GNU bug report logs - #67245
[PATCH] store: Use a non-blocking socket for store connections.

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Christopher Baines <mail <at> cbaines.net>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#67245: closed ([PATCH] store: Use a non-blocking socket for
 store connections.)
Date: Mon, 13 May 2024 19:33:02 +0000

[Message part 1 (text/plain, inline)]

Your message dated Mon, 13 May 2024 20:32:16 +0100
with message-id <878r0d33un.fsf <at> cbaines.net>
and subject line Re: [bug#67245] [PATCH v2] store: Add with-store/non-blocking.
has caused the debbugs.gnu.org bug report #67245,
regarding [PATCH] store: Use a non-blocking socket for store connections.
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
67245: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=67245
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: Christopher Baines <mail <at> cbaines.net>
To: guix-patches <at> gnu.org
Subject: [PATCH] store: Use a non-blocking socket for store connections.
Date: Fri, 17 Nov 2023 18:05:14 +0000

For some applications, it's important to do this here rather than just making
the socket non-blocking after the connection is established because there can
be I/O on the socket that will block during the handshake.

I've noticed this blocking during the handshake causing issues in the build
coordinator for example.

* guix/store.scm (open-unix-domain-socket, open-inet-socket): Pass
SOCK_NONBLOCK when calling socket.

Change-Id: I8225762b78448bc1f7b698c8de5d736e13f577bf
---
 guix/store.scm | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/guix/store.scm b/guix/store.scm
index f8e77b2cd9..216be98c05 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -460,7 +460,9 @@ (define (open-unix-domain-socket file)
 '&store-connection-error' upon error."
   (let ((s (with-fluids ((%default-port-encoding #f))
              ;; This trick allows use of the `scm_c_read' optimization.
-             (socket PF_UNIX (logior SOCK_STREAM SOCK_CLOEXEC) 0)))
+             (socket PF_UNIX
+                     (logior SOCK_STREAM SOCK_CLOEXEC SOCK_NONBLOCK)
+                     0)))
         (a (make-socket-address PF_UNIX file)))
 
     (system-error-to-connection-error file
@@ -488,7 +490,8 @@ (define (open-inet-socket host port)
       ((ai rest ...)
        (let ((s (socket (addrinfo:fam ai)
                         ;; TCP/IP only
-                        (logior SOCK_STREAM SOCK_CLOEXEC) IPPROTO_IP)))
+                        (logior SOCK_STREAM SOCK_CLOEXEC SOCK_NONBLOCK)
+                        IPPROTO_IP)))
 
          (catch 'system-error
            (lambda ()

base-commit: e35b7c5386c1bfacf47ed31bac9b503373dd26fc
-- 
2.41.0

[Message part 3 (message/rfc822, inline)]

From: Christopher Baines <mail <at> cbaines.net>
To: Ludovic Courtès <ludo <at> gnu.org>
Cc: 67245-done <at> debbugs.gnu.org
Subject: Re: [bug#67245] [PATCH v2] store: Add with-store/non-blocking.
Date: Mon, 13 May 2024 20:32:16 +0100

[Message part 4 (text/plain, inline)]

Ludovic Courtès <ludo <at> gnu.org> writes:

> Hi,
>
> Christopher Baines <mail <at> cbaines.net> skribis:
>
>> For some applications, it's important to establish a non-blocking connection
>> rather than just making the socket non-blocking after the connection is
>> established. This is because there is I/O on the socket that will block during
>> the handshake.
>>
>> I've noticed this blocking during the handshake causing issues in the build
>> coordinator for example.
>>
>> This commit adds a new with-store variant to avoid changing the behaviour of
>> with-store/open-connection to ensure that this change can't break anything
>> that depends on the blocking nature of the socket.
>>
>> * guix/store.scm (open-unix-domain-socket, open-inet-socket): Take
>>  #:non-blocking? and use SOCK_NONBLOCK when calling socket if appropriate.
>> (connect-to-daemon, open-connection, call-with-store): Take #:non-blocking?
>> and pass it on.
>> (with-store/non-blocking): New syntax rule.
>>
>> Change-Id: I8225762b78448bc1f7b698c8de5d736e13f577bf
>
> [...]
>
>> +(define* (open-unix-domain-socket file #:key non-blocking?)
>>    "Connect to the Unix-domain socket at FILE and return it.  Raise a
>> -'&store-connection-error' upon error."
>> +'&store-connection-error' upon error.  If NON-BLOCKING?, make the socket
>> +non-blocking."
>>    (let ((s (with-fluids ((%default-port-encoding #f))
>>               ;; This trick allows use of the `scm_c_read' optimization.
>> -             (socket PF_UNIX (logior SOCK_STREAM SOCK_CLOEXEC) 0)))
>> +             (socket PF_UNIX
>> +                     (logior SOCK_STREAM SOCK_CLOEXEC SOCK_NONBLOCK)
>> +                     0)))
>
> Make sure SOCK_NONBLOCK is added only when ‘non-blocking?’ is true.

Ah, yep, I've fixed this now.

>> +(define-syntax-rule (with-store/non-blocking store exp ...)
>> +  "Bind STORE to an non-blocking open connection to the store and evaluate
>> +EXPs; automatically close the store when the dynamic extent of EXP is left."
>> +  (call-with-store (lambda (store) exp ...) #:non-blocking? #t))
>
> I think we’ll need an entry in ‘.dir-locals.el’ and one in (guix
> read-print) for proper formatting.

I've added an entry in to .dir-locals.el, but unless I've missed
something, (guix read-print) doesn't handle with-store so maybe we need
to add with-store and with-store/non-blocking.

> OK for me with these changes!

Great, I've pushed to 3db1a8341c815af3673c367518fbb193f5592864 and I can
follow up with the (guix read-print) changes and updating the guix
package later.

Thanks,

Chris

[signature.asc (application/pgp-signature, inline)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.