在Node-RED中如何使用Elasticsearch的方法

2 年 ago

逸, 科

3 minutes

首先

由于在Node-RED中经常向Elasticsearch投放数据，因此我想写一些经验技巧。
虽然有各种附加节点，但Elasticsearch的版本更新很快，API也可能会发生变化。
因此，我认为最好的做法是结合使用标准节点。

软件环境

Elasticsearch 7.3.2

将流程细分化

首先，将与Elasticsearch通信的http节点拆分成子流程。这样，每次在安装节点时都不需要设置诸如BASIC身份验证之类的信息。另外，让我们始终在头部添加”Content-Type: ‘application/json'”。这样做可以节省一些连接Elasticsearch的设置时间。
由于URL和方法会根据请求的不同而变化，因此在子流程中不需要进行设置。

我写的代码如下。

[{"id":"3f7774f5.a6a20c","type":"subflow","name":"Elasticsearch","info":"","category":"","in":[{"x":50,"y":30,"wires":[{"id":"c5bb15c.4c10de8"}]}],"out":[{"x":580,"y":30,"wires":[{"id":"19d2a3b.d048a5c","port":0}]}],"env":[],"color":"#DDAA99"},{"id":"eeda88c1.f8b278","type":"http request","z":"3f7774f5.a6a20c","name":"Elasticsearch","method":"use","ret":"txt","paytoqs":false,"url":"","tls":"","persist":false,"proxy":"","authType":"basic","x":340,"y":30,"wires":[["19d2a3b.d048a5c"]]},{"id":"c5bb15c.4c10de8","type":"change","z":"3f7774f5.a6a20c","name":"msg.headers","rules":[{"t":"delete","p":"headers","pt":"msg"},{"t":"set","p":"headers","pt":"msg","to":"{\"Content-Type\":\"application/json\",\"Connection\":\"close\"}","tot":"json"}],"action":"","property":"","from":"","to":"","reg":false,"x":170,"y":30,"wires":[["eeda88c1.f8b278"]]},{"id":"19d2a3b.d048a5c","type":"json","z":"3f7774f5.a6a20c","name":"","property":"payload","action":"","pretty":false,"x":490,"y":30,"wires":[[]]}]

1. 数据导入

以下是一个接收来自环境传感器的信标并将数据投入Elasticsearch的示例，它被称为连接设备。

从连接扫描器节点传递的数据如下所示。

为了将此数据输入到Elasticsearch中，我们在Change节点中设置msg.method和msg.url。
msg.url使用前一个节点的值来生成动态URL。
虽然编写程序往往会依赖于function节点，但实际上可以不使用它来生成。

顺便提一句，使用JSONata表达式可以在Change节点中生成当前时间。

使用模板节点生成要投入到Elasticsearch的JSON数据。
使用Mustache模板，可以使用msg对象内的数据。

这个流程的输出在这里。(包括Elasticsearch子流程)

[{"id":"3f7774f5.a6a20c","type":"subflow","name":"Elasticsearch","info":"","category":"","in":[{"x":50,"y":30,"wires":[{"id":"c5bb15c.4c10de8"}]}],"out":[{"x":580,"y":30,"wires":[{"id":"19d2a3b.d048a5c","port":0}]}],"env":[],"color":"#DDAA99"},{"id":"eeda88c1.f8b278","type":"http request","z":"3f7774f5.a6a20c","name":"Elasticsearch","method":"use","ret":"txt","paytoqs":false,"url":"","tls":"","persist":false,"proxy":"","authType":"basic","x":340,"y":30,"wires":[["19d2a3b.d048a5c"]]},{"id":"c5bb15c.4c10de8","type":"change","z":"3f7774f5.a6a20c","name":"msg.headers","rules":[{"t":"delete","p":"headers","pt":"msg"},{"t":"set","p":"headers","pt":"msg","to":"{\"Content-Type\":\"application/json\",\"Connection\":\"close\"}","tot":"json"}],"action":"","property":"","from":"","to":"","reg":false,"x":170,"y":30,"wires":[["eeda88c1.f8b278"]]},{"id":"19d2a3b.d048a5c","type":"json","z":"3f7774f5.a6a20c","name":"","property":"payload","action":"","pretty":false,"x":490,"y":30,"wires":[[]]},{"id":"e6695b94.08cca8","type":"subflow:3f7774f5.a6a20c","z":"f4557e75.b0f3f","x":640,"y":140,"wires":[[]]},{"id":"7108220c.1b5d9c","type":"change","z":"f4557e75.b0f3f","name":"POST _doc","rules":[{"t":"set","p":"method","pt":"msg","to":"POST","tot":"str"},{"t":"set","p":"url","pt":"msg","to":"http://localhost:9200/sensor-","tot":"str"},{"t":"change","p":"url","pt":"msg","from":"$","fromt":"re","to":"payload.service","tot":"msg"},{"t":"change","p":"url","pt":"msg","from":"$","fromt":"re","to":"/_doc","tot":"str"},{"t":"set","p":"date","pt":"msg","to":"$now()","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":280,"y":140,"wires":[["69e18d2a.9e18d4"]]},{"id":"69e18d2a.9e18d4","type":"template","z":"f4557e75.b0f3f","name":"ES Query JSON","field":"payload","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"{\n    \"date\": \"{{{date}}}\",\n    \"device\": \"{{{payload.device}}}\",\n    \"{{payload.service}}\": {{{payload.data}}}\n}","output":"str","x":460,"y":140,"wires":[["e6695b94.08cca8"]]},{"id":"d541687c.a302d8","type":"linking-scanner","z":"f4557e75.b0f3f","name":"","autostart":true,"duration":"","interval":"30","x":100,"y":140,"wires":[["7108220c.1b5d9c"]]}]