source/aws-s3: implement the driver

source/aws-s3/README.md

@@ -0,0 +1,3 @@
+# aws-s3
+
+`s3://<bucket>/<prefix>`

source/aws-s3/s3.go

@@ -1 +1,125 @@
 package awss3
+
+import (
+	"fmt"
+	"io"
+	"net/url"
+	"os"
+	"path"
+	"strings"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/aws/aws-sdk-go/service/s3/s3iface"
+	"github.com/mattes/migrate/source"
+)
+
+func init() {
+	source.Register("s3", &s3Driver{})
+}
+
+type s3Driver struct {
+	s3client   s3iface.S3API
+	bucket     string
+	prefix     string
+	migrations *source.Migrations
+}
+
+func (s *s3Driver) Open(folder string) (source.Driver, error) {
+	u, err := url.Parse(folder)
+	if err != nil {
+		return nil, err
+	}
+	sess, err := session.NewSession()
+	if err != nil {
+		return nil, err
+	}
+	driver := s3Driver{
+		bucket:     u.Host,
+		prefix:     strings.Trim(u.Path, "/") + "/",
+		s3client:   s3.New(sess),
+		migrations: source.NewMigrations(),
+	}
+	err = driver.loadMigrations()
+	if err != nil {
+		return nil, err
+	}
+	return &driver, nil
+}
+
+func (s *s3Driver) loadMigrations() error {
+	output, err := s.s3client.ListObjects(&s3.ListObjectsInput{
+		Bucket:    aws.String(s.bucket),
+		Prefix:    aws.String(s.prefix),
+		Delimiter: aws.String("/"),
+	})
+	if err != nil {
+		return err
+	}
+	for _, object := range output.Contents {
+		_, fileName := path.Split(aws.StringValue(object.Key))
+		m, err := source.DefaultParse(fileName)
+		if err != nil {
+			continue
+		}
+		if !s.migrations.Append(m) {
+			return fmt.Errorf("unable to parse file %v", aws.StringValue(object.Key))
+		}
+	}
+	return nil
+}
+
+func (s *s3Driver) Close() error {
+	return nil
+}
+
+func (s *s3Driver) First() (uint, error) {
+	v, ok := s.migrations.First()
+	if !ok {
+		return 0, os.ErrNotExist
+	}
+	return v, nil
+}
+
+func (s *s3Driver) Prev(version uint) (uint, error) {
+	v, ok := s.migrations.Prev(version)
+	if !ok {
+		return 0, os.ErrNotExist
+	}
+	return v, nil
+}
+
+func (s *s3Driver) Next(version uint) (uint, error) {
+	v, ok := s.migrations.Next(version)
+	if !ok {
+		return 0, os.ErrNotExist
+	}
+	return v, nil
+}
+
+func (s *s3Driver) ReadUp(version uint) (io.ReadCloser, string, error) {
+	if m, ok := s.migrations.Up(version); ok {
+		return s.open(m)
+	}
+	return nil, "", os.ErrNotExist
+}
+
+func (s *s3Driver) ReadDown(version uint) (io.ReadCloser, string, error) {
+	if m, ok := s.migrations.Down(version); ok {
+		return s.open(m)
+	}
+	return nil, "", os.ErrNotExist
+}
+
+func (s *s3Driver) open(m *source.Migration) (io.ReadCloser, string, error) {
+	key := path.Join(s.prefix, m.Raw)
+	object, err := s.s3client.GetObject(&s3.GetObjectInput{
+		Bucket: aws.String(s.bucket),
+		Key:    aws.String(key),
+	})
+	if err != nil {
+		return nil, "", err
+	}
+	return object.Body, m.Identifier, nil
+}

source/aws-s3/s3_test.go

@@ -1 +1,82 @@
 package awss3
+
+import (
+	"errors"
+	"io/ioutil"
+	"strings"
+	"testing"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/mattes/migrate/source"
+	st "github.com/mattes/migrate/source/testing"
+)
+
+func Test(t *testing.T) {
+	s3Client := fakeS3{
+		bucket: "some-bucket",
+		objects: map[string]string{
+			"staging/migrations/1_foobar.up.sql":          "1 up",
+			"staging/migrations/1_foobar.down.sql":        "1 down",
+			"prod/migrations/1_foobar.up.sql":             "1 up",
+			"prod/migrations/1_foobar.down.sql":           "1 down",
+			"prod/migrations/3_foobar.up.sql":             "3 up",
+			"prod/migrations/4_foobar.up.sql":             "4 up",
+			"prod/migrations/4_foobar.down.sql":           "4 down",
+			"prod/migrations/5_foobar.down.sql":           "5 down",
+			"prod/migrations/7_foobar.up.sql":             "7 up",
+			"prod/migrations/7_foobar.down.sql":           "7 down",
+			"prod/migrations/not-a-migration.txt":         "",
+			"prod/migrations/0-random-stuff/whatever.txt": "",
+		},
+	}
+	driver := s3Driver{
+		bucket:     "some-bucket",
+		prefix:     "prod/migrations/",
+		migrations: source.NewMigrations(),
+		s3client:   &s3Client,
+	}
+	err := driver.loadMigrations()
+	if err != nil {
+		t.Fatal(err)
+	}
+	st.Test(t, &driver)
+}
+
+type fakeS3 struct {
+	s3.S3
+	bucket  string
+	objects map[string]string
+}
+
+func (s *fakeS3) ListObjects(input *s3.ListObjectsInput) (*s3.ListObjectsOutput, error) {
+	bucket := aws.StringValue(input.Bucket)
+	if bucket != s.bucket {
+		return nil, errors.New("bucket not found")
+	}
+	prefix := aws.StringValue(input.Prefix)
+	delimiter := aws.StringValue(input.Delimiter)
+	var output s3.ListObjectsOutput
+	for name := range s.objects {
+		if strings.HasPrefix(name, prefix) {
+			if delimiter == "" || !strings.Contains(strings.Replace(name, prefix, "", 1), delimiter) {
+				output.Contents = append(output.Contents, &s3.Object{
+					Key: aws.String(name),
+				})
+			}
+		}
+	}
+	return &output, nil
+}
+
+func (s *fakeS3) GetObject(input *s3.GetObjectInput) (*s3.GetObjectOutput, error) {
+	bucket := aws.StringValue(input.Bucket)
+	if bucket != s.bucket {
+		return nil, errors.New("bucket not found")
+	}
+	if data, ok := s.objects[aws.StringValue(input.Key)]; ok {
+		body := ioutil.NopCloser(strings.NewReader(data))
+		return &s3.GetObjectOutput{Body: body}, nil
+	}
+	return nil, errors.New("object not found")
+}