こちらにあるデータを使いました。
新型コロナワクチンの接種状況

データの取得

wget https://data.vrs.digital.go.jp/vaccination/opendata/latest/prefecture.ndjson

elastic_cloud_insert_ndjson.py

#! /usr/bin/python
#
#	elastic_cloud_insert_ndjson.py
#
#					Apr/04/2022
# ------------------------------------------------------------------
import  sys
import  json
import  ndjson
import  requests
# ------------------------------------------------------------------
def file_to_str_proc(file_in):
	str_out = ""
	try:
		fp_in = open(file_in,encoding='utf-8')
		str_out = fp_in.read()
		fp_in.close()
	except Exception as ee:
		sys.stderr.write("*** error *** file_to_str_proc ***\n")
		sys.stderr.write(str (ee))
#
	return	str_out
# ------------------------------------------------------------------
def elastic_insert_proc_exec(array_pp):
	sys.stderr.write("*** elastic_insert_proc_exec %d ***\n" % len(array_pp))
	json_str = json.dumps(array_pp)
	try:
		rr=requests.post(url, headers=headers, data=json_str.encode('utf-8'))
		print(rr)
	except Exception as ee:
		sys.stderr.write("*** error *** in requests.post ***\n")
		sys.stderr.write(str(ee) + "\n")
#
# ------------------------------------------------------------------
def elastic_insert_proc(array_aa):
	sys.stderr.write("*** elastic_insert_proc %d ***\n" % len(array_aa))

	istart = 0
	while (istart < len(array_aa)):
		iend = istart + 100
		sys.stderr.write("*** %d\t%d ***\n" % (istart,iend))
		array_p100 = array_aa[slice(istart,iend)]
		elastic_insert_proc_exec(array_p100)
		istart += 100
#
# ------------------------------------------------------------------
host="https://mar29-project.ent.asia-northeast1.gcp.cloud.es.io"
private_key="private-*******"
name_engine="vaccine-data-apr04"
#
sys.stderr.write("*** 開始 ***\n")
file_json = sys.argv[1]
sys.stderr.write(file_json + "\n")
#
str_in = file_to_str_proc(file_json)
#
array_aa = ndjson.loads(str_in)
#
url=host + "/api/as/v1/engines/" + name_engine + "/documents"
headers = {"Content-Type": "application/json",
	"Authorization": "Bearer " + private_key}


elastic_insert_proc(array_aa)

sys.stderr.write("*** 終了 ***\n")
# ------------------------------------------------------------------

実行スクリプト

./elastic_cloud_insert_ndjson.py prefecture.ndjson