摘要:Elasticsearch
,Java
script是Elasticsearch的拓展功能,通过定制的表达式实现已经预设好的API无法完成的个性化需求,比如完成以下操作
update
, _update_by_query
,ctx._source
,Math,数组add/remove)_search
,doc
,script_fields
,return
)ctx._source
,ctx._source.remove
,条件判断)语法都遵循相同的模式
- "script": {
- "lang": "...",
- "source" | "id": "...",
- "params": { ... }
- }
其中三要素功能如下
lang
:指定编程语言,默认是painless
,还有其他编程语言选项如expression
等source | id
: source,id二者选其一,source后面接inline脚本(就是将脚本逻辑直接放在DSL里面),id对应一个stored脚本(就是预先设置类似UDF,使用的时候根据UDF的id进行调用和传参)params
:在脚本中任何有名字的参数,用params传参使用script脚本修改某文档的某个字段,先插入一条文档
- POST /hotel/_doc/100
- {
- "name": "苏州木棉花酒店",
- "city": "苏州",
- "price": 399,
- "start_date": "2023-01-01"
- }
- POST /hotel/_doc/100/_update
- {
- "script": {
- "source": "ctx._source.price=333"
- }
- }
注意在kibiban客户端带上_update
,否则相当于覆盖整个文档,新建了一个含有script字段的文档。本例中将price字段修改为333,如果是带有单引号的'333'则修改为字符串数据,字符串还可以使用\转义
- POST /hotel/_doc/100/_update
- {
- "script": {
- "source": "ctx._source.price=\"333\""
- }
- }
获取字段的方式除了使用ctx._source.字段
之外,还可以ctx._source['字段']
- POST /hotel/_doc/100/_update
- {
- "script": {
- "source": "ctx._source['price']=333"
- }
- }
只要inline脚本中的内容出现些许不一样就需要重新编译,因此推荐的方法是把inline中固定的部分编译一次,变量命名放在params中传参使用,这样只需要编译一次,下次使用调用缓存
- POST /hotel/_doc/100/_update
- {
- "script": {
- "source": "ctx._source.price=params.price",
- "params": {
- "price": 334
- }
- }
- }
这种类似于先注册UDF函数,使用PUT
对_scripts
传入脚本
- PUT /_scripts/my_script_1
- {
- "script": {
- "lang": "painless",
- "source": "ctx._source.price=params.price"
- }
- }
在插入之后使用GET
可以查看到对应的脚本内容
- GET /_scripts/my_script_1
- {
- "_id" : "my_script_1",
- "found" : true,
- "script" : {
- "lang" : "painless",
- "source" : "ctx._source.price=params.price"
- }
- }
脚本中并没有指定params,params在调用的是有进行设置,调用的时候使用id
指定my_script_1这个id即可,不再使用source
- POST /hotel/_doc/100/_update
- {
- "script": {
- "id": "my_script_1",
- "params": {
- "price": 335
- }
- }
- }
所有update/update_by_query 脚本使用 ctx._source
除了上面快速开始的直接使用=赋值修改的情况,还可以对字段做数值运算,比如加减乘除开方等等
- POST /hotel/_doc/100/_update
- {
- "script": {
- "source": "ctx._source.price += 100"
- }
- }
使用Math.pow
对数值进行开方
- POST /hotel/_doc/100/_update
- {
- "script": {
- "source": "ctx._source.price=Math.pow(ctx._source.price, 2)"
- }
- }
Math下的方法还有sqrt
,log
等
主要说明下数组类型字段的更新,使用ctx._source.字段.add/remove
,先新建一个带有数组字段的文档
- POST /hotel/_doc/101
- {
- "name": "苏州大酒店",
- "city": "苏州",
- "tag": ["贵"]
- }
使用script将tag数组字段增加元素,使用add
- POST /hotel/_doc/101/_update
- {
- "script": {
- "source": "ctx._source.tag.add('偏')"
- }
- }
插入新元素后看下数据,已经成功
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "101",
- "_score" : 1.0,
- "_source" : {
- "name" : "苏州大酒店",
- "city" : "苏州",
- "tag" : [
- "贵",
- "偏"
- ]
- }
删除数组元素使用remove指定对应的索引位置即可
- POST /hotel/_doc/101/_update
- {
- "script": {
- "source": "ctx._source.tag.remove(0)"
- }
- }
如果位数不足会报错类似数组越界
此功能使用search脚本,配合script中的doc
实现,整体效果类似于map操作,对所选定的文档操作返回
先设置一个字段schema
- POST /hotel/_doc/_mapping
- {
- "properties": {
- "dt": {
- "type": "date",
- "format": "yyyy-MM-dd HH:mm:ss"
- }
- }
- }
插入一条日期数据
- POST /hotel/_doc/301
- {
- "dt": "2021-01-01 13:13:13"
- }
插入效果如下
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "301",
- "_score" : 1.0,
- "_source" : {
- "dt" : "2021-01-01 13:13:13"
- }
下面检索所有文档,提取日期的年份,使用GET+_search请求,DSL中指定script_fields的自定义字段year,给year设置script脚本
- GET /hotel/_doc/_search
- {
- "script_fields": {
- "year": {
- "script": {"source": "if (doc.dt.length != 0) {doc.dt.value.year}"}
- }
- }
- }
doc的取值方式
假设有一个字段:"a": 1,那么:
- doc['a']返回的是[1],是一个数组,如果文档没有该字段,返回空数组及doc['a'].length=0
- doc['a'].value返回的是1,也就是取第一个元素。
- doc['a'].values与doc['a']表现一致,返回整个数组[1]
script_fields脚本字段
每个_search 请求的匹配(hit)可以使用 script_fields定制一些属性,一个 _search 请求能定义多于一个以上的 script field这些定制的属性通常是:
- 针对原有值的修改(比如,价钱的转换,不同的排序方法等)
- 一个崭新的及算出来的属性(比如,总和,加权,指数运算,距离测量等)
script_fields在结果中的返回是{fileds: 字段名:[]}的json格式和_source同一级
doc.dt.value获取第一个数组元素,存储数据类型为amic getter [org.elasticsearch.script.JodaComp
,该类型通过year属性获得年份。查看以下返回结果,由于没有筛选条件所有文档都被返回,存在dt字段的提取年份,不存在dt字段的也会有返回值为null,由此可见_search + doc操作实际上是完成了原始文档的一个映射转换操作,并产生了一个自定义的临时字段,不会对原始索引做任何更改操作
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "301",
- "_score" : 1.0,
- "fields" : {
- "year" : [
- 2021
- ]
- }
- },
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "002",
- "_score" : 1.0,
- "fields" : {
- "year" : [
- null
- ]
- }
- },
- ...
如果只返回存在dt字段的,需要在DSL中增加query
逻辑
- GET /hotel/_doc/_search
- {
- "query": {
- "exists": {
- "field": "dt"
- }
- },
- "script_fields": {
- "year": {
- "script": {"source": "doc.dt.value.year"}
- }
- }
- }
插入一个数值数组字段,搜索统计返回数组的和
- POST /hotel/_doc/_mapping
- {
- "properties": {
- "goals" : {"type": "keyword"}
- }
- }
插入数据
- POST /_bulk
- {"index": {"_index": "hotel", "_type": "_doc", "_id": "123"}}
- {"name": "a酒店","city": "扬州", "goals": [1, 5, 3] }
- {"index": {"_index": "hotel", "_type": "_doc", "_id": "124"}}
- {"name": "b酒店","city": "杭州", "goals": [9, 5, 1] }
- {"index": {"_index": "hotel", "_type": "_doc", "_id": "125"}}
- {"name": "c酒店","city": "云州", "goals": [2, 7, 9] }
下面计算有goals字段的求goals的和到一个临时字段
- GET /hotel/_doc/_search
- {
- "query": {
- "exists": {
- "field": "goals"
- }
- },
- "script_fields": {
- "goals_sum": {
- "script": {"source": """
- int total =0;
- for (int i=0; i < doc.goals.length; i++) {
- total += Integer.parseInt(doc.goals[i])
- }
- return total
- """
- }
- }
- }
- }
在script中每一行结束要加分号;
,使用Java语法的循环求得数组的和,每个数组元素需要使用Java语法中的Integer.parseInt解析,否则报错String类型无法转Num,查看返回
- "hits" : [
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "123",
- "_score" : 1.0,
- "fields" : {
- "goals_sum" : [
- 9
- ]
- }
- },
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "124",
- "_score" : 1.0,
- "fields" : {
- "goals_sum" : [
- 15
- ]
- }
- },
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "125",
- "_score" : 1.0,
- "fields" : {
- "goals_sum" : [
- 18
- ]
- }
- }
新建字段和删除字段都是update操作,使用ctx._source
对于存在dt字段的文档,新增一个字段dt_year,值为dt的年份
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "exists": {
- "field": "dt"
- }
- },
- "script": {
- "source": "ctx._source.dt_year = ctx._source.dt.year"
- }
- }
以上直接在source中使用ctx._source.dt_year引入一个新列,可惜直接报错
- "reason": "dynamic getter [java.lang.String, year] not found
此处并没有向doc一样数据为日期类型而是字符串,因此需要引入Java解析
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "exists": {
- "field": "dt"
- }
- },
- "script": {
- "source": """
- LocalDateTime time2Parse = LocalDateTime.parse(ctx._source.dt, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
- ctx._source.dt_year = time2Parse.getYear()
- """
- }
- }
查看结果
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "301",
- "_score" : 1.0,
- "_source" : {
- "dt" : "2021-01-01 13:13:13",
- "dt_year" : 2021
- }
- }
也可以做其他操作比如获得LocalDateTime类型之后再做格式化输出
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "exists": {
- "field": "dt"
- }
- },
- "script": {
- "source": """
- LocalDateTime time2Parse = LocalDateTime.parse(ctx._source.dt, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
- ctx._source.dt_year = time2Parse.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"))
- """
- }
- }
删除字段直接使用ctx._source.remove(\"字段名\")
,可以删除单个文档,也可以update_by_query批量删除
- POST /hotel/_doc/123
- {
- "script": {
- "source": "ctx._source.remove(\"goals\")"
- }
- }
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "exists": {
- "field": "goals"
- }
- },
- "script": {
- "source": "ctx._source.remove(\"goals\")"
- }
- }
支持if,else if,else,比如根据某值进行二值判断生成新字段
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "exists": {
- "field": "price"
- }
- },
- "script": {
- "source": """
- double price = ctx._source.price;
- if (price >= 10) {
- ctx._source.expensive = 1
- } else {
- ctx._source.expensive = 0
- }
- """
- }
- }
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "exists": {
- "field": "price"
- }
- },
- "script": {
- "source": """
- double price = ctx._source.price;
- if (price >= 10) {
- ctx._source.expensive = 1
- } else if (price == 0) {
- ctx._source.expensive = -1
- } else {
- ctx._source.expensive = 0
- }
- """
- }
- }
注意:经过多轮测试如果source中有多轮if判断语法会报错,貌似只能支持一个if,解决方案是使用Java的三元表达式
?;
,三元表达式写多少个判断都行
return用在_search操作中,配合script_fields使用,例如在搜索结果中新增一个字段area为china,此字段不更新到索引只是在搜索时返回
- GET /hotel/_doc/_search
- {
- "_source": true,
- "script_fields": {
- "area": {
- "script": {
- "source": "return \"china\""
- }
- }
- }
- }
以上指定"_source": true防止被script_fields覆盖,一条输出结果如下
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "123",
- "_score" : 1.0,
- "_source" : {
- "city" : "扬州",
- "name" : "a酒店"
- },
- "fields" : {
- "area" : [
- "china"
- ]
- }
先插入3个子模型分,在生成一个总分,权重是0.6,0.2,0.2
- POST /_bulk
- {"index": {"_index": "hotel", "_type": "_doc", "_id": "333"}}
- {"name": "K酒店","city": "扬州", "model_1": 0.79, "model_2": 0.39, "model_3": 0.72}
- {"index": {"_index": "hotel", "_type": "_doc", "_id": "334"}}
- {"name": "L酒店","city": "江州", "model_1": 0.62, "model_2": 0.55, "model_3": 0.89}
- {"index": {"_index": "hotel", "_type": "_doc", "_id": "335"}}
- {"name": "S酒店","city": "兖州", "model_1": 0.83, "model_2": 0.45, "model_3": 0.58}
现在计算总分给到score字段
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "bool": {
- "must": [
- {"exists": {
- "field": "model_1"
- }},
- {"exists": {
- "field": "model_2"
- }},
- {"exists": {
- "field": "model_3"
- }}
- ]
- }
- },
- "script": {
- "source": "ctx._source.score = 0.6 * ctx._source.model_1 + 0.2 * ctx._source.model_2 + 0.2 * ctx._source.model_3"
- }
- }
看一下运行结果
- GET /hotel/_doc/_search
- {
- "query": {
- "exists": {
- "field": "score"
- }
- }
- }
- "hits" : [
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "335",
- "_score" : 1.0,
- "_source" : {
- "score" : 0.704,
- "city" : "兖州",
- "name" : "S酒店",
- "model_1" : 0.83,
- "model_3" : 0.58,
- "model_2" : 0.45
- }
- },
- {
- "_index" : "hotel",
- "_type" : "_doc",
- "_id" : "333",
- "_score" : 1.0,
- "_source" : {
- "score" : 0.6960000000000001,
- "city" : "扬州",
- "name" : "K酒店",
- "model_1" : 0.79,
- "model_3" : 0.72,
- "model_2" : 0.39
- }
- },
- ...
直接取ctx._source对应字段进行比较,使用Java三元表达式?:
赋值给新字段
- POST /hotel/_doc/_update_by_query
- {
- "query": {
- "bool": {
- "must": [
- {"exists": {
- "field": "model_1"
- }},
- {"exists": {
- "field": "model_2"
- }}
- ]
- }
- },
- "script": {
- "source": "ctx._source.max_score = ctx._source.model_1 > ctx._source.model_2 ? ctx._source.model_1 : ctx._source.model_2"
- }
- }
有两种情况字段为null和params为null
如果某字段为空,文档不存在该字段,则填充为0
- POST /hotel/_doc/_update_by_query
- {
- "script": {
- "source": "if (ctx._source.score == null) ctx._source.score = 0.0"
- }
- }
如果传入params不存在某个key,则删除该字段
- POST /hotel/_doc/_update_by_query
- {
- "script": {
- "source": """
- String[] cols = new String[3];
- cols[0] = "name";
- cols[1] = "city";
- cols[2] = "price";
- for (String c : cols) {
- if (params[c] == null) {
- ctx._source.remove(c)
- } else {
- ctx._source[c] = params[c]
- }
- }
- """,
- "params": {
- "name": "test",
- "city": "test_loc"
- }
- }
- }
注意:在循环中拿到局部变量c传递给params,
params[c]
不能用点.
或者带有双引号params["c"]
,否则是判断params中是否有c这个名字的字段
在本例中使用String[] cols = new String[3];
创建了一个静态变量,对于这种集合类的变量painless的语法和Java略有不同,写几个例子如下
- ArrayList l = new ArrayList(); // Declare an ArrayList variable l and set it to a newly allocated ArrayList
- Map m = new HashMap(); // Declare a Map variable m and set it to a newly allocated HashMap
-
- List l = new ArrayList(); // Declare List variable l and set it a newly allocated ArrayList
- List m; // Declare List variable m and set it the default value null
- int[] ia1; //Declare int[] ia1; store default null to ia1
- int[] ia2 = new int[2]; //Allocate 1-d int array instance with length [2] → 1-d int array reference; store 1-d int array reference to ia1
- ia2[0] = 1; //Load from ia1 → 1-d int array reference; store int 1 to index [0] of 1-d int array reference
- int[][] ic2 = new int[2][5]; //Declare int[][] ic2; allocate 2-d int array instance with length [2, 5] → 2-d int array reference; store 2-d int array reference to ic2
- ic2[1][3] = 2; //Load from ic2 → 2-d int array reference; store int 2 to index [1, 3] of 2-d int array reference
- ic2[0] = ia1; //Load from ia1 → 1-d int array reference; load from ic2 → 2-d int array reference; store 1-d int array reference to index [0] of 2-d int array reference; (note ia1, ib1, and index [0] of ia2 refer to the same instance)
List,Map这些集合都没有泛型,并且集合的值貌似不能直接初始化,需要add,put进来
查看某列的值大于某列,在query下可以使用script,注意格式script下还套着一个script,search请求使用doc获取值
- GET /hotel/_doc/_search
- {
- "query": {
- "script" : {
- "script" : {
- "source": "doc.score.value < doc.model_3.value"
- }
- }
- }
- }
以上语句会报warn,doc选取字段如果字段为空会填充默认值,因此再限制一下字段不为空
- GET /hotel/_doc/_search
- {
- "query": {
- "bool" : {
- "must" : [{
- "script" : {
- "script" : {
- "source": "doc.score.value < doc.model_3.value"
- }
- }
- },
- {"exists": {"field": "score"}},
- {"exists": {"field": "model_3"}}
- ]
- }
- }
- }
作者:xiaogp
链接:https://www.jianshu.com/p/66a72d7ba3da
来源:简书
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