Add new site config sub-system intended to replace region (#13672)

- New sub-system has "region" and "name" fields.

- `region` subsystem is marked as deprecated, however still works, unless the
new region parameter under `site` is set - in this case, the region subsystem is
ignored. `region` subsystem is hidden from top-level help (i.e. from `mc admin
config set myminio`), but appears when specifically requested (i.e. with `mc
admin config set myminio region`).

- MINIO_REGION, MINIO_REGION_NAME are supported as legacy environment variables for server region.

- Adds MINIO_SITE_REGION as the current environment variable to configure the
server region and MINIO_SITE_NAME for the site name.

internal/config/config.go

@@ -55,6 +55,8 @@ const (
 	EnableOn  = madmin.EnableOn
 	EnableOff = madmin.EnableOff
 
+	RegionKey  = "region"
+	NameKey    = "name"
 	RegionName = "name"
 	AccessKey  = "access_key"
 	SecretKey  = "secret_key"
@@ -69,6 +71,7 @@ const (
 	IdentityLDAPSubSys   = "identity_ldap"
 	IdentityTLSSubSys    = "identity_tls"
 	CacheSubSys          = "cache"
+	SiteSubSys           = "site"
 	RegionSubSys         = "region"
 	EtcdSubSys           = "etcd"
 	StorageClassSubSys   = "storage_class"
@@ -104,6 +107,7 @@ const (
 // SubSystems - all supported sub-systems
 var SubSystems = set.CreateStringSet(
 	CredentialsSubSys,
+	SiteSubSys,
 	RegionSubSys,
 	EtcdSubSys,
 	CacheSubSys,
@@ -144,6 +148,7 @@ var SubSystemsDynamic = set.CreateStringSet(
 // SubSystemsSingleTargets - subsystems which only support single target.
 var SubSystemsSingleTargets = set.CreateStringSet([]string{
 	CredentialsSubSys,
+	SiteSubSys,
 	RegionSubSys,
 	EtcdSubSys,
 	CacheSubSys,
@@ -202,6 +207,19 @@ func RegisterHelpSubSys(helpKVSMap map[string]HelpKVS) {
 	}
 }
 
+// HelpDeprecatedSubSysMap - help for all deprecated sub-systems, that may be
+// removed in the future.
+var HelpDeprecatedSubSysMap map[string]HelpKV
+
+// RegisterHelpDeprecatedSubSys - saves input help KVS for deprecated
+// sub-systems globally. Should be called only once at init.
+func RegisterHelpDeprecatedSubSys(helpDeprecatedKVMap map[string]HelpKV) {
+	HelpDeprecatedSubSysMap = map[string]HelpKV{}
+	for k, v := range helpDeprecatedKVMap {
+		HelpDeprecatedSubSysMap[k] = v
+	}
+}
+
 // KV - is a shorthand of each key value.
 type KV struct {
 	Key   string `json:"key"`
@@ -449,6 +467,17 @@ var (
 		},
 	}
 
+	DefaultSiteKVS = KVS{
+		KV{
+			Key:   NameKey,
+			Value: "",
+		},
+		KV{
+			Key:   RegionKey,
+			Value: "",
+		},
+	}
+
 	DefaultRegionKVS = KVS{
 		KV{
 			Key:   RegionName,
@@ -471,26 +500,66 @@ func LookupCreds(kv KVS) (auth.Credentials, error) {
 	return auth.CreateCredentials(accessKey, secretKey)
 }
 
+// Site - holds site info - name and region.
+type Site struct {
+	Name   string
+	Region string
+}
+
 var validRegionRegex = regexp.MustCompile("^[a-zA-Z][a-zA-Z0-9-_-]+$")
 
-// LookupRegion - get current region.
-func LookupRegion(kv KVS) (string, error) {
-	if err := CheckValidKeys(RegionSubSys, kv, DefaultRegionKVS); err != nil {
-		return "", err
+// validSiteNameRegex - allows lowercase letters, digits and '-', starts with
+// letter. At least 2 characters long.
+var validSiteNameRegex = regexp.MustCompile("^[a-z][a-z0-9-]+$")
+
+// LookupSite - get site related configuration. Loads configuration from legacy
+// region sub-system as well.
+func LookupSite(siteKV KVS, regionKV KVS) (s Site, err error) {
+	if err = CheckValidKeys(SiteSubSys, siteKV, DefaultSiteKVS); err != nil {
+		return
 	}
 	region := env.Get(EnvRegion, "")
 	if region == "" {
-		region = env.Get(EnvRegionName, kv.Get(RegionName))
+		env.Get(EnvRegionName, "")
+	}
+	if region == "" {
+		region = env.Get(EnvSiteRegion, siteKV.Get(RegionKey))
+	}
+	if region == "" {
+		// No region config found in the site-subsystem. So lookup the legacy
+		// region sub-system.
+		if err = CheckValidKeys(RegionSubSys, regionKV, DefaultRegionKVS); err != nil {
+			// An invalid key was found in the region sub-system.
+			// Since the region sub-system cannot be (re)set as it
+			// is legacy, we return an error to tell the user to
+			// reset the region via the new command.
+			err = Errorf("could not load region from legacy configuration as it was invalid - use 'mc admin config set myminio site region=myregion name=myname' to set a region and name (%v)", err)
+			return
+		}
+
+		region = regionKV.Get(RegionName)
 	}
 	if region != "" {
-		if validRegionRegex.MatchString(region) {
-			return region, nil
+		if !validRegionRegex.MatchString(region) {
+			err = Errorf(
+				"region '%s' is invalid, expected simple characters such as [us-east-1, myregion...]",
+				region)
+			return
 		}
-		return "", Errorf(
-			"region '%s' is invalid, expected simple characters such as [us-east-1, myregion...]",
-			region)
+		s.Region = region
 	}
-	return "", nil
+
+	name := env.Get(EnvSiteName, siteKV.Get(NameKey))
+	if name != "" {
+		if !validSiteNameRegex.MatchString(name) {
+			err = Errorf(
+				"site name '%s' is invalid, expected simple characters such as [cal-rack0, myname...]",
+				name)
+			return
+		}
+		s.Name = name
+	}
+	return
 }
 
 // CheckValidKeys - checks if inputs KVS has the necessary keys,
@@ -626,9 +695,14 @@ func (c Config) GetKVS(s string, defaultKVS map[string]KVS) (Targets, error) {
 			KVS:       kvs,
 		})
 	} else {
-		hkvs := HelpSubSysMap[""]
-		// Use help for sub-system to preserve the order.
-		for _, hkv := range hkvs {
+		// Use help for sub-system to preserve the order. Add deprecated
+		// keys at the end (in some order).
+		kvsOrder := append([]HelpKV{}, HelpSubSysMap[""]...)
+		for _, v := range HelpDeprecatedSubSysMap {
+			kvsOrder = append(kvsOrder, v)
+		}
+
+		for _, hkv := range kvsOrder {
 			if !strings.HasPrefix(hkv.Key, subSysPrefix) {
 				continue
 			}

internal/config/constants.go

@@ -31,12 +31,14 @@ const (
 
 	EnvBrowser    = "MINIO_BROWSER"
 	EnvDomain     = "MINIO_DOMAIN"
-	EnvRegionName = "MINIO_REGION_NAME"
 	EnvPublicIPs  = "MINIO_PUBLIC_IPS"
 	EnvFSOSync    = "MINIO_FS_OSYNC"
 	EnvArgs       = "MINIO_ARGS"
 	EnvDNSWebhook = "MINIO_DNS_WEBHOOK_ENDPOINT"
 
+	EnvSiteName   = "MINIO_SITE_NAME"
+	EnvSiteRegion = "MINIO_SITE_REGION"
+
 	EnvMinIOSubnetLicense      = "MINIO_SUBNET_LICENSE"
 	EnvMinIOServerURL          = "MINIO_SERVER_URL"
 	EnvMinIOBrowserRedirectURL = "MINIO_BROWSER_REDIRECT_URL"
@@ -51,7 +53,8 @@ const (
 	EnvKESClientCert = "MINIO_KMS_KES_CERT_FILE"
 	EnvKESServerCA   = "MINIO_KMS_KES_CAPATH"
 
-	EnvEndpoints = "MINIO_ENDPOINTS" // legacy
-	EnvWorm      = "MINIO_WORM"      // legacy
-	EnvRegion    = "MINIO_REGION"    // legacy
+	EnvEndpoints  = "MINIO_ENDPOINTS"   // legacy
+	EnvWorm       = "MINIO_WORM"        // legacy
+	EnvRegion     = "MINIO_REGION"      // legacy
+	EnvRegionName = "MINIO_REGION_NAME" // legacy
 )

internal/config/help.go

@@ -49,13 +49,34 @@ func (hkvs HelpKVS) Lookup(key string) (HelpKV, bool) {
 // DefaultComment used across all sub-systems.
 const DefaultComment = "optionally add a comment to this setting"
 
-// Region and Worm help is documented in default config
+// Region help is documented in default config
 var (
+	SiteHelp = HelpKVS{
+		HelpKV{
+			Key:         NameKey,
+			Type:        "string",
+			Description: `name for the site e.g. "cal-rack0"`,
+			Optional:    true,
+		},
+		HelpKV{
+			Key:         RegionKey,
+			Type:        "string",
+			Description: `name of the location of the server e.g. "us-west-1"`,
+			Optional:    true,
+		},
+		HelpKV{
+			Key:         Comment,
+			Type:        "sentence",
+			Description: DefaultComment,
+			Optional:    true,
+		},
+	}
+
 	RegionHelp = HelpKVS{
 		HelpKV{
 			Key:         RegionName,
 			Type:        "string",
-			Description: `name of the location of the server e.g. "us-west-rack2"`,
+			Description: `[DEPRECATED] name of the location of the server e.g. "us-west-rack2"`,
 			Optional:    true,
 		},
 		HelpKV{