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// Copyright 2013 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package rules
import (
"context"
"errors"
"fmt"
"math"
"net/url"
"sort"
"sync"
"time"
html_template "html/template"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
opentracing "github.com/opentracing/opentracing-go"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/pkg/rulefmt"
"github.com/prometheus/prometheus/pkg/timestamp"
"github.com/prometheus/prometheus/pkg/value"
"github.com/prometheus/prometheus/promql"
"github.com/prometheus/prometheus/storage"
)
// RuleHealth describes the health state of a target.
type RuleHealth string
// The possible health states of a rule based on the last execution.
const (
HealthUnknown RuleHealth = "unknown"
HealthGood RuleHealth = "ok"
HealthBad RuleHealth = "err"
)
// Constants for instrumentation.
const namespace = "prometheus"
var (
evalDuration = prometheus.NewSummary(
prometheus.SummaryOpts{
Namespace: namespace,
Name: "rule_evaluation_duration_seconds",
Help: "The duration for a rule to execute.",
},
)
evalFailures = prometheus.NewCounter(
prometheus.CounterOpts{
Namespace: namespace,
Name: "rule_evaluation_failures_total",
Help: "The total number of rule evaluation failures.",
},
)
evalTotal = prometheus.NewCounter(
prometheus.CounterOpts{
Namespace: namespace,
Name: "rule_evaluations_total",
Help: "The total number of rule evaluations.",
},
)
iterationDuration = prometheus.NewSummary(prometheus.SummaryOpts{
Namespace: namespace,
Name: "rule_group_duration_seconds",
Help: "The duration of rule group evaluations.",
Objectives: map[float64]float64{0.01: 0.001, 0.05: 0.005, 0.5: 0.05, 0.90: 0.01, 0.99: 0.001},
})
iterationsMissed = prometheus.NewCounter(prometheus.CounterOpts{
Namespace: namespace,
Name: "rule_group_iterations_missed_total",
Help: "The total number of rule group evaluations missed due to slow rule group evaluation.",
})
iterationsScheduled = prometheus.NewCounter(prometheus.CounterOpts{
Namespace: namespace,
Name: "rule_group_iterations_total",
Help: "The total number of scheduled rule group evaluations, whether executed or missed.",
})
lastEvaluation = prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "rule_group_last_evaluation_timestamp_seconds"),
"The timestamp of the last rule group evaluation in seconds.",
[]string{"rule_group"},
nil,
)
lastDuration = prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "rule_group_last_duration_seconds"),
"The duration of the last rule group evaluation.",
[]string{"rule_group"},
nil,
)
groupInterval = prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "rule_group_interval_seconds"),
"The interval of a rule group.",
[]string{"rule_group"},
nil,
)
)
func init() {
prometheus.MustRegister(iterationDuration)
prometheus.MustRegister(iterationsScheduled)
prometheus.MustRegister(iterationsMissed)
prometheus.MustRegister(evalFailures)
prometheus.MustRegister(evalDuration)
}
// QueryFunc processes PromQL queries.
type QueryFunc func(ctx context.Context, q string, t time.Time) (promql.Vector, error)
// EngineQueryFunc returns a new query function that executes instant queries against
// the given engine.
// It converts scalar into vector results.
func EngineQueryFunc(engine *promql.Engine, q storage.Queryable) QueryFunc {
return func(ctx context.Context, qs string, t time.Time) (promql.Vector, error) {
q, err := engine.NewInstantQuery(q, qs, t)
if err != nil {
return nil, err
}
res := q.Exec(ctx)
if res.Err != nil {
return nil, res.Err
}
switch v := res.Value.(type) {
case promql.Vector:
return v, nil
case promql.Scalar:
return promql.Vector{promql.Sample{
Point: promql.Point(v),
Metric: labels.Labels{},
}}, nil
default:
return nil, fmt.Errorf("rule result is not a vector or scalar")
}
}
}
// A Rule encapsulates a vector expression which is evaluated at a specified
// interval and acted upon (currently either recorded or used for alerting).
type Rule interface {
Name() string
// eval evaluates the rule, including any associated recording or alerting actions.
Eval(context.Context, time.Time, QueryFunc, *url.URL) (promql.Vector, error)
// String returns a human-readable string representation of the rule.
String() string
// SetLastErr sets the current error experienced by the rule.
SetLastError(error)
// LastErr returns the last error experienced by the rule.
LastError() error
// SetHealth sets the current health of the rule.
SetHealth(RuleHealth)
// Health returns the current health of the rule.
Health() RuleHealth
SetEvaluationDuration(time.Duration)
GetEvaluationDuration() time.Duration
SetEvaluationTimestamp(time.Time)
GetEvaluationTimestamp() time.Time
// HTMLSnippet returns a human-readable string representation of the rule,
// decorated with HTML elements for use the web frontend.
HTMLSnippet(pathPrefix string) html_template.HTML
}
// Group is a set of rules that have a logical relation.
type Group struct {
name string
file string
interval time.Duration
rules []Rule
seriesInPreviousEval []map[string]labels.Labels // One per Rule.
opts *ManagerOptions
mtx sync.Mutex
evaluationDuration time.Duration
evaluationTimestamp time.Time
shouldRestore bool
done chan struct{}
terminated chan struct{}
logger log.Logger
}
// NewGroup makes a new Group with the given name, options, and rules.
func NewGroup(name, file string, interval time.Duration, rules []Rule, shouldRestore bool, opts *ManagerOptions) *Group {
return &Group{
name: name,
file: file,
interval: interval,
rules: rules,
shouldRestore: shouldRestore,
opts: opts,
seriesInPreviousEval: make([]map[string]labels.Labels, len(rules)),
done: make(chan struct{}),
terminated: make(chan struct{}),
logger: log.With(opts.Logger, "group", name),
}
}
// Name returns the group name.
func (g *Group) Name() string { return g.name }
// File returns the group's file.
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)
// Wait an initial amount to have consistently slotted intervals.
evalTimestamp := g.evalTimestamp().Add(g.interval)
select {
case <-time.After(time.Until(evalTimestamp)):
case <-g.done:
return
}
iter := func() {
iterationsScheduled.Inc()
start := time.Now()
g.Eval(ctx, evalTimestamp)
timeSinceStart := time.Since(start)
iterationDuration.Observe(timeSinceStart.Seconds())
g.SetEvaluationDuration(timeSinceStart)
g.SetEvaluationTimestamp(start)
}
// The assumption here is that since the ticker was started after having
// waited for `evalTimestamp` to pass, the ticks will trigger soon
// after each `evalTimestamp + N * g.interval` occurrence.
tick := time.NewTicker(g.interval)
defer tick.Stop()
iter()
if g.shouldRestore {
// If we have to restore, we wait for another Eval to finish.
// The reason behind this is, during first eval (or before it)
// we might not have enough data scraped, and recording rules would not
// have updated the latest values, on which some alerts might depend.
select {
case <-g.done:
return
case <-tick.C:
missed := (time.Since(evalTimestamp) / g.interval) - 1
if missed > 0 {
iterationsMissed.Add(float64(missed))
iterationsScheduled.Add(float64(missed))
}
evalTimestamp = evalTimestamp.Add((missed + 1) * g.interval)
iter()
}
g.RestoreForState(time.Now())
g.shouldRestore = false
}
for {
select {
case <-g.done:
return
default:
select {
case <-g.done:
return
case <-tick.C:
missed := (time.Since(evalTimestamp) / g.interval) - 1
if missed > 0 {
iterationsMissed.Add(float64(missed))
iterationsScheduled.Add(float64(missed))
}
evalTimestamp = evalTimestamp.Add((missed + 1) * g.interval)
iter()
}
}
}
}
func (g *Group) stop() {
close(g.done)
<-g.terminated
}
func (g *Group) hash() uint64 {
l := labels.New(
labels.Label{"name", g.name},
labels.Label{"file", g.file},
)
return l.Hash()
}
// GetEvaluationDuration returns the time in seconds it took to evaluate the rule group.
func (g *Group) GetEvaluationDuration() time.Duration {
g.mtx.Lock()
defer g.mtx.Unlock()
return g.evaluationDuration
}
// SetEvaluationDuration sets the time in seconds the last evaluation took.
func (g *Group) SetEvaluationDuration(dur time.Duration) {
g.mtx.Lock()
defer g.mtx.Unlock()
g.evaluationDuration = dur
}
// SetEvaluationTimestamp updates evaluationTimestamp to the timestamp of when the rule group was last evaluated.
func (g *Group) SetEvaluationTimestamp(ts time.Time) {
g.mtx.Lock()
defer g.mtx.Unlock()
g.evaluationTimestamp = ts
}
// GetEvaluationTimestamp returns the time the last evaluation of the rule group took place.
func (g *Group) GetEvaluationTimestamp() time.Time {
g.mtx.Lock()
defer g.mtx.Unlock()
return g.evaluationTimestamp
}
// evalTimestamp returns the immediately preceding consistently slotted evaluation time.
func (g *Group) evalTimestamp() time.Time {
var (
offset = int64(g.hash() % uint64(g.interval))
now = time.Now().UnixNano()
adjNow = now - offset
base = adjNow - (adjNow % int64(g.interval))
)
return time.Unix(0, base+offset)
}
// CopyState copies the alerting rule and staleness related state from the given group.
//
// Rules are matched based on their name. If there are duplicates, the
// first is matched with the first, second with the second etc.
func (g *Group) CopyState(from *Group) {
g.evaluationDuration = from.evaluationDuration
ruleMap := make(map[string][]int, len(from.rules))
for fi, fromRule := range from.rules {
l := ruleMap[fromRule.Name()]
ruleMap[fromRule.Name()] = append(l, fi)
}
for i, rule := range g.rules {
indexes := ruleMap[rule.Name()]
if len(indexes) == 0 {
continue
}
fi := indexes[0]
g.seriesInPreviousEval[i] = from.seriesInPreviousEval[fi]
ruleMap[rule.Name()] = indexes[1:]
ar, ok := rule.(*AlertingRule)
if !ok {
continue
}
far, ok := from.rules[fi].(*AlertingRule)
if !ok {
continue
}
for fp, a := range far.active {
ar.active[fp] = a
}
}
}
// Eval runs a single evaluation cycle in which all rules are evaluated sequentially.
func (g *Group) Eval(ctx context.Context, ts time.Time) {
for i, rule := range g.rules {
select {
case <-g.done:
return
default:
}
func(i int, rule Rule) {
sp, ctx := opentracing.StartSpanFromContext(ctx, "rule")
sp.SetTag("name", rule.Name())
defer func(t time.Time) {
sp.Finish()
evalDuration.Observe(time.Since(t).Seconds())
rule.SetEvaluationDuration(time.Since(t))
rule.SetEvaluationTimestamp(t)
}(time.Now())
evalTotal.Inc()
vector, err := rule.Eval(ctx, ts, g.opts.QueryFunc, g.opts.ExternalURL)
if err != nil {
// Canceled queries are intentional termination of queries. This normally
// happens on shutdown and thus we skip logging of any errors here.
if _, ok := err.(promql.ErrQueryCanceled); !ok {
level.Warn(g.logger).Log("msg", "Evaluating rule failed", "rule", rule, "err", err)
}
evalFailures.Inc()
return
}
if ar, ok := rule.(*AlertingRule); ok {
ar.sendAlerts(ctx, ts, g.opts.ResendDelay, g.interval, g.opts.NotifyFunc)
}
var (
numOutOfOrder = 0
numDuplicates = 0
)
app, err := g.opts.Appendable.Appender()
if err != nil {
level.Warn(g.logger).Log("msg", "creating appender failed", "err", err)
return
}
seriesReturned := make(map[string]labels.Labels, len(g.seriesInPreviousEval[i]))
for _, s := range vector {
if _, err := app.Add(s.Metric, s.T, s.V); err != nil {
switch err {
case storage.ErrOutOfOrderSample:
numOutOfOrder++
level.Debug(g.logger).Log("msg", "Rule evaluation result discarded", "err", err, "sample", s)
case storage.ErrDuplicateSampleForTimestamp:
numDuplicates++
level.Debug(g.logger).Log("msg", "Rule evaluation result discarded", "err", err, "sample", s)
default:
level.Warn(g.logger).Log("msg", "Rule evaluation result discarded", "err", err, "sample", s)
}
} else {
seriesReturned[s.Metric.String()] = s.Metric
}
}
if numOutOfOrder > 0 {
level.Warn(g.logger).Log("msg", "Error on ingesting out-of-order result from rule evaluation", "numDropped", numOutOfOrder)
}
if numDuplicates > 0 {
level.Warn(g.logger).Log("msg", "Error on ingesting results from rule evaluation with different value but same timestamp", "numDropped", numDuplicates)
}
for metric, lset := range g.seriesInPreviousEval[i] {
if _, ok := seriesReturned[metric]; !ok {
// Series no longer exposed, mark it stale.
_, err = app.Add(lset, timestamp.FromTime(ts), math.Float64frombits(value.StaleNaN))
switch err {
case nil:
case storage.ErrOutOfOrderSample, storage.ErrDuplicateSampleForTimestamp:
// Do not count these in logging, as this is expected if series
// is exposed from a different rule.
default:
level.Warn(g.logger).Log("msg", "adding stale sample failed", "sample", metric, "err", err)
}
}
}
if err := app.Commit(); err != nil {
level.Warn(g.logger).Log("msg", "rule sample appending failed", "err", err)
} else {
g.seriesInPreviousEval[i] = seriesReturned
}
}(i, rule)
}
}
// RestoreForState restores the 'for' state of the alerts
// by looking up last ActiveAt from storage.
func (g *Group) RestoreForState(ts time.Time) {
maxtMS := int64(model.TimeFromUnixNano(ts.UnixNano()))
// We allow restoration only if alerts were active before after certain time.
mint := ts.Add(-g.opts.OutageTolerance)
mintMS := int64(model.TimeFromUnixNano(mint.UnixNano()))
q, err := g.opts.TSDB.Querier(g.opts.Context, mintMS, maxtMS)
if err != nil {
level.Error(g.logger).Log("msg", "Failed to get Querier", "err", err)
return
}
defer q.Close()
for _, rule := range g.Rules() {
alertRule, ok := rule.(*AlertingRule)
if !ok {
continue
}
alertHoldDuration := alertRule.HoldDuration()
if alertHoldDuration < g.opts.ForGracePeriod {
// If alertHoldDuration is already less than grace period, we would not
// like to make it wait for `g.opts.ForGracePeriod` time before firing.
// Hence we skip restoration, which will make it wait for alertHoldDuration.
alertRule.SetRestored(true)
continue
}
alertRule.ForEachActiveAlert(func(a *Alert) {
smpl := alertRule.forStateSample(a, time.Now(), 0)
var matchers []*labels.Matcher
for _, l := range smpl.Metric {
mt, err := labels.NewMatcher(labels.MatchEqual, l.Name, l.Value)
if err != nil {
panic(err)
}
matchers = append(matchers, mt)
}
sset, err, _ := q.Select(nil, matchers...)
if err != nil {
level.Error(g.logger).Log("msg", "Failed to restore 'for' state",
labels.AlertName, alertRule.Name(), "stage", "Select", "err", err)
return
}
seriesFound := false
var s storage.Series
for sset.Next() {
// Query assures that smpl.Metric is included in sset.At().Labels(),
// hence just checking the length would act like equality.
// (This is faster than calling labels.Compare again as we already have some info).
if len(sset.At().Labels()) == len(smpl.Metric) {
s = sset.At()
seriesFound = true
break
}
}
if !seriesFound {
return
}
// Series found for the 'for' state.
var t int64
var v float64
it := s.Iterator()
for it.Next() {
t, v = it.At()
}
if it.Err() != nil {
level.Error(g.logger).Log("msg", "Failed to restore 'for' state",
labels.AlertName, alertRule.Name(), "stage", "Iterator", "err", it.Err())
return
}
if value.IsStaleNaN(v) { // Alert was not active.
return
}
downAt := time.Unix(t/1000, 0)
restoredActiveAt := time.Unix(int64(v), 0)
timeSpentPending := downAt.Sub(restoredActiveAt)
timeRemainingPending := alertHoldDuration - timeSpentPending
if timeRemainingPending <= 0 {
// It means that alert was firing when prometheus went down.
// In the next Eval, the state of this alert will be set back to
// firing again if it's still firing in that Eval.
// Nothing to be done in this case.
} else if timeRemainingPending < g.opts.ForGracePeriod {
// (new) restoredActiveAt = (ts + m.opts.ForGracePeriod) - alertHoldDuration
// /* new firing time */ /* moving back by hold duration */
//
// Proof of correctness:
// firingTime = restoredActiveAt.Add(alertHoldDuration)
// = ts + m.opts.ForGracePeriod - alertHoldDuration + alertHoldDuration
// = ts + m.opts.ForGracePeriod
//
// Time remaining to fire = firingTime.Sub(ts)
// = (ts + m.opts.ForGracePeriod) - ts
// = m.opts.ForGracePeriod
restoredActiveAt = ts.Add(g.opts.ForGracePeriod).Add(-alertHoldDuration)
} else {
// By shifting ActiveAt to the future (ActiveAt + some_duration),
// the total pending time from the original ActiveAt
// would be `alertHoldDuration + some_duration`.
// Here, some_duration = downDuration.
downDuration := ts.Sub(downAt)
restoredActiveAt = restoredActiveAt.Add(downDuration)
}
a.ActiveAt = restoredActiveAt
level.Debug(g.logger).Log("msg", "'for' state restored",
labels.AlertName, alertRule.Name(), "restored_time", a.ActiveAt.Format(time.RFC850),
"labels", a.Labels.String())
})
alertRule.SetRestored(true)
}
}
// The Manager manages recording and alerting rules.
type Manager struct {
opts *ManagerOptions
groups map[string]*Group
mtx sync.RWMutex
block chan struct{}
restored bool
logger log.Logger
}
// Appendable returns an Appender.
type Appendable interface {
Appender() (storage.Appender, error)
}
// NotifyFunc sends notifications about a set of alerts generated by the given expression.
type NotifyFunc func(ctx context.Context, expr string, alerts ...*Alert)
// ManagerOptions bundles options for the Manager.
type ManagerOptions struct {
ExternalURL *url.URL
QueryFunc QueryFunc
NotifyFunc NotifyFunc
Context context.Context
Appendable Appendable
TSDB storage.Storage
Logger log.Logger
Registerer prometheus.Registerer
OutageTolerance time.Duration
ForGracePeriod time.Duration
ResendDelay time.Duration
}
// NewManager returns an implementation of Manager, ready to be started
// by calling the Run method.
func NewManager(o *ManagerOptions) *Manager {
m := &Manager{
groups: map[string]*Group{},
opts: o,
block: make(chan struct{}),
logger: o.Logger,
}
if o.Registerer != nil {
o.Registerer.MustRegister(m)
}
return m
}
// Run starts processing of the rule manager.
func (m *Manager) Run() {
close(m.block)
}
// Stop the rule manager's rule evaluation cycles.
func (m *Manager) Stop() {
m.mtx.Lock()
defer m.mtx.Unlock()
level.Info(m.logger).Log("msg", "Stopping rule manager...")
for _, eg := range m.groups {
eg.stop()
}
level.Info(m.logger).Log("msg", "Rule manager stopped")
}
// Update the rule manager's state as the config requires. If
// loading the new rules failed the old rule set is restored.
func (m *Manager) Update(interval time.Duration, files []string) error {
m.mtx.Lock()
defer m.mtx.Unlock()
groups, errs := m.LoadGroups(interval, files...)
if errs != nil {
for _, e := range errs {
level.Error(m.logger).Log("msg", "loading groups failed", "err", e)
}
return errors.New("error loading rules, previous rule set restored")
}
m.restored = true
var wg sync.WaitGroup
for _, newg := range groups {
wg.Add(1)
// If there is an old group with the same identifier, stop it and wait for
// it to finish the current iteration. Then copy it into the new group.
gn := groupKey(newg.name, newg.file)
oldg, ok := m.groups[gn]
delete(m.groups, gn)
go func(newg *Group) {
if ok {
oldg.stop()
newg.CopyState(oldg)
}
go func() {
// Wait with starting evaluation until the rule manager
// is told to run. This is necessary to avoid running
// queries against a bootstrapping storage.
<-m.block
newg.run(m.opts.Context)
}()
wg.Done()
}(newg)
}
// Stop remaining old groups.
for _, oldg := range m.groups {
oldg.stop()
}
wg.Wait()
m.groups = groups
return nil
}
// LoadGroups reads groups from a list of files.
func (m *Manager) LoadGroups(interval time.Duration, filenames ...string) (map[string]*Group, []error) {
groups := make(map[string]*Group)
shouldRestore := !m.restored
for _, fn := range filenames {
rgs, errs := rulefmt.ParseFile(fn)
if errs != nil {
return nil, errs
}
for _, rg := range rgs.Groups {
itv := interval
if rg.Interval != 0 {
itv = time.Duration(rg.Interval)
}
rules := make([]Rule, 0, len(rg.Rules))
for _, r := range rg.Rules {
expr, err := promql.ParseExpr(r.Expr)
if err != nil {
return nil, []error{err}
}
if r.Alert != "" {
rules = append(rules, NewAlertingRule(
r.Alert,
expr,
time.Duration(r.For),
labels.FromMap(r.Labels),
labels.FromMap(r.Annotations),
m.restored,
log.With(m.logger, "alert", r.Alert),
))
continue
}
rules = append(rules, NewRecordingRule(
r.Record,
expr,
labels.FromMap(r.Labels),
))
}
groups[groupKey(rg.Name, fn)] = NewGroup(rg.Name, fn, itv, rules, shouldRestore, m.opts)
}
}
return groups, nil
}
// Group names need not be unique across filenames.
func groupKey(name, file string) string {
return name + ";" + file
}
// RuleGroups returns the list of manager's rule groups.
func (m *Manager) RuleGroups() []*Group {
m.mtx.RLock()
defer m.mtx.RUnlock()
rgs := make([]*Group, 0, len(m.groups))
for _, g := range m.groups {
rgs = append(rgs, g)
}
sort.Slice(rgs, func(i, j int) bool {
return rgs[i].file < rgs[j].file && rgs[i].name < rgs[j].name
})
return rgs
}
// Rules returns the list of the manager's rules.
func (m *Manager) Rules() []Rule {
m.mtx.RLock()
defer m.mtx.RUnlock()
var rules []Rule
for _, g := range m.groups {
rules = append(rules, g.rules...)
}
return rules
}
// AlertingRules returns the list of the manager's alerting rules.
func (m *Manager) AlertingRules() []*AlertingRule {
m.mtx.RLock()
defer m.mtx.RUnlock()
alerts := []*AlertingRule{}
for _, rule := range m.Rules() {
if alertingRule, ok := rule.(*AlertingRule); ok {
alerts = append(alerts, alertingRule)
}
}
return alerts
}
// Describe implements prometheus.Collector.
func (m *Manager) Describe(ch chan<- *prometheus.Desc) {
ch <- lastEvaluation
ch <- lastDuration
ch <- groupInterval
}
// Collect implements prometheus.Collector.
func (m *Manager) Collect(ch chan<- prometheus.Metric) {
for _, g := range m.RuleGroups() {
lastEvaluationTime := g.GetEvaluationTimestamp()
lastEvaluationTimestamp := math.Inf(-1)
if !lastEvaluationTime.IsZero() {
lastEvaluationTimestamp = float64(lastEvaluationTime.UnixNano()) / 1e9
}
key := groupKey(g.file, g.name)
ch <- prometheus.MustNewConstMetric(lastEvaluation,
prometheus.GaugeValue,
lastEvaluationTimestamp,
key)
ch <- prometheus.MustNewConstMetric(lastDuration,
prometheus.GaugeValue,
g.GetEvaluationDuration().Seconds(),
key)
}
for _, g := range m.RuleGroups() {
ch <- prometheus.MustNewConstMetric(groupInterval,
prometheus.GaugeValue,
g.interval.Seconds(),
groupKey(g.file, g.name))
}
}