Prometheus: Add support for cloud partners Prometheus data sources (#103482)

* wip

* Add prom flavor support for data source variables and export/import dashboards (#103321)

* add dashboard and data source var selection

* use match plugin id instead

* use updated matchpluginid

* formatting

* cleanup

* regex anchor

* update error msg

* Alerting: Clean up prometheus-flavored types and functions (#103703)

* clean up types and utility functions for dealing with
prometheus-flavored data sources

* Refactor alerting datasource types to use constants as source of truth

* Alerting: Clean up prometheus-flavored types and functions on the bac… (#103716)

Alerting: Clean up prometheus-flavored types and functions on the backend

* add matchPluginId tests

* Update matchPluginId func to bidirectional (#103746)

* update matchpluginid func to bidirectional

* lint

* formatting

* use actual isSupportedExternalRulesSourceType in test

* add tests in datasource_srv

* betterer

* remove type assertion

* remove unnecessary case

* use satisifies to not have to convert tuple to an array of string

* add prometheus_flavor test

---------

Co-authored-by: Andrew Hackmann <5140848+bossinc@users.noreply.github.com>
Co-authored-by: Gilles De Mey <gilles.de.mey@gmail.com>
Co-authored-by: Alexander Akhmetov <me@alx.cx>

pkg/services/ngalert/api/util.go

@@ -31,7 +31,28 @@ const (
 	groupQueryTag     = "QUERY_GROUP"
 )
 
-var searchRegex = regexp.MustCompile(`\{(\w+)\}`)
+var (
+	searchRegex = regexp.MustCompile(`\{(\w+)\}`)
+
+	prometheusCompatibleDsTypes = []string{
+		datasources.DS_PROMETHEUS,
+		datasources.DS_AMAZON_PROMETHEUS,
+		datasources.DS_AZURE_PROMETHEUS,
+	}
+)
+
+func isPrometheusCompatible(dsType string) bool {
+	for _, t := range prometheusCompatibleDsTypes {
+		if dsType == t {
+			return true
+		}
+	}
+	return false
+}
+
+func isLotexRulerCompatible(dsType string) bool {
+	return dsType == datasources.DS_LOKI || isPrometheusCompatible(dsType)
+}
 
 func toMacaronPath(path string) string {
 	return string(searchRegex.ReplaceAllFunc([]byte(path), func(s []byte) []byte {
@@ -52,8 +73,8 @@ func getDatasourceByUID(ctx *contextmodel.ReqContext, cache datasources.CacheSer
 			return nil, unexpectedDatasourceTypeError(ds.Type, "alertmanager")
 		}
 	case apimodels.LoTexRulerBackend:
-		if ds.Type != "loki" && ds.Type != "prometheus" {
-			return nil, unexpectedDatasourceTypeError(ds.Type, "loki, prometheus")
+		if !isLotexRulerCompatible(ds.Type) {
+			return nil, unexpectedDatasourceTypeError(ds.Type, "loki, prometheus, amazon prometheus, azure prometheus")
 		}
 	default:
 		return nil, unexpectedDatasourceTypeError(ds.Type, expectedType.String())