server: Move all the top level files into cmd folder. (#2490)

This change brings a change which was done for the 'mc'
package to allow for clean repo and have a cleaner
github drop in experience.

cmd/bucket-policy-migrate.go

@@ -0,0 +1,83 @@
+/*
+ * Minio Cloud Storage, (C) 2016 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 cmd
+
+import (
+	"bytes"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const policyJSON = "policy.json"
+
+func getBucketFromPolicyPath(oldPolicyPath string) string {
+	bucketPrefix, _ := filepath.Split(oldPolicyPath)
+	_, bucketName := filepath.Split(strings.TrimSuffix(bucketPrefix, slashSeparator))
+	return bucketName
+}
+
+func cleanupOldBucketPolicyConfigs() error {
+	// Get old bucket policy config directory.
+	oldBucketsConfigDir, err := getOldBucketsConfigPath()
+	fatalIf(err, "Unable to fetch buckets config path to migrate bucket policy")
+
+	// Recursively remove configDir/buckets/ - old bucket policy config location.
+	// N B This is called only if all bucket policies were successfully migrated.
+	return os.RemoveAll(oldBucketsConfigDir)
+}
+
+func migrateBucketPolicyConfig(objAPI ObjectLayer) error {
+	// Get old bucket policy config directory.
+	oldBucketsConfigDir, err := getOldBucketsConfigPath()
+	fatalIf(err, "Unable to fetch buckets config path to migrate bucket policy")
+
+	// Check if config directory holding bucket policy exists before
+	// migration.
+	_, err = os.Stat(oldBucketsConfigDir)
+	if os.IsNotExist(err) {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+
+	// WalkFunc that migrates access-policy.json to
+	// .minio.sys/buckets/bucketName/policy.json on all disks.
+	migrateBucketPolicy := func(policyPath string, fileInfo os.FileInfo, err error) error {
+		// policyFile - e.g /configDir/sample-bucket/access-policy.json
+		if err != nil {
+			return err
+		}
+		// Skip entries that aren't bucket policy files.
+		if fileInfo.Name() != "access-policy.json" {
+			return nil
+		}
+		// Get bucketName from old policy file path.
+		bucketName := getBucketFromPolicyPath(policyPath)
+		// Read bucket policy config from old location.
+		policyBytes, err := ioutil.ReadFile(policyPath)
+		fatalIf(err, "Unable to read bucket policy to migrate bucket policy", policyPath)
+		newPolicyPath := retainSlash(bucketConfigPrefix) + retainSlash(bucketName) + policyJSON
+		// Erasure code the policy config to all the disks.
+		_, err = objAPI.PutObject(minioMetaBucket, newPolicyPath, int64(len(policyBytes)), bytes.NewReader(policyBytes), nil)
+		fatalIf(err, "Unable to write bucket policy during migration.", newPolicyPath)
+		return nil
+	}
+	return filepath.Walk(oldBucketsConfigDir, migrateBucketPolicy)
+}