feat: add the show-stats flag

When this flag is used, the plugin writes another table for
each namespace that contains various statistics measurements
about resource requests and VPA recommendations.

Author: wI2L

.codecov.yml

@@ -4,7 +4,7 @@ coverage:
     # Prevent small variations of coverage from failing CI.
     project:
       default:
-        threshold: 1%
+        threshold: 10% # TODO: reduce once we have a better coverage
     patch: off
 ignore:
-  - internal/version
+  - internal/version

cli/command.go

@@ -215,7 +215,7 @@ func (co *CommandOptions) Execute() error {
 }
 
 // bindRecommendationsAndRequests returns a table that bind the
-// recommendations of the VPA in the list to the actual resource
+// recommendation of the VPA(s) in the list to the actual resource
 // requests of their target controller's pods.
 func (co *CommandOptions) bindRecommendationsAndRequests(list []*vpav1.VerticalPodAutoscaler) table {
 	var table table

cli/flags.go

@@ -18,6 +18,7 @@ const (
 	flagShowKindShorthand       = "k"
 	flagShowContainers          = "show-containers"
 	flagShowContainersShorthand = "c"
+	flagShowStats               = "show-stats"
 	flagNoColors                = "no-colors"
 	flagNoHeaders               = "no-headers"
 	flagSortOrder               = "sort-order"
@@ -48,6 +49,7 @@ type Flags struct {
 	ShowNamespace      bool
 	ShowKind           bool
 	ShowContainers     bool
+	ShowStats          bool
 	NoColors           bool
 	NoHeaders          bool
 	SortOrder          sortOrder
@@ -108,6 +110,9 @@ func (f *Flags) AddFlags(flags *pflag.FlagSet) {
 
 	flags.Var(&f.RecommendationType, flagRecommendationType,
 		fmt.Sprintf("The type of recommendation to use in comparisons. One of: %s", strings.Join(recommendationTypeFlagValues(), ", ")))
+
+	flags.BoolVar(&f.ShowStats, flagShowStats, f.ShowStats,
+		"Show statistics about all VPA recommendations and requests")
 }
 
 // Tidy post-processes the flags.

cli/table.go

@@ -4,11 +4,14 @@ import (
 	"fmt"
 	"io"
 	"math"
+	"os"
 	"sort"
 	"strings"
 
+	"github.com/dustin/go-humanize"
 	"github.com/muesli/termenv"
 	"github.com/olekukonko/tablewriter"
+	"gopkg.in/inf.v0"
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 
@@ -141,8 +144,7 @@ const (
 
 // Print writes the table to w.
 func (t table) Print(w io.Writer, flags *Flags) error {
-	tw := tablewriter.NewWriter(w)
-	setKubectlTableFormat(tw)
+	tw := newKubectlTableWriter(w)
 
 	if !flags.NoHeaders {
 		var headers []string
@@ -168,23 +170,140 @@ func (t table) Print(w io.Writer, flags *Flags) error {
 	}
 	tw.Render()
 
+	if flags.ShowStats {
+		_, err := os.Stdout.WriteString("\n")
+		if err != nil {
+			return err
+		}
+		return t.printStats(w)
+	}
 	return nil
 }
 
-// setKubectlTableFormat configures the given writer
-// to print according to the Kubectl output format.
-func setKubectlTableFormat(t *tablewriter.Table) {
-	t.SetAutoWrapText(false)
-	t.SetAutoFormatHeaders(true)
-	t.SetNoWhiteSpace(true)
-	t.SetHeaderLine(false)
-	t.SetHeaderAlignment(tablewriter.ALIGN_LEFT)
-	t.SetAlignment(tablewriter.ALIGN_LEFT)
-	t.SetCenterSeparator("")
-	t.SetColumnSeparator("")
-	t.SetRowSeparator("")
-	t.SetTablePadding("   ")
-	t.SetBorder(false)
+type tableStatFn func(column func(i int) *resource.Quantity) *resource.Quantity
+
+func (t table) printStats(w io.Writer) error {
+	tw := newKubectlTableWriter(w)
+
+	statFuncs := []tableStatFn{
+		t.sumQuantities,
+		t.meanQuantities,
+		t.medianQuantities,
+	}
+	rows := []struct {
+		name    string
+		getter  func(i int) *resource.Quantity
+		asBytes bool
+	}{
+		{"CPU Recommendations (# cores)", func(i int) *resource.Quantity { return t[i].Recommendations.CPU }, false},
+		{"CPU Requests (# cores)", func(i int) *resource.Quantity { return t[i].Requests.CPU }, false},
+		{"MEM Recommendations (IEC/SI)", func(i int) *resource.Quantity { return t[i].Recommendations.Memory }, true},
+		{"MEM Requests (IEC/SI)", func(i int) *resource.Quantity { return t[i].Requests.Memory }, true},
+	}
+	for _, row := range rows {
+		values := make([]string, 0, len(statFuncs))
+		for _, fn := range statFuncs {
+			q := fn(row.getter)
+
+			var str string
+			if q == nil {
+				str = tableUnsetCell
+			} else {
+				if row.asBytes {
+					tmp := inf.Dec{}
+					tmp.Round(q.AsDec(), 0, inf.RoundUp)
+					big := tmp.UnscaledBig()
+					str = humanize.BigIBytes(big) + "/" + humanize.BigBytes(big)
+					str = strings.ReplaceAll(str, " ", "")
+				} else {
+					str = q.AsDec().String()
+				}
+			}
+			values = append(values, str)
+		}
+		tw.Append(append([]string{row.name}, values...))
+	}
+	tw.SetHeader([]string{"Description", "Total", "Mean", "Median"})
+	tw.Render()
+
+	return nil
+}
+
+func (t table) sumQuantities(column func(i int) *resource.Quantity) *resource.Quantity {
+	var sum resource.Quantity
+	for i := range t {
+		v := column(i)
+		if v != nil {
+			sum.Add(*v)
+		}
+	}
+	return &sum
+}
+
+func (t table) meanQuantities(column func(i int) *resource.Quantity) *resource.Quantity {
+	sum := t.sumQuantities(column)
+	dec := sum.AsDec()
+	tmp := inf.Dec{}
+	tmp.QuoRound(dec, inf.NewDec(int64(len(t)), 0), dec.Scale(), inf.RoundDown)
+
+	return resource.NewDecimalQuantity(tmp, resource.DecimalSI)
+}
+
+func (t table) medianQuantities(column func(i int) *resource.Quantity) *resource.Quantity {
+	var values []*resource.Quantity
+
+	// Collect all values and sort them.
+	for i := range t {
+		v := column(i)
+		if v != nil {
+			values = append(values, v)
+		}
+	}
+	sort.Slice(values, func(i, j int) bool {
+		b := compareQuantities(values[i], values[j])
+		switch b {
+		case -1:
+			return true
+		default:
+			return false
+		}
+	})
+	// No math is needed if there are no numbers.
+	// For even numbers we add the two middle values
+	// and divide by two.
+	// For odd numbers we just use the middle value.
+	l := len(values)
+	if l == 0 {
+		return nil
+	} else if l%2 == 0 {
+		q := values[l/2-1]
+		q.Add(*(values[l/2+1]))
+		tmp := inf.Dec{}
+		tmp.QuoRound(q.AsDec(), inf.NewDec(2, 0), 0, inf.RoundDown)
+
+		return resource.NewDecimalQuantity(tmp, resource.DecimalSI)
+	}
+	return values[l/2]
+}
+
+// newKubectlTableWriter returns a new table writer that writes
+// to w and print according to the Kubectl output format.
+func newKubectlTableWriter(w io.Writer) *tablewriter.Table {
+	tw := tablewriter.NewWriter(w)
+
+	tw.SetAutoWrapText(false)
+	tw.SetAutoFormatHeaders(true)
+	tw.SetNoWhiteSpace(true)
+	tw.SetHeaderLine(false)
+	tw.SetHeaderAlignment(tablewriter.ALIGN_LEFT)
+	tw.SetAlignment(tablewriter.ALIGN_LEFT)
+	tw.SetCenterSeparator("")
+	tw.SetColumnSeparator("")
+	tw.SetRowSeparator("")
+	tw.SetTablePadding("   ")
+	tw.SetBorder(false)
+
+	return tw
 }
 
 // multiTableSorter implements the sort.Sort interface

go.mod

@@ -3,6 +3,7 @@ module github.com/wI2L/kubectl-vpa-recommendation
 go 1.17
 
 require (
+	github.com/dustin/go-humanize v1.0.0
 	github.com/muesli/termenv v0.9.0
 	github.com/olekukonko/tablewriter v0.0.5
 	github.com/spf13/cobra v1.3.0

go.sum

@@ -151,6 +151,8 @@ github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8
 github.com/docker/distribution v2.7.1+incompatible/go.mod h1:J2gT2udsDAN96Uj4KfcMRqY0/ypR+oyYUYmja8H+y+w=
 github.com/docker/spdystream v0.0.0-20160310174837-449fdfce4d96/go.mod h1:Qh8CwZgvJUkLughtfhJv5dyTYa91l1fOUCrgjqmcifM=
 github.com/docopt/docopt-go v0.0.0-20180111231733-ee0de3bc6815/go.mod h1:WwZ+bS3ebgob9U8Nd0kOddGdZWjyMGR8Wziv+TBNwSE=
+github.com/dustin/go-humanize v1.0.0 h1:VSnTsYCnlFHaM2/igO1h6X3HA71jcobQuxemgkq4zYo=
+github.com/dustin/go-humanize v1.0.0/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
 github.com/elazarl/goproxy v0.0.0-20180725130230-947c36da3153 h1:yUdfgN0XgIJw7foRItutHYUIhlcKzcSf5vDpdhQAKTc=
 github.com/elazarl/goproxy v0.0.0-20180725130230-947c36da3153/go.mod h1:/Zj4wYkgs4iZTTu3o/KG3Itv/qCCa8VVMlb3i9OVuzc=
 github.com/emicklei/go-restful v0.0.0-20170410110728-ff4f55a20633/go.mod h1:otzb+WCGbkyDHkqmQmT5YD2WR4BBwUdeQoFo8l/7tVs=