cloudflared-mirror/management/events.go

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package management
import (
"context"
"errors"
"fmt"
"io"
jsoniter "github.com/json-iterator/go"
"github.com/rs/zerolog"
"nhooyr.io/websocket"
)
var (
errInvalidMessageType = fmt.Errorf("invalid message type was provided")
)
// ServerEventType represents the event types that can come from the server
type ServerEventType string
// ClientEventType represents the event types that can come from the client
type ClientEventType string
const (
UnknownClientEventType ClientEventType = ""
StartStreaming ClientEventType = "start_streaming"
StopStreaming ClientEventType = "stop_streaming"
UnknownServerEventType ServerEventType = ""
Logs ServerEventType = "logs"
)
// ServerEvent is the base struct that informs, based of the Type field, which Event type was provided from the server.
type ServerEvent struct {
Type ServerEventType `json:"type,omitempty"`
// The raw json message is provided to allow better deserialization once the type is known
event jsoniter.RawMessage
}
// ClientEvent is the base struct that informs, based of the Type field, which Event type was provided from the client.
type ClientEvent struct {
Type ClientEventType `json:"type,omitempty"`
// The raw json message is provided to allow better deserialization once the type is known
event jsoniter.RawMessage
}
// EventStartStreaming signifies that the client wishes to start receiving log events.
// Additional filters can be provided to augment the log events requested.
type EventStartStreaming struct {
ClientEvent
Filters []string `json:"filters"`
}
// EventStopStreaming signifies that the client wishes to halt receiving log events.
type EventStopStreaming struct {
ClientEvent
}
// EventLog is the event that the server sends to the client with the log events.
type EventLog struct {
ServerEvent
Logs []*Log `json:"logs"`
}
// 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
const (
// Cloudflared events are signficant to cloudflared operations like connection state changes.
// Cloudflared is also the default event type for any events that haven't been separated into a proper event type.
Cloudflared LogEventType = iota
HTTP
TCP
UDP
)
func (l LogEventType) String() string {
switch l {
case Cloudflared:
return "cloudflared"
case HTTP:
return "http"
case TCP:
return "tcp"
case UDP:
return "udp"
default:
return ""
}
}
// 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
const (
Debug LogLevel = "debug"
Info LogLevel = "info"
Warn LogLevel = "warn"
Error LogLevel = "error"
)
const (
// TimeKey aligns with the zerolog.TimeFieldName
TimeKey = "time"
// LevelKey aligns with the zerolog.LevelFieldName
LevelKey = "level"
// LevelKey aligns with the zerolog.MessageFieldName
MessageKey = "message"
// EventTypeKey is the custom JSON key of the LogEventType in ZeroLogEvent
EventTypeKey = "event"
// FieldsKey is a custom JSON key to match and store every other key for a zerolog event
FieldsKey = "fields"
)
// Log is the basic structure of the events that are sent to the client.
type Log struct {
Time string `json:"time,omitempty"`
Level LogLevel `json:"level,omitempty"`
Message string `json:"message,omitempty"`
Event LogEventType `json:"event,omitempty"`
Fields map[string]interface{} `json:"fields,omitempty"`
}
// IntoClientEvent unmarshals the provided ClientEvent into the proper type.
func IntoClientEvent[T EventStartStreaming | EventStopStreaming](e *ClientEvent, eventType ClientEventType) (*T, bool) {
if e.Type != eventType {
return nil, false
}
event := new(T)
err := json.Unmarshal(e.event, event)
if err != nil {
return nil, false
}
return event, true
}
// IntoServerEvent unmarshals the provided ServerEvent into the proper type.
func IntoServerEvent[T EventLog](e *ServerEvent, eventType ServerEventType) (*T, bool) {
if e.Type != eventType {
return nil, false
}
event := new(T)
err := json.Unmarshal(e.event, event)
if err != nil {
return nil, false
}
return event, true
}
// ReadEvent will read a message from the websocket connection and parse it into a valid ServerEvent.
func ReadServerEvent(c *websocket.Conn, ctx context.Context) (*ServerEvent, error) {
message, err := readMessage(c, ctx)
if err != nil {
return nil, err
}
event := ServerEvent{}
if err := json.Unmarshal(message, &event); err != nil {
return nil, err
}
switch event.Type {
case Logs:
event.event = message
return &event, nil
case UnknownServerEventType:
return nil, errInvalidMessageType
default:
return nil, fmt.Errorf("invalid server message type was provided: %s", event.Type)
}
}
// ReadEvent will read a message from the websocket connection and parse it into a valid ClientEvent.
func ReadClientEvent(c *websocket.Conn, ctx context.Context) (*ClientEvent, error) {
message, err := readMessage(c, ctx)
if err != nil {
return nil, err
}
event := ClientEvent{}
if err := json.Unmarshal(message, &event); err != nil {
return nil, err
}
switch event.Type {
case StartStreaming, StopStreaming:
event.event = message
return &event, nil
case UnknownClientEventType:
return nil, errInvalidMessageType
default:
return nil, fmt.Errorf("invalid client message type was provided: %s", event.Type)
}
}
// readMessage will read a message from the websocket connection and return the payload.
func readMessage(c *websocket.Conn, ctx context.Context) ([]byte, error) {
messageType, reader, err := c.Reader(ctx)
if err != nil {
return nil, err
}
if messageType != websocket.MessageText {
return nil, errInvalidMessageType
}
return io.ReadAll(reader)
}
// WriteEvent will write a Event type message to the websocket connection.
func WriteEvent(c *websocket.Conn, ctx context.Context, event any) error {
payload, err := json.Marshal(event)
if err != nil {
return err
}
return c.Write(ctx, websocket.MessageText, payload)
}
// IsClosed returns true if the websocket error is a websocket.CloseError; returns false if not a
// websocket.CloseError
func IsClosed(err error, log *zerolog.Logger) bool {
var closeErr websocket.CloseError
if errors.As(err, &closeErr) {
if closeErr.Code != websocket.StatusNormalClosure {
log.Debug().Msgf("connection is already closed: (%d) %s", closeErr.Code, closeErr.Reason)
}
return true
}
return false
}
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func AsClosed(err error) *websocket.CloseError {
var closeErr websocket.CloseError
if errors.As(err, &closeErr) {
return &closeErr
}
return nil
}