“go mod graph” を視覚化する

$ go mod graph
github.com/spiegel-im-spiegel/gpgpdump github.com/BurntSushi/toml@v0.3.1
github.com/spiegel-im-spiegel/gpgpdump github.com/inconshreveable/mousetrap@v1.0.0
github.com/spiegel-im-spiegel/gpgpdump github.com/pkg/errors@v0.8.1
github.com/spiegel-im-spiegel/gpgpdump github.com/spf13/cobra@v0.0.3
github.com/spiegel-im-spiegel/gpgpdump github.com/spf13/pflag@v1.0.3
github.com/spiegel-im-spiegel/gpgpdump github.com/spiegel-im-spiegel/gocli@v0.9.1
github.com/spiegel-im-spiegel/gpgpdump golang.org/x/crypto@v0.0.0-20190208162236-193df9c0f06f
github.com/spiegel-im-spiegel/gocli@v0.9.1 github.com/mattn/go-isatty@v0.0.4

package main

import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

var mapPackage = map[string]string{}

type pair struct {
	left  string
	right string
}

var graph = []pair{}

func split(text string, count int) int {
	ss := strings.Split(text, " ")
	for _, s := range ss {
		if _, ok := mapPackage[s]; !ok {
			count++
			mapPackage[s] = fmt.Sprintf("P%d", count)
		}
	}
	p := pair{left: mapPackage[ss[0]], right: mapPackage[ss[1]]}
	graph = append(graph, p)
	return count
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	count := 0
	for scanner.Scan() {
		count = split(scanner.Text(), count)
	}
	if err := scanner.Err(); err != nil {
		fmt.Fprintln(os.Stderr, err)
		return
	}

	fmt.Println("@startuml")
	fmt.Println("hide circle")
	fmt.Println("hide empty members")
	for k, v := range mapPackage {
		fmt.Printf("class \"%v\" as %v\n", strings.Replace(k, "@", "\\n", -1), v)
	}
	for _, p := range graph {
		fmt.Printf("\"%v\" ..> \"%v\"\n", p.left, p.right)
	}
	fmt.Println("@enduml")

	return
}

$ go build mod-graph.go

$ go mod graph | mod-graph
@startuml
hide circle
hide empty members
class "github.com/spiegel-im-spiegel/gpgpdump" as P1
class "github.com/BurntSushi/toml\nv0.3.1" as P2
class "github.com/pkg/errors\nv0.8.1" as P4
class "github.com/spiegel-im-spiegel/gocli\nv0.9.1" as P7
class "github.com/mattn/go-isatty\nv0.0.4" as P9
class "github.com/inconshreveable/mousetrap\nv1.0.0" as P3
class "github.com/spf13/cobra\nv0.0.3" as P5
class "github.com/spf13/pflag\nv1.0.3" as P6
class "golang.org/x/crypto\nv0.0.0-20190208162236-193df9c0f06f" as P8
"P1" ..> "P2"
"P1" ..> "P3"
"P1" ..> "P4"
"P1" ..> "P5"
"P1" ..> "P6"
"P1" ..> "P7"
"P1" ..> "P8"
"P7" ..> "P9"
@enduml

$ go mod graph | mod-graph > gpgpdump.puml
java -jar plantuml.jar -nometadata -charset utf-8 -tpng *.puml