Support for remote tier management (#12090)

With this change, MinIO's ILM supports transitioning objects to a remote tier.
This change includes support for Azure Blob Storage, AWS S3 compatible object
storage incl. MinIO and Google Cloud Storage as remote tier storage backends.

Some new additions include:

 - Admin APIs remote tier configuration management

 - Simple journal to track remote objects to be 'collected'
   This is used by object API handlers which 'mutate' object versions by
   overwriting/replacing content (Put/CopyObject) or removing the version
   itself (e.g DeleteObjectVersion).

 - Rework of previous ILM transition to fit the new model
   In the new model, a storage class (a.k.a remote tier) is defined by the
   'remote' object storage type (one of s3, azure, GCS), bucket name and a
   prefix.

* Fixed bugs, review comments, and more unit-tests

- Leverage inline small object feature
- Migrate legacy objects to the latest object format before transitioning
- Fix restore to particular version if specified
- Extend SharedDataDirCount to handle transitioned and restored objects
- Restore-object should accept version-id for version-suspended bucket (#12091)
- Check if remote tier creds have sufficient permissions
- Bonus minor fixes to existing error messages

Co-authored-by: Poorna Krishnamoorthy <poorna@minio.io>
Co-authored-by: Krishna Srinivas <krishna@minio.io>
Signed-off-by: Harshavardhana <harsha@minio.io>

pkg/madmin/tier-config_test.go

@@ -0,0 +1,126 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package madmin
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+// TestUnmarshalInvalidTierConfig tests that TierConfig parsing can catch invalid tier configs
+func TestUnmarshalInvalidTierConfig(t *testing.T) {
+	testCases := []struct {
+		cfg TierConfig
+		err error
+	}{
+		{
+			cfg: TierConfig{
+				Version: TierConfigV1,
+				Name:    "S3TIER?",
+				Type:    S3,
+				GCS: &TierGCS{
+					Creds:        "VWJ1bnR1IDIwLjA0LjEgTFRTIFxuIFxsCgo",
+					Bucket:       "ilmtesting",
+					Endpoint:     "https://storage.googleapis.com/",
+					Prefix:       "testprefix",
+					Region:       "us-west-2",
+					StorageClass: "",
+				},
+			},
+			err: ErrTierInvalidConfig,
+		},
+		{
+			cfg: TierConfig{
+				Version: "invalid-version",
+				Name:    "INVALIDTIER",
+				Type:    GCS,
+				GCS: &TierGCS{
+					Creds:        "VWJ1bnR1IDIwLjA0LjEgTFRTIFxuIFxsCgo",
+					Bucket:       "ilmtesting",
+					Endpoint:     "https://storage.googleapis.com/",
+					Prefix:       "testprefix",
+					Region:       "us-west-2",
+					StorageClass: "",
+				},
+			},
+			err: ErrTierInvalidConfigVersion,
+		},
+		{
+			cfg: TierConfig{
+				Version: TierConfigV1,
+				Type:    GCS,
+				GCS: &TierGCS{
+					Creds:        "VWJ1bnR1IDIwLjA0LjEgTFRTIFxuIFxsCgo",
+					Bucket:       "ilmtesting",
+					Endpoint:     "https://storage.googleapis.com/",
+					Prefix:       "testprefix",
+					Region:       "us-west-2",
+					StorageClass: "",
+				},
+			},
+			err: ErrTierNameEmpty,
+		},
+		{
+			cfg: TierConfig{
+				Version: TierConfigV1,
+				Name:    "GCSTIER",
+				Type:    GCS,
+				GCS: &TierGCS{
+					Creds:        "VWJ1bnR1IDIwLjA0LjEgTFRTIFxuIFxsCgo",
+					Bucket:       "ilmtesting",
+					Endpoint:     "https://storage.googleapis.com/",
+					Prefix:       "testprefix",
+					Region:       "us-west-2",
+					StorageClass: "",
+				},
+			},
+			err: nil,
+		},
+	}
+	for i, tc := range testCases {
+		data, err := json.Marshal(tc.cfg)
+		if err != nil {
+			t.Fatalf("Test %d: Failed to marshal tier config %v: %v", i+1, tc.cfg, err)
+		}
+		var cfg TierConfig
+		err = json.Unmarshal(data, &cfg)
+		if err != tc.err {
+			t.Fatalf("Test %d: Failed in unmarshal tier config %s: expected %v got %v", i+1, data, tc.err, err)
+		}
+	}
+
+	// Test invalid tier type
+	evilJSON := []byte(`{
+                             "Version": "v1",
+                             "Type" : "not-a-type",
+                             "Name" : "GCSTIER3",
+                             "GCS" : {
+                               "Bucket" : "ilmtesting",
+                               "Prefix" : "testprefix3",
+                               "Endpoint" : "https://storage.googleapis.com/",
+                               "Creds": "VWJ1bnR1IDIwLjA0LjEgTFRTIFxuIFxsCgo",
+                               "Region" : "us-west-2",
+                               "StorageClass" : ""
+                             }
+                            }`)
+	var cfg TierConfig
+	err := json.Unmarshal(evilJSON, &cfg)
+	if err != ErrTierTypeUnsupported {
+		t.Fatalf("Expected to fail with unsupported type but got %v", err)
+	}
+}