add elasticsearch alerting

[wph95]

feature

• base on 5.0.1
• No Third-party elasticsearch Golang SDK used
• Strictly follow the implementation of other datasouce code [mostly influxdb datasource]
• Control line of source code is around 1000 lines [no including test]
• Code logic strictly follow the implementation of public/app/plugin/app/elasticsearch, e.g.
  • query.go -> query_builder.ts
  • response_parser.go -> elastic_response.ts

CODING PHASE 1 [Finished]

• parser Grafana internal elasticsearch query model -> model_parser.go
• convert query model to elasticsearch search body -> query_builder.go
• ElasticsearchExecutor -> elasticsarch.go
• parser elasticsarch response -> response_parser.go [in process]

in this phase, I plan to unsupported

• pipeline aggs [I haven't fully understood this part. =.=]

CODING PHASE 2 [Finished]

• get Series Name support
• index list support interval (maybe import third part golang moment lib)
• pipeline aggs support
• some necessary tests

CODING PHASE 3

• A full covering test suite exists.
  • test pipeline aggs response
• trim Datapoints support
• processAggregationDocs
• more clearly golang es model -> models.go

[bergquist]

How does this compare to #8934 ?

[wph95]

hi @bergquist , i see roadmap delayed elasticsearch alerting, and #8943 look like hard to merge and no one to maintain, so I want to contribute to the community. and write a simple, clea, small pr :)

Although #8934 has been running steadily for a year in the production environment, but is difficult to merge into Master for some reason #8934 (comment)

this pr solved most problems

i will finished CODING PHASE 1 in today [GMT+8] wph95#2
and plan to finished CODING PHASE 2 in this weekend

Finally, please forgive my English writing ability is not good

[marefr]

I'm closing this since we already have an open feature request issue for elasticsearch alerting. Further discussions around PR will be discussed in PR.