Admin Info API (#13)

* Admin Info API

* Address comments

* Fix tests

restapi/admin_info.go

@@ -0,0 +1,88 @@
+// This file is part of MinIO Console Server
+// Copyright (c) 2020 MinIO, Inc.
+//
+// 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 restapi
+
+import (
+	"context"
+	"log"
+
+	"github.com/go-openapi/runtime/middleware"
+	"github.com/go-openapi/swag"
+	"github.com/minio/m3/mcs/models"
+	"github.com/minio/m3/mcs/restapi/operations"
+	"github.com/minio/m3/mcs/restapi/operations/admin_api"
+)
+
+func registerAdminInfoHandlers(api *operations.McsAPI) {
+	// session check
+	api.AdminAPIAdminInfoHandler = admin_api.AdminInfoHandlerFunc(func(params admin_api.AdminInfoParams, principal *models.Principal) middleware.Responder {
+		infoResp, err := getAdminInfoResponse()
+		if err != nil {
+			return admin_api.NewAdminInfoDefault(500).WithPayload(&models.Error{Code: 500, Message: swag.String(err.Error())})
+		}
+		return admin_api.NewAdminInfoOK().WithPayload(infoResp)
+	})
+
+}
+
+type UsageInfo struct {
+	Buckets int64
+	Objects int64
+	Usage   int64
+}
+
+// getAdminInfo invokes admin info and returns a parsed `UsageInfo` structure
+func getAdminInfo(ctx context.Context, client MinioAdmin) (*UsageInfo, error) {
+	serverInfo, err := client.serverInfo(ctx)
+	if err != nil {
+		return nil, err
+	}
+	// we are trimming uint64 to int64 this will report an incorrect measurement for numbers greater than
+	// 9,223,372,036,854,775,807
+	return &UsageInfo{
+		Buckets: int64(serverInfo.Buckets.Count),
+		Objects: int64(serverInfo.Objects.Count),
+		Usage:   int64(serverInfo.Usage.Size),
+	}, nil
+}
+
+// getAdminInfoResponse returns the response containing total buckets, objects and usage.
+func getAdminInfoResponse() (*models.AdminInfoResponse, error) {
+	mAdmin, err := newMAdminClient()
+	if err != nil {
+		log.Println("error creating Madmin Client:", err)
+		return nil, err
+	}
+	// create a minioClient interface implementation
+	// defining the client to be used
+	adminClient := adminClient{client: mAdmin}
+	// 20 seconds timeout
+	ctx, cancel := context.WithTimeout(context.Background(), 20)
+	defer cancel()
+	// serialize output
+	usage, err := getAdminInfo(ctx, adminClient)
+	if err != nil {
+		log.Println("error getting information:", err)
+		return nil, err
+	}
+	sessionResp := &models.AdminInfoResponse{
+		Buckets: usage.Buckets,
+		Objects: usage.Objects,
+		Usage:   usage.Usage,
+	}
+	return sessionResp, nil
+}