Grafana Plugin - Druid

背景

Grafana从apache druid数据源获取数据。找到以下官方插件，但是很久不更新了。

官方插件开发：https://github.com/grafana-druid-plugin/druidplugin

维护者相关讨论：https://github.com/grafana-druid-plugin/druidplugin/issues/91

其中一个贡献者另外维护的的forked version

forked version：https://github.com/GoshPosh/druidplugin

两者对比如下表

Name	grafana-druid-plugin/druidplugin	GoshPosh/druidplugin
代码维护	较旧	较新
dashboard variable支持	无	无
Alert支持	无	支持 Issue Un-merged Commit

Compile, package and deployment

Clone from
git@github.com:aliceeee/druidplugin.git
OR
git@github.com:GoshPosh/druidplugin.git

npm install
grunt
cd ..
zip druidplugin.zip druidplugin

把zip放到grafana的plugins目录下，重启grafana

二次开发

Fix dashboard template variables（Based on grafana-druid-plugin/druidplugin）

讨论：https://github.com/grafana-druid-plugin/druidplugin/issues/47

参考以上讨论中的实现

src/datasource.ts

metricFindQuery(query: any) {

  let druidSqlQuery = {
    query: this.templateSrv.replace(query),  // 为了实现variable相互引用，实现级联查询
    context: {
      "sqlTimeZone": this.periodGranularity
    }
  }

  return new Promise((resolve, reject) => {
    this._druidQuery(druidSqlQuery, "/druid/v2/sql")
      .then(
        result => {
          let variableData =
            result.data
              .map(row => {
                let vals = []
                for (let property in row) {
                  vals.push({ "text": row[property] })
                }
                return vals;
              })
              .reduce((a, b) => {
                return a.concat(b)
              })

          resolve(variableData)
        },
        error => {
          console.log(error.data.errorMessage)
          reject(new Error(error.data.errorMessage))
        }
      )
  })
}
_druidQuery(query, path = "/druid/v2/") {
  let options = {
    method: 'POST',
    url: this.url + path,
    data: query
  };
  console.log("Make http request");
  console.log(options);
  return this.backendSrv.datasourceRequest(options);
};

参考

官方插件开发指南：https://grafana.com/docs/plugins/developing/development/
官方datasource插件开发：https://grafana.com/docs/plugins/developing/datasources/