Admin Lib: Implement Service API (#3426)

Three APIs were added to control a minio server

* NewAdminClient()
* ServiceStop()
* ServiceRestart()
* ServiceStatus()

pkg/madmin/utils.go

@@ -0,0 +1,108 @@
+/*
+ * 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 madmin
+
+import (
+	"crypto/sha256"
+	"io"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/minio/minio-go/pkg/s3utils"
+)
+
+// sum256 calculate sha256 sum for an input byte array.
+func sum256(data []byte) []byte {
+	hash := sha256.New()
+	hash.Write(data)
+	return hash.Sum(nil)
+}
+
+// getEndpointURL - construct a new endpoint.
+func getEndpointURL(endpoint string, secure bool) (*url.URL, error) {
+	if strings.Contains(endpoint, ":") {
+		host, _, err := net.SplitHostPort(endpoint)
+		if err != nil {
+			return nil, err
+		}
+		if !s3utils.IsValidIP(host) && !s3utils.IsValidDomain(host) {
+			msg := "Endpoint: " + endpoint + " does not follow ip address or domain name standards."
+			return nil, ErrInvalidArgument(msg)
+		}
+	} else {
+		if !s3utils.IsValidIP(endpoint) && !s3utils.IsValidDomain(endpoint) {
+			msg := "Endpoint: " + endpoint + " does not follow ip address or domain name standards."
+			return nil, ErrInvalidArgument(msg)
+		}
+	}
+	// If secure is false, use 'http' scheme.
+	scheme := "https"
+	if !secure {
+		scheme = "http"
+	}
+
+	// Construct a secured endpoint URL.
+	endpointURLStr := scheme + "://" + endpoint
+	endpointURL, err := url.Parse(endpointURLStr)
+	if err != nil {
+		return nil, err
+	}
+
+	// Validate incoming endpoint URL.
+	if err := isValidEndpointURL(endpointURL.String()); err != nil {
+		return nil, err
+	}
+	return endpointURL, nil
+}
+
+// Verify if input endpoint URL is valid.
+func isValidEndpointURL(endpointURL string) error {
+	if endpointURL == "" {
+		return ErrInvalidArgument("Endpoint url cannot be empty.")
+	}
+	url, err := url.Parse(endpointURL)
+	if err != nil {
+		return ErrInvalidArgument("Endpoint url cannot be parsed.")
+	}
+	if url.Path != "/" && url.Path != "" {
+		return ErrInvalidArgument("Endpoint url cannot have fully qualified paths.")
+	}
+	return nil
+}
+
+// closeResponse close non nil response with any response Body.
+// convenient wrapper to drain any remaining data on response body.
+//
+// Subsequently this allows golang http RoundTripper
+// to re-use the same connection for future requests.
+func closeResponse(resp *http.Response) {
+	// Callers should close resp.Body when done reading from it.
+	// If resp.Body is not closed, the Client's underlying RoundTripper
+	// (typically Transport) may not be able to re-use a persistent TCP
+	// connection to the server for a subsequent "keep-alive" request.
+	if resp != nil && resp.Body != nil {
+		// Drain any remaining Body and then close the connection.
+		// Without this closing connection would disallow re-using
+		// the same connection for future uses.
+		//  - http://stackoverflow.com/a/17961593/4465767
+		io.Copy(ioutil.Discard, resp.Body)
+		resp.Body.Close()
+	}
+}