Alerting: API to create rule groups using mimirtool (#100558)

What is this feature?

Adds an API endpoint to create alert rules with mimirtool:

- POST /convert/prometheus/config/v1/rules/{NamespaceTitle} - Accepts a single rule group in a Prometheus YAML format and creates or updates a Grafana rule group from it.

The endpoint uses the conversion package from #100224.

Key parts

The API works similarly to the provisioning API. If the rule does not exist, it will be created, otherwise updated. Any rules not present in the new group will be deleted, ensuring the group is fully synchronized with the provided configuration.

Since the API works with namespace titles (folders), the handler automatically creates a folder in the root based on the provided title if it does not exist. It also requires a special header, X-Grafana-Alerting-Datasource-UID. This header specifies which datasource to use for the new rules.

If the rule group's evaluation interval is not specified, it uses the DefaultRuleEvaluationInterval from settings.

pkg/services/ngalert/api/api_convert_prometheus.go

@@ -1,14 +1,60 @@
 package api
 
 import (
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+
 	"github.com/grafana/grafana/pkg/api/response"
+	"github.com/grafana/grafana/pkg/apimachinery/errutil"
 	"github.com/grafana/grafana/pkg/infra/log"
 	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
+	"github.com/grafana/grafana/pkg/services/datasources"
+	"github.com/grafana/grafana/pkg/services/folder"
 	apimodels "github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
+	"github.com/grafana/grafana/pkg/services/ngalert/models"
+	"github.com/grafana/grafana/pkg/services/ngalert/prom"
+	"github.com/grafana/grafana/pkg/services/ngalert/provisioning"
+	"github.com/grafana/grafana/pkg/setting"
 )
 
+const (
+	datasourceUIDHeader        = "X-Grafana-Alerting-Datasource-UID"
+	recordingRulesPausedHeader = "X-Grafana-Alerting-Recording-Rules-Paused"
+	alertRulesPausedHeader     = "X-Grafana-Alerting-Alert-Rules-Paused"
+)
+
+var (
+	errDatasourceUIDHeaderMissing = errutil.ValidationFailed(
+		"alerting.datasourceUIDHeaderMissing",
+		errutil.WithPublicMessage(fmt.Sprintf("Missing datasource UID header: %s", datasourceUIDHeader)),
+	).Errorf("missing datasource UID header")
+
+	errInvalidHeaderValueMsg  = "Invalid value for header {{.Public.Header}}: must be 'true' or 'false'"
+	errInvalidHeaderValueBase = errutil.ValidationFailed("aleting.invalidHeaderValue").MustTemplate(errInvalidHeaderValueMsg, errutil.WithPublic(errInvalidHeaderValueMsg))
+)
+
+func errInvalidHeaderValue(header string) error {
+	return errInvalidHeaderValueBase.Build(errutil.TemplateData{Public: map[string]any{"Header": header}})
+}
+
 type ConvertPrometheusSrv struct {
-	logger log.Logger
+	cfg              *setting.UnifiedAlertingSettings
+	logger           log.Logger
+	ruleStore        RuleStore
+	datasourceCache  datasources.CacheService
+	alertRuleService *provisioning.AlertRuleService
+}
+
+func NewConvertPrometheusSrv(cfg *setting.UnifiedAlertingSettings, logger log.Logger, ruleStore RuleStore, datasourceCache datasources.CacheService, alertRuleService *provisioning.AlertRuleService) *ConvertPrometheusSrv {
+	return &ConvertPrometheusSrv{
+		cfg:              cfg,
+		logger:           logger,
+		ruleStore:        ruleStore,
+		datasourceCache:  datasourceCache,
+		alertRuleService: alertRuleService,
+	}
 }
 
 func (srv *ConvertPrometheusSrv) RouteConvertPrometheusGetRules(c *contextmodel.ReqContext) response.Response {
@@ -28,9 +74,131 @@ func (srv *ConvertPrometheusSrv) RouteConvertPrometheusGetNamespace(c *contextmo
 }
 
 func (srv *ConvertPrometheusSrv) RouteConvertPrometheusGetRuleGroup(c *contextmodel.ReqContext, namespaceTitle string, group string) response.Response {
-	return response.Error(501, "Not implemented", nil)
+	// Just to make the mimirtool rules load work. It first checks if the group exists, and if the endpoint returns 501 it fails.
+	return response.YAML(http.StatusOK, apimodels.PrometheusRuleGroup{})
 }
 
-func (srv *ConvertPrometheusSrv) RouteConvertPrometheusPostRuleGroup(c *contextmodel.ReqContext, namespaceTitle string, prometheusGroup apimodels.PrometheusRuleGroup) response.Response {
-	return response.Error(501, "Not implemented", nil)
+func (srv *ConvertPrometheusSrv) RouteConvertPrometheusPostRuleGroup(c *contextmodel.ReqContext, namespaceTitle string, promGroup apimodels.PrometheusRuleGroup) response.Response {
+	logger := srv.logger.FromContext(c.Req.Context())
+	logger = logger.New("folder_title", namespaceTitle, "group", promGroup.Name)
+
+	logger.Info("Converting Prometheus rule group", "rules", len(promGroup.Rules))
+
+	ns, errResp := srv.getOrCreateNamespace(c, namespaceTitle, logger)
+	if errResp != nil {
+		return errResp
+	}
+
+	datasourceUID := strings.TrimSpace(c.Req.Header.Get(datasourceUIDHeader))
+	if datasourceUID == "" {
+		return response.Err(errDatasourceUIDHeaderMissing)
+	}
+	ds, err := srv.datasourceCache.GetDatasourceByUID(c.Req.Context(), datasourceUID, c.SignedInUser, c.SkipDSCache)
+	if err != nil {
+		logger.Error("Failed to get datasource", "datasource_uid", datasourceUID, "error", err)
+		return errorToResponse(err)
+	}
+
+	group, err := srv.convertToGrafanaRuleGroup(c, ds, ns.UID, promGroup, logger)
+	if err != nil {
+		return errorToResponse(err)
+	}
+
+	err = srv.alertRuleService.ReplaceRuleGroup(c.Req.Context(), c.SignedInUser, *group, models.ProvenanceConvertedPrometheus)
+	if err != nil {
+		logger.Error("Failed to replace rule group", "error", err)
+		return errorToResponse(err)
+	}
+
+	return response.JSON(http.StatusAccepted, map[string]string{"status": "success"})
+}
+
+func (srv *ConvertPrometheusSrv) getOrCreateNamespace(c *contextmodel.ReqContext, title string, logger log.Logger) (*folder.Folder, response.Response) {
+	logger.Debug("Getting or creating a new folder")
+
+	ns, err := srv.ruleStore.GetOrCreateNamespaceInRootByTitle(
+		c.Req.Context(),
+		title,
+		c.SignedInUser.GetOrgID(),
+		c.SignedInUser,
+	)
+	if err != nil {
+		logger.Error("Failed to get or create a new folder", "error", err)
+		return nil, toNamespaceErrorResponse(err)
+	}
+
+	logger.Debug("Using folder for the converted rules", "folder_uid", ns.UID)
+
+	return ns, nil
+}
+
+func (srv *ConvertPrometheusSrv) convertToGrafanaRuleGroup(c *contextmodel.ReqContext, ds *datasources.DataSource, namespaceUID string, promGroup apimodels.PrometheusRuleGroup, logger log.Logger) (*models.AlertRuleGroup, error) {
+	logger.Info("Converting Prometheus rules to Grafana rules", "rules", len(promGroup.Rules), "folder_uid", namespaceUID, "datasource_uid", ds.UID, "datasource_type", ds.Type)
+
+	rules := make([]prom.PrometheusRule, len(promGroup.Rules))
+	for i, r := range promGroup.Rules {
+		rules[i] = prom.PrometheusRule{
+			Alert:         r.Alert,
+			Expr:          r.Expr,
+			For:           r.For,
+			KeepFiringFor: r.KeepFiringFor,
+			Labels:        r.Labels,
+			Annotations:   r.Annotations,
+			Record:        r.Record,
+		}
+	}
+	group := prom.PrometheusRuleGroup{
+		Name:     promGroup.Name,
+		Interval: promGroup.Interval,
+		Rules:    rules,
+	}
+
+	pauseRecordingRules, err := parseBooleanHeader(c.Req.Header.Get(recordingRulesPausedHeader), recordingRulesPausedHeader)
+	if err != nil {
+		return nil, err
+	}
+
+	pauseAlertRules, err := parseBooleanHeader(c.Req.Header.Get(alertRulesPausedHeader), alertRulesPausedHeader)
+	if err != nil {
+		return nil, err
+	}
+
+	converter, err := prom.NewConverter(
+		prom.Config{
+			DatasourceUID:   ds.UID,
+			DatasourceType:  ds.Type,
+			DefaultInterval: srv.cfg.DefaultRuleEvaluationInterval,
+			RecordingRules: prom.RulesConfig{
+				IsPaused: pauseRecordingRules,
+			},
+			AlertRules: prom.RulesConfig{
+				IsPaused: pauseAlertRules,
+			},
+		},
+	)
+	if err != nil {
+		logger.Error("Failed to create Prometheus converter", "datasource_uid", ds.UID, "datasource_type", ds.Type, "error", err)
+		return nil, err
+	}
+
+	grafanaGroup, err := converter.PrometheusRulesToGrafana(c.SignedInUser.GetOrgID(), namespaceUID, group)
+	if err != nil {
+		logger.Error("Failed to convert Prometheus rules to Grafana rules", "error", err)
+		return nil, err
+	}
+
+	return grafanaGroup, nil
+}
+
+// parseBooleanHeader parses a boolean header value, returning an error if the header
+// is present but invalid. If the header is not present, returns (false, nil).
+func parseBooleanHeader(header string, headerName string) (bool, error) {
+	if header == "" {
+		return false, nil
+	}
+	val, err := strconv.ParseBool(header)
+	if err != nil {
+		return false, errInvalidHeaderValue(headerName)
+	}
+	return val, nil
 }