feat: add graphviz

Makefile

@@ -1,3 +1,4 @@
 .PHONY: test
 test:
 	go test -v ./...
+	cd examples; go test -v ./...

attr.go

@@ -19,11 +19,18 @@ func (a *Attrs) Merge(b Attrs) {
 	}
 }
 
+func (a *Attrs) Del(key string) {
+	delete(*a, key)
+}
+
 func (a Attrs) IsEmpty() bool { return len(a) == 0 }
 
 func (a Attrs) String() string {
+	if a == nil {
+		return "[INVALID]"
+	}
 	if len(a) == 0 {
-		return ""
+		return "[]"
 	}
 	elems := []string{}
 	for key, val := range a {
@@ -39,6 +46,13 @@ func (a Attrs) SetTitle(title string) Attrs {
 	return a
 }
 
+func (a Attrs) GetTitle() string {
+	if attr, found := a["title"]; found {
+		return attr.(string)
+	}
+	return ""
+}
+
 func (a Attrs) SetPert(opt, real, pess float64) Attrs {
 	a["pert"] = &PertAttrs{
 		Optimistic:  opt,
@@ -49,9 +63,28 @@ func (a Attrs) SetPert(opt, real, pess float64) Attrs {
 }
 
 func (a Attrs) GetPert() *PertAttrs {
-	pa, found := a["pert"]
-	if !found {
-		return nil
+	if attr, found := a["pert"]; found {
+		return attr.(*PertAttrs)
+	}
+	return nil
+}
+
+func (a Attrs) Clone() Attrs {
+	newAttrs := Attrs{}
+	for k, v := range a {
+		newAttrs[k] = v
+	}
+	return newAttrs
+}
+
+func (a Attrs) SetColor(color string) Attrs {
+	a["color"] = color
+	return a
+}
+
+func (a Attrs) GetColor() string {
+	if attr, found := a["color"]; found {
+		return attr.(string)
 	}
-	return pa.(*PertAttrs)
+	return ""
 }

edge.go

@@ -27,6 +27,9 @@ func newEdge(src, dst *Vertex, attrs ...Attrs) *Edge {
 	}
 }
 
+func (e Edge) Dst() *Vertex { return e.dst }
+func (e Edge) Src() *Vertex { return e.src }
+
 func (e *Edge) Vertices() Vertices {
 	return Vertices{e.src, e.dst}
 }

examples/go.mod

@@ -0,0 +1,11 @@
+module moul.io/graphman/examples
+
+go 1.12
+
+require moul.io/graphman v0.0.0
+
+require moul.io/graphman/viz v0.0.0
+
+replace moul.io/graphman => ../
+
+replace moul.io/graphman/viz => ../viz/

examples/go.sum

@@ -0,0 +1,2 @@
+github.com/awalterschulze/gographviz v0.0.0-20190522210029-fa59802746ab h1:+cdNqtOJWjvepyhxy23G7z7vmpYCoC65AP0nqi1f53s=
+github.com/awalterschulze/gographviz v0.0.0-20190522210029-fa59802746ab/go.mod h1:GEV5wmg4YquNw7v1kkyoX9etIk8yVmXj+AkDHuuETHs=

examples/graphviz/Makefile

@@ -0,0 +1,5 @@
+.PHONY: run
+run:
+	set -eo pipefail; go run . | tee /tmp/graphman.dot
+	set -eo pipefail; cat /tmp/graphman.dot | dot -Tsvg > /tmp/graphman.svg
+	open /tmp/graphman.svg

examples/graphviz/main.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"moul.io/graphman"
+	"moul.io/graphman/viz"
+)
+
+func main() {
+	graph := graphman.New()
+	graph.AddEdge("1", "2")
+	graph.AddEdge("2", "3")
+	graph.AddEdge("2", "4")
+	graph.AddEdge("3", "5")
+	graph.AddEdge("3", "6")
+	graph.AddEdge("4", "5")
+	graph.AddEdge("4", "9")
+	graph.AddEdge("5", "7")
+	graph.AddEdge("6", "8")
+	graph.AddEdge("6", "12")
+	graph.AddEdge("7", "8")
+	graph.AddEdge("7", "10")
+	graph.AddEdge("8", "11")
+	graph.AddEdge("9", "10")
+	graph.AddEdge("9", "15")
+	graph.AddEdge("10", "13")
+	graph.AddEdge("11", "12")
+	graph.AddEdge("11", "14")
+	graph.AddEdge("12", "17")
+	graph.AddEdge("13", "14")
+	graph.AddEdge("13", "15")
+	graph.AddEdge("14", "16")
+	graph.AddEdge("15", "18")
+	graph.AddEdge("16", "17")
+	graph.AddEdge("17", "19")
+	graph.AddEdge("18", "19")
+	graph.AddEdge("19", "20")
+
+	log.Println("all paths from 1 to 20:")
+	for _, path := range graph.FindAllPaths("1", "20") {
+		log.Println("-", path)
+	}
+	log.Println("shortest path from 1 to 20:")
+	path, dist := graph.FindShortestPath("1", "20")
+	log.Println("-", path, "dist:", dist)
+
+	for _, edge := range path {
+		edge.Dst().SetColor("red")
+		edge.SetColor("red")
+	}
+	path.FirstVertex().SetColor("blue")
+	path.LastVertex().SetColor("blue")
+
+	s, err := viz.ToGraphviz(graph)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println(s)
+}

graph.go

@@ -187,6 +187,8 @@ func (g *Graph) AddVertex(id string, attrs ...Attrs) *Vertex {
 	var a Attrs
 	if len(attrs) > 0 {
 		a = attrs[0]
+	} else {
+		a = make(Attrs)
 	}
 
 	v := g.GetVertex(id)
@@ -223,6 +225,8 @@ func (g *Graph) AddEdge(srcID, dstID string, attrs ...Attrs) *Edge {
 	var a Attrs
 	if len(attrs) > 0 {
 		a = attrs[0]
+	} else {
+		a = make(Attrs)
 	}
 
 	src := g.AddVertex(srcID)

viz/go.mod

@@ -0,0 +1,5 @@
+module moul.io/graphman/viz
+
+go 1.12
+
+require github.com/awalterschulze/gographviz v0.0.0-20190522210029-fa59802746ab

viz/go.sum

@@ -0,0 +1,2 @@
+github.com/awalterschulze/gographviz v0.0.0-20190522210029-fa59802746ab h1:+cdNqtOJWjvepyhxy23G7z7vmpYCoC65AP0nqi1f53s=
+github.com/awalterschulze/gographviz v0.0.0-20190522210029-fa59802746ab/go.mod h1:GEV5wmg4YquNw7v1kkyoX9etIk8yVmXj+AkDHuuETHs=

viz/graphviz.go

@@ -0,0 +1,93 @@
+package viz // import "moul.io/graphman/viz"
+
+import (
+	"fmt"
+
+	graphviz "github.com/awalterschulze/gographviz"
+	"moul.io/graphman"
+)
+
+func ToGraphviz(g *graphman.Graph) (string, error) {
+	gv := graphviz.NewGraph()
+	if err := gv.SetName("G"); err != nil {
+		return "", err
+	}
+	if err := gv.SetDir(true); err != nil {
+		return "", err
+	}
+	for k, v := range attrsFromGraph(g) {
+		if err := gv.AddAttr("G", k, v); err != nil {
+			return "", err
+		}
+	}
+	for _, vertex := range g.Vertices() {
+		if err := gv.AddNode(
+			"G",
+			vertex.ID(),
+			attrsFromVertex(vertex),
+		); err != nil {
+			return "", err
+		}
+	}
+	for _, edge := range g.Edges() {
+		if err := gv.AddEdge(
+			edge.Src().ID(),
+			edge.Dst().ID(),
+			true,
+			attrsFromEdge(edge),
+		); err != nil {
+			return "", err
+		}
+	}
+	return gv.String(), nil
+}
+
+func attrsFromGraph(graph *graphman.Graph) map[string]string {
+	attrs := map[string]string{}
+	attrs[string(graphviz.RankDir)] = "LR"
+	attrsGeneric(graph.Attrs, attrs)
+	return attrs
+}
+
+func attrsFromVertex(vertex *graphman.Vertex) map[string]string {
+	attrs := map[string]string{}
+	attrs[string(graphviz.Shape)] = "box"
+	attrs[string(graphviz.Style)] = "rounded"
+	attrs[string(graphviz.Label)] = vertex.ID()
+	attrsGeneric(vertex.Attrs, attrs)
+	return attrs
+}
+
+func attrsFromEdge(edge *graphman.Edge) map[string]string {
+	attrs := map[string]string{}
+	attrs[string(graphviz.Label)] = ""
+	attrsGeneric(edge.Attrs, attrs)
+	return attrs
+}
+
+func attrsGeneric(a graphman.Attrs, attrs map[string]string) {
+	ac := a.Clone()
+	if color := a.GetColor(); color != "" {
+		attrs[string(graphviz.Color)] = color
+		ac.Del("color")
+	}
+	if title := a.GetTitle(); title != "" {
+		attrs[string(graphviz.Label)] = title
+		ac.Del("title")
+	}
+	if len(ac) > 0 {
+		for k, v := range ac {
+			line := fmt.Sprintf("\n%s: %v", k, v)
+			attrs[string(graphviz.Label)] += line
+		}
+	}
+	if label := attrs[string(graphviz.Label)]; label != "" {
+		attrs[string(graphviz.Label)] = escape(label)
+	} else {
+		delete(attrs, string(graphviz.Label))
+	}
+}
+
+func escape(input string) string {
+	return fmt.Sprintf("%q", input)
+}