Add config to store subnet license (#13194)

Command to set subnet license:

`mc admin config set {alias} subnet license={token}`

Signed-off-by: Shireesh Anjal <shireesh@minio.io>
Co-authored-by: Harshavardhana <harsha@minio.io>

internal/config/config.go

@@ -58,6 +58,7 @@ const (
 	RegionName = "name"
 	AccessKey  = "access_key"
 	SecretKey  = "secret_key"
+	License    = "license"
 )
 
 // Top level config constants.
@@ -79,6 +80,7 @@ const (
 	HealSubSys           = "heal"
 	ScannerSubSys        = "scanner"
 	CrawlerSubSys        = "crawler"
+	SubnetSubSys         = "subnet"
 
 	// Add new constants here if you add new fields to config.
 )
@@ -127,6 +129,7 @@ var SubSystems = set.CreateStringSet(
 	NotifyPostgresSubSys,
 	NotifyRedisSubSys,
 	NotifyWebhookSubSys,
+	SubnetSubSys,
 )
 
 // SubSystemsDynamic - all sub-systems that have dynamic config.
@@ -135,6 +138,7 @@ var SubSystemsDynamic = set.CreateStringSet(
 	CompressionSubSys,
 	ScannerSubSys,
 	HealSubSys,
+	SubnetSubSys,
 )
 
 // SubSystemsSingleTargets - subsystems which only support single target.

internal/config/subnet/license.go

@@ -0,0 +1,71 @@
+// 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 subnet
+
+import (
+	jwtgo "github.com/golang-jwt/jwt"
+	"github.com/minio/minio/internal/config"
+	"github.com/minio/pkg/env"
+)
+
+var (
+	// DefaultKVS - default KV config for subnet settings
+	DefaultKVS = config.KVS{
+		config.KV{
+			Key:   config.License,
+			Value: "",
+		},
+	}
+
+	// HelpLicense - provides help for license config
+	HelpLicense = config.HelpKVS{
+		config.HelpKV{
+			Key:         config.License,
+			Type:        "string",
+			Description: "Subnet license token for the cluster",
+			Optional:    true,
+		},
+	}
+)
+
+// Config represents the subnet related configuration
+type Config struct {
+	// The subnet license token
+	License string `json:"license"`
+}
+
+func validateLicenseFormat(lic string) error {
+	if len(lic) == 0 {
+		return nil
+	}
+
+	// Only verifying that the string is a parseable JWT token as of now
+	_, _, err := new(jwtgo.Parser).ParseUnverified(lic, jwtgo.MapClaims{})
+	return err
+}
+
+// LookupConfig - lookup config and override with valid environment settings if any.
+func LookupConfig(kvs config.KVS) (cfg Config, err error) {
+	if err = config.CheckValidKeys(config.SubnetSubSys, kvs, DefaultKVS); err != nil {
+		return cfg, err
+	}
+
+	cfg.License = env.Get(config.EnvMinIOSubnetLicense, kvs.Get(config.License))
+
+	return cfg, validateLicenseFormat(cfg.License)
+}