Provide an option to specify base context for RPC connection

Signed-off-by: Dzmitry Mikhalapau <dzmitry.mikhalapau@gmail.com>

Author: homier

rpc/rpc.go

@@ -88,10 +88,11 @@ type Conn struct {
 	bootstrap    capnp.Client
 	er           errReporter
 	abortTimeout time.Duration
+	baseContext  func() context.Context
 
 	// bgctx is a Context that is canceled when shutdown starts. Note
-	// that it's parent is context.Background(), so we can rely on this
-	// being the *only* time it will be canceled.
+	// that if baseContext is not provided. it's parent is context.Background(),
+	// so we can rely on this being the *only* time it will be canceled.
 	bgctx context.Context
 
 	// tasks block shutdown.
@@ -202,6 +203,11 @@ type Options struct {
 	// by Dial or Accept on the Network itself; application code should not
 	// set this.
 	Network Network
+
+	// BaseContext is an optional funcation that returns a base context
+	// for any incoming connection. If ommitted, the context.Background()
+	// will be used instead.
+	BaseContext func() context.Context
 }
 
 // Logger is used for logging by the RPC system. Each method logs
@@ -231,8 +237,9 @@ type Logger interface {
 // requests from the transport.
 func NewConn(t Transport, opts *Options) *Conn {
 	c := &Conn{
-		transport: t,
-		closed:    make(chan struct{}),
+		transport:   t,
+		baseContext: context.Background,
+		closed:      make(chan struct{}),
 	}
 
 	sender := spsc.New[asyncSend]()
@@ -248,6 +255,10 @@ func NewConn(t Transport, opts *Options) *Conn {
 		c.abortTimeout = opts.AbortTimeout
 		c.network = opts.Network
 		c.remotePeerID = opts.RemotePeerID
+
+		if opts.BaseContext != nil {
+			c.baseContext = opts.BaseContext
+		}
 	}
 	if c.abortTimeout == 0 {
 		c.abortTimeout = 100 * time.Millisecond
@@ -261,7 +272,7 @@ func NewConn(t Transport, opts *Options) *Conn {
 func (c *Conn) startBackgroundTasks() {
 	// We use an errgroup to link the lifetime of background tasks
 	// to each other.
-	ctx, cancel := context.WithCancel(context.Background())
+	ctx, cancel := context.WithCancel(c.baseContext())
 	g, ctx := errgroup.WithContext(ctx)
 
 	c.bgctx = ctx