20、分布式文档系统_Elasticsearch动手实战演练基于

es有个内置的脚本支持的，可以基于groovy脚本实现各种各样的复杂操作。
基于groovy脚本，如何执行partial update
es scripting module初步了解
首先构造一个document数据

PUT /test_index/test_type/11
{
  "num":0,
  "tags":[]
}
-----------------------------------结果-----------------------------------
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "_version": 1,
  "result": "created",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "created": true
}

1、内置脚本

POST /test_index/test_type/11/_update
{
  "script": "ctx._source.num+=1"
}
-----------------------------------查看结果-----------------------------------
GET test_index/test_type/11
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "_version": 2,
  "found": true,
  "_source": {
    "num": 1,
    "tags": []
  }
}

2、外部脚本

在Elasticsearch\elasticsearch-5.2.0\config\scripts目录下创建groovy脚本
例如：创建名为test-add-tags.groovy的文件，文件脚本为给tags添加新内容ctx._source.tags+=new_tag

如图所示在\config\scripts文件夹下创建test-add-tags.groovy脚本
脚本内容

运行脚本，lang指定脚本后缀类型，file指定脚本文件名，params指定参数
POST test_index/test_type/11/_update
{
  "script": {
    "lang": "groovy",
    "file": "test-add-tags",
    "params": {
      "new_tag":"tag1"
    }
  }
}
-----------------------------------运行结果成功-----------------------------------
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "_version": 3,
  "result": "updated",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  }
}
-----------------------------------查看数据-----------------------------------
GET /test_index/test_type/11
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "_version": 3,
  "found": true,
  "_source": {
    "num": 1,
    "tags": [
      "tag1"
    ]
  }
}

3、用脚本删除文档

步骤同上，创建groovy脚本文件，写入脚本内容:
ctx.op = ctx._source.num == count ? 'delete' : 'none'

POST /test_index/test_type/11/_update
{
  "script": {
    "lang": "groovy",
    "file": "test-delete-document",
    "params": {
      "count":1
    }
  }
}
-----------------------------------运行结果成功-----------------------------------
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "_version": 4,
  "result": "deleted",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  }
}
-----------------------------------查看数据-----------------------------------
GET /test_index/test_type/11
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "found": false
}

如果document数据以删除标记为deleted，那么对该条数据进行partial update时会报错

POST test_index/test_type/11/_update
{
  "doc": {
    "num":1
  }
}
-----------------------------------运行结果返回异常-----------------------------------
{
  "error": {
    "root_cause": [
      {
        "type": "document_missing_exception",
        "reason": "[test_type][11]: document missing",
        "index_uuid": "8GnE3L60TnWxjSrPQ7Xa2A",
        "shard": "0",
        "index": "test_index"
      }
    ],
    "type": "document_missing_exception",
    "reason": "[test_type][11]: document missing",
    "index_uuid": "8GnE3L60TnWxjSrPQ7Xa2A",
    "shard": "0",
    "index": "test_index"
  },
  "status": 404
}

4、upsert操作

如果指定的document不存在，就执行upsert中的初始化操作；如果指定的document存在，就执行doc或者script指定的partial update操作

POST test_index/test_type/11/_update
{
  "script": "ctx._source.num+=1",
  "upsert": {
    "num":0,
    "tags":[]
  }
}
-----------------------------------运行结果返回成功-----------------------------------
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "_version": 1,
  "result": "created",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  }
}
-----------------------------------查看document数据-----------------------------------
GET /test_index/test_type/11
{
  "_index": "test_index",
  "_type": "test_type",
  "_id": "11",
  "_version": 1,
  "found": true,
  "_source": {
    "num": 0,
    "tags": []
  }
}
因为document id为11的数据被删除为deleted，所以运行upsert中的初始化操作，最终数据为upsert初始化后的值。