#109: Graphviz support (#115)

* #109: Graphviz: initial code

* #109: Lightcolored theme

* #109: Add usage of constants

* #109: Add missing semicolon

* Refactor DotTemplateData

* Exclude last hop from the tracing

* Add space for graphviz property

* Add more unit tests

formatter/format.go

@@ -12,13 +12,15 @@ const (
 	MarkdownOutput OutputFormat = "md"
 	// JSONOutput constant defines OutputFormat for JavaScript Object Notation, which is more useful for machine-related operations (parsing)
 	JSONOutput OutputFormat = "json"
+	// DotOutput constant defined OutputFormat for Dot (Graphviz), which can be used to generate various graphs
+	DotOutput OutputFormat = "dot"
 )
 
 // IsValid checks whether requested output format is valid
 func (of OutputFormat) IsValid() bool {
 	// markdown & md is essentially the same thing
 	switch of {
-	case "markdown", "md", "html", "csv", "json":
+	case "markdown", "md", "html", "csv", "json", "dot":
 		return true
 	}
 	return false
@@ -35,6 +37,8 @@ func (of OutputFormat) FileOutputFormat() OutputFormat {
 		return CSVOutput
 	case "json":
 		return JSONOutput
+	case "dot":
+		return DotOutput
 	}
 	return HTMLOutput
 }

formatter/format_test.go

@@ -41,6 +41,11 @@ func TestOutputFormat_FileOutputFormat(t *testing.T) {
 			of:   "json",
 			want: "json",
 		},
+		{
+			name: "dot",
+			of:   "dot",
+			want: "dot",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -87,6 +92,11 @@ func TestOutputFormat_IsValid(t *testing.T) {
 			of:   "csv",
 			want: true,
 		},
+		{
+			name: "dot",
+			of:   "dot",
+			want: true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

formatter/formatter.go

@@ -25,6 +25,10 @@ func New(config *Config) Formatter {
 		return &CSVFormatter{
 			config,
 		}
+	case DotOutput:
+		return &DotFormatter{
+			config,
+		}
 	}
 	return nil
 }

formatter/formatter_dot.go

@@ -0,0 +1,111 @@
+package formatter
+
+import (
+	_ "embed"
+	"fmt"
+	"strings"
+	"text/template"
+)
+
+type DotFormatter struct {
+	config *Config
+}
+
+//go:embed resources/templates/graphviz.tmpl
+// DotTemplate variable is used to store contents of graphviz template
+var DotTemplate string
+
+const (
+	DotOpenPortColor     = "#228B22"
+	DotFilteredPortColor = "#FFAE00"
+	DotClosedPortColor   = "#DC143C"
+	DotDefaultColor      = "gray"
+
+	DotFontStyle = "monospace"
+
+	DotLayout = "dot"
+)
+
+var DotDefaultOptions = map[string]string{
+	"default_font":  DotFontStyle,
+	"layout":        DotLayout,
+	"color_default": DotDefaultColor,
+}
+
+type DotTemplateData struct {
+	NMAPRun   *NMAPRun
+	Constants map[string]string
+}
+
+// Format the data and output it to appropriate io.Writer
+func (f *DotFormatter) Format(td *TemplateData, templateContent string) (err error) {
+	tmpl := template.New("dot")
+	f.defineTemplateFunctions(tmpl)
+	tmpl, err = tmpl.Parse(templateContent)
+	if err != nil {
+		return
+	}
+	dotTemplateData := DotTemplateData{
+		NMAPRun:   &td.NMAPRun,
+		Constants: DotDefaultOptions,
+	}
+	return tmpl.Execute(f.config.Writer, dotTemplateData)
+}
+
+// defaultTemplateContent returns default template content for any typical chosen formatter (HTML or Markdown)
+func (f *DotFormatter) defaultTemplateContent() string {
+	return DotTemplate
+}
+
+// defineTemplateFunctions defines all template functions that are used in dot templates
+func (f *DotFormatter) defineTemplateFunctions(tmpl *template.Template) {
+	tmpl.Funcs(
+		template.FuncMap{
+			"clean_ip":         cleanIP,
+			"port_state_color": portStateColor,
+			"hop_list":         hopList,
+		},
+	)
+}
+
+// cleanIP removes dots from IP address to make it possible to use in graphviz as an ID
+func cleanIP(ip string) string {
+	return strings.ReplaceAll(ip, ".", "")
+}
+
+// portStateColor returns hexademical color value for state port
+func portStateColor(port *Port) string {
+	switch port.State.State {
+	case "open":
+		return DotOpenPortColor
+	case "filtered":
+		return DotFilteredPortColor
+	case "closed":
+		return DotClosedPortColor
+	}
+	return DotDefaultColor
+}
+
+// hopList function returns a map with a list of hops where very first hop is `startHop` (scanner itself)
+func hopList(hops []Hop, startHop string, endHopName string, endHopKey int) map[string]string {
+	var hopList map[string]string = map[string]string{}
+	var previous *Hop = nil
+	for i := range hops {
+		// Skip last hop, because it has the same IP as the target server
+		if i == len(hops)-1 {
+			break
+		}
+		if i == 0 {
+			hopList[startHop] = fmt.Sprintf("hop%s", hops[i].IPAddr)
+		} else {
+			hopList[fmt.Sprintf("hop%s", previous.IPAddr)] = fmt.Sprintf("hop%s", hops[i].IPAddr)
+		}
+		previous = &hops[i]
+	}
+	if previous != nil {
+		hopList[fmt.Sprintf("hop%s", previous.IPAddr)] = fmt.Sprintf("%s%d", endHopName, endHopKey)
+	} else {
+		hopList[startHop] = fmt.Sprintf("%s%d", endHopName, endHopKey)
+	}
+	return hopList
+}