lib/querytracer: put the version of VictoriaMetrics in the first message of query trace

This should simplify further debugging, since the first thing to start the debugging by query trace
is to know the version of VictoriaMetrics, which produced this trace.

docs/CHANGELOG.md

@@ -57,6 +57,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
 * FEATURE: [vmui](https://docs.victoriametrics.com/#vmui): provide fast path for hiding results for all the queries except the given one by clicking `eye` icon with `ctrl` key pressed. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3446).
 * FEATURE: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): add `range_trim_spikes(phi, q)` function for trimming `phi` percent of the largest spikes per each time series returned by `q`. See [these docs](https://docs.victoriametrics.com/MetricsQL.html#range_trim_spikes).
 * FEATURE: [vmgateway](https://docs.victoriametrics.com/vmgateway.html): add support for JWT token signature verification. See [these docs](https://docs.victoriametrics.com/vmgateway.html#jwt-signature-verification) for details.
+* FEATURE: put the version of VictoriaMetrics in the first message of [query trace](https://docs.victoriametrics.com/#query-tracing). This should simplify debugging.
 
 * BUGFIX: [vmalert](https://docs.victoriametrics.com/vmalert.html): properly pass HTTP headers during the alert state restore procedure. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3418).
 * BUGFIX: [vmalert](https://docs.victoriametrics.com/vmalert.html): properly specify rule evaluation step during the [replay mode](https://docs.victoriametrics.com/vmalert.html#rules-backfilling). The `step` value was previously overriden by `-datasource.queryStep` command-line flag.

lib/querytracer/tracer.go

@@ -8,6 +8,8 @@ import (
 	"io"
 	"strings"
 	"time"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/buildinfo"
 )
 
 var denyQueryTracing = flag.Bool("denyQueryTracing", false, "Whether to disable the ability to trace queries. See https://docs.victoriametrics.com/#query-tracing")
@@ -42,8 +44,10 @@ func New(enabled bool, format string, args ...interface{}) *Tracer {
 	if *denyQueryTracing || !enabled {
 		return nil
 	}
+	message := fmt.Sprintf(format, args...)
+	message = buildinfo.Version + ": " + message
 	return &Tracer{
-		message:   fmt.Sprintf(format, args...),
+		message:   message,
 		startTime: time.Now(),
 	}
 }