VictoriaMetrics/app/vmalert/notifier/alert.go
Roman Khavronenko 0157566fdb vmalert: cleanup and restructure of code to improve maintainability (#471)
The change introduces new entity `manager` which replaces
`watchdog`, decouples requestHandler and groups. Manager
supposed to control life cycle of groups, rules and
config reloads.

Groups export an ID method which returns a hash
from filename and group name. ID supposed to be unique
identifier across all loaded groups.

Some tests were added to improve coverage.

Bug with wrong annotation value if $value is used in
 templates after metrics being restored fixed.

Notifier interface was extended to accept context.

New set of metrics was introduced for config reload.
2020-05-11 14:35:55 +03:00

106 lines
2.7 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
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
}
const tplHeader = `{{ $value := .Value }}{{ $labels := .Labels }}`
// 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}
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 %s, template %s:%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
}