参照官网链接
https://www.elastic.co/guide/en/elasticsearch/reference/6.4/accessing-data-in-pipelines.html#accessing-ingest-metadata
创建摄取管道：
PUT _ingest/pipeline/set_timestamp
{
"description": "adds the timestamp when a document is indexed",
"processors": [
{
"set": {
"field": "indexed_at",
"value": "{{_ingest.timestamp}}"
}
}
]
}
更新文档，并引用管道：
PUT tmp/_doc/1?pipeline=set_timestamp
{
"test": "foo"
}
查询文档，会发现多一个字段：
GET tmp/_doc/1
{
"test" : "foo",
"indexed_at" : "2019-10-03T13:19:03.181Z"
}
