Re: [PATCH] guix-daemon: Add option to disable garbage collection.

[ludovic.courtes@inria.fr (Ludovic Courtès)]

Roel Janssen <roel@gnu.org> skribis:

> Ludovic Courtès <ludovic.courtes@inria.fr> writes:

[...]

>>> diff --git a/nix/nix-daemon/nix-daemon.cc b/nix/nix-daemon/nix-daemon.cc
>>> index deb7003d7..65770ba95 100644
>>> --- a/nix/nix-daemon/nix-daemon.cc
>>> +++ b/nix/nix-daemon/nix-daemon.cc
>>> @@ -529,6 +529,11 @@ static void performOp(bool trusted, unsigned int clientVersion,
>>>      }
>>>  
>>>      case wopCollectGarbage: {
>>> +        if (settings.isRemoteConnection) {
>>> +            throw Error("Garbage collection is disabled for remote hosts.");
>>> +            break;
>>> +        }
>>>          GCOptions options;
>>>          options.action = (GCOptions::GCAction) readInt(from);
>>>          options.pathsToDelete = readStorePaths<PathSet>(from);
>>
>> I was wondering if we would like to allow some of the ‘GCAction’ values,
>> but maybe it’s better to disallow them altogether like this code does.
>
> Could we please start with a “disable any GC” and start allowing cases
> on a case-by-case basis?

Sure, that’s what I was suggesting.  :-)

>> Last thing: could you add a couple of tests?  tests/guix-daemon.sh
>> already has tests for ‘--listen’, so you could take inspiration from
>> those.
>
> I included a test, but I don't know how I can properly run this test.
> Could you elaborate on how I can test the test(s)?

Run:

  make check TESTS=tests/guix-daemon.sh

See
<https://www.gnu.org/software/guix/manual/html_node/Running-the-Test-Suite.html>.

> From b29d3a90e1487ebda5ac5b6bc146f8c95218eab6 Mon Sep 17 00:00:00 2001
> From: Roel Janssen <roel@gnu.org>
> Date: Thu, 19 Apr 2018 14:01:49 +0200
> Subject: [PATCH] guix-daemon: Disable garbage collection for remote hosts.
>
> * nix/nix-daemon/nix-daemon.cc (performOp): Display appropriate error message;
>   (acceptConnection): Set isRemoteConnection when connection is over TCP.

Rather:

* nix/nix-daemon/nix-daemon.cc (isRemoteConnection): New variable.
(performOp): For wopCollectGarbage, throw an error when
isRemoteConnection is set.
(acceptConnection): Set isRemoteConnection when connection is not AF_UNIX.

> +output=`GUIX_DAEMON_SOCKET="$socket" guix gc`
> +if [[ "$output" != *"GUIX_DAEMON_SOCKET=$socket" ]];
> +then
> +    exit 1
> +fi

Perhaps simply check the exit code of ‘guix gc’ and fail if it succeeds?

Like:

  if guix gc; then false; else true; fi

Also please try to avoid Bash-specific constructs like [[ this ]].

Could you send an updated patch?

Thank you,
Ludo’.