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cache.go
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cache.go
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package state
import (
"context"
"fmt"
"net/url"
"strings"
"sync"
"github.com/grafana/grafana-plugin-sdk-go/data"
"github.com/grafana/grafana/pkg/infra/log"
"github.com/grafana/grafana/pkg/services/ngalert/eval"
"github.com/grafana/grafana/pkg/services/ngalert/metrics"
ngModels "github.com/grafana/grafana/pkg/services/ngalert/models"
)
type cache struct {
states map[int64]map[string]map[string]*State // orgID > alertRuleUID > stateID > state
mtxStates sync.RWMutex
log log.Logger
metrics *metrics.State
externalURL *url.URL
}
func newCache(logger log.Logger, metrics *metrics.State, externalURL *url.URL) *cache {
return &cache{
states: make(map[int64]map[string]map[string]*State),
log: logger,
metrics: metrics,
externalURL: externalURL,
}
}
func (c *cache) getOrCreate(ctx context.Context, alertRule *ngModels.AlertRule, result eval.Result, extraLabels data.Labels) *State {
c.mtxStates.Lock()
defer c.mtxStates.Unlock()
ruleLabels, annotations := c.expandRuleLabelsAndAnnotations(ctx, alertRule, result, extraLabels)
lbs := make(data.Labels, len(extraLabels)+len(ruleLabels)+len(result.Instance))
dupes := make(data.Labels)
for key, val := range extraLabels {
lbs[key] = val
}
for key, val := range ruleLabels {
ruleVal, ok := lbs[key]
// if duplicate labels exist, reserved label will take precedence
if ok {
if ruleVal != val {
dupes[key] = val
}
} else {
lbs[key] = val
}
}
if len(dupes) > 0 {
c.log.Warn("Rule declares one or many reserved labels. Those rules labels will be ignored", "labels", dupes)
}
dupes = make(data.Labels)
for key, val := range result.Instance {
_, ok := lbs[key]
// if duplicate labels exist, reserved or alert rule label will take precedence
if ok {
dupes[key] = val
} else {
lbs[key] = val
}
}
if len(dupes) > 0 {
c.log.Warn("evaluation result contains either reserved labels or labels declared in the rules. Those labels from the result will be ignored", "labels", dupes)
}
il := ngModels.InstanceLabels(lbs)
id, err := il.StringKey()
if err != nil {
c.log.Error("error getting cacheId for entry", "err", err.Error())
}
if _, ok := c.states[alertRule.OrgID]; !ok {
c.states[alertRule.OrgID] = make(map[string]map[string]*State)
}
if _, ok := c.states[alertRule.OrgID][alertRule.UID]; !ok {
c.states[alertRule.OrgID][alertRule.UID] = make(map[string]*State)
}
if state, ok := c.states[alertRule.OrgID][alertRule.UID][id]; ok {
// Annotations can change over time, however we also want to maintain
// certain annotations across evaluations
for k, v := range state.Annotations {
if _, ok := ngModels.InternalAnnotationNameSet[k]; ok {
// If the annotation is not present then it should be copied from the
// previous state to the next state
if _, ok := annotations[k]; !ok {
annotations[k] = v
}
}
}
state.Annotations = annotations
c.states[alertRule.OrgID][alertRule.UID][id] = state
return state
}
// If the first result we get is alerting, set StartsAt to EvaluatedAt because we
// do not have data for determining StartsAt otherwise
newState := &State{
AlertRuleUID: alertRule.UID,
OrgID: alertRule.OrgID,
CacheId: id,
Labels: lbs,
Annotations: annotations,
EvaluationDuration: result.EvaluationDuration,
}
if result.State == eval.Alerting {
newState.StartsAt = result.EvaluatedAt
}
c.states[alertRule.OrgID][alertRule.UID][id] = newState
return newState
}
func (c *cache) expandRuleLabelsAndAnnotations(ctx context.Context, alertRule *ngModels.AlertRule, alertInstance eval.Result, extraLabels data.Labels) (data.Labels, data.Labels) {
// use labels from the result and extra labels to expand the labels and annotations declared by the rule
templateLabels := mergeLabels(extraLabels, alertInstance.Instance)
expand := func(original map[string]string) map[string]string {
expanded := make(map[string]string, len(original))
for k, v := range original {
ev, err := expandTemplate(ctx, alertRule.Title, v, templateLabels, alertInstance, c.externalURL)
expanded[k] = ev
if err != nil {
c.log.Error("error in expanding template", "name", k, "value", v, "err", err.Error())
// Store the original template on error.
expanded[k] = v
}
}
return expanded
}
return expand(alertRule.Labels), expand(alertRule.Annotations)
}
func (c *cache) set(entry *State) {
c.mtxStates.Lock()
defer c.mtxStates.Unlock()
if _, ok := c.states[entry.OrgID]; !ok {
c.states[entry.OrgID] = make(map[string]map[string]*State)
}
if _, ok := c.states[entry.OrgID][entry.AlertRuleUID]; !ok {
c.states[entry.OrgID][entry.AlertRuleUID] = make(map[string]*State)
}
c.states[entry.OrgID][entry.AlertRuleUID][entry.CacheId] = entry
}
func (c *cache) get(orgID int64, alertRuleUID, stateId string) (*State, error) {
c.mtxStates.RLock()
defer c.mtxStates.RUnlock()
if state, ok := c.states[orgID][alertRuleUID][stateId]; ok {
return state, nil
}
return nil, fmt.Errorf("no entry for %s:%s was found", alertRuleUID, stateId)
}
func (c *cache) getAll(orgID int64) []*State {
var states []*State
c.mtxStates.RLock()
defer c.mtxStates.RUnlock()
for _, v1 := range c.states[orgID] {
for _, v2 := range v1 {
states = append(states, v2)
}
}
return states
}
func (c *cache) getStatesForRuleUID(orgID int64, alertRuleUID string) []*State {
var ruleStates []*State
c.mtxStates.RLock()
defer c.mtxStates.RUnlock()
for _, state := range c.states[orgID][alertRuleUID] {
ruleStates = append(ruleStates, state)
}
return ruleStates
}
// removeByRuleUID deletes all entries in the state cache that match the given UID.
func (c *cache) removeByRuleUID(orgID int64, uid string) {
c.mtxStates.Lock()
defer c.mtxStates.Unlock()
delete(c.states[orgID], uid)
}
func (c *cache) reset() {
c.mtxStates.Lock()
defer c.mtxStates.Unlock()
c.states = make(map[int64]map[string]map[string]*State)
}
func (c *cache) recordMetrics() {
c.mtxStates.RLock()
defer c.mtxStates.RUnlock()
// Set default values to zero such that gauges are reset
// after all values from a single state disappear.
ct := map[eval.State]int{
eval.Normal: 0,
eval.Alerting: 0,
eval.Pending: 0,
eval.NoData: 0,
eval.Error: 0,
}
for org, orgMap := range c.states {
c.metrics.GroupRules.WithLabelValues(fmt.Sprint(org)).Set(float64(len(orgMap)))
for _, rule := range orgMap {
for _, state := range rule {
n := ct[state.State]
ct[state.State] = n + 1
}
}
}
for k, n := range ct {
c.metrics.AlertState.WithLabelValues(strings.ToLower(k.String())).Set(float64(n))
}
}
// if duplicate labels exist, keep the value from the first set
func mergeLabels(a, b data.Labels) data.Labels {
newLbs := make(data.Labels, len(a)+len(b))
for k, v := range a {
newLbs[k] = v
}
for k, v := range b {
if _, ok := newLbs[k]; !ok {
newLbs[k] = v
}
}
return newLbs
}
func (c *cache) deleteEntry(orgID int64, alertRuleUID, cacheID string) {
c.mtxStates.Lock()
defer c.mtxStates.Unlock()
delete(c.states[orgID][alertRuleUID], cacheID)
}