From: "Lénaïc Huard" <lenaic@lhuard.fr>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>,
"Derrick Stolee" <dstolee@microsoft.com>,
"Eric Sunshine" <sunshine@sunshineco.com>,
"brian m . carlson" <sandals@crustytoothpaste.net>,
"Bagas Sanjaya" <bagasdotme@gmail.com>,
"Phillip Wood" <phillip.wood123@gmail.com>,
"Đoàn Trần Công Danh" <congdanhqx@gmail.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Lénaïc Huard" <lenaic@lhuard.fr>
Subject: [PATCH v2 0/1] maintenance: use systemd timers on Linux
Date: Sun, 9 May 2021 23:32:16 +0200 [thread overview]
Message-ID: <20210509213217.449489-1-lenaic@lhuard.fr> (raw)
In-Reply-To: <20210501145220.2082670-1-lenaic@lhuard.fr>
Hello,
Thank you all for your valuable feedback!
I tried to address all the discussed points in this new version of the
patch.
Do not hesitate to let me know if I forgot anything.
The main new thing in this version is the `--scheduler=<scheduler>`
parameter that has been added to `git maintenance start` command. It
allows the end user to choose between `cron` or user systemd timers
for scheduling git maintenance tasks.
I also addressed the migration problematic during an upgrade.
If a user invokes `git maintenance start --scheduler=systemd-timer`
first, and then invokes `git maintenance start --scheduler=cron`
without invoking `git maintenance stop` in between, the git
maintenance tasks will be removed from `systemd-timer` to be sure that
the same tasks won’t be scheduled concurrently twice by both
`systemd-timer` and `cron`. And the same in the other way round.
On its side, `git maintenance stop` don’t have any
`--scheduler=<scheduler>` parameter as it will try to remove the git
maintenance tasks from all the schedulers available on the system.
The default scheduler when `--scheduler=<scheduler>` isn’t specified
is `auto` which means “choose an appropriate scheduler”.
On Windows and MacOS, it always chooses the specific scheduler on
those platforms, `schtasks` and `launchctl`.
On Linux, it chooses user systemd timers if they are available and
`cron` otherwise.
This order has been a subject of discussion so, let me explain why I
chose this order.
On my system, I uses systemd and all the packages of my distribution
that are needing regular scheduled tasks are defining systemd timers
instead of cron task.
So, I don’t use crontab anymore. However, a cron package is installed
because it is an indirect dependency of a package I installed through
my Linux distribution package manager. But the cron daemon isn’t
started.
`systemctl --user list-timers` is the CLI command that actually talks
to the daemon in charge of scheduling timers. So, if `systemctl --user
list-timers` succeed, we can be sure that user systemd timers are
functional.
Concretely, the `is_systemd_timer_available` function of this patch is
reliable.
`crontab`, on the other hand, only reads and writes to
`/var/spool/cron/$USER` but this command can work also if the `cron`
daemon isn’t running. In this case, the scheduled tasks will never
run.
Concretely, the `is_crontab_available` function of this patch is less
reliable.
We would need to check if the `cron` daemon is really running.
Relying on `systemctl` to check if the service is enabled and running
isn’t ideal since we want to support systems that don’t have systemd.
Parsing directly `/proc` is challenging since its content is OS
specific. `/proc` content on a Solaris system is different than its
content on a Linux system.
We could rely on `ps` but we must keep in mind its interface is very
different from one system to another. It doesn’t implement both the
standard syntax and the BSD syntax for its arguments on all platforms
for example.
Moreover, Linux distributions are proposing several different
implementations of `cron`: `cronie`, `fcron`, `dcron`, `vixie-cron`,
`scron`, `bcron`.
See:
* https://wiki.archlinux.org/title/Cron#Installation
* https://wiki.gentoo.org/wiki/Cron#Which_cron_is_right_for_the_job.3F
Depending on the `cron` implementation, the name of the `cron` daemon
process might differ.
So, reliably detecting if a `cron` daemon is running may require to
review each `cron` implementation.
With this new version of the patch, advanced users that care about
systemd timers versus `cron` can explicitly choose which one they want to
use.
For less advanced users that don’t care, I prefer to choose the method
which has the higher probability of working.
But since this order is a subject of debate, what I can propose is a
`./configure` compile time option to select which `cron` or systemd
timers should be chosen in priority if both are available.
In addition to this big change, this new version of the patch also honors
the `XDG_CONFIG_HOME` environment variable and removes the code
duplication between `systemd_timer_timer_filename()` and
`systemd_timer_service_filename()`.
It also fixes other points raised in the code review.
Lénaïc Huard (1):
maintenance: use systemd timers on Linux
Documentation/git-maintenance.txt | 60 +++++
builtin/gc.c | 375 ++++++++++++++++++++++++++++--
t/t7900-maintenance.sh | 51 ++++
3 files changed, 462 insertions(+), 24 deletions(-)
--
2.31.1
next prev parent reply other threads:[~2021-05-09 21:36 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-01 14:52 [PATCH] maintenance: use systemd timers on Linux Lénaïc Huard
2021-05-01 20:02 ` brian m. carlson
2021-05-02 5:28 ` Bagas Sanjaya
2021-05-02 6:49 ` Eric Sunshine
2021-05-02 6:45 ` Eric Sunshine
2021-05-02 14:10 ` Phillip Wood
2021-05-05 12:19 ` Đoàn Trần Công Danh
2021-05-05 14:57 ` Phillip Wood
2021-05-05 12:01 ` Ævar Arnfjörð Bjarmason
2021-05-09 22:34 ` Lénaïc Huard
2021-05-10 13:03 ` Ævar Arnfjörð Bjarmason
2021-05-02 11:12 ` Bagas Sanjaya
2021-05-03 12:04 ` Derrick Stolee
2021-05-09 21:32 ` Lénaïc Huard [this message]
2021-05-09 21:32 ` [PATCH v2 1/1] " Lénaïc Huard
2021-05-10 1:20 ` Đoàn Trần Công Danh
2021-05-10 2:48 ` Eric Sunshine
2021-05-10 6:25 ` Junio C Hamano
2021-05-12 0:29 ` Đoàn Trần Công Danh
2021-05-12 6:59 ` Felipe Contreras
2021-05-12 13:26 ` Phillip Wood
2021-05-12 13:38 ` Phillip Wood
2021-05-12 15:41 ` Đoàn Trần Công Danh
2021-05-10 18:03 ` Phillip Wood
2021-05-10 18:25 ` Eric Sunshine
2021-05-10 20:09 ` Phillip Wood
2021-05-10 20:52 ` Eric Sunshine
2021-06-08 14:55 ` Lénaïc Huard
2021-05-10 19:15 ` Martin Ågren
2021-05-11 14:50 ` Phillip Wood
2021-05-11 17:31 ` Derrick Stolee
2021-05-20 22:13 ` [PATCH v3 0/4] " Lénaïc Huard
2021-05-20 22:13 ` [PATCH v3 1/4] cache.h: rename "xdg_config_home" to "xdg_config_home_git" Lénaïc Huard
2021-05-20 23:44 ` Đoàn Trần Công Danh
2021-05-20 22:13 ` [PATCH v3 2/4] maintenance: introduce ENABLE/DISABLE for code clarity Lénaïc Huard
2021-05-20 22:13 ` [PATCH v3 3/4] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-05-21 9:52 ` Bagas Sanjaya
2021-05-20 22:13 ` [PATCH v3 4/4] maintenance: optionally use systemd timers on Linux Lénaïc Huard
2021-05-21 9:59 ` Bagas Sanjaya
2021-05-21 16:59 ` Derrick Stolee
2021-05-22 6:57 ` Johannes Schindelin
2021-05-23 18:36 ` Felipe Contreras
2021-05-23 23:27 ` brian m. carlson
2021-05-24 1:18 ` Felipe Contreras
2021-05-24 7:03 ` Ævar Arnfjörð Bjarmason
2021-05-24 15:51 ` Junio C Hamano
2021-05-25 1:50 ` Johannes Schindelin
2021-05-25 11:13 ` Felipe Contreras
2021-05-26 10:29 ` CoC, inclusivity etc. (was "Re: [...] systemd timers on Linux") Ævar Arnfjörð Bjarmason
2021-05-26 16:05 ` Felipe Contreras
2021-05-27 14:24 ` Jeff King
2021-05-27 17:30 ` Felipe Contreras
2021-05-27 23:58 ` Junio C Hamano
2021-05-28 14:44 ` Phillip Susi
2021-05-30 21:58 ` Jeff King
2021-05-24 17:52 ` [PATCH v3 4/4] maintenance: optionally use systemd timers on Linux Felipe Contreras
2021-05-24 7:15 ` [PATCH v4 0/4] add support for " Lénaïc Huard
2021-05-24 7:15 ` [PATCH v4 1/4] cache.h: Introduce a generic "xdg_config_home_for(…)" function Lénaïc Huard
2021-05-24 9:33 ` Phillip Wood
2021-05-24 12:23 ` Đoàn Trần Công Danh
2021-05-24 7:15 ` [PATCH v4 2/4] maintenance: introduce ENABLE/DISABLE for code clarity Lénaïc Huard
2021-05-24 9:41 ` Phillip Wood
2021-05-24 12:36 ` Đoàn Trần Công Danh
2021-05-25 7:18 ` Lénaïc Huard
2021-05-25 8:02 ` Junio C Hamano
2021-05-24 9:47 ` Ævar Arnfjörð Bjarmason
2021-05-24 7:15 ` [PATCH v4 3/4] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-05-24 10:12 ` Phillip Wood
2021-05-30 6:39 ` Lénaïc Huard
2021-05-30 10:16 ` Phillip Wood
2021-05-24 7:15 ` [PATCH v4 4/4] maintenance: add support for systemd timers on Linux Lénaïc Huard
2021-05-24 9:55 ` Ævar Arnfjörð Bjarmason
2021-05-24 16:39 ` Eric Sunshine
2021-05-24 18:08 ` Felipe Contreras
2021-05-26 10:26 ` Phillip Wood
2021-05-24 9:04 ` [PATCH v4 0/4] " Junio C Hamano
2021-06-08 13:39 ` [PATCH v5 0/3] " Lénaïc Huard
2021-06-08 13:39 ` [PATCH v5 1/3] cache.h: Introduce a generic "xdg_config_home_for(…)" function Lénaïc Huard
2021-06-08 13:39 ` [PATCH v5 2/3] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-06-08 13:40 ` [PATCH v5 3/3] maintenance: add support for systemd timers on Linux Lénaïc Huard
2021-06-09 9:34 ` Jeff King
2021-06-09 15:01 ` Phillip Wood
2021-06-09 0:21 ` [PATCH v5 0/3] " Junio C Hamano
2021-06-09 14:54 ` Phillip Wood
2021-06-12 16:50 ` [PATCH v6 0/3] maintenance: " Lénaïc Huard
2021-06-12 16:50 ` [PATCH v6 1/3] cache.h: Introduce a generic "xdg_config_home_for(…)" function Lénaïc Huard
2021-06-12 16:50 ` [PATCH v6 2/3] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-06-14 4:36 ` Eric Sunshine
2021-06-16 18:12 ` Derrick Stolee
2021-06-17 4:11 ` Eric Sunshine
2021-06-17 14:26 ` Phillip Wood
2021-07-02 15:04 ` Lénaïc Huard
2021-06-12 16:50 ` [PATCH v6 3/3] maintenance: add support for systemd timers on Linux Lénaïc Huard
2021-07-02 14:25 ` [PATCH v7 0/3] " Lénaïc Huard
2021-07-02 14:25 ` [PATCH v7 1/3] cache.h: Introduce a generic "xdg_config_home_for(…)" function Lénaïc Huard
2021-07-02 14:25 ` [PATCH v7 2/3] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-07-06 19:56 ` Ævar Arnfjörð Bjarmason
2021-07-06 20:52 ` Junio C Hamano
2021-07-13 0:15 ` Jeff King
2021-07-13 2:22 ` Eric Sunshine
2021-07-13 3:56 ` Jeff King
2021-07-13 5:17 ` Eric Sunshine
2021-07-13 7:04 ` Bagas Sanjaya
2021-07-06 21:18 ` Felipe Contreras
2021-08-23 20:06 ` Lénaïc Huard
2021-08-23 22:30 ` Junio C Hamano
2021-07-02 14:25 ` [PATCH v7 3/3] maintenance: add support for systemd timers on Linux Lénaïc Huard
2021-07-06 20:03 ` Ævar Arnfjörð Bjarmason
2021-07-02 18:18 ` [PATCH v7 0/3] " Junio C Hamano
2021-07-06 13:18 ` Phillip Wood
2021-08-23 20:40 ` [PATCH v8 " Lénaïc Huard
2021-08-23 20:40 ` [PATCH v8 1/3] cache.h: Introduce a generic "xdg_config_home_for(…)" function Lénaïc Huard
2021-08-23 20:40 ` [PATCH v8 2/3] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-08-24 17:45 ` Derrick Stolee
2021-08-23 20:40 ` [PATCH v8 3/3] maintenance: add support for systemd timers on Linux Lénaïc Huard
2021-08-24 17:45 ` Derrick Stolee
2021-08-24 17:47 ` [PATCH v8 0/3] " Derrick Stolee
2021-08-27 21:02 ` [PATCH v9 " Lénaïc Huard
2021-08-27 21:02 ` [PATCH v9 1/3] cache.h: Introduce a generic "xdg_config_home_for(…)" function Lénaïc Huard
2021-08-27 21:02 ` [PATCH v9 2/3] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-08-27 23:54 ` Ramsay Jones
2021-08-27 21:02 ` [PATCH v9 3/3] maintenance: add support for systemd timers on Linux Lénaïc Huard
2021-09-04 20:54 ` [PATCH v10 0/3] " Lénaïc Huard
2021-09-04 20:54 ` [PATCH v10 1/3] cache.h: Introduce a generic "xdg_config_home_for(…)" function Lénaïc Huard
2021-09-04 20:54 ` [PATCH v10 2/3] maintenance: `git maintenance run` learned `--scheduler=<scheduler>` Lénaïc Huard
2021-09-04 20:55 ` [PATCH v10 3/3] maintenance: add support for systemd timers on Linux Lénaïc Huard
2021-09-07 16:48 ` [PATCH v10 0/3] " Derrick Stolee
2021-09-08 11:44 ` Derrick Stolee
2021-09-09 5:52 ` Lénaïc Huard
2021-09-09 19:55 ` Derrick Stolee
2021-09-27 12:50 ` Ævar Arnfjörð Bjarmason
2021-09-27 21:44 ` Lénaïc Huard
2021-08-17 17:22 ` [PATCH v5 0/3] " Derrick Stolee
2021-08-17 19:43 ` Phillip Wood
2021-08-17 20:29 ` Derrick Stolee
2021-08-18 5:56 ` Lénaïc Huard
2021-08-18 13:28 ` Derrick Stolee
2021-08-18 18:23 ` Junio C Hamano
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