From: Fiona Ebner <f.ebner@proxmox.com>
To: Max Carrara <m.carrara@proxmox.com>,
Proxmox VE development discussion <pve-devel@lists.proxmox.com>
Subject: Re: [pve-devel] [RFC storage 10/23] plugin: introduce new_backup_provider() method
Date: Fri, 26 Jul 2024 14:45:34 +0200 [thread overview]
Message-ID: <c07395cb-851c-45cc-b646-b3f046606e7e@proxmox.com> (raw)
In-Reply-To: <D2ZGEL5EHGPF.34PJ6J89RS0YT@proxmox.com>
Am 26.07.24 um 14:02 schrieb Max Carrara:
> On Fri Jul 26, 2024 at 11:52 AM CEST, Fiona Ebner wrote:
>> Am 25.07.24 um 17:32 schrieb Max Carrara:
>>> On Thu Jul 25, 2024 at 3:11 PM CEST, Fiona Ebner wrote:
>>
>> I don't quite get your point about not needing to update the call sites.
>> If you change the structure of the passed-in hash you still need to do that.
>
> Pardon me, I was a bit imprecise there. You're completely right that the
> passed hash has to be changed as well, of course.
>
> What I meant in particular was that because the signature (most likely)
> won't change, we won't have to take special care to update the
> individual arguments that are passed to a method when e.g. a parameter
> is deprecated (or removed) or added.
>
> For example, optional arguments are often just left out (because that's
> possible in Perl), so if we introduced another parameter ...
>
> * after the optional one, we'd have to pass something like `0` or
> `undef` for the optional one first before passing the new one:
>
> # before
> $plugin->foo($first, $second);
>
> # after
> $plugin->foo($first, $second, undef, $new);
>
> * before the optional one, we'd have to make sure the order of arguments
> is correct:
>
> # before
> $plugin->foo($first, $second, 1);
>
> # after
> $plugin->foo($first, $second, $new, 1);
>
> If we were to use a hash representing the parameters instead, the cases
> would look like this respectively:
>
> $plugin->foo({ first => $first, second => $second, new => $new });
>
> $plugin->foo({ first => $first, second => $second, optional => 1, new = $new });
>
> More examples of that pattern would be `PVE::Tools::run_command` and
> `PVE::RADOS::mon_command`.
>
> These changes can (and IMO should) still be guarded by an API age +
> version mechanism, it's just that the *surrounding maintenance work*
> becomes easier IMO, even if the initial cost for us and for implementors
> is a bit higher.
>
> Of course, this is all a suggestion and I really don't want to seem like
> I'm telling you what to do here! If you decide not to have a parameter
> hash etc. then that's also completely fine by me, of course. :)
>
Okay, I see what you mean. I agree that having a hash for optional
arguments is cleaner API-wise, but I do think fixed arguments (e.g. vmid
and drive ID for VM backup will always be present) should go directly
into the signature, not into a hash. I'll probably go with something
like what I wrote before about having mechanism-agnostic signatures, one
for VMs and one for containers.
>
> Also, thanks for going through this discussion here with me - even if
> you choose to not incorporate my suggestions, I'm glad we have these
> little exchanges, because they periodically update my perspective(s) on
> Perl code as well :P
>
No worries, your feedback is very welcome :)
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next prev parent reply other threads:[~2024-07-26 12:45 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-23 9:56 [pve-devel] [RFC qemu/storage/qemu-server/container/manager 00/23] backup provider API Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu 01/23] block/reqlist: allow adding overlapping requests Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu 02/23] PVE backup: fixup error handling for fleecing Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu 03/23] PVE backup: factor out setting up snapshot access " Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu 04/23] PVE backup: save device name in device info structure Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu 05/23] PVE backup: include device name in error when setting up snapshot access fails Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC qemu 06/23] PVE backup: add target ID in backup state Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC qemu 07/23] PVE backup: get device info: allow caller to specify filter for which devices use fleecing Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC qemu 08/23] PVE backup: implement backup access setup and teardown API for external providers Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC qemu 09/23] PVE backup: implement bitmap support for external backup access Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC storage 10/23] plugin: introduce new_backup_provider() method Fiona Ebner
2024-07-25 9:48 ` Max Carrara
2024-07-25 13:11 ` Fiona Ebner
2024-07-25 13:25 ` Fiona Ebner
2024-07-25 15:32 ` Max Carrara
2024-07-26 9:52 ` Fiona Ebner
2024-07-26 12:02 ` Max Carrara
2024-07-26 12:45 ` Fiona Ebner [this message]
2024-07-23 9:56 ` [pve-devel] [RFC storage 11/23] extract backup config: delegate to backup provider if there is one Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [POC storage 12/23] add backup provider example Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu-server 13/23] move nbd_stop helper to QMPHelpers module Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu-server 14/23] backup: move cleanup of fleecing images to cleanup method Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu-server 15/23] backup: cleanup: check if VM is running before issuing QMP commands Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC qemu-server 16/23] backup: allow adding fleecing images also for EFI and TPM Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC qemu-server 17/23] backup: implement backup for external providers Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH qemu-server 18/23] restore: die early when there is no size for a device Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC qemu-server 19/23] backup: implement restore for external providers Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC container 20/23] backup: implement backup " Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC container 21/23] backup: implement restore " Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [PATCH manager 22/23] ui: backup: also check for backup subtype to classify archive Fiona Ebner
2024-07-23 9:56 ` [pve-devel] [RFC manager 23/23] backup: implement backup for external providers Fiona Ebner
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