interfaces.go

package storage

import (
	"io"

	s3 "github.com/minio/minio-go"
)

// BucketCreator is a *(github.com/minio/minio-go).Client compatible interface, restricted to just the MakeBucket function. You can use it in your code for easier unit testing without any external dependencies
type BucketCreator interface {
	MakeBucket(bucketName string, acl s3.BucketACL, location string) error
}

type FakeMakeBucketCall struct {
	BucketName string
	ACL        s3.BucketACL
	Location   string
}

// FakeBucketCreator is a mock function that can be swapped in for an BucketCreator, so you can unit test your code
type FakeBucketCreator struct {
	Fn    func(string, s3.BucketACL, string) error
	Calls []FakeMakeBucketCall
}

// PutObject is the interface definition
func (f *FakeBucketCreator) MakeBucket(name string, acl s3.BucketACL, location string) error {
	f.Calls = append(f.Calls, FakeMakeBucketCall{BucketName: name, ACL: acl, Location: location})
	return f.Fn(name, acl, location)
}

// ObjectStatter is a *(github.com/minio/minio-go).Client compatible interface, restricted to just the StatObject function. You can use it in your code for easier unit testing without any external dependencies
type ObjectStatter interface {
	StatObject(bucketName, objectKey string) (s3.ObjectInfo, error)
}

type FakeStatObjectCall struct {
	BucketName string
	ObjectKey  string
}

// FakeObjectStatter is a mock function that can be swapped in for an ObjectStatter, so you can unit test your code
type FakeObjectStatter struct {
	Fn    func(string, string) (s3.ObjectInfo, error)
	Calls []FakeStatObjectCall
}

// PutObject is the interface definition
func (f *FakeObjectStatter) StatObject(bucketName, objectKey string) (s3.ObjectInfo, error) {
	f.Calls = append(f.Calls, FakeStatObjectCall{BucketName: bucketName, ObjectKey: objectKey})
	return f.Fn(bucketName, objectKey)
}

// ObjectPutter is a *(github.com/minio/minio-go).Client compatible interface, restricted to just the PutObject function. You can use it in your code for easier unit testing without any external dependencies
type ObjectPutter interface {
	PutObject(bucketName, objectKey string, reader io.Reader, contentType string) (int64, error)
}

type FakePutObjectCall struct {
	BucketName  string
	ObjectKey   string
	Reader      io.Reader
	ContentType string
}

// FakeObjectPutter is a mock function that can be swapped in for an ObjectPutter, so you can unit test your code
type FakeObjectPutter struct {
	Fn    func(bucketName, objectKey string, reader io.Reader, contentType string) (int64, error)
	Calls []FakePutObjectCall
}

// PutObject is the interface definition
func (f *FakeObjectPutter) PutObject(bucketName, objectKey string, reader io.Reader, contentType string) (int64, error) {
	f.Calls = append(f.Calls, FakePutObjectCall{
		BucketName:  bucketName,
		ObjectKey:   objectKey,
		Reader:      reader,
		ContentType: contentType,
	})
	return f.Fn(bucketName, objectKey, reader, contentType)
}

// The s3.Object already satisfies this interface. As long as it has some or all of the functions as s3.Object, it satisfies it. We're making it have all of the functions in this case. You can create a fake object that also has all of these functions.
type Object interface {
	// This is called an interface composition - it automatically gives your interface the function in io.Reader (https://godoc.org/io#Reader) and the function in io.Closer (https://godoc.org/io#Closer)
	io.ReadCloser
	// This is also an interface composition. It gives your interface the function in io.Seeker (https://godoc.org/io#Seeker)
	io.Seeker
	// This is also interface composition. It gives your interface the function in io.ReaderAt (https://godoc.org/io#ReaderAt)
	io.ReaderAt
	// This function is the last one we have to add to make this interface have all the same functions as s3.Object
	Stat() (s3.ObjectInfo, error)
}

// The minio client doesn't already satisfy this interface, because the GetObject func (https://godoc.org/github.com/minio/minio-go#Client.GetObject) doesn't return an Object. Instead, it returns a *s3.Object. We'll create an adapter below
type ObjectGetter interface {
	// GetObject is *almost* the same function as the GetObject func in the minio client, but it returns Object instead of *s3.Object
	GetObject(string, string) (Object, error)
}

// RealObjectGetter is an adapter to make the *s3.Client GetObject function compatible with the ObjectGetter interface
type RealObjectGetter struct {
	Client *s3.Client
}

func (r *RealObjectGetter) GetObject(bucket, objKey string) (Object, error) {
	obj, err := r.Client.GetObject(bucket, objKey)
	if err != nil {
		// you can return nil for an interface
		return nil, err
	}
	// obj is a *s3.Object, but as we said above, it automatically implements our Object interface without any other work
	return obj, nil
}

type FakeGetObjectCall struct {
	BucketName string
	ObjectKey  string
}

// FakeObjectGetter is a mock function that can be swapped in for an ObjectGetter, so you can unit test your code
type FakeObjectGetter struct {
	Fn    func(string, string) (Object, error)
	Calls []FakeGetObjectCall
}

// GetObject is the interface definition
func (f *FakeObjectGetter) GetObject(bucketName, objectKey string) (Object, error) {
	f.Calls = append(f.Calls, FakeGetObjectCall{BucketName: bucketName, ObjectKey: objectKey})
	return f.Fn(bucketName, objectKey)
}

// FakeObject is a mock function that can be swapped in for an *s3.Object, so you can unit test your code
type FakeObject struct {
	Data string
}

// Read is the interface definition
func (f *FakeObject) Read(b []byte) (n int, err error) {
	copy(b, f.Data[:])
	return len(f.Data), io.EOF
}

// Close is the interface definition
func (f *FakeObject) Close() (err error) {
	return nil
}

// ReadAt is the interface definition
func (f *FakeObject) ReadAt(b []byte, offset int64) (n int, err error) {
	return 0, nil
}

// Seek is the interface definition
func (f *FakeObject) Seek(offset int64, whence int) (n int64, err error) {
	return 0, nil
}

// Stat is the interface definition
func (f *FakeObject) Stat() (s3.ObjectInfo, error) {
	return s3.ObjectInfo{}, nil
}