bug#25831: Expose http_proxy setting on GuixSD

[Mathieu Lirzin <mthl@gnu.org>]

Hi,

Leo Famulari <leo@famulari.name> writes:

> On Tue, Feb 21, 2017 at 07:17:03PM +0100, Mathieu Lirzin wrote:
>> Not sure if this is an appropriate answer, but to customize the guix daemon
>> service field like described in the example here:
>> 
>>   https://www.gnu.org/software/guix/manual/html_node/Using-the-Configuration-System.html#System-Services
>> 
>> you would have to patch "gnu/services/base.scm" by adding a field to the
>> 'guix-configuration' that would be then be passed to the
>> '#:environment-variables' option of 'make-forkexec-constructor' in
>> 'guix-shepherd-service'.
>
> Thank you, that helped a lot!
>
> What do the two of you think of the attached patch?
>
> Using the attached OS declaration, I verified that the http_proxy
> environment variable is set in the guix-daemon's environment, but I
> don't have a proxy to test with.
>
> From 1e6e95ea5b43231d09279b9e54f5c581462486f6 Mon Sep 17 00:00:00 2001
> From: Leo Famulari <leo@famulari.name>
> Date: Tue, 21 Feb 2017 14:57:02 -0500
> Subject: [PATCH] services: guix: Support using an HTTP proxy.
>
> * gnu/services/base.scm (<guix-configuration>)[http-proxy]: New field.
> (guix-shepherd-service): Use 'http-proxy' in #:environment-variables.
> * doc/guix.texi ...
> ---
>  doc/guix.texi         |  4 ++++
>  gnu/services/base.scm | 13 +++++++++----
>  2 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/doc/guix.texi b/doc/guix.texi
> index 6cdb5e592..19a31c659 100644
> --- a/doc/guix.texi
> +++ b/doc/guix.texi
> @@ -8611,6 +8611,10 @@ are written.
>  @item @code{lsof} (default: @var{lsof})
>  The lsof package to use.
>  
> +@item @code{http-proxy} (default: @code{#f})
> +The HTTP proxy used for downloading fixed-output derivations and
> +substitutes.
> +

I don't know much about HTTP proxying but when reading
'in-band-download' in "guix/download.scm"  I see a line like this:

  #:leaked-env-vars '("http_proxy" "https_proxy")

which makes me think that maybe we should add an https_proxy toggle in
'guix-configuration' too?

However I see that 'open-connection-for-uri' in "guix/download.scm"
ignores "https_proxy" with a comment from 2015:

  ;; For HTTPS URIs, honor 'https_proxy', not 'http_proxy'.
  ;; FIXME: Proxying is not supported for https.

Do you have any idea if this could be easily fixed?

>  @end table
>  @end deftp
>  
> diff --git a/gnu/services/base.scm b/gnu/services/base.scm
> index 57601eab8..352a90be7 100644
> --- a/gnu/services/base.scm
> +++ b/gnu/services/base.scm
> @@ -3,7 +3,7 @@
>  ;;; Copyright © 2015, 2016 Alex Kost <alezost@gmail.com>
>  ;;; Copyright © 2015, 2016 Mark H Weaver <mhw@netris.org>
>  ;;; Copyright © 2015 Sou Bunnbu <iyzsong@gmail.com>
> -;;; Copyright © 2016 Leo Famulari <leo@famulari.name>
> +;;; Copyright © 2016, 2017 Leo Famulari <leo@famulari.name>
>  ;;; Copyright © 2016 David Craven <david@craven.ch>
>  ;;; Copyright © 2016 Ricardo Wurmus <rekado@elephly.net>
>  ;;;
> @@ -1114,7 +1114,9 @@ failed to register hydra.gnu.org public key: ~a~%" status))))))))
>    (log-file         guix-configuration-log-file   ;string
>                      (default "/var/log/guix-daemon.log"))
>    (lsof             guix-configuration-lsof       ;<package>
> -                    (default lsof)))
> +                    (default lsof))
> +  (http-proxy       guix-http-proxy               ;string
> +                    (default #f)))

'#f' is not a string.  So either specify ';string | #f' or make the
default value '""'.

>  
>  (define %default-guix-configuration
>    (guix-configuration))
> @@ -1125,7 +1127,7 @@ failed to register hydra.gnu.org public key: ~a~%" status))))))))
>      (($ <guix-configuration> guix build-group build-accounts
>                               authorize-key? keys
>                               use-substitutes? substitute-urls extra-options
> -                             log-file lsof)
> +                             log-file lsof http-proxy)
>       (list (shepherd-service
>              (documentation "Run the Guix daemon.")
>              (provision '(guix-daemon))
> @@ -1142,7 +1144,10 @@ failed to register hydra.gnu.org public key: ~a~%" status))))))))
>  
>                  ;; Add 'lsof' (for the GC) to the daemon's $PATH.
>                  #:environment-variables
> -                (list (string-append "PATH=" #$lsof "/bin"))
> +                (list (string-append "PATH=" #$lsof "/bin")
> +                      #$@(if http-proxy
> +                           #~((string-append"http_proxy=" #$http-proxy))
> +                           #~()))

I think it would be more readable like this:

  #$@(if http-proxy
         (list (string-append "http_proxy=" http-proxy))
         '())

or if '""' is the default value:

  #$@(if (string-null? http-proxy)
         '()
         (list (string-append "http_proxy=" http-proxy)))

Thanks.

-- 
Mathieu Lirzin
GPG: F2A3 8D7E EB2B 6640 5761  070D 0ADE E100 9460 4D37