go-graphviz

Go bindings for Graphviz

Features

Graphviz version is here

• Pure Go Library
• No need to install Graphviz library ( brew install graphviz or apt-get install graphviz )
  • The Graphviz library has been converted to WebAssembly (WASM) and embedded it, so it works consistently across all environments
• Supports encoding/decoding for DOT language
• Supports custom renderer for custom format
• Supports setting graph properties in a type-safe manner

Supported Layout

circo dot fdp neato nop nop1 nop2 osage patchwork sfdp twopi

Supported Format

dot svg png jpg

The above are the formats supported by default. You can also add custom formats.

Installation

$ go get github.com/goccy/go-graphviz

Synopsis

1. Write DOT Graph in Go

package main

import (
  "bytes"
  "context"
  "fmt"
  "log"

  "github.com/goccy/go-graphviz"
)

func main() {
  ctx := context.Background()
  g, err := graphviz.New(ctx)
  if err != nil { panic(err )}

  graph, err := g.Graph()
  if err != nil { panic(err) }
  defer func() {
    if err := graph.Close(); err != nil { panic(err) }
    g.Close()
  }()
  n, err := graph.CreateNodeByName("n")
  if err != nil { panic(err) }

  m, err := graph.CreateNodeByName("m")
  if err != nil { panic(err) }

  e, err := graph.CreateEdgeByName("e", n, m)
  if err != nil { panic(err) }
  e.SetLabel("e")

  var buf bytes.Buffer
  if err := g.Render(ctx, graph, "dot", &buf); err != nil {
    log.Fatal(err)
  }
  fmt.Println(buf.String())
}

2. Parse DOT Graph

path := "/path/to/dot.gv"
b, err := os.ReadFile(path)
if err != nil { panic(err) }
graph, err := graphviz.ParseBytes(b)

3. Render Graph

ctx := context.Background()
g, err := graphviz.New(ctx)
if err != nil { panic(err) }

graph, err := g.Graph()
if err != nil { panic(err) }

// create your graph

// 1. write encoded PNG data to buffer
var buf bytes.Buffer
if err := g.Render(ctx, graph, graphviz.PNG, &buf); err != nil { panic(err) }

// 2. get as image.Image instance
image, err := g.RenderImage(ctx, graph)
if err != nil { panic(err) }

// 3. write to file directly
if err := g.RenderFilename(ctx, graph, graphviz.PNG, "/path/to/graph.png"); err != nil { panic(err) }

Tool

dot

Installation

$ go install github.com/goccy/go-graphviz/cmd/dot@latest

Usage

Usage:
  dot [OPTIONS]

Application Options:
  -T=         specify output format ( currently supported: dot svg png jpg ) (default: dot)
  -K=         specify layout engine ( currently supported: circo dot fdp neato nop nop1 nop2 osage patchwork sfdp twopi )
  -o=         specify output file name

Help Options:
  -h, --help  Show this help message

How it works

1. Generates bindings between Go and C from Protocol Buffers file.
2. Builds graphviz.wasm on the docker container.
3. Uses Graphviz functionality from a sub-packages ( cdt cgraph gvc ) via the internal/wasm package.
4. graphviz package provides facade interface for all sub packages.

License

MIT

This library embeds and uses graphviz.wasm, which is generated based on the original source code of Graphviz. Therefore, the graphviz.wasm follows the license adopted by Graphviz ( Eclipse Public License ).