Files
go-honeybee/transport/connection.go
T
2026-05-21 08:19:37 -04:00

525 lines
10 KiB
Go

package transport
import (
"context"
"errors"
"fmt"
"log/slog"
"math/rand"
"net/url"
"sync"
"sync/atomic"
"time"
"git.wisehodl.dev/jay/go-honeybee/types"
"git.wisehodl.dev/jay/go-mana-component"
"github.com/gorilla/websocket"
)
// ----------------------------------------------------------------------------
// Types
// ----------------------------------------------------------------------------
type ConnectionState int
const (
StateDisconnected ConnectionState = iota
StateConnecting
StateConnected
StateClosed
)
func (s ConnectionState) String() string {
switch s {
case StateDisconnected:
return "disconnected"
case StateConnecting:
return "connecting"
case StateConnected:
return "connected"
case StateClosed:
return "closed"
default:
return "unknown"
}
}
type ConnectionStats struct {
ChanIncoming int
ChanErrors int
TotalReceived uint64
TotalSent uint64
TotalHeartbeats uint64
}
// ----------------------------------------------------------------------------
// Connection
// ----------------------------------------------------------------------------
// ---------------------------/
// Constructors
// -------------------------/
type Connection struct {
url *url.URL
dialer types.Dialer
socket types.Socket
config *ConnectionConfig
logger *slog.Logger
incoming chan []byte
heartbeat chan struct{}
errors chan error
done chan struct{}
incomingCount *atomic.Uint64
outgoingCount *atomic.Uint64
heartbeatCount *atomic.Uint64
state ConnectionState
wg sync.WaitGroup
closed bool
mu sync.RWMutex
writeMu sync.Mutex
doneOnce sync.Once
cleanupOnce sync.Once
}
func NewConnection(ctx context.Context, urlStr string, config *ConnectionConfig, handler slog.Handler) (*Connection, error) {
if config == nil {
config = GetDefaultConnectionConfig()
}
if err := ValidateConnectionConfig(config); err != nil {
return nil, err
}
url, err := ParseURL(urlStr)
if err != nil {
return nil, err
}
if component.FromContext(ctx) == nil {
ctx = component.MustNew(ctx, "honeybee", "connection")
} else {
ctx = component.MustExtend(ctx, "connection")
}
conn := &Connection{
url: url,
dialer: NewDialer(),
socket: nil,
config: config,
incoming: make(chan []byte, config.IncomingBufferSize),
heartbeat: make(chan struct{}, 1),
errors: make(chan error, config.ErrorsBufferSize),
incomingCount: &atomic.Uint64{},
outgoingCount: &atomic.Uint64{},
heartbeatCount: &atomic.Uint64{},
state: StateDisconnected,
done: make(chan struct{}),
}
if handler != nil {
comp := component.FromContext(ctx)
conn.logger = slog.New(handler).With(slog.Any("component", comp))
}
return conn, nil
}
func NewConnectionFromSocket(
ctx context.Context, socket types.Socket, config *ConnectionConfig, handler slog.Handler,
) (*Connection, error) {
if socket == nil {
return nil, NewConnectionError(ErrNilSocket)
}
if config == nil {
config = GetDefaultConnectionConfig()
}
if err := ValidateConnectionConfig(config); err != nil {
return nil, err
}
if component.FromContext(ctx) == nil {
ctx = component.MustNew(ctx, "honeybee", "connection")
} else {
ctx = component.MustExtend(ctx, "connection")
}
conn := &Connection{
url: nil,
dialer: nil,
socket: socket,
config: config,
incoming: make(chan []byte, config.IncomingBufferSize),
heartbeat: make(chan struct{}, 1),
errors: make(chan error, config.ErrorsBufferSize),
incomingCount: &atomic.Uint64{},
outgoingCount: &atomic.Uint64{},
heartbeatCount: &atomic.Uint64{},
state: StateConnected,
done: make(chan struct{}),
}
if handler != nil {
comp := component.FromContext(ctx)
conn.logger = slog.New(handler).With(slog.Any("component", comp))
}
// initialize
if config.CloseHandler != nil {
socket.SetCloseHandler(config.CloseHandler)
}
conn.setupPongHandler()
if conn.config.PingInterval > 0 {
conn.wg.Go(conn.startPinger)
}
conn.wg.Go(conn.startReader)
return conn, nil
}
// ---------------------------/
// Methods
// -------------------------/
func (c *Connection) Connect(ctx context.Context) error {
c.mu.Lock()
defer c.mu.Unlock()
if c.socket != nil {
return NewConnectionError(ErrSocketExists)
}
if c.closed {
return NewConnectionError(ErrConnectionClosed)
}
// begin connecting
if c.logger != nil {
c.logger.Debug("connecting")
}
c.state = StateConnecting
// obtain socket
retryMgr := NewRetryManager(c.config.Retry)
socket, _, err := AcquireSocket(
ctx, retryMgr, c.dialer, c.url.String(), c.config.RequestHeader, c.logger)
if err != nil {
// socket acquisition failed
c.state = StateDisconnected
if c.logger != nil {
c.logger.Warn("connection failed", "error", err)
}
return NewConnectionError(err)
}
// got socket
c.socket = socket
// initialize
if c.config.CloseHandler != nil {
c.socket.SetCloseHandler(c.config.CloseHandler)
}
c.setupPongHandler()
if c.config.PingInterval > 0 {
c.wg.Go(c.startPinger)
}
c.wg.Go(c.startReader)
// connected
c.state = StateConnected
if c.logger != nil {
c.logger.Debug("connected")
}
return nil
}
func (c *Connection) Send(data []byte) error {
c.writeMu.Lock()
defer c.writeMu.Unlock()
if c.closed {
return NewConnectionError(ErrConnectionClosed)
}
// setup
if c.config.WriteTimeout > 0 {
if err := c.socket.SetWriteDeadline(time.Now().Add(c.config.WriteTimeout)); err != nil {
if c.logger != nil {
c.logger.Error("write deadline error", "error", err)
}
return NewConnectionError(fmt.Errorf("%w: %w", ErrFailedWriteDeadline, err))
}
}
// send
err := c.socket.WriteMessage(websocket.TextMessage, data)
if err != nil {
if c.logger != nil {
c.logger.Error("write error", "error", err)
}
return NewConnectionError(fmt.Errorf("%w: %w", ErrWriteFailed, err))
}
c.outgoingCount.Add(1)
return nil
}
func (c *Connection) Incoming() <-chan []byte {
return c.incoming
}
func (c *Connection) Heartbeat() <-chan struct{} {
return c.heartbeat
}
func (c *Connection) Errors() <-chan error {
return c.errors
}
func (c *Connection) State() ConnectionState {
c.mu.RLock()
defer c.mu.RUnlock()
return c.state
}
func (c *Connection) Stats() ConnectionStats {
return ConnectionStats{
ChanIncoming: len(c.incoming),
ChanErrors: len(c.errors),
TotalReceived: c.incomingCount.Load(),
TotalSent: c.outgoingCount.Load(),
TotalHeartbeats: c.heartbeatCount.Load(),
}
}
func (c *Connection) SetDialer(d types.Dialer) {
c.dialer = d
}
// ---------------------------/
// Reader loop
// -------------------------/
func (c *Connection) startReader() {
defer c.shutdownInternal()
for {
select {
case <-c.done:
return
default:
messageType, data, err := c.socket.ReadMessage()
if err != nil {
select {
case <-c.done:
case c.errors <- c.classifyCloseError(err):
}
return
}
if messageType == websocket.TextMessage ||
messageType == websocket.BinaryMessage {
select {
case <-c.done:
return
case c.incoming <- data:
c.incomingCount.Add(1)
}
}
}
}
}
func (c *Connection) classifyCloseError(err error) error {
var classifiedError error
var closeErr *websocket.CloseError
if errors.As(err, &closeErr) {
switch closeErr.Code {
case websocket.CloseNormalClosure, websocket.CloseGoingAway:
if c.logger != nil {
c.logger.Debug("connection closed by peer",
"code", closeErr.Code,
"text", closeErr.Text,
)
}
classifiedError = fmt.Errorf("%w: %w", ErrPeerClosedClean, err)
default:
if c.logger != nil {
c.logger.Warn("unexpected close",
"code", closeErr.Code,
"text", closeErr.Text,
)
}
classifiedError = fmt.Errorf("%w: %w", ErrPeerClosedUnexpected, err)
}
} else {
isLocalClose := false
select {
case <-c.done:
isLocalClose = true
default:
}
if c.logger != nil {
if isLocalClose {
c.logger.Debug("read loop terminated", "error", err)
} else {
c.logger.Error("read error", "error", err)
}
}
classifiedError = fmt.Errorf("%w: %w", ErrReadError, err)
}
return classifiedError
}
// ---------------------------/
// Heartbeat Handling
// -------------------------/
func (c *Connection) setupPongHandler() {
c.socket.SetPongHandler(func(appData string) error {
select {
case c.heartbeat <- struct{}{}:
c.heartbeatCount.Add(1)
default:
}
return nil
})
}
func (c *Connection) startPinger() {
defer c.shutdownInternal()
// Calculate 10% jitter window
jitter := c.config.PingInterval / 10
for {
offset := time.Duration(rand.Int63n(int64(jitter*2))) - jitter
next := c.config.PingInterval + offset
timer := time.NewTimer(next)
select {
case <-c.done:
timer.Stop()
return
case <-timer.C:
deadline := time.Now().Add(c.config.WriteTimeout)
err := c.socket.WriteControl(websocket.PingMessage, nil, deadline)
if err != nil {
return
}
}
}
}
// ---------------------------/
// Shutdown
// -------------------------/
func (c *Connection) Close() {
c.shutdownExternal()
}
func (c *Connection) shutdownExternal() {
// set closed
c.mu.Lock()
if c.closed {
// idempotent shutdown
c.mu.Unlock()
return
}
c.closed = true
c.state = StateClosed
c.mu.Unlock()
// perform shutdown
c.shutdownInner()
c.shutdownCleanup()
}
// shutdownInternal defers final cleanup to allow it to return.
// Otherwise, a deadlock occurs where startReader triggers a shutdown and
// must wait for itself to exit.
func (c *Connection) shutdownInternal() {
// set closed
c.mu.Lock()
if c.closed {
// idempotent shutdown
c.mu.Unlock()
return
}
c.closed = true
c.state = StateClosed
c.mu.Unlock()
// perform shutdown
c.shutdownInner()
// defer cleanup to avoid deadlock
go func() {
c.shutdownCleanup()
}()
}
func (c *Connection) shutdownInner() {
c.doneOnce.Do(func() {
close(c.done)
})
if c.logger != nil {
c.logger.Debug("closing")
}
if c.socket != nil {
// force unblock of any network operations immediately
expired := time.Now().Add(-1 * time.Minute)
c.socket.SetReadDeadline(expired)
c.socket.SetWriteDeadline(expired)
// close socket
err := c.socket.Close()
if err != nil && c.logger != nil {
c.logger.Error("socket close failed", "error", err)
}
}
}
func (c *Connection) shutdownCleanup() {
c.cleanupOnce.Do(func() {
c.wg.Wait()
close(c.incoming)
close(c.errors)
if c.logger != nil {
c.logger.Debug("closed")
}
})
}