- Lightweight. Has minimal number of third-party dependencies and all these deps are small. See this article for details.
- Easy to use. See the API docs.
- Fast.
- Allows exporting distinct metric sets via distinct endpoints. See Set.
- Supports easy-to-use histograms, which just work without any tuning. Read more about VictoriaMetrics histograms at this article.
- Can push metrics to VictoriaMetrics or to any other remote storage, which accepts metrics in Prometheus text exposition format. See these docs.
- It doesn't implement advanced functionality from github.com/prometheus/client_golang.
import "github.com/VictoriaMetrics/metrics"
// Register various metrics.
// Metric name may contain labels in Prometheus format - see below.
var (
// Register counter without labels.
requestsTotal = metrics.NewCounter("requests_total")
// Register summary with a single label.
requestDuration = metrics.NewSummary(`requests_duration_seconds{path="/foobar/baz"}`)
// Register gauge with two labels.
queueSize = metrics.NewGauge(`queue_size{queue="foobar",topic="baz"}`, func() float64 {
return float64(foobarQueue.Len())
})
// Register histogram with a single label.
responseSize = metrics.NewHistogram(`response_size{path="/foo/bar"}`)
)
// ...
func requestHandler() {
// Increment requestTotal counter.
requestsTotal.Inc()
startTime := time.Now()
processRequest()
// Update requestDuration summary.
requestDuration.UpdateDuration(startTime)
// Update responseSize histogram.
responseSize.Update(responseSize)
}
// Expose the registered metrics at `/metrics` path.
http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
metrics.WritePrometheus(w, true)
})
// ... or push registered metrics every 10 seconds to http://victoria-metrics:8428/api/v1/import/prometheus
// with the added `instance="foobar"` label to all the pushed metrics.
metrics.InitPush("http://victoria-metrics:8428/api/v1/import/prometheus", 10*time.Second, `instance="foobar"`, true)
See docs for more info.
Metrics
has been extracted from VictoriaMetrics sources. See this article for more info aboutVictoriaMetrics
.
Because the github.com/prometheus/client_golang
is too complex and is hard to use.
How to implement CounterVec in metrics
?
Just use GetOrCreateCounter
instead of CounterVec.With
. See this example for details.
Why Histogram buckets contain vmrange
labels instead of le
labels like in Prometheus histograms?
Buckets with vmrange
labels occupy less disk space compared to Promethes-style buckets with le
labels,
because vmrange
buckets don't include counters for the previous ranges. VictoriaMetrics provides prometheus_buckets
function, which converts vmrange
buckets to Prometheus-style buckets with le
labels. This is useful for building heatmaps in Grafana.
Additionally, its' histogram_quantile
function transparently handles histogram buckets with vmrange
labels.