TUN-7132 TUN-7136: Add filter support for streaming logs

Additionally adds similar support in cloudflared tail to provide
filters for events and log level.

management/events.go

@@ -48,7 +48,12 @@ type ClientEvent struct {
 // Additional filters can be provided to augment the log events requested.
 type EventStartStreaming struct {
 	ClientEvent
-	Filters []string `json:"filters"`
+	Filters *StreamingFilters `json:"filters,omitempty"`
+}
+
+type StreamingFilters struct {
+	Events []LogEventType `json:"events,omitempty"`
+	Level  *LogLevel      `json:"level,omitempty"`
 }
 
 // EventStopStreaming signifies that the client wishes to halt receiving log events.
@@ -65,7 +70,7 @@ type EventLog struct {
 // LogEventType is the way that logging messages are able to be filtered.
 // Example: assigning LogEventType.Cloudflared to a zerolog event will allow the client to filter for only
 // the Cloudflared-related events.
-type LogEventType int
+type LogEventType int8
 
 const (
 	// Cloudflared events are signficant to cloudflared operations like connection state changes.
@@ -76,6 +81,20 @@ const (
 	UDP
 )
 
+func ParseLogEventType(s string) (LogEventType, bool) {
+	switch s {
+	case "cloudflared":
+		return Cloudflared, true
+	case "http":
+		return HTTP, true
+	case "tcp":
+		return TCP, true
+	case "udp":
+		return UDP, true
+	}
+	return -1, false
+}
+
 func (l LogEventType) String() string {
 	switch l {
 	case Cloudflared:
@@ -91,18 +110,79 @@ func (l LogEventType) String() string {
 	}
 }
 
+func (l LogEventType) MarshalJSON() ([]byte, error) {
+	return json.Marshal(l.String())
+}
+
+func (e *LogEventType) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return errors.New("unable to unmarshal LogEventType string")
+	}
+	if event, ok := ParseLogEventType(s); ok {
+		*e = event
+		return nil
+	}
+	return errors.New("unable to unmarshal LogEventType")
+}
+
 // LogLevel corresponds to the zerolog logging levels
 // "panic", "fatal", and "trace" are exempt from this list as they are rarely used and, at least
 // the the first two are limited to failure conditions that lead to cloudflared shutting down.
-type LogLevel string
+type LogLevel int8
 
 const (
-	Debug LogLevel = "debug"
-	Info  LogLevel = "info"
-	Warn  LogLevel = "warn"
-	Error LogLevel = "error"
+	Debug LogLevel = 0
+	Info  LogLevel = 1
+	Warn  LogLevel = 2
+	Error LogLevel = 3
 )
 
+func ParseLogLevel(l string) (LogLevel, bool) {
+	switch l {
+	case "debug":
+		return Debug, true
+	case "info":
+		return Info, true
+	case "warn":
+		return Warn, true
+	case "error":
+		return Error, true
+	}
+	return -1, false
+}
+
+func (l LogLevel) String() string {
+	switch l {
+	case Debug:
+		return "debug"
+	case Info:
+		return "info"
+	case Warn:
+		return "warn"
+	case Error:
+		return "error"
+	default:
+		return ""
+	}
+}
+
+func (l LogLevel) MarshalJSON() ([]byte, error) {
+	return json.Marshal(l.String())
+}
+
+func (l *LogLevel) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return errors.New("unable to unmarshal LogLevel string")
+	}
+	if level, ok := ParseLogLevel(s); ok {
+		*l = level
+		return nil
+	}
+	return fmt.Errorf("unable to unmarshal LogLevel")
+}
+
 const (
 	// TimeKey aligns with the zerolog.TimeFieldName
 	TimeKey = "time"