prometheus/rules/manager.go
Bryan Boreham 70e2d23027
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Merge pull request #11474 from clwluvw/group-label
[FEATURE] rules: add labels at group level
2024-10-21 14:47:12 +01:00

523 lines
15 KiB
Go

// 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"
"log/slog"
"net/url"
"slices"
"strings"
"sync"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/promslog"
"golang.org/x/sync/semaphore"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/model/rulefmt"
"github.com/prometheus/prometheus/notifier"
"github.com/prometheus/prometheus/promql"
"github.com/prometheus/prometheus/promql/parser"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/util/strutil"
)
// 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.QueryEngine, q storage.Queryable) QueryFunc {
return func(ctx context.Context, qs string, t time.Time) (promql.Vector, error) {
q, err := engine.NewInstantQuery(ctx, q, nil, 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{
T: v.T,
F: v.V,
Metric: labels.Labels{},
}}, nil
default:
return nil, errors.New("rule result is not a vector or scalar")
}
}
}
// DefaultEvalIterationFunc is the default implementation of
// GroupEvalIterationFunc that is periodically invoked to evaluate the rules
// in a group at a given point in time and updates Group state and metrics
// accordingly. Custom GroupEvalIterationFunc implementations are recommended
// to invoke this function as well, to ensure correct Group state and metrics
// are maintained.
func DefaultEvalIterationFunc(ctx context.Context, g *Group, evalTimestamp time.Time) {
g.metrics.IterationsScheduled.WithLabelValues(GroupKey(g.file, g.name)).Inc()
start := time.Now()
g.Eval(ctx, evalTimestamp)
timeSinceStart := time.Since(start)
g.metrics.IterationDuration.Observe(timeSinceStart.Seconds())
g.setEvaluationTime(timeSinceStart)
g.setLastEvaluation(start)
g.setLastEvalTimestamp(evalTimestamp)
}
// The Manager manages recording and alerting rules.
type Manager struct {
opts *ManagerOptions
groups map[string]*Group
mtx sync.RWMutex
block chan struct{}
done chan struct{}
restored bool
logger *slog.Logger
}
// 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 storage.Appendable
Queryable storage.Queryable
Logger *slog.Logger
Registerer prometheus.Registerer
OutageTolerance time.Duration
ForGracePeriod time.Duration
ResendDelay time.Duration
GroupLoader GroupLoader
DefaultRuleQueryOffset func() time.Duration
MaxConcurrentEvals int64
ConcurrentEvalsEnabled bool
RuleConcurrencyController RuleConcurrencyController
RuleDependencyController RuleDependencyController
Metrics *Metrics
}
// NewManager returns an implementation of Manager, ready to be started
// by calling the Run method.
func NewManager(o *ManagerOptions) *Manager {
if o.Metrics == nil {
o.Metrics = NewGroupMetrics(o.Registerer)
}
if o.GroupLoader == nil {
o.GroupLoader = FileLoader{}
}
if o.RuleConcurrencyController == nil {
if o.ConcurrentEvalsEnabled {
o.RuleConcurrencyController = newRuleConcurrencyController(o.MaxConcurrentEvals)
} else {
o.RuleConcurrencyController = sequentialRuleEvalController{}
}
}
if o.RuleDependencyController == nil {
o.RuleDependencyController = ruleDependencyController{}
}
if o.Logger == nil {
o.Logger = promslog.NewNopLogger()
}
m := &Manager{
groups: map[string]*Group{},
opts: o,
block: make(chan struct{}),
done: make(chan struct{}),
logger: o.Logger,
}
return m
}
// Run starts processing of the rule manager. It is blocking.
func (m *Manager) Run() {
m.logger.Info("Starting rule manager...")
m.start()
<-m.done
}
func (m *Manager) start() {
close(m.block)
}
// Stop the rule manager's rule evaluation cycles.
func (m *Manager) Stop() {
m.mtx.Lock()
defer m.mtx.Unlock()
m.logger.Info("Stopping rule manager...")
for _, eg := range m.groups {
eg.stop()
}
// Shut down the groups waiting multiple evaluation intervals to write
// staleness markers.
close(m.done)
m.logger.Info("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.
// This method will no-op in case the manager is already stopped.
func (m *Manager) Update(interval time.Duration, files []string, externalLabels labels.Labels, externalURL string, groupEvalIterationFunc GroupEvalIterationFunc) error {
m.mtx.Lock()
defer m.mtx.Unlock()
// We cannot update a stopped manager
select {
case <-m.done:
return nil
default:
}
groups, errs := m.LoadGroups(interval, externalLabels, externalURL, groupEvalIterationFunc, files...)
if errs != nil {
for _, e := range errs {
m.logger.Error("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 {
// If there is an old group with the same identifier,
// check if new group equals with the old group, if yes then skip it.
// If not equals, stop it and wait for it to finish the current iteration.
// Then copy it into the new group.
gn := GroupKey(newg.file, newg.name)
oldg, ok := m.groups[gn]
delete(m.groups, gn)
if ok && oldg.Equals(newg) {
groups[gn] = oldg
continue
}
wg.Add(1)
go func(newg *Group) {
if ok {
oldg.stop()
newg.CopyState(oldg)
}
wg.Done()
// 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)
}(newg)
}
// Stop remaining old groups.
wg.Add(len(m.groups))
for n, oldg := range m.groups {
go func(n string, g *Group) {
g.markStale = true
g.stop()
if m := g.metrics; m != nil {
m.IterationsMissed.DeleteLabelValues(n)
m.IterationsScheduled.DeleteLabelValues(n)
m.EvalTotal.DeleteLabelValues(n)
m.EvalFailures.DeleteLabelValues(n)
m.GroupInterval.DeleteLabelValues(n)
m.GroupLastEvalTime.DeleteLabelValues(n)
m.GroupLastDuration.DeleteLabelValues(n)
m.GroupRules.DeleteLabelValues(n)
m.GroupSamples.DeleteLabelValues((n))
}
wg.Done()
}(n, oldg)
}
wg.Wait()
m.groups = groups
return nil
}
// GroupLoader is responsible for loading rule groups from arbitrary sources and parsing them.
type GroupLoader interface {
Load(identifier string) (*rulefmt.RuleGroups, []error)
Parse(query string) (parser.Expr, error)
}
// FileLoader is the default GroupLoader implementation. It defers to rulefmt.ParseFile
// and parser.ParseExpr.
type FileLoader struct{}
func (FileLoader) Load(identifier string) (*rulefmt.RuleGroups, []error) {
return rulefmt.ParseFile(identifier)
}
func (FileLoader) Parse(query string) (parser.Expr, error) { return parser.ParseExpr(query) }
// LoadGroups reads groups from a list of files.
func (m *Manager) LoadGroups(
interval time.Duration, externalLabels labels.Labels, externalURL string, groupEvalIterationFunc GroupEvalIterationFunc, filenames ...string,
) (map[string]*Group, []error) {
groups := make(map[string]*Group)
shouldRestore := !m.restored
for _, fn := range filenames {
rgs, errs := m.opts.GroupLoader.Load(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 := m.opts.GroupLoader.Parse(r.Expr.Value)
if err != nil {
return nil, []error{fmt.Errorf("%s: %w", fn, err)}
}
mLabels := FromMaps(rg.Labels, r.Labels)
if r.Alert.Value != "" {
rules = append(rules, NewAlertingRule(
r.Alert.Value,
expr,
time.Duration(r.For),
time.Duration(r.KeepFiringFor),
mLabels,
labels.FromMap(r.Annotations),
externalLabels,
externalURL,
m.restored,
m.logger.With("alert", r.Alert),
))
continue
}
rules = append(rules, NewRecordingRule(
r.Record.Value,
expr,
mLabels,
))
}
// Check dependencies between rules and store it on the Rule itself.
m.opts.RuleDependencyController.AnalyseRules(rules)
groups[GroupKey(fn, rg.Name)] = NewGroup(GroupOptions{
Name: rg.Name,
File: fn,
Interval: itv,
Limit: rg.Limit,
Rules: rules,
ShouldRestore: shouldRestore,
Opts: m.opts,
QueryOffset: (*time.Duration)(rg.QueryOffset),
done: m.done,
EvalIterationFunc: groupEvalIterationFunc,
})
}
}
return groups, nil
}
// 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)
}
slices.SortFunc(rgs, func(a, b *Group) int {
fileCompare := strings.Compare(a.file, b.file)
// If its 0, then the file names are the same.
// Lets look at the group names in that case.
if fileCompare != 0 {
return fileCompare
}
return strings.Compare(a.name, b.name)
})
return rgs
}
// Rules returns the list of the manager's rules.
func (m *Manager) Rules(matcherSets ...[]*labels.Matcher) []Rule {
m.mtx.RLock()
defer m.mtx.RUnlock()
var rules []Rule
for _, g := range m.groups {
rules = append(rules, g.Rules(matcherSets...)...)
}
return rules
}
// AlertingRules returns the list of the manager's alerting rules.
func (m *Manager) AlertingRules() []*AlertingRule {
alerts := []*AlertingRule{}
for _, rule := range m.Rules() {
if alertingRule, ok := rule.(*AlertingRule); ok {
alerts = append(alerts, alertingRule)
}
}
return alerts
}
type Sender interface {
Send(alerts ...*notifier.Alert)
}
// SendAlerts implements the rules.NotifyFunc for a Notifier.
func SendAlerts(s Sender, externalURL string) NotifyFunc {
return func(ctx context.Context, expr string, alerts ...*Alert) {
var res []*notifier.Alert
for _, alert := range alerts {
a := &notifier.Alert{
StartsAt: alert.FiredAt,
Labels: alert.Labels,
Annotations: alert.Annotations,
GeneratorURL: externalURL + strutil.TableLinkForExpression(expr),
}
if !alert.ResolvedAt.IsZero() {
a.EndsAt = alert.ResolvedAt
} else {
a.EndsAt = alert.ValidUntil
}
res = append(res, a)
}
if len(alerts) > 0 {
s.Send(res...)
}
}
}
// RuleDependencyController controls whether a set of rules have dependencies between each other.
type RuleDependencyController interface {
// AnalyseRules analyses dependencies between the input rules. For each rule that it's guaranteed
// not having any dependants and/or dependency, this function should call Rule.SetNoDependentRules(true)
// and/or Rule.SetNoDependencyRules(true).
AnalyseRules(rules []Rule)
}
type ruleDependencyController struct{}
// AnalyseRules implements RuleDependencyController.
func (c ruleDependencyController) AnalyseRules(rules []Rule) {
depMap := buildDependencyMap(rules)
for _, r := range rules {
r.SetNoDependentRules(depMap.dependents(r) == 0)
r.SetNoDependencyRules(depMap.dependencies(r) == 0)
}
}
// RuleConcurrencyController controls concurrency for rules that are safe to be evaluated concurrently.
// Its purpose is to bound the amount of concurrency in rule evaluations to avoid overwhelming the Prometheus
// server with additional query load. Concurrency is controlled globally, not on a per-group basis.
type RuleConcurrencyController interface {
// Allow determines if the given rule is allowed to be evaluated concurrently.
// If Allow() returns true, then Done() must be called to release the acquired slot and corresponding cleanup is done.
// It is important that both *Group and Rule are not retained and only be used for the duration of the call.
Allow(ctx context.Context, group *Group, rule Rule) bool
// Done releases a concurrent evaluation slot.
Done(ctx context.Context)
}
// concurrentRuleEvalController holds a weighted semaphore which controls the concurrent evaluation of rules.
type concurrentRuleEvalController struct {
sema *semaphore.Weighted
}
func newRuleConcurrencyController(maxConcurrency int64) RuleConcurrencyController {
return &concurrentRuleEvalController{
sema: semaphore.NewWeighted(maxConcurrency),
}
}
func (c *concurrentRuleEvalController) Allow(_ context.Context, _ *Group, rule Rule) bool {
// To allow a rule to be executed concurrently, we need 3 conditions:
// 1. The rule must not have any rules that depend on it.
// 2. The rule itself must not depend on any other rules.
// 3. If 1 & 2 are true, then and only then we should try to acquire the concurrency slot.
if rule.NoDependentRules() && rule.NoDependencyRules() {
return c.sema.TryAcquire(1)
}
return false
}
func (c *concurrentRuleEvalController) Done(_ context.Context) {
c.sema.Release(1)
}
// sequentialRuleEvalController is a RuleConcurrencyController that runs every rule sequentially.
type sequentialRuleEvalController struct{}
func (c sequentialRuleEvalController) Allow(_ context.Context, _ *Group, _ Rule) bool {
return false
}
func (c sequentialRuleEvalController) Done(_ context.Context) {}
// FromMaps returns new sorted Labels from the given maps, overriding each other in order.
func FromMaps(maps ...map[string]string) labels.Labels {
mLables := make(map[string]string)
for _, m := range maps {
for k, v := range m {
mLables[k] = v
}
}
return labels.FromMap(mLables)
}