How to creatte an index pattern in Opensearch use the API? - amazon-web-services

Question

I want to create an index pattern using the Opensearch API. The issue i'm having is with the message body type. I'm getting the following message when running my script
I'm running opensearch 1.3
Invoke-RestMethod: {"statusCode":400,"error":"Bad Request","message":"[request body.attributes]: expected value of type [object] but got [undefined]"}
$baseuri = "https://<clusterendpoint>.<region>.es.amazonaws.com"
#obtain auth cookie
$authbody = #"
{"username":"$apiUserName", "password":"$apiPassword"}
"#
$authUri = "$baseuri/_dashboards/auth/login"
Invoke-RestMethod -Method Post -Uri $authUri -Headers #{"osd-xsrf"="true"} -ContentType "application/json" -Body $authbody -SessionVariable S1
#### create index pattern
$indexid = "indexname"
$body=#"
{
"index_pattern": {
"title": "indexname-*",
"timeFieldName": "#timestamp"
}
}
"#
$uri = "$baseuri/_dashboards/api/saved_objects/index-pattern/$indexid"
Invoke-RestMethod -Method Post -Uri $uri -Headers #{"osd-xsrf"="true"} -ContentType "application/json" -WebSession $S1 -Body $body -Verbose
i've attempted various ways of defining an object with no luck. when I run the invoke with ($body | convertfrom-json) i get a different error message.
Invoke-RestMethod: {"statusCode":400,"error":"Bad Request","message":"[request body]: expected a plain object value, but found [null] instead."}
UPDATE: I did originally attempt to use the create index pattern API for elastic, but this results in a new index being created, not an opensearch index_pattern.
$body=#{
"index_pattern"= #{
"title"= "ai-summary"
}
}
$uri = "$baseuri/api/index_patterns/$indexid"
Invoke-RestMethod -Method Post -Uri $uri -Headers #{"osd-xsrf"="true"} -ContentType "application/json" -WebSession $S1 -Body ($body | ConvertTo-Json) -Verbose -Credential $credObject