[feature] S3 support (#674)

* feat: vendor minio client

* feat: introduce storage package with s3 support

* feat: serve s3 files directly

this saves a lot of bandwith as the files are fetched from the object
store directly

* fix: use explicit local storage in tests

* feat: integrate s3 storage with the main server

* fix: add s3 config to cli tests

* docs: explicitly set values in example config

also adds license header to the storage package

* fix: use better http status code on s3 redirect

HTTP 302 Found is the best fit, as it signifies that the resource
requested was found but not under its presumed URL

307/TemporaryRedirect would mean that this resource is usually located
here, not in this case

303/SeeOther indicates that the redirection does not link to the
requested resource but to another page

* refactor: use context in storage driver interface

3 files changed, 215 insertions, 0 deletions

diff --git a/internal/storage/local.go b/internal/storage/local.go
new file mode 100644
index 000000000..da57631f9
--- /dev/null
+++ b/internal/storage/local.go
@@ -0,0 +1,50 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package storage
+
+import (
+	"context"
+	"io"
+	"net/url"
+
+	"codeberg.org/gruf/go-store/kv"
+)
+
+type Local struct {
+	KVStore *kv.KVStore
+}
+
+func (l *Local) Get(ctx context.Context, key string) ([]byte, error) {
+	return l.KVStore.Get(key)
+}
+func (l *Local) GetStream(ctx context.Context, key string) (io.ReadCloser, error) {
+	return l.KVStore.GetStream(key)
+}
+func (l *Local) PutStream(ctx context.Context, key string, r io.Reader) error {
+	return l.KVStore.PutStream(key, r)
+}
+func (l *Local) Put(ctx context.Context, key string, value []byte) error {
+	return l.KVStore.Put(key, value)
+}
+func (l *Local) Delete(ctx context.Context, key string) error {
+	return l.KVStore.Delete(key)
+}
+func (l *Local) URL(ctx context.Context, key string) *url.URL {
+	return nil
+}
diff --git a/internal/storage/s3.go b/internal/storage/s3.go
new file mode 100644
index 000000000..a15114488
--- /dev/null
+++ b/internal/storage/s3.go
@@ -0,0 +1,87 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package storage
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"mime"
+	"net/url"
+	"path"
+	"time"
+
+	"github.com/minio/minio-go/v7"
+)
+
+type S3 struct {
+	mc     *minio.Client
+	bucket string
+}
+
+func NewS3(mc *minio.Client, bucket string) *S3 {
+	return &S3{
+		mc:     mc,
+		bucket: bucket,
+	}
+}
+
+func (s *S3) Get(ctx context.Context, key string) ([]byte, error) {
+	r, err := s.GetStream(ctx, key)
+	if err != nil {
+		return nil, err
+	}
+	defer r.Close()
+	b, err := io.ReadAll(r)
+	if err != nil {
+		return nil, fmt.Errorf("reading data from s3: %w", err)
+	}
+	return b, nil
+}
+func (s *S3) GetStream(ctx context.Context, key string) (io.ReadCloser, error) {
+	o, err := s.mc.GetObject(ctx, s.bucket, key, minio.GetObjectOptions{})
+	if err != nil {
+		err = fmt.Errorf("retrieving object from s3: %w", err)
+	}
+	return o, err
+}
+func (s *S3) PutStream(ctx context.Context, key string, r io.Reader) error {
+	if _, err := s.mc.PutObject(ctx, s.bucket, key, r, -1, minio.PutObjectOptions{}); err != nil {
+		return fmt.Errorf("uploading data stream: %w", err)
+	}
+	return nil
+}
+func (s *S3) Put(ctx context.Context, key string, value []byte) error {
+	if _, err := s.mc.PutObject(ctx, s.bucket, key, bytes.NewBuffer(value), -1, minio.PutObjectOptions{}); err != nil {
+		return fmt.Errorf("uploading data slice: %w", err)
+	}
+	return nil
+}
+func (s *S3) Delete(ctx context.Context, key string) error {
+	return s.mc.RemoveObject(ctx, s.bucket, key, minio.RemoveObjectOptions{})
+}
+func (s *S3) URL(ctx context.Context, key string) *url.URL {
+	// it's safe to ignore the error here, as we just fall back to fetching the
+	// file if the url request fails
+	url, _ := s.mc.PresignedGetObject(ctx, s.bucket, key, time.Hour, url.Values{
+		"response-content-type": []string{mime.TypeByExtension(path.Ext(key))},
+	})
+	return url
+}
diff --git a/internal/storage/storage.go b/internal/storage/storage.go
new file mode 100644
index 000000000..88577442f
--- /dev/null
+++ b/internal/storage/storage.go
@@ -0,0 +1,78 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package storage
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/url"
+	"path"
+
+	"codeberg.org/gruf/go-store/kv"
+	"codeberg.org/gruf/go-store/storage"
+	"github.com/minio/minio-go/v7"
+	"github.com/minio/minio-go/v7/pkg/credentials"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+)
+
+var (
+	ErrNotSupported = errors.New("driver does not suppport functionality")
+)
+
+// Driver implements the functionality to store and retrieve blobs
+// (images,video,audio)
+type Driver interface {
+	Get(ctx context.Context, key string) ([]byte, error)
+	GetStream(ctx context.Context, key string) (io.ReadCloser, error)
+	PutStream(ctx context.Context, key string, r io.Reader) error
+	Put(ctx context.Context, key string, value []byte) error
+	Delete(ctx context.Context, key string) error
+	URL(ctx context.Context, key string) *url.URL
+}
+
+func AutoConfig() (Driver, error) {
+	switch config.GetStorageBackend() {
+	case "s3":
+		mc, err := minio.New(config.GetStorageS3Endpoint(), &minio.Options{
+			Creds:  credentials.NewStaticV4(config.GetStorageS3AccessKey(), config.GetStorageS3SecretKey(), ""),
+			Secure: config.GetStorageS3UseSSL(),
+		})
+		if err != nil {
+			return nil, fmt.Errorf("creating minio client: %w", err)
+		}
+		return NewS3(mc, config.GetStorageS3BucketName()), nil
+	case "local":
+		storageBasePath := config.GetStorageLocalBasePath()
+		storage, err := kv.OpenFile(storageBasePath, &storage.DiskConfig{
+			// Put the store lockfile in the storage dir itself.
+			// Normally this would not be safe, since we could end up
+			// overwriting the lockfile if we store a file called 'store.lock'.
+			// However, in this case it's OK because the keys are set by
+			// GtS and not the user, so we know we're never going to overwrite it.
+			LockFile: path.Join(storageBasePath, "store.lock"),
+		})
+		if err != nil {
+			return nil, fmt.Errorf("error creating storage backend: %s", err)
+		}
+		return &Local{KVStore: storage}, nil
+	}
+	return nil, fmt.Errorf("invalid storage backend %s", config.GetStorageBackend())
+}