golaroid

media transformation service

Usage

Basic usage with common included modules

package main

import (
	"runtime"

	"github.com/axyz/golaroid"
	"github.com/axyz/golaroid/cache"
	"github.com/axyz/golaroid/reader"
	"github.com/axyz/golaroid/transform"
	"github.com/axyz/golaroid/writer"
)

func init() {
	runtime.GOMAXPROCS(runtime.NumCPU())
}

func main() {
	options := golaroid.Options{
		Port: 8080,
		Readers: golaroid.Readers{
			"local": reader.Local,
		},
		Transformers: golaroid.Transformers{
			"resize": transform.Resize,
			"strip":  transform.Strip,
			"jpeg":   transform.Jpeg,
		},
		Writers: golaroid.Writers{
			"local": writer.Local,
		},
		Caches: golaroid.Caches{
			"local": cache.Local,
		},
	}

	golaroid.Run(options)
}

example config:

entities:
- Name: media
  Route: "/media/"

  InputReader:
    name: local
    options:
      folder: "./media"

  OutputWriters:
  - name: local
    options:
      folder: "./output"

  CachingLayer:
    name: local
    options:
      folder: "./cache"

  Variants:
    thumb:
      transformations:
      - name: resize
        options:
          width: 200
          height: 600
          filter: lanczos
          multistep: true
      - name: strip
      - name: jpeg
        options:
          quality: 85

Modules

golaroid is extremely modular and custom Readers, Writers, Caches and Transformers for each entity can be defined and plugged as required.

Some basic modules are provided with the golaroid package itself:

• golaroid.reader
  • Local: simple local file reader
• golaroid.writer
  • Local: simple local file writer
• golaroid.cache
  • Local: simple file based cache
• golaroid.transform
  • Jpeg: jpeg encoding using imageMagick
  • Resize: resizing using imageMagick with multi-step support
  • Strip: metadata removal for size reduction

Writing your own modules is also possible and simple as you only have to define functions operating on binary data.

Readers

A Reader should have type

func(variant string, path string, opts map[string]interface{}) ([]byte, error)

Given the variant name, a path for the media item and arbitrary options should return the binary data for the media item and an error object.

Writers

A Writer should have type

func(variant string, path string, data []byte, opts map[string]interface{}) error

Given the variant name, a path for the media item, the media item itself as binary data and arbitrary options should write somewhere the data by side effect and return an error object.

Caches

a Cache should be a golaroid.Cache struct that defines Get and a Set methods.

type Cache struct {
	Get func(variant string, path string, opts map[string]interface{}) ([]byte, error)
	Set func(variant string, path string, data []byte, opts map[string]interface{}) error
}

Get and Set methods should allow to save and retrieve binary data for the media items given the variant, the path and arbitrary options.