VictoriaMetrics/app/vmalert/datasource/datasource.go
Roman Khavronenko 9f578e389c vmalert: add function "query", "first" and "value" to alert templates functions (#960)
The commit adds a support for template function `query`,
`first` and `value`. The function `query` executes
a MetricsQL query for active alerts. In vmalert we
update templates on every evaluation for active alerts
to keep them up to date. With `query` func it may become
a perf issue since it will fire a query on every execution.
We should keep it in mind for now.

https://github.com/VictoriaMetrics/VictoriaMetrics/issues/539
2020-12-14 20:12:16 +02:00

52 lines
1.1 KiB
Go

package datasource
import "context"
// Querier interface wraps Query method which
// executes given query and returns list of Metrics
// as result
type Querier interface {
Query(ctx context.Context, query string) ([]Metric, error)
}
// Metric is the basic entity which should be return by datasource
// It represents single data point with full list of labels
type Metric struct {
Labels []Label
Timestamp int64
Value float64
}
// SetLabel adds or updates existing one label
// by the given key and label
func (m *Metric) SetLabel(key, value string) {
for i, l := range m.Labels {
if l.Name == key {
m.Labels[i].Value = value
return
}
}
m.AddLabel(key, value)
}
// AddLabel appends the given label to the label set
func (m *Metric) AddLabel(key, value string) {
m.Labels = append(m.Labels, Label{Name: key, Value: value})
}
// Label returns the given label value.
// If label is missing empty string will be returned
func (m *Metric) Label(key string) string {
for _, l := range m.Labels {
if l.Name == key {
return l.Value
}
}
return ""
}
// Label represents metric's label
type Label struct {
Name string
Value string
}