FEATURE: Output memory statistics (--full)

commands/ppreviewPush.go

@@ -8,11 +8,13 @@ import (
 	"fmt"
 	"os"
 	"regexp"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
+	"unsafe"
 
 	"github.com/StackExchange/dnscontrol/v4/models"
 	"github.com/StackExchange/dnscontrol/v4/pkg/bindserial"
@@ -25,6 +27,7 @@ import (
 	"github.com/StackExchange/dnscontrol/v4/pkg/providers"
 	"github.com/StackExchange/dnscontrol/v4/pkg/rfc4183"
 	"github.com/StackExchange/dnscontrol/v4/pkg/zonerecs"
+	"github.com/dustin/go-humanize"
 	"github.com/nozzle/throttler"
 	"github.com/urfave/cli/v3"
 	"golang.org/x/exp/slices"
@@ -409,8 +412,10 @@ func prun(args PPreviewArgs, push bool, interactive bool, out printer.CLI, repor
 		fmt.Fprintf(os.Stderr, "##teamcity[buildStatus status='SUCCESS' text='%d corrections']", totalCorrections)
 	}
 	rfc4183.PrintWarning()
+	out.PrintfIf(fullMode, "Inaccurate statistics: %s\n", stats(cfg))
 	notifier.Done()
 	out.Printf("Done. %d corrections.\n", totalCorrections)
+
 	err = writeReport(report, reportItems)
 	if err != nil {
 		return errors.New("could not write report")
@@ -424,6 +429,56 @@ func prun(args PPreviewArgs, push bool, interactive bool, out printer.CLI, repor
 	return nil
 }
 
+// stats returns a JSON string with memory usage statistics.
+// These stats are unofficial and subject to change without notice.
+// "average_mem_per_record" is misleading because it includes all memory overhead.
+func stats(cfg *models.DNSConfig) string {
+
+	// https://www.datadoghq.com/blog/go-memory-metrics/
+	// [T]he following expression accurately reflects the value the runtime attempts to maintain as the limit:
+	// runtime.MemStats.Sys − runtime.MemStats.HeapReleased
+	runtime.GC()
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+	memoryInUse := m.Sys - m.HeapReleased
+
+	numRecords := countRecords(cfg)
+	memPerRecord := int64(float64(memoryInUse) / float64(max(1, numRecords)))
+	memPerRecordStr := humanize.IBytes(uint64(memPerRecord)) + " bytes"
+
+	statsInfo := struct {
+		MemoryInUse    uint64 `json:"memory_in_use"`
+		MemoryInUseStr string `json:"memory_in_use_str"`
+		NumRecords     int    `json:"num_records"`
+		NumZones       int    `json:"num_zones"`
+		RCSize         int    `json:"rc_size"`
+		Benchmark1     int64  `json:"benchmark1"`
+		Benchmark1Str  string `json:"benchmark1str"`
+	}{
+		MemoryInUse:    memoryInUse,
+		MemoryInUseStr: humanize.Bytes(memoryInUse),
+		NumRecords:     numRecords,
+		NumZones:       len(cfg.Domains),
+		RCSize:         int(unsafe.Sizeof((models.RecordConfig{}))),
+		Benchmark1:     memPerRecord,
+		Benchmark1Str:  memPerRecordStr,
+	}
+
+	jsonBytes, err := json.Marshal(statsInfo)
+	if err != nil {
+		return fmt.Sprintf("error marshaling stats: %v", err)
+	}
+	return string(jsonBytes)
+}
+
+func countRecords(cfg *models.DNSConfig) int {
+	total := 0
+	for _, domain := range cfg.Domains {
+		total += len(domain.Records)
+	}
+	return total
+}
+
 // whichZonesToProcess takes a list of DomainConfigs and a filter string and
 // returns a list of DomainConfigs whose Domain.UniqueName matched the
 // filter. The filter string is a comma-separated list of domain names. If the

go.mod

@@ -62,6 +62,7 @@ require (
 	github.com/aliyun/alibaba-cloud-sdk-go v1.63.107
 	github.com/aws/aws-sdk-go-v2/service/sts v1.41.6
 	github.com/centralnicgroup-opensource/rtldev-middleware-go-sdk/v5 v5.0.18
+	github.com/dustin/go-humanize v1.0.1
 	github.com/failsafe-go/failsafe-go v0.9.5
 	github.com/fatih/color v1.18.0
 	github.com/fbiville/markdown-table-formatter v0.3.0

go.sum

@@ -126,6 +126,8 @@ github.com/ditashi/jsbeautifier-go v0.0.0-20141206144643-2520a8026a9c h1:+Zo5Ca9
 github.com/ditashi/jsbeautifier-go v0.0.0-20141206144643-2520a8026a9c/go.mod h1:HJGU9ULdREjOcVGZVPB5s6zYmHi1RxzT71l2wQyLmnE=
 github.com/dnsimple/dnsimple-go v1.7.0 h1:JKu9xJtZ3SqOC+BuYgAWeab7+EEx0sz422vu8j611ZY=
 github.com/dnsimple/dnsimple-go v1.7.0/go.mod h1:EKpuihlWizqYafSnQHGCd/gyvy3HkEQJ7ODB4KdV8T8=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=