Merge pull request #4318 from mxinden/expose-alerts-and-rules

api/v1: Expose rules and alerts

docs/querying/api.md

@@ -363,6 +363,103 @@ $ curl http://localhost:9090/api/v1/targets
 }
 ```
 
+
+## Rules
+
+The `/rules` API endpoint returns a list of alerting and recording rules that
+are currently loaded. In addition it returns the currently active alerts fired
+by the Prometheus instance of each alerting rule.
+
+As the `/rules` endpoint is fairly new, it does not have the same stability
+guarantees as the overarching API v1.
+
+```
+GET /api/v1/rules
+```
+
+```json
+$ curl http://localhost:9090/api/v1/rules
+
+{
+    "data": {
+        "groups": [
+            {
+                "rules": [
+                    {
+                        "alerts": [
+                            {
+                                "activeAt": "2018-07-04T20:27:12.60602144+02:00",
+                                "annotations": {
+                                    "summary": "High request latency"
+                                },
+                                "labels": {
+                                    "alertname": "HighRequestLatency",
+                                    "severity": "page"
+                                },
+                                "state": "firing",
+                                "value": 1
+                            }
+                        ],
+                        "annotations": {
+                            "summary": "High request latency"
+                        },
+                        "duration": 600,
+                        "labels": {
+                            "severity": "page"
+                        },
+                        "name": "HighRequestLatency",
+                        "query": "job:request_latency_seconds:mean5m{job=\"myjob\"} > 0.5",
+                        "type": "alerting"
+                    },
+                    {
+                        "name": "job:http_inprogress_requests:sum",
+                        "query": "sum(http_inprogress_requests) by (job)",
+                        "type": "recording"
+                    }
+                ],
+                "file": "/rules.yaml",
+                "interval": 60,
+                "name": "example"
+            }
+        ]
+    },
+    "status": "success"
+}
+```
+
+
+## Alerts
+
+The `/alerts` endpoint returns a list of all active alerts.
+
+As the `/alerts` endpoint is fairly new, it does not have the same stability
+guarantees as the overarching API v1.
+
+```
+GET /api/v1/alerts
+```
+
+```json
+$ curl http://localhost:9090/api/v1/alerts
+
+{
+    "data": {
+        "alerts": [
+            {
+                "activeAt": "2018-07-04T20:27:12.60602144+02:00",
+                "annotations": {},
+                "labels": {
+                    "alertname": "my-alert"
+                },
+                "state": "firing",
+                "value": 1
+            }
+        ]
+    },
+    "status": "success"
+}
+```
+
 ## Querying target metadata
 
 The following endpoint returns metadata about metrics currently scraped by targets.

rules/alerting.go

@@ -126,11 +126,31 @@ func NewAlertingRule(name string, vec promql.Expr, hold time.Duration, lbls, ann
 	}
 }
 
-// Name returns the name of the alert.
+// Name returns the name of the alerting rule.
 func (r *AlertingRule) Name() string {
 	return r.name
 }
 
+// Query returns the query expression of the alerting rule.
+func (r *AlertingRule) Query() promql.Expr {
+	return r.vector
+}
+
+// Duration returns the hold duration of the alerting rule.
+func (r *AlertingRule) Duration() time.Duration {
+	return r.holdDuration
+}
+
+// Labels returns the labels of the alerting rule.
+func (r *AlertingRule) Labels() labels.Labels {
+	return r.labels
+}
+
+// Annotations returns the annotations of the alerting rule.
+func (r *AlertingRule) Annotations() labels.Labels {
+	return r.annotations
+}
+
 func (r *AlertingRule) equal(o *AlertingRule) bool {
 	return r.name == o.name && labels.Equal(r.labels, o.labels)
 }

rules/manager.go

@@ -188,6 +188,9 @@ func (g *Group) File() string { return g.file }
 // Rules returns the group's rules.
 func (g *Group) Rules() []Rule { return g.rules }
 
+// Interval returns the group's interval.
+func (g *Group) Interval() time.Duration { return g.interval }
+
 func (g *Group) run(ctx context.Context) {
 	defer close(g.terminated)
 

rules/recording.go

@@ -52,6 +52,16 @@ func (rule *RecordingRule) Name() string {
 	return rule.name
 }
 
+// Query returns the rule query expression.
+func (rule *RecordingRule) Query() promql.Expr {
+	return rule.vector
+}
+
+// Labels returns the rule labels.
+func (rule *RecordingRule) Labels() labels.Labels {
+	return rule.labels
+}
+
 // Eval evaluates the rule and then overrides the metric names and labels accordingly.
 func (rule *RecordingRule) Eval(ctx context.Context, ts time.Time, query QueryFunc, _ *url.URL) (promql.Vector, error) {
 	vector, err := query(ctx, rule.vector.String(), ts)

web/api/v1/api.go

@@ -41,6 +41,7 @@ import (
 	"github.com/prometheus/prometheus/pkg/timestamp"
 	"github.com/prometheus/prometheus/prompb"
 	"github.com/prometheus/prometheus/promql"
+	"github.com/prometheus/prometheus/rules"
 	"github.com/prometheus/prometheus/scrape"
 	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/storage/remote"
@@ -95,6 +96,11 @@ type alertmanagerRetriever interface {
 	DroppedAlertmanagers() []*url.URL
 }
 
+type rulesRetriever interface {
+	RuleGroups() []*rules.Group
+	AlertingRules() []*rules.AlertingRule
+}
+
 type response struct {
 	Status    status      `json:"status"`
 	Data      interface{} `json:"data,omitempty"`
@@ -119,7 +125,7 @@ type API struct {
 
 	targetRetriever       targetRetriever
 	alertmanagerRetriever alertmanagerRetriever
-
+	rulesRetriever        rulesRetriever
 	now                   func() time.Time
 	config                func() config.Config
 	flagsMap              map[string]string
@@ -142,6 +148,7 @@ func NewAPI(
 	db func() *tsdb.DB,
 	enableAdmin bool,
 	logger log.Logger,
+	rr rulesRetriever,
 ) *API {
 	return &API{
 		QueryEngine:           qe,
@@ -154,6 +161,7 @@ func NewAPI(
 		ready:          readyFunc,
 		db:             db,
 		enableAdmin:    enableAdmin,
+		rulesRetriever: rr,
 	}
 }
 
@@ -199,6 +207,9 @@ func (api *API) Register(r *route.Router) {
 	r.Get("/status/flags", wrap(api.serveFlags))
 	r.Post("/read", api.ready(http.HandlerFunc(api.remoteRead)))
 
+	r.Get("/alerts", wrap(api.alerts))
+	r.Get("/rules", wrap(api.rules))
+
 	// Admin APIs
 	r.Post("/admin/tsdb/delete_series", wrap(api.deleteSeries))
 	r.Post("/admin/tsdb/clean_tombstones", wrap(api.cleanTombstones))
@@ -578,6 +589,132 @@ func (api *API) alertmanagers(r *http.Request) (interface{}, *apiError, func())
 	return ams, nil, nil
 }
 
+// AlertDiscovery has info for all active alerts.
+type AlertDiscovery struct {
+	Alerts []*Alert `json:"alerts"`
+}
+
+// Alert has info for an alert.
+type Alert struct {
+	Labels      labels.Labels `json:"labels"`
+	Annotations labels.Labels `json:"annotations"`
+	State       string        `json:"state"`
+	ActiveAt    *time.Time    `json:"activeAt,omitempty"`
+	Value       float64       `json:"value"`
+}
+
+func (api *API) alerts(r *http.Request) (interface{}, *apiError, func()) {
+	alertingRules := api.rulesRetriever.AlertingRules()
+	alerts := []*Alert{}
+
+	for _, alertingRule := range alertingRules {
+		alerts = append(
+			alerts,
+			rulesAlertsToAPIAlerts(alertingRule.ActiveAlerts())...,
+		)
+	}
+
+	res := &AlertDiscovery{Alerts: alerts}
+
+	return res, nil, nil
+}
+
+func rulesAlertsToAPIAlerts(rulesAlerts []*rules.Alert) []*Alert {
+	apiAlerts := make([]*Alert, len(rulesAlerts))
+	for i, ruleAlert := range rulesAlerts {
+		apiAlerts[i] = &Alert{
+			Labels:      ruleAlert.Labels,
+			Annotations: ruleAlert.Annotations,
+			State:       ruleAlert.State.String(),
+			ActiveAt:    &ruleAlert.ActiveAt,
+			Value:       ruleAlert.Value,
+		}
+	}
+
+	return apiAlerts
+}
+
+// RuleDiscovery has info for all rules
+type RuleDiscovery struct {
+	RuleGroups []*RuleGroup `json:"groups"`
+}
+
+// RuleGroup has info for rules which are part of a group
+type RuleGroup struct {
+	Name string `json:"name"`
+	File string `json:"file"`
+	// In order to preserve rule ordering, while exposing type (alerting or recording)
+	// specific properties, both alerting and recording rules are exposed in the
+	// same array.
+	Rules    []rule  `json:"rules"`
+	Interval float64 `json:"interval"`
+}
+
+type rule interface{}
+
+type alertingRule struct {
+	Name        string        `json:"name"`
+	Query       string        `json:"query"`
+	Duration    float64       `json:"duration"`
+	Labels      labels.Labels `json:"labels"`
+	Annotations labels.Labels `json:"annotations"`
+	Alerts      []*Alert      `json:"alerts"`
+	// Type of an alertingRule is always "alerting".
+	Type string `json:"type"`
+}
+
+type recordingRule struct {
+	Name   string        `json:"name"`
+	Query  string        `json:"query"`
+	Labels labels.Labels `json:"labels,omitempty"`
+	// Type of a recordingRule is always "recording".
+	Type string `json:"type"`
+}
+
+func (api *API) rules(r *http.Request) (interface{}, *apiError, func()) {
+	ruleGroups := api.rulesRetriever.RuleGroups()
+	res := &RuleDiscovery{RuleGroups: make([]*RuleGroup, len(ruleGroups))}
+	for i, grp := range ruleGroups {
+		apiRuleGroup := &RuleGroup{
+			Name:     grp.Name(),
+			File:     grp.File(),
+			Interval: grp.Interval().Seconds(),
+			Rules:    []rule{},
+		}
+
+		for _, r := range grp.Rules() {
+			var enrichedRule rule
+
+			switch rule := r.(type) {
+			case *rules.AlertingRule:
+				enrichedRule = alertingRule{
+					Name:        rule.Name(),
+					Query:       rule.Query().String(),
+					Duration:    rule.Duration().Seconds(),
+					Labels:      rule.Labels(),
+					Annotations: rule.Annotations(),
+					Alerts:      rulesAlertsToAPIAlerts(rule.ActiveAlerts()),
+					Type:        "alerting",
+				}
+			case *rules.RecordingRule:
+				enrichedRule = recordingRule{
+					Name:   rule.Name(),
+					Query:  rule.Query().String(),
+					Labels: rule.Labels(),
+					Type:   "recording",
+				}
+			default:
+				err := fmt.Errorf("failed to assert type of rule '%v'", rule.Name())
+				return nil, &apiError{errorInternal, err}, nil
+			}
+
+			apiRuleGroup.Rules = append(apiRuleGroup.Rules, enrichedRule)
+		}
+		res.RuleGroups[i] = apiRuleGroup
+	}
+	return res, nil, nil
+}
+
 type prometheusConfig struct {
 	YAML string `json:"yaml"`
 }

web/api/v1/api_test.go

@@ -19,6 +19,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"github.com/go-kit/kit/log"
 	"io/ioutil"
 	"math"
 	"net/http"
@@ -41,9 +42,11 @@ import (
 	"github.com/prometheus/prometheus/pkg/timestamp"
 	"github.com/prometheus/prometheus/prompb"
 	"github.com/prometheus/prometheus/promql"
+	"github.com/prometheus/prometheus/rules"
 	"github.com/prometheus/prometheus/scrape"
 	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/storage/remote"
+	"github.com/prometheus/prometheus/util/testutil"
 )
 
 type testTargetRetriever struct{}
@@ -98,6 +101,73 @@ func (t testAlertmanagerRetriever) DroppedAlertmanagers() []*url.URL {
 	}
 }
 
+type rulesRetrieverMock struct {
+	testing *testing.T
+}
+
+func (m rulesRetrieverMock) AlertingRules() []*rules.AlertingRule {
+	expr1, err := promql.ParseExpr(`absent(test_metric3) != 1`)
+	if err != nil {
+		m.testing.Fatalf("unable to parse alert expression: %s", err)
+	}
+	expr2, err := promql.ParseExpr(`up == 1`)
+	if err != nil {
+		m.testing.Fatalf("Unable to parse alert expression: %s", err)
+	}
+
+	rule1 := rules.NewAlertingRule(
+		"test_metric3",
+		expr1,
+		time.Second,
+		labels.Labels{},
+		labels.Labels{},
+		log.NewNopLogger(),
+	)
+	rule2 := rules.NewAlertingRule(
+		"test_metric4",
+		expr2,
+		time.Second,
+		labels.Labels{},
+		labels.Labels{},
+		log.NewNopLogger(),
+	)
+	var r []*rules.AlertingRule
+	r = append(r, rule1)
+	r = append(r, rule2)
+	return r
+}
+
+func (m rulesRetrieverMock) RuleGroups() []*rules.Group {
+	var ar rulesRetrieverMock
+	arules := ar.AlertingRules()
+	storage := testutil.NewStorage(m.testing)
+	defer storage.Close()
+
+	engine := promql.NewEngine(nil, nil, 10, 10*time.Second)
+	opts := &rules.ManagerOptions{
+		QueryFunc:  rules.EngineQueryFunc(engine, storage),
+		Appendable: storage,
+		Context:    context.Background(),
+		Logger:     log.NewNopLogger(),
+	}
+
+	var r []rules.Rule
+
+	for _, alertrule := range arules {
+		r = append(r, alertrule)
+	}
+
+	recordingExpr, err := promql.ParseExpr(`vector(1)`)
+	if err != nil {
+		m.testing.Fatalf("unable to parse alert expression: %s", err)
+	}
+	recordingRule := rules.NewRecordingRule("recording-rule-1", recordingExpr, labels.Labels{})
+	r = append(r, recordingRule)
+
+	group := rules.NewGroup("grp", "/path/to/file", time.Second, r, opts)
+	return []*rules.Group{group}
+}
+
 var samplePrometheusCfg = config.Config{
 	GlobalConfig:       config.GlobalConfig{},
 	AlertingConfig:     config.AlertingConfig{},
@@ -130,7 +200,19 @@ func TestEndpoints(t *testing.T) {
 
 	now := time.Now()
 
+	var algr rulesRetrieverMock
+	algr.testing = t
+	algr.AlertingRules()
+	algr.RuleGroups()
+
 	t.Run("local", func(t *testing.T) {
+		var algr rulesRetrieverMock
+		algr.testing = t
+
+		algr.AlertingRules()
+
+		algr.RuleGroups()
+
 		api := &API{
 			Queryable:             suite.Storage(),
 			QueryEngine:           suite.QueryEngine(),
@@ -140,6 +222,7 @@ func TestEndpoints(t *testing.T) {
 			config:         func() config.Config { return samplePrometheusCfg },
 			flagsMap:       sampleFlagMap,
 			ready:          func(f http.HandlerFunc) http.HandlerFunc { return f },
+			rulesRetriever: algr,
 		}
 
 		testEndpoints(t, api, true)
@@ -176,6 +259,13 @@ func TestEndpoints(t *testing.T) {
 			t.Fatal(err)
 		}
 
+		var algr rulesRetrieverMock
+		algr.testing = t
+
+		algr.AlertingRules()
+
+		algr.RuleGroups()
+
 		api := &API{
 			Queryable:             remote,
 			QueryEngine:           suite.QueryEngine(),
@@ -185,6 +275,7 @@ func TestEndpoints(t *testing.T) {
 			config:         func() config.Config { return samplePrometheusCfg },
 			flagsMap:       sampleFlagMap,
 			ready:          func(f http.HandlerFunc) http.HandlerFunc { return f },
+			rulesRetriever: algr,
 		}
 
 		testEndpoints(t, api, false)
@@ -237,7 +328,6 @@ func setupRemote(s storage.Storage) *httptest.Server {
 }
 
 func testEndpoints(t *testing.T, api *API, testLabelAPI bool) {
-
 	start := time.Unix(0, 0)
 
 	type test struct {
@@ -567,6 +657,50 @@ func testEndpoints(t *testing.T, api *API, testLabelAPI bool) {
 			endpoint: api.serveFlags,
 			response: sampleFlagMap,
 		},
+		{
+			endpoint: api.alerts,
+			response: &AlertDiscovery{
+				Alerts: []*Alert{},
+			},
+		},
+		{
+			endpoint: api.rules,
+			response: &RuleDiscovery{
+				RuleGroups: []*RuleGroup{
+					{
+						Name:     "grp",
+						File:     "/path/to/file",
+						Interval: 1,
+						Rules: []rule{
+							alertingRule{
+								Name:        "test_metric3",
+								Query:       "absent(test_metric3) != 1",
+								Duration:    1,
+								Labels:      labels.Labels{},
+								Annotations: labels.Labels{},
+								Alerts:      []*Alert{},
+								Type:        "alerting",
+							},
+							alertingRule{
+								Name:        "test_metric4",
+								Query:       "up == 1",
+								Duration:    1,
+								Labels:      labels.Labels{},
+								Annotations: labels.Labels{},
+								Alerts:      []*Alert{},
+								Type:        "alerting",
+							},
+							recordingRule{
+								Name:   "recording-rule-1",
+								Query:  "vector(1)",
+								Labels: labels.Labels{},
+								Type:   "recording",
+							},
+						},
+					},
+				},
+			},
+		},
 	}
 
 	if testLabelAPI {
@@ -646,7 +780,21 @@ func testEndpoints(t *testing.T, api *API, testLabelAPI bool) {
 				t.Fatalf("Expected error of type %q but got none", test.errType)
 			}
 			if !reflect.DeepEqual(resp, test.response) {
-				t.Fatalf("Response does not match, expected:\n%+v\ngot:\n%+v", test.response, resp)
+				respJSON, err := json.Marshal(resp)
+				if err != nil {
+					t.Fatalf("failed to marshal response as JSON: %v", err.Error())
+				}
+
+				expectedRespJSON, err := json.Marshal(test.response)
+				if err != nil {
+					t.Fatalf("failed to marshal expected response as JSON: %v", err.Error())
+				}
+
+				t.Fatalf(
+					"Response does not match, expected:\n%+v\ngot:\n%+v",
+					string(expectedRespJSON),
+					string(respJSON),
+				)
 			}
 		}
 	}

web/web.go

@@ -228,6 +228,7 @@ func New(logger log.Logger, o *Options) *Handler {
 		h.options.TSDB,
 		h.options.EnableAdminAPI,
 		logger,
+		h.ruleManager,
 	)
 
 	if o.RoutePrefix != "/" {