Split config and storage files to clarify structure

storage/config.go

@@ -0,0 +1,7 @@
+package storage
+
+// Config is an interface of factory method for Storage
+type Config interface {
+	// NewStorage returns a new instance of Storage.
+	NewStorage() (Storage, error)
+}

storage/local/config.go

@@ -0,0 +1,18 @@
+package local
+
+import "github.com/minamijoyo/tfmigrate/storage"
+
+// Config is a config for local storage.
+type Config struct {
+	// Path to a migration history file. Relative to the current working directory.
+	Path string `hcl:"path"`
+}
+
+// Config implements a storage.Config.
+var _ storage.Config = (*Config)(nil)
+
+// NewStorage returns a new instance of storage.Storage.
+func (c *Config) NewStorage() (storage.Storage, error) {
+	s := NewStorage(c.Path)
+	return s, nil
+}

storage/local/config_test.go

@@ -0,0 +1,34 @@
+package local
+
+import "testing"
+
+func TestConfigNewStorage(t *testing.T) {
+	cases := []struct {
+		desc   string
+		config *Config
+		ok     bool
+	}{
+		{
+			desc: "valid",
+			config: &Config{
+				Path: "tmp/history.json",
+			},
+			ok: true,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.desc, func(t *testing.T) {
+			got, err := tc.config.NewStorage()
+			if tc.ok && err != nil {
+				t.Fatalf("unexpected err: %s", err)
+			}
+			if !tc.ok && err == nil {
+				t.Fatalf("expected to return an error, but no error, got: %#v", got)
+			}
+			if tc.ok {
+				_ = got.(*Storage)
+			}
+		})
+	}
+}

storage/local/storage.go

@@ -8,21 +8,6 @@ import (
 	"github.com/minamijoyo/tfmigrate/storage"
 )
 
-// Config is a config for local storage.
-type Config struct {
-	// Path to a migration history file. Relative to the current working directory.
-	Path string `hcl:"path"`
-}
-
-// Config implements a storage.Config.
-var _ storage.Config = (*Config)(nil)
-
-// NewStorage returns a new instance of storage.Storage.
-func (c *Config) NewStorage() (storage.Storage, error) {
-	s := NewStorage(c.Path)
-	return s, nil
-}
-
 // Storage is a storage.Storage implementation for local file.
 // This was originally intended for debugging purposes, but it can also be used
 // as a workaround if Storage doesn't support your cloud provider.

storage/local/storage_test.go

@@ -8,37 +8,6 @@ import (
 	"testing"
 )
 
-func TestConfigNewStorage(t *testing.T) {
-	cases := []struct {
-		desc   string
-		config *Config
-		ok     bool
-	}{
-		{
-			desc: "valid",
-			config: &Config{
-				Path: "tmp/history.json",
-			},
-			ok: true,
-		},
-	}
-
-	for _, tc := range cases {
-		t.Run(tc.desc, func(t *testing.T) {
-			got, err := tc.config.NewStorage()
-			if tc.ok && err != nil {
-				t.Fatalf("unexpected err: %s", err)
-			}
-			if !tc.ok && err == nil {
-				t.Fatalf("expected to return an error, but no error, got: %#v", got)
-			}
-			if tc.ok {
-				_ = got.(*Storage)
-			}
-		})
-	}
-}
-
 func TestStorageWrite(t *testing.T) {
 	cases := []struct {
 		desc     string

storage/mock/config.go

@@ -0,0 +1,33 @@
+package mock
+
+import "github.com/minamijoyo/tfmigrate/storage"
+
+// Config is a config for mock storage.
+type Config struct {
+	// Data stores a serialized data for history.
+	Data string `hcl:"data"`
+	// WriteError is a flag to return an error on Write().
+	WriteError bool `hcl:"write_error"`
+	// ReadError is a flag to return an error on Read().
+	ReadError bool `hcl:"read_error"`
+
+	// A reference to an instance of mock storage for testing.
+	s *Storage
+}
+
+// Config implements a storage.Config.
+var _ storage.Config = (*Config)(nil)
+
+// NewStorage returns a new instance of storage.Storage.
+func (c *Config) NewStorage() (storage.Storage, error) {
+	s := NewStorage(c.Data, c.WriteError, c.ReadError)
+
+	// store a reference for test assertion.
+	c.s = s
+	return s, nil
+}
+
+// StorageData returns a raw data in mock storage for testing.
+func (c *Config) StorageData() string {
+	return c.s.data
+}

storage/mock/config_test.go

@@ -0,0 +1,36 @@
+package mock
+
+import "testing"
+
+func TestConfigNewStorage(t *testing.T) {
+	cases := []struct {
+		desc   string
+		config *Config
+		ok     bool
+	}{
+		{
+			desc: "valid",
+			config: &Config{
+				Data:       "foo",
+				WriteError: true,
+				ReadError:  false,
+			},
+			ok: true,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.desc, func(t *testing.T) {
+			got, err := tc.config.NewStorage()
+			if tc.ok && err != nil {
+				t.Fatalf("unexpected err: %s", err)
+			}
+			if !tc.ok && err == nil {
+				t.Fatalf("expected to return an error, but no error, got: %#v", got)
+			}
+			if tc.ok {
+				_ = got.(*Storage)
+			}
+		})
+	}
+}

storage/mock/storage.go

@@ -7,36 +7,6 @@ import (
 	"github.com/minamijoyo/tfmigrate/storage"
 )
 
-// Config is a config for mock storage.
-type Config struct {
-	// Data stores a serialized data for history.
-	Data string `hcl:"data"`
-	// WriteError is a flag to return an error on Write().
-	WriteError bool `hcl:"write_error"`
-	// ReadError is a flag to return an error on Read().
-	ReadError bool `hcl:"read_error"`
-
-	// A reference to an instance of mock storage for testing.
-	s *Storage
-}
-
-// Config implements a storage.Config.
-var _ storage.Config = (*Config)(nil)
-
-// NewStorage returns a new instance of storage.Storage.
-func (c *Config) NewStorage() (storage.Storage, error) {
-	s := NewStorage(c.Data, c.WriteError, c.ReadError)
-
-	// store a reference for test assertion.
-	c.s = s
-	return s, nil
-}
-
-// StorageData returns a raw data in mock storage for testing.
-func (c *Config) StorageData() string {
-	return c.s.data
-}
-
 // Storage is a storage.Storage implementation for testing.
 // It writes and reads data from memory.
 type Storage struct {

storage/mock/storage_test.go

@@ -5,39 +5,6 @@ import (
 	"testing"
 )
 
-func TestConfigNewStorage(t *testing.T) {
-	cases := []struct {
-		desc   string
-		config *Config
-		ok     bool
-	}{
-		{
-			desc: "valid",
-			config: &Config{
-				Data:       "foo",
-				WriteError: true,
-				ReadError:  false,
-			},
-			ok: true,
-		},
-	}
-
-	for _, tc := range cases {
-		t.Run(tc.desc, func(t *testing.T) {
-			got, err := tc.config.NewStorage()
-			if tc.ok && err != nil {
-				t.Fatalf("unexpected err: %s", err)
-			}
-			if !tc.ok && err == nil {
-				t.Fatalf("expected to return an error, but no error, got: %#v", got)
-			}
-			if tc.ok {
-				_ = got.(*Storage)
-			}
-		})
-	}
-}
-
 func TestStorageWrite(t *testing.T) {
 	cases := []struct {
 		desc       string

storage/s3/client.go

@@ -0,0 +1,60 @@
+package s3
+
+import (
+	"fmt"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/request"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/aws/aws-sdk-go/service/s3/s3iface"
+	awsbase "github.com/hashicorp/aws-sdk-go-base"
+)
+
+// Client is an abstraction layer for AWS S3 API.
+// It is intended to be replaced with a mock for testing.
+type Client interface {
+	// PutObjectWithContext puts a file to S3.
+	PutObjectWithContext(ctx aws.Context, input *s3.PutObjectInput, opts ...request.Option) (*s3.PutObjectOutput, error)
+	// GetObjectWithContext gets a file from S3.
+	GetObjectWithContext(ctx aws.Context, input *s3.GetObjectInput, opts ...request.Option) (*s3.GetObjectOutput, error)
+}
+
+// client is a real implementation of the Client.
+type client struct {
+	s3api s3iface.S3API
+}
+
+// newClient returns a new instance of Client.
+func newClient(config *Config) (Client, error) {
+	cfg := &awsbase.Config{
+		AccessKey:            config.AccessKey,
+		AssumeRoleARN:        config.RoleARN,
+		Profile:              config.Profile,
+		Region:               config.Region,
+		SecretKey:            config.SecretKey,
+		SkipCredsValidation:  config.SkipCredentialsValidation,
+		SkipMetadataApiCheck: config.SkipMetadataAPICheck,
+	}
+
+	sess, err := awsbase.GetSession(cfg)
+	if err != nil {
+		return nil, fmt.Errorf("failed to new s3 client: %s", err)
+	}
+
+	client := s3.New(sess.Copy(&aws.Config{
+		Endpoint:         aws.String(config.Endpoint),
+		S3ForcePathStyle: aws.Bool(config.ForcePathStyle),
+	}))
+
+	return client, nil
+}
+
+// PutObjectWithContext puts a file to S3.
+func (c *client) PutObjectWithContext(ctx aws.Context, input *s3.PutObjectInput, opts ...request.Option) (*s3.PutObjectOutput, error) {
+	return c.s3api.PutObjectWithContext(ctx, input, opts...)
+}
+
+// GetObjectWithContext gets a file from S3.
+func (c *client) GetObjectWithContext(ctx aws.Context, input *s3.GetObjectInput, opts ...request.Option) (*s3.GetObjectOutput, error) {
+	return c.s3api.GetObjectWithContext(ctx, input, opts...)
+}

storage/s3/config.go

@@ -0,0 +1,45 @@
+package s3
+
+import "github.com/minamijoyo/tfmigrate/storage"
+
+// Config is a config for s3 storage.
+// This is expected to have almost the same options as Terraform s3 backend.
+// https://www.terraform.io/docs/backends/types/s3.html
+// However, it has many minor options and it's a pain to test all options from
+// first, so we added only options we need for now.
+type Config struct {
+	// Name of the bucket.
+	Bucket string `hcl:"bucket"`
+	// Path to the migration history file.
+	Key string `hcl:"key"`
+
+	// AWS region.
+	Region string `hcl:"region,optional"`
+	// Custom endpoint for the AWS S3 API.
+	Endpoint string `hcl:"endpoint,optional"`
+	// AWS access key.
+	AccessKey string `hcl:"access_key,optional"`
+	// AWS secret key.
+	SecretKey string `hcl:"secret_key,optional"`
+	// Name of AWS profile in AWS shared credentials file.
+	Profile string `hcl:"profile,optional"`
+	// Amazon Resource Name (ARN) of the IAM Role to assume.
+	RoleARN string `hcl:"role_arn,optional"`
+	// Skip credentials validation via the STS API.
+	SkipCredentialsValidation bool `hcl:"skip_credentials_validation,optional"`
+	// Skip usage of EC2 Metadata API.
+	SkipMetadataAPICheck bool `hcl:"skip_metadata_api_check,optional"`
+	// Enable path-style S3 URLs (https://<HOST>/<BUCKET>
+	// instead of https://<BUCKET>.<HOST>).
+	ForcePathStyle bool `hcl:"force_path_style,optional"`
+	// SSE KMS Key Id for optional server-side encryption enablement
+	KmsKeyID string `hcl:"kms_key_id,optional"`
+}
+
+// Config implements a storage.Config.
+var _ storage.Config = (*Config)(nil)
+
+// NewStorage returns a new instance of storage.Storage.
+func (c *Config) NewStorage() (storage.Storage, error) {
+	return NewStorage(c, nil)
+}