Revert and bring back B2 gateway implementation (#7224)

This PR is simply a revert of 3265112
just for B2 gateway.

cmd/gateway/b2/gateway-b2_test.go

@@ -0,0 +1,119 @@
+/*
+ * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package b2
+
+import (
+	"fmt"
+	"testing"
+
+	b2 "github.com/minio/blazer/base"
+
+	minio "github.com/minio/minio/cmd"
+)
+
+// Test b2 object error.
+func TestB2ObjectError(t *testing.T) {
+	testCases := []struct {
+		params      []string
+		b2Err       error
+		expectedErr error
+	}{
+		{
+			[]string{}, nil, nil,
+		},
+		{
+			[]string{}, fmt.Errorf("Not *Error"), fmt.Errorf("Not *Error"),
+		},
+		{
+			[]string{}, fmt.Errorf("Non B2 Error"), fmt.Errorf("Non B2 Error"),
+		},
+		{
+			[]string{"bucket"}, b2.Error{
+				StatusCode: 1,
+				Code:       "duplicate_bucket_name",
+			}, minio.BucketAlreadyOwnedByYou{
+				Bucket: "bucket",
+			},
+		},
+		{
+			[]string{"bucket"}, b2.Error{
+				StatusCode: 1,
+				Code:       "bad_request",
+			}, minio.BucketNotFound{
+				Bucket: "bucket",
+			},
+		},
+		{
+			[]string{"bucket", "object"}, b2.Error{
+				StatusCode: 1,
+				Code:       "bad_request",
+			}, minio.ObjectNameInvalid{
+				Bucket: "bucket",
+				Object: "object",
+			},
+		},
+		{
+			[]string{"bucket"}, b2.Error{
+				StatusCode: 1,
+				Code:       "bad_bucket_id",
+			}, minio.BucketNotFound{Bucket: "bucket"},
+		},
+		{
+			[]string{"bucket", "object"}, b2.Error{
+				StatusCode: 1,
+				Code:       "file_not_present",
+			}, minio.ObjectNotFound{
+				Bucket: "bucket",
+				Object: "object",
+			},
+		},
+		{
+			[]string{"bucket", "object"}, b2.Error{
+				StatusCode: 1,
+				Code:       "not_found",
+			}, minio.ObjectNotFound{
+				Bucket: "bucket",
+				Object: "object",
+			},
+		},
+		{
+			[]string{"bucket"}, b2.Error{
+				StatusCode: 1,
+				Code:       "cannot_delete_non_empty_bucket",
+			}, minio.BucketNotEmpty{
+				Bucket: "bucket",
+			},
+		},
+		{
+			[]string{"bucket", "object", "uploadID"}, b2.Error{
+				StatusCode: 1,
+				Message:    "No active upload for",
+			}, minio.InvalidUploadID{
+				UploadID: "uploadID",
+			},
+		},
+	}
+
+	for i, testCase := range testCases {
+		actualErr := b2ToObjectError(testCase.b2Err, testCase.params...)
+		if actualErr != nil {
+			if actualErr.Error() != testCase.expectedErr.Error() {
+				t.Errorf("Test %d: Expected %s, got %s", i+1, testCase.expectedErr, actualErr)
+			}
+		}
+	}
+}

cmd/gateway/gateway.go

@@ -23,5 +23,9 @@ import (
 	_ "github.com/minio/minio/cmd/gateway/nas"
 	_ "github.com/minio/minio/cmd/gateway/oss"
 	_ "github.com/minio/minio/cmd/gateway/s3"
+
+	// B2 is specifically kept here to avoid re-ordering by goimports,
+	// please ask on github.com/minio/minio/issues before changing this.
+	_ "github.com/minio/minio/cmd/gateway/b2"
 	// Add your gateway here.
 )

docs/gateway/README.md

@@ -5,3 +5,5 @@ Minio Gateway adds Amazon S3 compatibility to third party cloud storage provider
 - [S3](https://github.com/minio/minio/blob/master/docs/gateway/s3.md)
 - [Google Cloud Storage](https://github.com/minio/minio/blob/master/docs/gateway/gcs.md)
 - [Alibaba Cloud Storage](https://github.com/minio/minio/blob/master/docs/gateway/oss.md)
+- [Backblaze B2](https://github.com/minio/minio/blob/master/docs/gateway/b2.md)
+

docs/gateway/b2.md

@@ -0,0 +1,58 @@
+# Minio B2 Gateway [![Slack](https://slack.minio.io/slack?type=svg)](https://slack.minio.io)
+Minio Gateway adds Amazon S3 compatibility to Backblaze B2 Cloud Storage.
+
+## Run Minio Gateway for Backblaze B2 Cloud Storage
+Please follow this [guide](https://www.backblaze.com/b2/docs/quick_account.html) to create an account on backblaze.com to obtain your access credentials for B2 Cloud storage.
+
+### Using Docker
+```
+docker run -p 9000:9000 --name b2-s3 \
+ -e "MINIO_ACCESS_KEY=b2_account_id" \
+ -e "MINIO_SECRET_KEY=b2_application_key" \
+ minio/minio gateway b2
+```
+
+### Using Binary
+```
+export MINIO_ACCESS_KEY=b2_account_id
+export MINIO_SECRET_KEY=b2_application_key
+minio gateway b2
+```
+
+## Test using Minio Browser
+Minio Gateway comes with an embedded web based object browser. Point your web browser to http://127.0.0.1:9000 to ensure that your server has started successfully.
+
+![Screenshot](https://raw.githubusercontent.com/minio/minio/master/docs/screenshots/minio-browser-gateway.png)
+
+## Test using Minio Client `mc`
+`mc` provides a modern alternative to UNIX commands such as ls, cat, cp, mirror, diff etc. It supports filesystems and Amazon S3 compatible cloud storage services.
+
+### Configure `mc`
+```
+mc config host add myb2 http://gateway-ip:9000 b2_account_id b2_application_key
+```
+
+### List buckets on Backblaze B2
+```
+mc ls myb2
+[2017-02-22 01:50:43 PST]     0B ferenginar/
+[2017-02-26 21:43:51 PST]     0B my-bucket/
+[2017-02-26 22:10:11 PST]     0B test-bucket1/
+```
+
+### Known limitations
+Gateway inherits the following B2 limitations:
+
+- No support for CopyObject S3 API (There are no equivalent APIs available on Backblaze B2).
+- No support for CopyObjectPart S3 API (There are no equivalent APIs available on Backblaze B2).
+- Only read-only bucket policy supported at bucket level, all other variations will return API Notimplemented error.
+- DeleteObject() might not delete the object right away on Backblaze B2, so you might see the object immediately after a Delete request.
+
+Other limitations:
+
+- Bucket notification APIs are not supported.
+
+## Explore Further
+- [`mc` command-line interface](https://docs.minio.io/docs/minio-client-quickstart-guide)
+- [`aws` command-line interface](https://docs.minio.io/docs/aws-cli-with-minio)
+- [`minio-go` Go SDK](https://docs.minio.io/docs/golang-client-quickstart-guide)