Add image flip step

config/example.json

@@ -21,8 +21,12 @@
             }
         },
         {
-            "name": "grayscale",
+            "name": "flip image",
             "type": 2
+        },
+        {
+            "name": "grayscale",
+            "type": 3
         }
     ],
     "output": {

pipelines/executable_step.go

@@ -1,6 +1,8 @@
 package pipelines
 
 import (
+	"errors"
+	"fmt"
 	"github.com/disintegration/imaging"
 	"image"
 )
@@ -39,6 +41,28 @@ func (s RotateImageStep) Execute(src image.Image) (image.Image, error) {
 	return src, nil
 }
 
+// Flip image
+
+type FlipImageStep struct {
+	Step
+	Options struct {
+		Direction string `json:"direction"`
+	} `json:"options"`
+}
+
+func (s FlipImageStep) Execute(src image.Image) (image.Image, error) {
+	switch s.Options.Direction {
+	case "h":
+		src = imaging.FlipH(src)
+	case "v":
+		src = imaging.FlipH(src)
+	default:
+		return src, errors.New(fmt.Sprintf("invalid flip direction: %s", s.Options.Direction))
+	}
+
+	return src, nil
+}
+
 // Grayscale image
 
 type GrayscaleImageStep struct {

pipelines/pipeline_test.go

@@ -190,6 +190,88 @@ func TestExecuteSteps(t *testing.T) {
 		os.Remove(storageProvider.GetPath(Bucket, dest))
 	})
 
+	t.Run("Image flip step is successful", func(t *testing.T) {
+		const Bucket string = "pipeline_test_06"
+		const Payload string = `{
+			"name": "example pipeline",
+			"type": 1,
+			"removeMetadata": false,
+			"steps": [
+				{
+					"name": "flip image",
+					"type": 2,
+					"options": {
+						"direction": "h"
+					}
+				}
+			]
+		}`
+
+		wd, _ := os.Getwd()
+		pipe := DeserializePipelines([][]byte{[]byte(Payload)})[0]
+
+		storageProvider := storage.GetFileSystemStorageProvider("test", "..")
+
+		// copy test file to storage bucket
+		_, err := storageProvider.StoreExisting(Bucket, "source.jpg", filepath.Join(wd, "../tests/files/800x500.jpg"))
+		assert.Nil(t, err, "Test file should be readable")
+		assert.FileExists(t, storageProvider.GetPath(Bucket, "source.jpg"))
+
+		// run pipeline steps
+		dest, err := pipe.Run("source.jpg", Bucket, storageProvider)
+		assert.Nil(t, err)
+		assert.FileExists(t, storageProvider.GetPath(Bucket, dest))
+
+		// read image config
+		file, err := storageProvider.OpenFile(Bucket, dest)
+		assert.Nil(t, err)
+
+		imgConf, _, err := image.DecodeConfig(file)
+		assert.Nil(t, err)
+
+		assert.Equal(t, 800, imgConf.Width)
+		assert.Equal(t, 500, imgConf.Height)
+
+		// clean up
+		os.Remove(storageProvider.GetPath(Bucket, "source.jpg"))
+		os.Remove(storageProvider.GetPath(Bucket, dest))
+	})
+
+	t.Run("Image flip step direction validation is successful", func(t *testing.T) {
+		const Bucket string = "pipeline_test_06"
+		const Payload string = `{
+			"name": "example pipeline",
+			"type": 1,
+			"removeMetadata": false,
+			"steps": [
+				{
+					"name": "flip image",
+					"type": 2,
+					"options": {
+						"direction": "f"
+					}
+				}
+			]
+		}`
+
+		wd, _ := os.Getwd()
+		pipe := DeserializePipelines([][]byte{[]byte(Payload)})[0]
+
+		storageProvider := storage.GetFileSystemStorageProvider("test", "..")
+
+		// copy test file to storage bucket
+		_, err := storageProvider.StoreExisting(Bucket, "source.jpg", filepath.Join(wd, "../tests/files/800x500.jpg"))
+		assert.Nil(t, err, "Test file should be readable")
+		assert.FileExists(t, storageProvider.GetPath(Bucket, "source.jpg"))
+
+		// run pipeline steps
+		_, err = pipe.Run("source.jpg", Bucket, storageProvider)
+		assert.EqualError(t, err, "invalid flip direction: f")
+
+		// clean up
+		os.Remove(storageProvider.GetPath(Bucket, "source.jpg"))
+	})
+
 	t.Run("Image grayscale step is successful", func(t *testing.T) {
 		const Bucket string = "pipeline_test_05"
 		const Payload string = `{
@@ -199,7 +281,7 @@ func TestExecuteSteps(t *testing.T) {
 			"steps": [
 				{
 					"name": "grayscale",
-					"type": 2
+					"type": 3
 				}
 			]
 		}`

pipelines/step.go

@@ -10,6 +10,7 @@ type StepType int
 const (
 	TypeResizeImageStep StepType = iota
 	TypeRotateImageStep
+	TypeFlipImageStep
 	TypeGrayscaleImageStep
 )
 
@@ -36,6 +37,13 @@ func (s Step) GetExecutable() (IExecutableStep, error) {
 		}
 		return step, nil
 
+	case TypeFlipImageStep:
+		step := FlipImageStep{}
+		if err := json.Unmarshal(s.Options, &step.Options); err != nil {
+			return nil, err
+		}
+		return step, nil
+
 	case TypeGrayscaleImageStep:
 		return GrayscaleImageStep{}, nil
 	}