Ltree Visualizer

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A golang library to visualize postgres ltree type data using DOT language and Graphviz

alt text

What is Ltree?

Ltree is a data type which is used to represent the hierarchical tree-like structures in flat rows and columns in postgres DB For more info-refer this

Sample Hierarchy: alt text

why do we need this library ?

Ltree Labels are separated using Dot . like and it is not easy to visualize like a tree.

This Library can produce output into two different formats:

  • DOT Graph
  • Image

DOT Graph:

DOT is a graph description language, using this language we can represent Directed, Undirected and FlowCharts.

b -> c;
b -> d;

digraph graphname {
    a -> b -> c;
    b -> d;

alt text

How to use?

  • get LtreeVisualizer

  go get
  • import and use it like below for to generate the output in DOT graph string:
  import ""
  import ""
  l := ltreevisualizer.Visualizer{}
  resp, err := l.GenerateDotGraph(context.Background(), //json data)
  • import and use it like below for to generate the output as an image:
  import ""
  import ""
  l := ltreevisualizer.Visualizer{}
  err := l.ConvertLtreeDataToImage(context.Background(), //json data)

Note: This will create a graph.png image if you don’t specify Filepath

You can refer examples directory for more info


//Visualizer config
type Visualizer struct {
	LogLevel log.Level
	RankDir  string
	FilePath string

RankDir: Sets the direction of tree layout( and supported values are

  • TB (Top to Bottom)
  • RL (Right to Left)
  • LR (Left to Right)
  • BT (Bottom to Top) Note: Default is TB

FilePath: FilePath to save the image, this parameter is optional for GenerateDotGraph. Note: Default value of FilePath is graph.png


Ltree Visualizer accepts data in this format

//VisualizerSchema Contract to send to ltreevisualizer
type VisualizerSchema struct {
	Data []data `json:"data"`

type data struct {
	ID   int32  `json:"id"`
	Name string `json:"name"`
	Path string `json:"path"`
	Type string `json:"type"`

Refer data.json file under examples directory for sample data

How to test?

Refer visualizer_test.go for sample tests