Package: guix-patches;
Reported by: Carlo Zancanaro <carlo <at> zancanaro.id.au>
Date: Mon, 26 Nov 2018 11:42:01 UTC
Severity: normal
Tags: patch
Done: Ludovic Courtès <ludo <at> gnu.org>
Bug is archived. No further changes may be made.
Message #8 received at 33508 <at> debbugs.gnu.org (full text, mbox):
From: Clément Lassieur <clement <at> lassieur.org> To: Carlo Zancanaro <carlo <at> zancanaro.id.au> Cc: 33508 <at> debbugs.gnu.org Subject: Re: [bug#33508] [PATCH] gnu: Add ability to restart services on system reconfigure Date: Mon, 26 Nov 2018 13:42:02 +0100
Hi Carlo,
It might be safer to 'reload' some services, rather than 'restarting'
them. E.g. for nginx and prosody. Do you think it would be possible
add a 'custom' value that would point to a custom Shepherd action?
Thank you for your work on this!
Clément
Carlo Zancanaro <carlo <at> zancanaro.id.au> writes:
> Hey Guix!
>
> A few months ago I mentioned the idea of adding the ability to
> have services automatically restarted when running "guix system
> reconfigure". These patches are a start on making that happen.
> They're incomplete (in particular, documentation is missing), but
> I'm offering them up for comment.
>
> The broad idea is to add a new field to our guix shepherd
> services: restart-strategy. There are three valid values:
>
> - always: this service is always safe to restart when running
> reconfigure
>
> - manual: this service may not be safe to restart when running
> reconfigure - a message will be printed telling the user to
> restart the service manually, or they can provide the
> --restart-services flag to reconfigure to automatically restart
> them
>
> - never: this service is never safe to restart when running
> reconfigure (eg. udev)
>
> I have added the flag to the guix daemon's shepherd service to
> show how it works. I tested this by changing my substitute servers
> in config.scm, and after running "reconfigure" I saw my updated
> substitute servers in ps without having to run "sudo herd restart
> guix-daemon".
>
> If nobody has any feedback in the next few days then I'll update
> the manual and send through another patch.
>
> Carlo
>
> From 8b92ebac4fa13a2a89f279b249be152051f31d94 Mon Sep 17 00:00:00 2001
> From: Carlo Zancanaro <carlo <at> zancanaro.id.au>
> Date: Mon, 26 Nov 2018 22:38:08 +1100
> Subject: [PATCH 1/3] gnu: Add ability to restart services on system
> reconfigure
>
> * gnu/services/herd.scm (restart-service): New procedure.
> * gnu/services/shepherd.scm (<shepherd-service>)[restart-strategy]: New
> field.
> (shepherd-service-upgrade): Return lists of services to automatically and
> manually restart.
> * guix/scripts/system.scm (call-with-service-upgrade-info): Pass through
> services to be automatically and manually restarted.
> (upgrade-shepherd-services): Automatically restart services that should be
> automatically restarted, and print a message about manually restarting
> services that should be manually restarted.
> ---
> gnu/services/herd.scm | 5 +++++
> gnu/services/shepherd.scm | 35 ++++++++++++++++++++++--------
> guix/scripts/system.scm | 45 ++++++++++++++++++++++++---------------
> 3 files changed, 59 insertions(+), 26 deletions(-)
>
> diff --git a/gnu/services/herd.scm b/gnu/services/herd.scm
> index 8ff817759..c8d6eb04e 100644
> --- a/gnu/services/herd.scm
> +++ b/gnu/services/herd.scm
> @@ -52,6 +52,7 @@
> load-services
> load-services/safe
> start-service
> + restart-service
> stop-service))
>
> ;;; Commentary:
> @@ -256,6 +257,10 @@ when passed a service with an already-registered name."
> (with-shepherd-action name ('start) result
> result))
>
> +(define (restart-service name)
> + (with-shepherd-action name ('restart) result
> + result))
> +
> (define (stop-service name)
> (with-shepherd-action name ('stop) result
> result))
> diff --git a/gnu/services/shepherd.scm b/gnu/services/shepherd.scm
> index 49d08cc30..0c80e44f2 100644
> --- a/gnu/services/shepherd.scm
> +++ b/gnu/services/shepherd.scm
> @@ -159,7 +159,9 @@ DEFAULT is given, use it as the service's default value."
> (auto-start? shepherd-service-auto-start? ;Boolean
> (default #t))
> (modules shepherd-service-modules ;list of module names
> - (default %default-modules)))
> + (default %default-modules))
> + (restart-strategy shepherd-service-restart-strategy
> + (default 'manual)))
>
> (define-record-type* <shepherd-action>
> shepherd-action make-shepherd-action
> @@ -344,9 +346,10 @@ symbols provided/required by a service."
> #t))))))
>
> (define (shepherd-service-upgrade live target)
> - "Return two values: the subset of LIVE (a list of <live-service>) that needs
> -to be unloaded, and the subset of TARGET (a list of <shepherd-service>) that
> -need to be restarted to complete their upgrade."
> + "Return three values: (a) the subset of LIVE (a list of <live-service>) that
> +needs to be unloaded, (b) the subset of TARGET (a list of <shepherd-service>)
> +that can be restarted automatically, and (c) the subset of TARGET that must be
> +restarted manually."
> (define (essential? service)
> (memq (first (live-service-provision service))
> '(root shepherd)))
> @@ -373,14 +376,28 @@ need to be restarted to complete their upgrade."
> (#f (every obsolete? (live-service-dependents service)))
> (_ #f)))
>
> - (define to-restart
> - ;; Restart services that are currently running.
> - (filter running? target))
> -
> (define to-unload
> ;; Unload services that are no longer required.
> (remove essential? (filter obsolete? live)))
>
> - (values to-unload to-restart))
> + (define to-automatically-restart
> + ;; Automatically restart services that are currently running and can
> + ;; always be restarted.
> + (filter (lambda (service)
> + (and (running? service)
> + (eq? (shepherd-service-restart-strategy service)
> + 'always)))
> + target))
> +
> + (define to-manually-restart
> + ;; Manually restart services that are currently running and must be
> + ;; manually restarted.
> + (filter (lambda (service)
> + (and (running? service)
> + (eq? (shepherd-service-restart-strategy service)
> + 'manual)))
> + target))
> +
> + (values to-unload to-automatically-restart to-manually-restart))
>
> ;;; shepherd.scm ends here
> diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm
> index d92ec7d5a..6f14b1395 100644
> --- a/guix/scripts/system.scm
> +++ b/guix/scripts/system.scm
> @@ -322,11 +322,12 @@ names of services to load (upgrade), and the list of names of services to
> unload."
> (match (current-services)
> ((services ...)
> - (let-values (((to-unload to-restart)
> + (let-values (((to-unload to-automatically-restart to-manually-restart)
> (shepherd-service-upgrade services new-services)))
> - (mproc to-restart
> - (map (compose first live-service-provision)
> - to-unload))))
> + (mproc (map (compose first live-service-provision)
> + to-unload)
> + to-automatically-restart
> + to-manually-restart)))
> (#f
> (with-monad %store-monad
> (warning (G_ "failed to obtain list of shepherd services~%"))
> @@ -347,7 +348,7 @@ bring the system down."
> ;; Arrange to simply emit a warning if the service upgrade fails.
> (with-shepherd-error-handling
> (call-with-service-upgrade-info new-services
> - (lambda (to-restart to-unload)
> + (lambda (to-unload to-automatically-restart to-manually-restart)
> (for-each (lambda (unload)
> (info (G_ "unloading service '~a'...~%") unload)
> (unload-service unload))
> @@ -355,27 +356,37 @@ bring the system down."
>
> (with-monad %store-monad
> (munless (null? new-services)
> - (let ((new-service-names (map shepherd-service-canonical-name new-services))
> - (to-restart-names (map shepherd-service-canonical-name to-restart))
> - (to-start (filter shepherd-service-auto-start? new-services)))
> - (info (G_ "loading new services:~{ ~a~}...~%") new-service-names)
> - (unless (null? to-restart-names)
> - ;; Listing TO-RESTART-NAMES in the message below wouldn't help
> - ;; because many essential services cannot be meaningfully
> - ;; restarted. See <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22039#30>.
> - (format #t (G_ "To complete the upgrade, run 'herd restart SERVICE' to stop,
> -upgrade, and restart each service that was not automatically restarted.\n")))
> + (let ((new-service-names (map shepherd-service-canonical-name new-services))
> + (to-start-names (map shepherd-service-canonical-name (filter shepherd-service-auto-start? new-services)))
> + (to-automatically-restart-names (map shepherd-service-canonical-name to-automatically-restart))
> + (to-manually-restart-names (map shepherd-service-canonical-name to-manually-restart)))
> + (set! to-start-names
> + (remove (lambda (name)
> + (or (member name to-automatically-restart-names)
> + (member name to-manually-restart-names)))
> + to-start-names))
> +
> (mlet %store-monad ((files (mapm %store-monad
> (compose lower-object
> shepherd-service-file)
> new-services)))
> + (for-each restart-service to-automatically-restart-names)
> +
> ;; Here we assume that FILES are exactly those that were computed
> ;; as part of the derivation that built OS, which is normally the
> ;; case.
> + (info (G_ "loading new services:~{ ~a~}~%") new-service-names)
> (load-services/safe (map derivation->output-path files))
> -
> + (info (G_ "starting services:~{ ~a~}~%") to-start-names)
> (for-each start-service
> - (map shepherd-service-canonical-name to-start))
> + to-start-names)
> + (info (G_ "restarting services:~{ ~a~}~%") to-automatically-restart-names)
> + (for-each restart-service
> + to-automatically-restart-names)
> +
> + (unless (null? to-manually-restart-names)
> + (format #t (G_ "To complete the upgrade, the following services need to be manually restarted:~{ ~a~}~%")
> + to-manually-restart-names))
> (return #t)))))))))
>
> (define* (switch-to-system os
> --
> 2.19.1
>
> From 3fdef27c8f11b6a0f013afa9b6e619659ce78dec Mon Sep 17 00:00:00 2001
> From: Carlo Zancanaro <carlo <at> zancanaro.id.au>
> Date: Mon, 26 Nov 2018 22:38:18 +1100
> Subject: [PATCH 2/3] system: Add --restart-services flag for reconfigure
>
> * guix/scripts/system.scm (upgrade-shepherd-services): Add parameter to
> automatically restart services marked as needing manual restart.
> (switch-to-system): Pass through restart-services? flag.
> (perform-action): Pass through restart-services? flag.
> (%options): Add --restart-services flag.
> (%default-options): Add #f as default value for --restart-services flag.
> (process-action): Pass through restart-services? flag.
> ---
> guix/scripts/system.scm | 24 +++++++++++++++++-------
> 1 file changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm
> index 6f14b1395..bf632c534 100644
> --- a/guix/scripts/system.scm
> +++ b/guix/scripts/system.scm
> @@ -333,7 +333,7 @@ unload."
> (warning (G_ "failed to obtain list of shepherd services~%"))
> (return #f)))))
>
> -(define (upgrade-shepherd-services os)
> +(define (upgrade-shepherd-services os restart-services?)
> "Upgrade the Shepherd (PID 1) by unloading obsolete services and loading new
> services specified in OS and not currently running.
>
> @@ -360,6 +360,10 @@ bring the system down."
> (to-start-names (map shepherd-service-canonical-name (filter shepherd-service-auto-start? new-services)))
> (to-automatically-restart-names (map shepherd-service-canonical-name to-automatically-restart))
> (to-manually-restart-names (map shepherd-service-canonical-name to-manually-restart)))
> + (when restart-services?
> + (set! to-automatically-restart-names (append to-automatically-restart-names
> + to-manually-restart-names))
> + (set! to-manually-restart-names '()))
> (set! to-start-names
> (remove (lambda (name)
> (or (member name to-automatically-restart-names)
> @@ -389,7 +393,7 @@ bring the system down."
> to-manually-restart-names))
> (return #t)))))))))
>
> -(define* (switch-to-system os
> +(define* (switch-to-system os restart-services?
> #:optional (profile %system-profile))
> "Make a new generation of PROFILE pointing to the directory of OS, switch to
> it atomically, and then run OS's activation script."
> @@ -417,7 +421,7 @@ it atomically, and then run OS's activation script."
> (primitive-load (derivation->output-path script))))
>
> ;; Finally, try to update system services.
> - (upgrade-shepherd-services os))))
> + (upgrade-shepherd-services os restart-services?))))
>
> (define-syntax-rule (unless-file-not-found exp)
> (catch 'system-error
> @@ -825,7 +829,8 @@ and TARGET arguments."
> use-substitutes? bootloader-target target
> image-size file-system-type full-boot?
> (mappings '())
> - (gc-root #f))
> + (gc-root #f)
> + (restart-services? #f))
> "Perform ACTION for OS. INSTALL-BOOTLOADER? specifies whether to install
> bootloader; BOOTLOADER-TAGET is the target for the bootloader; TARGET is the
> target root directory; IMAGE-SIZE is the size of the image to be built, for
> @@ -907,7 +912,7 @@ static checks."
> (case action
> ((reconfigure)
> (mbegin %store-monad
> - (switch-to-system os)
> + (switch-to-system os restart-services?)
> (mwhen install-bootloader?
> (install-bootloader bootloader-script
> #:bootcfg bootcfg
> @@ -1090,6 +1095,9 @@ Some ACTIONS support additional ARGS.\n"))
> (option '(#\r "root") #t #f
> (lambda (opt name arg result)
> (alist-cons 'gc-root arg result)))
> + (option '("restart-services") #f #f
> + (lambda (opt name arg result)
> + (alist-cons 'restart-services? #t result)))
> %standard-build-options))
>
> (define %default-options
> @@ -1104,7 +1112,8 @@ Some ACTIONS support additional ARGS.\n"))
> (verbosity . 0)
> (file-system-type . "ext4")
> (image-size . guess)
> - (install-bootloader? . #t)))
> + (install-bootloader? . #t)
> + (restart-services? . #f)))
>
>
> ;;;
> @@ -1177,7 +1186,8 @@ resulting from command-line parsing."
> #:install-bootloader? bootloader?
> #:target target
> #:bootloader-target bootloader-target
> - #:gc-root (assoc-ref opts 'gc-root)))))
> + #:gc-root (assoc-ref opts 'gc-root)
> + #:restart-services? (assoc-ref opts 'restart-services?)))))
> #:system system))
> (warn-about-disk-space)))
>
> --
> 2.19.1
>
> From 099a8e2e6e28b38816ed1ba895c407f1d9efe62e Mon Sep 17 00:00:00 2001
> From: Carlo Zancanaro <carlo <at> zancanaro.id.au>
> Date: Mon, 26 Nov 2018 22:38:26 +1100
> Subject: [PATCH 3/3] services: Always restart guix daemon
>
> * gnu/services/base.scm (guix-shepherd-service): Add restart-strategy of
> 'always.
> ---
> gnu/services/base.scm | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/gnu/services/base.scm b/gnu/services/base.scm
> index 228d3c592..7e0fdcb3e 100644
> --- a/gnu/services/base.scm
> +++ b/gnu/services/base.scm
> @@ -1573,6 +1573,7 @@ failed to register hydra.gnu.org public key: ~a~%" status))))))))
> (documentation "Run the Guix daemon.")
> (provision '(guix-daemon))
> (requirement '(user-processes))
> + (restart-strategy 'always)
> (modules '((srfi srfi-1)))
> (start
> #~(make-forkexec-constructor
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