composed_of' support for template creation with setup commands

[novaksam]

Describe the enhancement: Add the ability to attach component templates to the V2 templates create by the various beat setup processes.

Describe a specific use case for the enhancement or feature: I have a lowercasing normalizer I attach to certain fields for winlogbeat, to make searching easier (less case sensitive). I'm working on shifting from legacy to v2 templates, and I'd like to have a way to include certain component templates that I've made to the templates created by the setup process.

I looked at https://github.com/kvch/beats/blob/master/libbeat/template/config.go but there doesn't appear to be support for appending 'composed_of' to templates this way. I've tested a handful of different ways with the existing reference file, but did not have any success, though I apologize if I missed something and this already works.

Ideally it could be something like setup.template.composed_of: ["component1", "component2"]

For reference, this is the normalizer I have configured:

component template

{
  "template": {
    "settings": {
      "index": {
        "analysis": {
          "normalizer": {
            "normalizer_lowercase": {
              "filter": [
                "lowercase",
                "asciifolding"
              ],
              "type": "custom",
              "char_filter": []
            }
          },
          "analyzer": {
            "analyzer_case_insensitive": {
              "filter": "lowercase",
              "tokenizer": "keyword"
            }
          }
        }
      }
    },
    "mappings": {
      "_source": {
        "enabled": true,
        "includes": [],
        "excludes": []
      },
      "_routing": {
        "required": false
      },
      "dynamic": true,
      "numeric_detection": false,
      "date_detection": true,
      "dynamic_date_formats": [
        "strict_date_optional_time",
        "yyyy/MM/dd HH:mm:ss Z||yyyy/MM/dd Z"
      ],
      "dynamic_templates": [],
      "properties": {
        "process": {
          "type": "object",
          "properties": {
            "args": {
              "type": "keyword",
              "normalizer": "normalizer_lowercase",
              "ignore_above": 1024
            },
            "executable": {
              "type": "keyword",
              "normalizer": "normalizer_lowercase",
              "ignore_above": 1024
            },
            "name": {
              "type": "keyword",
              "normalizer": "normalizer_lowercase",
              "ignore_above": 1024
            },
            "parent": {
              "type": "object",
              "properties": {
                "args": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "executable": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "name": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                }
              }
            }
          }
        },
        "winlog": {
          "type": "object",
          "properties": {
            "event_data": {
              "type": "object",
              "properties": {
                "CommandLine": {
                  "type": "keyword",
                  "index": true,
                  "normalizer": "normalizer_lowercase",
                  "eager_global_ordinals": false,
                  "norms": false,
                  "split_queries_on_whitespace": false,
                  "doc_values": true,
                  "store": false,
                  "index_options": "docs"
                },
                "NewProcessName": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "ObjectDN": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "ObjectName": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "ParentProcessName": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "ProcessCommandLine": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 8191
                },
                "ProcessName": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "RelativeTargetName": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "ScriptBlockText": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "ShareLocalPath": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "SubjectDomainName": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "SubjectUserDomainName": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                },
                "TargetObject": {
                  "type": "keyword",
                  "normalizer": "normalizer_lowercase",
                  "ignore_above": 1024
                }
              }
            }
          }
        }
      }
    }
  }
}

[elasticmachine]

Pinging @elastic/elastic-agent (Team:Elastic-Agent)

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[botelastic]

Hi!
We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1.
Thank you for your contribution!

[lucabelluccini]

Hello @pierrehilbert
Is it normal this issue is marked as completed?

[pierrehilbert]

No just has been stalled for too long.

[botelastic]

Hi!
We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1.
Thank you for your contribution!