handletelegram,gotd: add missing log context

pkg/gotd/mtproto/conn.go

@@ -175,7 +175,7 @@ func New(dialer Dialer, opt Options) *Conn {
 // handleClose closes rpc engine and underlying connection on context done.
 func (c *Conn) handleClose(ctx context.Context) error {
 	<-ctx.Done()
-	c.log.Info("Connection context done, closing")
+	c.log.Info("Connection context done, closing", zap.NamedError("ctx_err", context.Cause(ctx)))
 
 	// Close RPC Engine.
 	c.rpc.ForceClose()
@@ -187,6 +187,8 @@ func (c *Conn) handleClose(ctx context.Context) error {
 	return nil
 }
 
+var errRunReturned = errors.New("Conn.Run() returned")
+
 // Run initializes MTProto connection to server and blocks until disconnection.
 //
 // When connection is ready, Handler.OnSession is called.
@@ -199,8 +201,8 @@ func (c *Conn) Run(ctx context.Context, f func(ctx context.Context) error) error
 		return errors.New("do Run on closed connection")
 	}
 
-	ctx, cancel := context.WithCancel(ctx)
-	defer cancel()
+	ctx, cancel := context.WithCancelCause(ctx)
+	defer cancel(errRunReturned)
 
 	c.log.Info("Run: start")
 	defer c.log.Info("Run: end")

pkg/gotd/telegram/client.go

@@ -114,7 +114,7 @@ type Client struct {
 
 	// Client context. Will be canceled by Run on exit.
 	ctx    context.Context
-	cancel context.CancelFunc
+	cancel context.CancelCauseFunc
 
 	// Client config.
 	appID   int    // immutable

pkg/gotd/telegram/client_test.go

@@ -84,7 +84,7 @@ func newTestClient(h testHandler) *Client {
 		appHash:       TestAppHash,
 		conn:          &testConn{engine: engine, ready: ready},
 		ctx:           context.Background(),
-		cancel:        func() {},
+		cancel:        func(error) {},
 		updateHandler: UpdateHandlerFunc(func(ctx context.Context, u tg.UpdatesClass) error { return nil }),
 		onTransfer:    noopOnTransfer,
 	}

pkg/gotd/telegram/connect.go

@@ -2,6 +2,7 @@ package telegram
 
 import (
 	"context"
+	"fmt"
 	"time"
 
 	"github.com/cenkalti/backoff/v4"
@@ -117,6 +118,8 @@ func (c *Client) resetReady() {
 	c.ready.Reset()
 }
 
+var errRunReturned = errors.New("Client.Run() returned")
+
 // Run starts client session and blocks until connection close.
 // The f callback is called on successful session initialization and Run
 // will return on f() result.
@@ -137,12 +140,12 @@ func (c *Client) Run(ctx context.Context, f func(ctx context.Context) error) (er
 
 	// Setting up client context for background operations like updates
 	// handling or pool creation.
-	c.ctx, c.cancel = context.WithCancel(ctx)
+	c.ctx, c.cancel = context.WithCancelCause(ctx)
 
 	c.log.Info("Client starting")
 	defer c.log.Info("Client closed")
 	// Cancel client on exit.
-	defer c.cancel()
+	defer c.cancel(errRunReturned)
 	defer func() {
 		c.subConnsMux.Lock()
 		defer c.subConnsMux.Unlock()
@@ -164,7 +167,7 @@ func (c *Client) Run(ctx context.Context, f func(ctx context.Context) error) (er
 	g.Go(func(ctx context.Context) error {
 		select {
 		case <-ctx.Done():
-			c.cancel()
+			c.cancel(fmt.Errorf("Client.Run group context done: %w", context.Cause(ctx)))
 			return ctx.Err()
 		case <-c.ctx.Done():
 			return c.ctx.Err()

pkg/gotd/telegram/migrate_to_dc_test.go

@@ -112,7 +112,7 @@ func newMigrationClient(t *testing.T, h migrationTestHandler) *Client {
 		}),
 		newConnBackoff:   defaultBackoff(clock.System),
 		ctx:              context.Background(),
-		cancel:           func() {},
+		cancel:           func(error) {},
 		migrationTimeout: 10 * time.Second,
 	}
 	client.init()