Add unit-tests for formatting disks during initialization (#2635)

* Add unit-tests for formatting disks during initialization

- Fixed corresponding code at places where it was deviating from the
  tabular spec.

* Added more test cases and simplified algo

... based on feedback from ``go test -coverprofile``.

cmd/prepare-storage.go

@@ -60,7 +60,7 @@ func init() {
   | Quorum   | 				|  "Heal via minioctl"  |
   |          | Quorum UnFormatted   	|                   	|
   +----------+--------------------------+-----------------------+
-  | No       |           		|  Wait till enough     |
+  | No       |          		|  Wait till enough     |
   | Quorum   |          _  		|  nodes are online and |
   |	     |                          |  one of the above     |
   |          |				|  sections apply       |
@@ -121,22 +121,28 @@ func prepForInit(disks []string, sErrs []error, diskCount int) InitActions {
 			return FormatDisks
 		}
 		return WaitForFormatting
-	} else if (disksUnformatted >= quorum) && (disksUnformatted+disksOffline == diskCount) {
+	} else if disksUnformatted >= quorum {
-		return WaitForAll
+		if disksUnformatted+disksOffline == diskCount {
+			return WaitForAll
+		}
+		// Some disks possibly corrupted.
+		return WaitForHeal
 	}
 
 	// Already formatted, proceed to initialization of object layer.
 	if disksFormatted == diskCount {
 		return InitObjectLayer
-	} else if disksFormatted >= quorum && disksFormatted+disksOffline == diskCount {
-		return InitObjectLayer
 	} else if disksFormatted >= quorum {
-		// TODO: Print minioctl heal command
+		if (disksFormatted+disksOffline == diskCount) ||
-		return InitObjectLayer
+			(disksFormatted+disksUnformatted == diskCount) {
+			return InitObjectLayer
+		}
+		// Some disks possibly corrupted.
+		return WaitForHeal
 	}
 
 	// No Quorum.
-	if disksOffline > quorum {
+	if disksOffline >= quorum {
 		return WaitForQuorum
 	}
 

cmd/prepare-storage_test.go

@@ -0,0 +1,153 @@
+/*
+ * 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 (
+	"runtime"
+	"testing"
+)
+
+func (action InitActions) String() string {
+	switch action {
+	case InitObjectLayer:
+		return "InitObjectLayer"
+	case FormatDisks:
+		return "FormatDisks"
+	case WaitForFormatting:
+		return "WaitForFormatting"
+	case WaitForHeal:
+		return "WaitForHeal"
+	case WaitForAll:
+		return "WaitForAll"
+	case WaitForQuorum:
+		return "WaitForQuorum"
+	case Abort:
+		return "Abort"
+	default:
+		return "Unknown"
+	}
+}
+func TestPrepForInit(t *testing.T) {
+	var disks []string
+	if runtime.GOOS == "windows" {
+		disks = []string{
+			`c:\mnt\disk1`,
+			`c:\mnt\disk2`,
+			`c:\mnt\disk3`,
+			`c:\mnt\disk4`,
+			`c:\mnt\disk5`,
+			`c:\mnt\disk6`,
+			`c:\mnt\disk7`,
+			`c:\mnt\disk8`,
+		}
+	} else {
+		disks = []string{
+			"/mnt/disk1",
+			"/mnt/disk2",
+			"/mnt/disk3",
+			"/mnt/disk4",
+			"/mnt/disk5",
+			"/mnt/disk6",
+			"/mnt/disk7",
+			"/mnt/disk8",
+		}
+	}
+	// Building up disks that resolve to localhost and remote w.r.t isLocalStorage().
+	var (
+		disksLocal  []string
+		disksRemote []string
+	)
+	for i := range disks {
+		disksLocal = append(disksLocal, "localhost:"+disks[i])
+	}
+	// Using 4.4.4.4 as a known non-local address.
+	for i := range disks {
+		disksRemote = append(disksRemote, "4.4.4.4:"+disks[i])
+	}
+	// All disks are unformatted, a fresh setup.
+	allUnformatted := []error{
+		errUnformattedDisk, errUnformattedDisk, errUnformattedDisk, errUnformattedDisk,
+		errUnformattedDisk, errUnformattedDisk, errUnformattedDisk, errUnformattedDisk,
+	}
+	// All disks are formatted, possible restart of a node in a formatted setup.
+	allFormatted := []error{
+		nil, nil, nil, nil,
+		nil, nil, nil, nil,
+	}
+	// Quorum number of disks are formatted and rest are offline.
+	quorumFormatted := []error{
+		nil, nil, nil, nil,
+		nil, errDiskNotFound, errDiskNotFound, errDiskNotFound,
+	}
+	// Minority disks are corrupted, can be healed.
+	minorityCorrupted := []error{
+		errCorruptedFormat, errCorruptedFormat, errCorruptedFormat, nil,
+		nil, nil, nil, nil,
+	}
+	// Majority disks are corrupted, pretty bad setup.
+	majorityCorrupted := []error{
+		errCorruptedFormat, errCorruptedFormat, errCorruptedFormat, errCorruptedFormat,
+		errCorruptedFormat, nil, nil, nil,
+	}
+	// Quorum disks are unformatted, remaining yet to come online.
+	quorumUnformatted := []error{
+		errUnformattedDisk, errUnformattedDisk, errUnformattedDisk, errUnformattedDisk,
+		errUnformattedDisk, errDiskNotFound, errDiskNotFound, errDiskNotFound,
+	}
+	quorumUnformattedSomeCorrupted := []error{
+		errUnformattedDisk, errUnformattedDisk, errUnformattedDisk, errUnformattedDisk,
+		errUnformattedDisk, errCorruptedFormat, errCorruptedFormat, errDiskNotFound,
+	}
+	// Quorum number of disks not online yet.
+	noQuourm := []error{
+		errDiskNotFound, errDiskNotFound, errDiskNotFound, errDiskNotFound,
+		errDiskNotFound, nil, nil, nil,
+	}
+
+	testCases := []struct {
+		// Params for prepForInit().
+		disks     []string
+		errs      []error
+		diskCount int
+		action    InitActions
+	}{
+		// Local disks.
+		{disksLocal, allFormatted, 8, InitObjectLayer},
+		{disksLocal, quorumFormatted, 8, InitObjectLayer},
+		{disksLocal, allUnformatted, 8, FormatDisks},
+		{disksLocal, quorumUnformatted, 8, WaitForAll},
+		{disksLocal, quorumUnformattedSomeCorrupted, 8, WaitForHeal},
+		{disksLocal, noQuourm, 8, WaitForQuorum},
+		{disksLocal, minorityCorrupted, 8, WaitForHeal},
+		{disksLocal, majorityCorrupted, 8, Abort},
+		// Remote disks.
+		{disksRemote, allFormatted, 8, InitObjectLayer},
+		{disksRemote, quorumFormatted, 8, InitObjectLayer},
+		{disksRemote, allUnformatted, 8, WaitForFormatting},
+		{disksRemote, quorumUnformatted, 8, WaitForAll},
+		{disksRemote, quorumUnformattedSomeCorrupted, 8, WaitForHeal},
+		{disksRemote, noQuourm, 8, WaitForQuorum},
+		{disksRemote, minorityCorrupted, 8, WaitForHeal},
+		{disksRemote, majorityCorrupted, 8, Abort},
+	}
+	for i, test := range testCases {
+		actual := prepForInit(test.disks, test.errs, test.diskCount)
+		if actual != test.action {
+			t.Errorf("Test %d expected %s but receieved %s\n", i+1, test.action, actual)
+		}
+	}
+}