How to add mapping via go-elasticsearch package

Basically when I am trying to insert a new document to non-existing index, it is automatically sets to dynamic mapping.
But I have issues where in sometimes I want to change the data type of the fields on the ES.

I want to set it via my go-lang service but looks like go-elasticsearch package doesn't support it? correct me if I am wrong

You can create an index along with its mapping using go-elasticsearch/esapi go-elasticsearch/esapi

Create a request as below:

mapping := `{
	"settings": {
		"number_of_shards": 1,
		"number_of_replicas": 1
	  },
	  "mappings": {
		"properties": {
		  "name": {
			"type": "text",
			"fields": {
			  "keyword": {
				"type": "keyword",
				"ignore_above": 256
			  }
			}
		  },
		  "message": {
			"type": "text",
			"fields": {
			  "keyword": {
				"type": "keyword",
				"ignore_above": 256
			  }
			}
		  },
		}
}`

// Index - pass index name
// Body - pass mapping, settings etc
indexReq := esapi.IndicesCreateRequest{
	Index: "my-index",
	Body: strings.NewReader(string(mapping)),
}

resp, err := indexReq.Do(ctx, elasticclient)
if err != nil {
	// handle error
}

by this way you can create a new index with specific mapping

You can use ElasticSearch Typed API

To create an index

	client := GetTypedClient()

	// create index if not exists
	index := "index_name"
	if !isIndexExists(GetClient(), index) {
		res, err := client.Indices.Create(getIndexName(index)).Do(context.Background())
		if err != nil {
			...
		}
	}

And put mapping as well

	// update mapping
	memoryMapping := types.NewNestedProperty()
	memoryMapping.Properties = map[string]types.Property{
		"total": types.NewIntegerNumberProperty(),
		"free":  types.NewIntegerNumberProperty(),
		"used":  types.NewIntegerNumberProperty(),
	}

	uptimeMapping := types.NewNestedProperty()
	uptimeMapping.Properties = map[string]types.Property{
		"app": types.NewIntegerNumberProperty(),
		"os":  types.NewIntegerNumberProperty(),
	}

	loadMapping := types.NewNestedProperty()
	loadMapping.Properties = map[string]types.Property{
		"avg1":  types.NewFloatNumberProperty(),
		"avg5":  types.NewFloatNumberProperty(),
		"avg15": types.NewFloatNumberProperty(),
	}

	res, err := client.Indices.PutMapping(index).
		Request(&putmapping.Request{
			Properties: map[string]types.Property{
				"createdAt": types.NewDateProperty(),
				"memory":    memoryMapping,
				"uptime":    uptimeMapping,
				"load":      loadMapping,
			},
		}).
		Do(context.Background())

	if err != nil {
		...
	}