From 8856e0e55902058a777c40edffd3e3178c57ddcb Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Sat, 4 Jul 2020 17:48:00 +0100
Subject: [PATCH] fshttp: Obey bwlimit in http Transport - fixes #4395

This change uses the bwlimit code to apply limits to the receive and
transmit data functions in the HTTP Transport.

This means that all HTTP transactions will have limiting applied -
this includes listings for example.

For HTTP based transorts this makes the limiting in Accounting
redundant and possibly counter productive
---
 fs/accounting/token_bucket.go |  2 ++
 fs/fshttp/http.go             | 25 +++++++++++++++----------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/fs/accounting/token_bucket.go b/fs/accounting/token_bucket.go
index 5b9ff03e3..949cfad44 100644
--- a/fs/accounting/token_bucket.go
+++ b/fs/accounting/token_bucket.go
@@ -20,6 +20,8 @@ type TokenBucketSlot int
 // Slots for the token bucket
 const (
 	TokenBucketSlotAccounting TokenBucketSlot = iota
+	TokenBucketSlotTransportRx
+	TokenBucketSlotTransportTx
 	TokenBucketSlots
 )
 
diff --git a/fs/fshttp/http.go b/fs/fshttp/http.go
index f9444ad36..be3029fb3 100644
--- a/fs/fshttp/http.go
+++ b/fs/fshttp/http.go
@@ -58,26 +58,31 @@ func (c *timeoutConn) nudgeDeadline() (err error) {
 	return c.Conn.SetDeadline(when)
 }
 
-// readOrWrite bytes doing idle timeouts
-func (c *timeoutConn) readOrWrite(f func([]byte) (int, error), b []byte) (n int, err error) {
-	n, err = f(b)
+// Read bytes doing idle timeouts
+func (c *timeoutConn) Read(b []byte) (n int, err error) {
+	// Ideally we would LimitBandwidth(len(b)) here and replace tokens we didn't use
+	n, err = c.Conn.Read(b)
+	accounting.TokenBucket.LimitBandwidth(accounting.TokenBucketSlotTransportRx, n)
 	// Don't nudge if no bytes or an error
 	if n == 0 || err != nil {
 		return
 	}
 	// Nudge the deadline on successful Read or Write
 	err = c.nudgeDeadline()
-	return
-}
-
-// Read bytes doing idle timeouts
-func (c *timeoutConn) Read(b []byte) (n int, err error) {
-	return c.readOrWrite(c.Conn.Read, b)
+	return n, err
 }
 
 // Write bytes doing idle timeouts
 func (c *timeoutConn) Write(b []byte) (n int, err error) {
-	return c.readOrWrite(c.Conn.Write, b)
+	accounting.TokenBucket.LimitBandwidth(accounting.TokenBucketSlotTransportTx, len(b))
+	n, err = c.Conn.Write(b)
+	// Don't nudge if no bytes or an error
+	if n == 0 || err != nil {
+		return
+	}
+	// Nudge the deadline on successful Read or Write
+	err = c.nudgeDeadline()
+	return n, err
 }
 
 // dial with context and timeouts