server: Sort ips based on their last octet value. (#2198)

host-to-ip.go

@@ -0,0 +1,47 @@
+/*
+ * 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 main
+
+import (
+	"net"
+	"sort"
+)
+
+// byLastOctet implements sort.Interface used in sorting a list
+// of ip address by their last octet value.
+type byLastOctet []net.IP
+
+func (n byLastOctet) Len() int      { return len(n) }
+func (n byLastOctet) Swap(i, j int) { n[i], n[j] = n[j], n[i] }
+func (n byLastOctet) Less(i, j int) bool {
+	return []byte(n[i].To4())[3] < []byte(n[j].To4())[3]
+}
+
+// getIPsFromHosts - returns a reverse sorted list of ips based on the last octet value.
+func getIPsFromHosts(hosts []string) (ips []net.IP) {
+	for _, host := range hosts {
+		ips = append(ips, net.ParseIP(host))
+	}
+	// Reverse sort ips by their last octet.
+	sort.Sort(sort.Reverse(byLastOctet(ips)))
+	return ips
+}
+
+// getHostToIP - parses a host string into net.IP value.
+func getHostToIP(host string) net.IP {
+	return net.ParseIP(host)
+}

host-to-ip_test.go

@@ -0,0 +1,61 @@
+/*
+ * 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 main
+
+import "testing"
+
+// Tests sorted list generated from hosts to ip.
+func TestHostToIP(t *testing.T) {
+	// Collection of test cases to validate last octet sorting.
+	testCases := []struct {
+		hosts       []string
+		sortedHosts []string
+	}{
+		{
+			// List of ip addresses that need to be sorted.
+			[]string{
+				"129.95.30.40",
+				"5.24.69.2",
+				"19.20.203.5",
+				"1.2.3.4",
+				"127.0.0.1",
+				"19.20.21.22",
+				"5.220.100.50",
+			},
+			// Numerical sorting result based on the last octet.
+			[]string{
+				"5.220.100.50",
+				"129.95.30.40",
+				"19.20.21.22",
+				"19.20.203.5",
+				"1.2.3.4",
+				"5.24.69.2",
+				"127.0.0.1",
+			},
+		},
+	}
+
+	// Tests the correct sorting behavior of getIPsFromHosts.
+	for j, testCase := range testCases {
+		ips := getIPsFromHosts(testCase.hosts)
+		for i, ip := range ips {
+			if ip.String() != testCase.sortedHosts[i] {
+				t.Fatalf("Test %d expected to pass but failed. Wanted ip %s, but got %s", j+1, testCase.sortedHosts[i], ip.String())
+			}
+		}
+	}
+}

server-main.go

@@ -21,7 +21,6 @@ import (
 	"net"
 	"net/http"
 	"os"
-	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -140,13 +139,14 @@ func finalizeEndpoints(tls bool, apiServer *http.Server) (endPoints []string) {
 		scheme = "https"
 	}
 
+	ips := getIPsFromHosts(hosts)
+
 	// Construct proper endpoints.
-	for _, host := range hosts {
-		endPoints = append(endPoints, fmt.Sprintf("%s://%s:%s", scheme, host, port))
+	for _, ip := range ips {
+		endPoints = append(endPoints, fmt.Sprintf("%s://%s:%s", scheme, ip.String(), port))
 	}
 
 	// Success.
-	sort.Strings(endPoints)
 	return endPoints
 }