Graphite: Backend tag values autocomplete endpoint (#110773)

* Add lint rules

* Backend decoupling

- Add standalone files
- Add graphite query type
- Add logger to Service
- Create logger in the ProvideService method
- Use a pointer for the HTTP client provider
- Update logger usage everywhere
- Update tracer type
- Replace simplejson with json
- Add dummy CallResource and CheckHealth methods
- Update tests

* Update ConfigEditor imports

* Update types imports

* Update datasource

- Switch to using semver package
- Update imports

* Update store imports

* Update helper imports and notification creation

* Update context import

* Update version numbers and logic

* Copy array_move from core

* Test updates

* Add required files and update plugin.json

* Update core references and packages

* Remove commented code

* Update wire

* Lint

* Fix import

* Copy null type

* More lint

* Update snapshot

* Refactor backend

- Split query logic into separate file
- Move utils to separate file

* Add health-check logic

- Support backend healthcheck if the FF is enabled

* Remove query import support as unneeded

* Add test

* Add util function for decoding responses

* Add events types

* Add resource handler

* Add events handler and generic resource req handler

* Tests

* Update frontend

- Add types
- Update events function to support backend requests

* Lint and typing

* Lint

* Add metrics find endpoint

- Add types
- Add generic response parser
- Add endpoint
- Tests

* Update FE functoin to use backend endpoint

* Lint

* Simplify request

* Update test

* Metrics expand type

* Extract shared logic and add metric expand endpoint

* Update tests

* Call metric expand from backend

* Rename type for clarity

* Add get resource req handler

* Refactor doGraphiteRequest, parseResponse

Update tests

* Migrate functions endpoint to backend

* Support tags autocomplete in backend

- Add tests
- Add types
- Remove unneeded comments

* Support tag values autocomplete

- Remove unused frontend endpoints
- Add types
- Update tests

* Add tests

* Review

* Review

* Fix packages

* Format

* Fix merge issues

* Review

* Fix undefined values

* Extract request creation

- Add method for create requests generically with tests
- Replace usage in query method
- Update usages in resource handlers
- Update tests
- Update types

* Lint

pkg/tsdb/graphite/graphite.go

@@ -109,8 +109,10 @@ func (s *Service) createRequest(ctx context.Context, dsInfo *datasourceInfo, par
 
 	if params.QueryParams != nil {
 		queryValues := u.Query()
-		for k, v := range params.QueryParams {
-			queryValues.Set(k, v)
+		for key, values := range params.QueryParams {
+			for _, value := range values {
+				queryValues.Add(key, value)
+			}
 		}
 		u.RawQuery = queryValues.Encode()
 	}