Migrate config to KV data format (#8392)

- adding oauth support to MinIO browser (#8400) by @kanagaraj
- supports multi-line get/set/del for all config fields
- add support for comments, allow toggle
- add extensive validation of config before saving
- support MinIO browser to support proper claims, using STS tokens
- env support for all config parameters, legacy envs are also
  supported with all documentation now pointing to latest ENVs
- preserve accessKey/secretKey from FS mode setups
- add history support implements three APIs
  - ClearHistory
  - RestoreHistory
  - ListHistory
- add help command support for each config parameters
- all the bug fixes after migration to KV, and other bug
  fixes encountered during testing.

pkg/madmin/config-history-commands.go

@@ -0,0 +1,107 @@
+/*
+ * MinIO Cloud Storage, (C) 2019 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 (
+	"encoding/json"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+// ClearConfigHistoryKV - clears the config entry represented by restoreID.
+// optionally allows setting `all` as a special keyword to automatically
+// erase all config set history entires.
+func (adm *AdminClient) ClearConfigHistoryKV(restoreID string) (err error) {
+	v := url.Values{}
+	v.Set("restoreId", restoreID)
+	reqData := requestData{
+		relPath:     adminAPIPrefix + "/clear-config-history-kv",
+		queryValues: v,
+	}
+
+	// Execute DELETE on /minio/admin/v2/clear-config-history-kv
+	resp, err := adm.executeMethod(http.MethodDelete, reqData)
+
+	defer closeResponse(resp)
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return httpRespToErrorResponse(resp)
+	}
+
+	return nil
+}
+
+// RestoreConfigHistoryKV - Restore a previous config set history.
+// Input is a unique id which represents the previous setting.
+func (adm *AdminClient) RestoreConfigHistoryKV(restoreID string) (err error) {
+	v := url.Values{}
+	v.Set("restoreId", restoreID)
+	reqData := requestData{
+		relPath:     adminAPIPrefix + "/restore-config-history-kv",
+		queryValues: v,
+	}
+
+	// Execute PUT on /minio/admin/v2/set-config-kv to set config key/value.
+	resp, err := adm.executeMethod(http.MethodPut, reqData)
+
+	defer closeResponse(resp)
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return httpRespToErrorResponse(resp)
+	}
+
+	return nil
+}
+
+// ConfigHistoryEntry - captures config set history with a unique
+// restore ID and createTime
+type ConfigHistoryEntry struct {
+	RestoreID  string    `json:"restoreId"`
+	CreateTime time.Time `json:"createTime"`
+}
+
+// ListConfigHistoryKV - lists a slice of ConfigHistoryEntries sorted by createTime.
+func (adm *AdminClient) ListConfigHistoryKV() ([]ConfigHistoryEntry, error) {
+	// Execute GET on /minio/admin/v2/list-config-history-kv
+	resp, err := adm.executeMethod(http.MethodGet,
+		requestData{
+			relPath: adminAPIPrefix + "/list-config-history-kv",
+		})
+	defer closeResponse(resp)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, httpRespToErrorResponse(resp)
+	}
+
+	var chEntries []ConfigHistoryEntry
+	d := json.NewDecoder(resp.Body)
+	d.DisallowUnknownFields()
+	if err = d.Decode(&chEntries); err != nil {
+		return chEntries, err
+	}
+	return chEntries, nil
+}