Date index name processor doesn't apply to updates with doc

[nik9000]

It looks like the date_index_name processor only works for index commands. Most ingest processors are happy to consume the update commands with a doc. Example:

curl -XPUT -HContent-Type:application/json -uelastic:password 'localhost:9200/_ingest/pipeline/monthlyindex?pretty' -d'{
  "description": "monthly date-time index naming",
  "processors" : [
    {
      "date_index_name" : {
        "field" : "date1",
        "index_name_prefix" : "my-index-",
        "date_rounding" : "M"
      }
    }
  ]
}'

curl -XPUT -HContent-Type:application/json -uelastic:password 'localhost:9200/_template/test_template?pretty' -d'{
  "index_patterns": ["my-index*"],
  "settings": {
    "index.default_pipeline": "monthlyindex"
  }
}'


curl -XDELETE -HContent-Type:application/json -uelastic:password localhost:9200/my-test-index
curl -XDELETE -HContent-Type:application/json -uelastic:password localhost:9200/my-index-2099-03-01
curl -XPOST -HContent-Type:application/json -uelastic:password 'localhost:9200/my-index-test/_bulk?pretty' -d'
{ "create": {}}
{ "date1": "2099-03-07T11:04:06.000Z", "my-keyword-field": "foo" }
'
# Expected:
# "create" : { "_index" : "my-index-2099-03-01", ...

curl -XPOST -HContent-Type:application/json -uelastic:password 'localhost:9200/my-index-test/_bulk?pretty' -d'
{"update": {"_id": "1"}}
{"doc": { "date1": "2099-03-07T11:04:06.000Z", "my-keyword-field": "foo" }, "doc_as_upsert": "true"}
'
# Unexpected:
# "update" : { "_index" : "my-index-test",
# Expected it to have been
# "update" : { "_index" : "my-index-2099-03-01",

I'm not sure the processor is meant to work on update's doc here, but if it isn't, I think we should document that.

[elasticmachine]

Pinging @elastic/es-data-management (Team:Data Management)

[joegallo]

I'm removing the team-discuss label from some older Team:Data Management issues -- we've had plenty of time to discuss them, but we haven't, so the label isn't serving its purpose. Feel free to delete this comment and/or re-add the team-discuss label.