VictoriaMetrics/app/vmalert/notifier/alert.go
Roman Khavronenko 270552fde4
vmalert: Add recording rules support. (#519)
* vmalert: Add recording rules support.

Recording rules support required additional service refactoring since
it wasn't planned to support them from the very beginning. The list
of changes is following:
* new entity RecordingRule was added for writing results of MetricsQL
expressions into remote storage;
* interface Rule now unites both recording and alerting rules;
* configuration parser was moved to separate package and now performs
more strict validation;
* new endpoint for listing all groups and rules in json format was added;
* evaluation interval may be set to every particular group;

* vmalert: uncomment tests

* vmalert: rm outdated TODO

* vmalert: fix typos in README
2020-06-01 13:46:37 +03:00

107 lines
2.8 KiB
Go

package notifier
import (
"bytes"
"fmt"
"io"
"strings"
"text/template"
"time"
)
// Alert the triggered alert
// TODO: Looks like alert name isn't unique
type Alert struct {
GroupID uint64
Name string
Labels map[string]string
Annotations map[string]string
State AlertState
Expr string
Start time.Time
End time.Time
Value float64
ID uint64
}
// AlertState type indicates the Alert state
type AlertState int
const (
// StateInactive is the state of an alert that is neither firing nor pending.
StateInactive AlertState = iota
// StatePending is the state of an alert that has been active for less than
// the configured threshold duration.
StatePending
// StateFiring is the state of an alert that has been active for longer than
// the configured threshold duration.
StateFiring
)
// String stringer for AlertState
func (as AlertState) String() string {
switch as {
case StateFiring:
return "firing"
case StatePending:
return "pending"
}
return "inactive"
}
type alertTplData struct {
Labels map[string]string
Value float64
Expr string
}
const tplHeader = `{{ $value := .Value }}{{ $labels := .Labels }}{{ $expr := .Expr }}`
// ExecTemplate executes the Alert template for give
// map of annotations.
func (a *Alert) ExecTemplate(annotations map[string]string) (map[string]string, error) {
tplData := alertTplData{Value: a.Value, Labels: a.Labels, Expr: a.Expr}
return templateAnnotations(annotations, tplHeader, tplData)
}
// ValidateTemplates validate annotations for possible template error, uses empty data for template population
func ValidateTemplates(annotations map[string]string) error {
_, err := templateAnnotations(annotations, tplHeader, alertTplData{
Labels: map[string]string{},
Value: 0,
})
return err
}
func templateAnnotations(annotations map[string]string, header string, data alertTplData) (map[string]string, error) {
var builder strings.Builder
var buf bytes.Buffer
eg := errGroup{}
r := make(map[string]string, len(annotations))
for key, text := range annotations {
r[key] = text
buf.Reset()
builder.Reset()
builder.Grow(len(header) + len(text))
builder.WriteString(header)
builder.WriteString(text)
if err := templateAnnotation(&buf, builder.String(), data); err != nil {
eg.errs = append(eg.errs, fmt.Sprintf("key %q, template %q: %s", key, text, err))
continue
}
r[key] = buf.String()
}
return r, eg.err()
}
func templateAnnotation(dst io.Writer, text string, data alertTplData) error {
tpl, err := template.New("").Funcs(tmplFunc).Option("missingkey=zero").Parse(text)
if err != nil {
return fmt.Errorf("error parsing annotation: %w", err)
}
if err = tpl.Execute(dst, data); err != nil {
return fmt.Errorf("error evaluating annotation template: %w", err)
}
return nil
}