MM-27493 Shared channels (MVP) (#17301)

Remote Cluster Service
- provides ability for multiple Mattermost cluster instances to create a trusted connection with each other and exchange messages
- trusted connections are managed via slash commands (for now)
- facilitates features requiring inter-cluster communication, such as Shared Channels
Shared Channels Service
- provides ability to shared channels between one or more Mattermost cluster instances (using trusted connection)
- sharing/unsharing of channels is managed via slash commands (for now)

shared/mlog/default.go

@@ -33,6 +33,10 @@ func defaultLog(level, msg string, fields ...Field) {
 	}
 }
 
+func defaultIsLevelEnabled(level LogLevel) bool {
+	return true
+}
+
 func defaultDebugLog(msg string, fields ...Field) {
 	defaultLog("debug", msg, fields...)
 }

shared/mlog/global.go

@@ -23,6 +23,7 @@ func InitGlobalLogger(logger *Logger) {
 	glob := *logger
 	glob.zap = glob.zap.WithOptions(zap.AddCallerSkip(1))
 	globalLogger = &glob
+	IsLevelEnabled = globalLogger.IsLevelEnabled
 	Debug = globalLogger.Debug
 	Info = globalLogger.Info
 	Warn = globalLogger.Warn
@@ -59,6 +60,7 @@ func RedirectStdLog(logger *Logger) {
 	log.SetOutput(logWriterFunc(writer))
 }
 
+type IsLevelEnabledFunc func(LogLevel) bool
 type LogFunc func(string, ...Field)
 type LogFuncCustom func(LogLevel, string, ...Field)
 type LogFuncCustomMulti func([]LogLevel, string, ...Field)
@@ -79,6 +81,7 @@ func GloballyEnableDebugLogForTest() {
 	globalLogger.consoleLevel.SetLevel(zapcore.DebugLevel)
 }
 
+var IsLevelEnabled IsLevelEnabledFunc = defaultIsLevelEnabled
 var Debug LogFunc = defaultDebugLog
 var Info LogFunc = defaultInfoLog
 var Warn LogFunc = defaultWarnLog

shared/mlog/levels.go

@@ -30,6 +30,18 @@ var (
 	// used by the TCP log target
 	LvlTcpLogTarget = LogLevel{ID: 120, Name: "TcpLogTarget"}
 
+	// used by Remote Cluster Service
+	LvlRemoteClusterServiceDebug = LogLevel{ID: 130, Name: "RemoteClusterServiceDebug"}
+	LvlRemoteClusterServiceError = LogLevel{ID: 131, Name: "RemoteClusterServiceError"}
+	LvlRemoteClusterServiceWarn  = LogLevel{ID: 132, Name: "RemoteClusterServiceWarn"}
+
+	// used by Shared Channel Sync Service
+	LvlSharedChannelServiceDebug            = LogLevel{ID: 200, Name: "SharedChannelServiceDebug"}
+	LvlSharedChannelServiceError            = LogLevel{ID: 201, Name: "SharedChannelServiceError"}
+	LvlSharedChannelServiceWarn             = LogLevel{ID: 202, Name: "SharedChannelServiceWarn"}
+	LvlSharedChannelServiceMessagesInbound  = LogLevel{ID: 203, Name: "SharedChannelServiceMsgInbound"}
+	LvlSharedChannelServiceMessagesOutbound = LogLevel{ID: 204, Name: "SharedChannelServiceMsgOutbound"}
+
 	// add more here ...
 )
 

shared/mlog/log.go

@@ -57,6 +57,17 @@ var NamedErr = zap.NamedError
 var Bool = zap.Bool
 var Duration = zap.Duration
 
+type LoggerIFace interface {
+	IsLevelEnabled(LogLevel) bool
+	Debug(string, ...Field)
+	Info(string, ...Field)
+	Warn(string, ...Field)
+	Error(string, ...Field)
+	Critical(string, ...Field)
+	Log(LogLevel, string, ...Field)
+	LogM([]LogLevel, string, ...Field)
+}
+
 type TargetInfo logr.TargetInfo
 
 type LoggerConfiguration struct {
@@ -207,6 +218,10 @@ func (l *Logger) Sugar() *SugarLogger {
 	}
 }
 
+func (l *Logger) IsLevelEnabled(level LogLevel) bool {
+	return isLevelEnabled(l.getLogger(), logr.Level(level))
+}
+
 func (l *Logger) Debug(message string, fields ...Field) {
 	l.zap.Debug(message, fields...)
 	if isLevelEnabled(l.getLogger(), logr.Debug) {