graphviz intergration

README.md

@@ -191,6 +191,17 @@ $ depth -json github.com/KyleBanks/depth/cmd/depth
 }
 ```
 
+#### `-graph`
+
+The `-graph` flag instructs `depth` to render the dependencies into a png file using graphviz
+
+```sh
+$ depth -graph github.com/KyleBanks/depth/cmd/depth
+```
+
+![graph.png](graph.png)
+
+
 ### Integrating With Your Project
 
 The `depth` package can easily be used to retrieve the dependency tree for a particular package in your own project. For example, here's how you would retrieve the dependency tree for the `strings` package:

cmd/depth/depth.go

@@ -1,10 +1,13 @@
 package main
 
 import (
+	"bytes"
 	"encoding/json"
 	"flag"
 	"fmt"
+	"github.com/goccy/go-graphviz"
 	"io"
+	"log"
 	"os"
 	"strings"
 
@@ -20,6 +23,7 @@ const (
 
 var outputJSON bool
 var explainPkg string
+var outputGraph bool
 
 type summary struct {
 	numInternal int
@@ -29,7 +33,7 @@ type summary struct {
 
 func main() {
 	t, pkgs := parse(os.Args[1:])
-	if err := handlePkgs(t, pkgs, outputJSON, explainPkg); err != nil {
+	if err := handlePkgs(t, pkgs, outputJSON, explainPkg, outputGraph); err != nil {
 		os.Exit(1)
 	}
 }
@@ -45,14 +49,15 @@ func parse(args []string) (*depth.Tree, []string) {
 	f.IntVar(&t.MaxDepth, "max", 0, "Sets the maximum depth of dependencies to resolve.")
 	f.BoolVar(&outputJSON, "json", false, "If set, outputs the depencies in JSON format.")
 	f.StringVar(&explainPkg, "explain", "", "If set, show which packages import the specified target")
+	f.BoolVar(&outputGraph, "graph", false, "If set, renders the dependencies in a graph and outputs as a png file")
 	f.Parse(args)
 
 	return &t, f.Args()
 }
 
 // handlePkgs takes a slice of package names, resolves a Tree on them,
 // and outputs each Tree to Stdout.
-func handlePkgs(t *depth.Tree, pkgs []string, outputJSON bool, explainPkg string) error {
+func handlePkgs(t *depth.Tree, pkgs []string, outputJSON bool, explainPkg string, outputGraph bool) error {
 	for _, pkg := range pkgs {
 
 		err := t.Resolve(pkg)
@@ -71,6 +76,11 @@ func handlePkgs(t *depth.Tree, pkgs []string, outputJSON bool, explainPkg string
 			continue
 		}
 
+		if outputGraph {
+			generateGraph(*t.Root)
+			continue
+		}
+
 		writePkg(os.Stdout, *t.Root)
 		writePkgSummary(os.Stdout, *t.Root)
 	}
@@ -161,3 +171,81 @@ func writeExplain(w io.Writer, pkg depth.Pkg, stack []string, explain string) {
 		writeExplain(w, p, stack, explain)
 	}
 }
+
+// generateGraph creates a node graph and renders it as a file
+func generateGraph(pkg depth.Pkg) {
+
+	//adjacency list
+	adjlist := make(map[string][]string)
+	for _, p := range pkg.Deps {
+
+		_, parentok := adjlist[p.Parent.Name]
+		if !parentok {
+			adjlist[p.Parent.Name] = make([]string, 0)
+		}
+		adjlist[p.Parent.Name] = append(adjlist[p.Parent.Name], p.Name)
+
+		_, ok := adjlist[p.Name]
+		if !ok {
+			adjlist[p.Name] = make([]string, 0)
+		}
+
+		generateGraphRec(p, p.Name, adjlist)
+	}
+
+	g := graphviz.New()
+	graph, err := g.Graph()
+
+	defer func() {
+		if err := graph.Close(); err != nil {
+			log.Fatal(err)
+		}
+		g.Close()
+	}()
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for parent, children := range adjlist {
+		n, err := graph.CreateNode(parent)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		for _, child := range children {
+			c, err := graph.CreateNode(child)
+			if err != nil {
+				log.Fatal(err)
+			}
+
+			_, err = graph.CreateEdge("", n, c)
+			if err != nil {
+				log.Fatal(err)
+			}
+
+		}
+	}
+
+	var buf bytes.Buffer
+	if err := g.Render(graph, "dot", &buf); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := g.RenderFilename(graph, graphviz.PNG, "graph.png"); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func generateGraphRec(pkg depth.Pkg, parent string, adjlist map[string][]string) {
+
+	for _, p := range pkg.Deps {
+		_, ok := adjlist[p.Name]
+		if !ok {
+			adjlist[p.Name] = make([]string, 0)
+		}
+
+		adjlist[parent] = append(adjlist[parent], p.Name)
+		generateGraphRec(p, p.Name, adjlist)
+	}
+}