| Message ID | 87v9v8k82l.fsf_-_@sdf.lonestar.org |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [bug#36952,v2] machine: Implement 'roll-back-machine'. | expand |
Thanks. I'm going to specifically loop in Dave... Dave, mind peering over this before I merge it? Jakob L. Kreuze writes: > * gnu/machine.scm (roll-back-machine, &deploy-error, deploy-error?) > (deploy-error-should-roll-back) > (deploy-error-captured-args): New variable. > * gnu/machine/ssh.scm (roll-back-managed-host): New variable. > * guix/scripts/deploy.scm (guix-deploy): Roll-back systems when a > deployment fails. > --- > gnu/machine.scm | 27 ++++++++++++++- > gnu/machine/ssh.scm | 75 +++++++++++++++++++++++++++++++++++++++-- > guix/remote.scm | 1 + > guix/scripts/deploy.scm | 17 ++++++++-- > 4 files changed, 114 insertions(+), 6 deletions(-) > > diff --git a/gnu/machine.scm b/gnu/machine.scm > index 30ae97f6ec..05b03b21d4 100644 > --- a/gnu/machine.scm > +++ b/gnu/machine.scm > @@ -24,6 +24,7 @@ > #:use-module (guix records) > #:use-module (guix store) > #:use-module ((guix utils) #:select (source-properties->location)) > + #:use-module (srfi srfi-35) > #:export (environment-type > environment-type? > environment-type-name > @@ -40,7 +41,13 @@ > machine-display-name > > deploy-machine > - machine-remote-eval)) > + roll-back-machine > + machine-remote-eval > + > + &deploy-error > + deploy-error? > + deploy-error-should-roll-back > + deploy-error-captured-args)) > > ;;; Commentary: > ;;; > @@ -66,6 +73,7 @@ > ;; of the form '(machine-remote-eval machine exp)'. > (machine-remote-eval environment-type-machine-remote-eval) ; procedure > (deploy-machine environment-type-deploy-machine) ; procedure > + (roll-back-machine environment-type-roll-back-machine) ; procedure > > ;; Metadata. > (name environment-type-name) ; symbol > @@ -105,3 +113,20 @@ are built and deployed to MACHINE beforehand." > MACHINE, activating it on MACHINE and switching MACHINE to the new generation." > (let ((environment (machine-environment machine))) > ((environment-type-deploy-machine environment) machine))) > + > +(define (roll-back-machine machine) > + "Monadic procedure rolling back to the previous system generation on > +MACHINE. Return the number of the generation that was current before switching > +and the new generation number." > + (let ((environment (machine-environment machine))) > + ((environment-type-roll-back-machine environment) machine))) > + > + > +;;; > +;;; Error types. > +;;; > + > +(define-condition-type &deploy-error &error > + deploy-error? > + (should-roll-back deploy-error-should-roll-back) > + (captured-args deploy-error-captured-args)) > diff --git a/gnu/machine/ssh.scm b/gnu/machine/ssh.scm > index 274d56db26..ae312597dd 100644 > --- a/gnu/machine/ssh.scm > +++ b/gnu/machine/ssh.scm > @@ -17,6 +17,7 @@ > ;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. > > (define-module (gnu machine ssh) > + #:use-module (gnu bootloader) > #:use-module (gnu machine) > #:autoload (gnu packages gnupg) (guile-gcrypt) > #:use-module (gnu system) > @@ -34,8 +35,10 @@ > #:use-module (guix store) > #:use-module (guix utils) > #:use-module (ice-9 match) > + #:use-module (srfi srfi-1) > #:use-module (srfi srfi-19) > #:use-module (srfi srfi-26) > + #:use-module (srfi srfi-34) > #:use-module (srfi srfi-35) > #:export (managed-host-environment-type > > @@ -304,6 +307,18 @@ of MACHINE's system profile, ordered from most recent to oldest." > (boot-parameters-kernel-arguments params)))))))) > generations)))) > > +(define-syntax-rule (with-roll-back should-roll-back? mbody ...) > + "Catch exceptions that arise when binding MBODY, a monadic expression in > +%STORE-MONAD, and collect their arguments in a &deploy-error condition, with > +the 'should-roll-back' field set to SHOULD-ROLL-BACK?" > + (catch #t > + (lambda () > + mbody ...) > + (lambda args > + (raise (condition (&deploy-error > + (should-roll-back should-roll-back?) > + (captured-args args))))))) > + > (define (deploy-managed-host machine) > "Internal implementation of 'deploy-machine' for MACHINE instances with an > environment type of 'managed-host." > @@ -316,9 +331,62 @@ environment type of 'managed-host." > (bootloader-configuration (operating-system-bootloader os)) > (bootcfg (operating-system-bootcfg os menu-entries))) > (mbegin %store-monad > - (switch-to-system eval os) > - (upgrade-shepherd-services eval os) > - (install-bootloader eval bootloader-configuration bootcfg))))) > + (with-roll-back #f > + (switch-to-system eval os)) > + (with-roll-back #t > + (mbegin %store-monad > + (upgrade-shepherd-services eval os) > + (install-bootloader eval bootloader-configuration bootcfg))))))) > + > + > +;;; > +;;; Roll-back. > +;;; > + > +(define (roll-back-managed-host machine) > + "Internal implementation of 'roll-back-machine' for MACHINE instances with > +an environment type of 'managed-host." > + (define remote-exp > + (with-extensions (list guile-gcrypt) > + (with-imported-modules (source-module-closure '((guix config) > + (guix profiles))) > + #~(begin > + (use-modules (guix config) > + (guix profiles)) > + > + (define %system-profile > + (string-append %state-directory "/profiles/system")) > + > + (define target-generation > + (relative-generation-spec->number %system-profile "-1")) > + > + (if target-generation > + (switch-to-generation %system-profile target-generation) > + 'error))))) > + > + (define roll-back-failure > + (condition (&message (message (G_ "could not roll-back machine"))))) > + > + (mlet* %store-monad ((boot-parameters (machine-boot-parameters machine)) > + (_ -> (if (< (length boot-parameters) 2) > + (raise roll-back-failure))) > + (entries -> (map boot-parameters->menu-entry > + (list (second boot-parameters)))) > + (old-entries -> (map boot-parameters->menu-entry > + (drop boot-parameters 2))) > + (bootloader -> (operating-system-bootloader > + (machine-operating-system machine))) > + (bootcfg (lower-object > + ((bootloader-configuration-file-generator > + (bootloader-configuration-bootloader > + bootloader)) > + bootloader entries > + #:old-entries old-entries))) > + (eval -> (cut machine-remote-eval machine <>)) > + (remote-result (machine-remote-eval machine > + remote-exp))) > + (when (eqv? 'error remote-result) > + (raise roll-back-failure)))) > > > ;;; > @@ -329,6 +397,7 @@ environment type of 'managed-host." > (environment-type > (machine-remote-eval managed-host-remote-eval) > (deploy-machine deploy-managed-host) > + (roll-back-machine roll-back-managed-host) > (name 'managed-host-environment-type) > (description "Provisioning for machines that are accessible over SSH > and have a known host-name. This entails little more than maintaining an SSH > diff --git a/guix/remote.scm b/guix/remote.scm > index 5fecd954e9..853029c54f 100644 > --- a/guix/remote.scm > +++ b/guix/remote.scm > @@ -24,6 +24,7 @@ > #:use-module (guix monads) > #:use-module (guix modules) > #:use-module (guix derivations) > + #:use-module (guix utils) > #:use-module (ssh popen) > #:use-module (srfi srfi-1) > #:use-module (ice-9 match) > diff --git a/guix/scripts/deploy.scm b/guix/scripts/deploy.scm > index ebc99e52cc..d16e7d7480 100644 > --- a/guix/scripts/deploy.scm > +++ b/guix/scripts/deploy.scm > @@ -28,6 +28,8 @@ > #:use-module (guix grafts) > #:use-module (ice-9 format) > #:use-module (srfi srfi-1) > + #:use-module (srfi srfi-34) > + #:use-module (srfi srfi-35) > #:use-module (srfi srfi-37) > #:export (guix-deploy)) > > @@ -91,8 +93,19 @@ Perform the deployment specified by FILE.\n")) > (with-store store > (set-build-options-from-command-line store opts) > (for-each (lambda (machine) > - (info (G_ "deploying to ~a...") (machine-display-name machine)) > + (info (G_ "deploying to ~a...~%") > + (machine-display-name machine)) > (parameterize ((%current-system (assq-ref opts 'system)) > (%graft? (assq-ref opts 'graft?))) > - (run-with-store store (deploy-machine machine)))) > + (guard (c ((message-condition? c) > + (report-error (G_ "failed to deploy ~a: '~a'~%") > + (machine-display-name machine) > + (condition-message c))) > + ((deploy-error? c) > + (when (deploy-error-should-roll-back c) > + (info (G_ "rolling back ~a...~%") > + (machine-display-name machine)) > + (run-with-store store (roll-back-machine machine))) > + (apply throw (deploy-error-captured-args c)))) > + (run-with-store store (deploy-machine machine))))) > machines))))
Hi Jakob, > +(define (roll-back-managed-host machine) > + "Internal implementation of 'roll-back-machine' for MACHINE instances with > +an environment type of 'managed-host." > + (define remote-exp > + (with-extensions (list guile-gcrypt) > + (with-imported-modules (source-module-closure '((guix config) > + (guix profiles))) > + #~(begin > + (use-modules (guix config) > + (guix profiles)) > + > + (define %system-profile > + (string-append %state-directory "/profiles/system")) > + > + (define target-generation > + (relative-generation-spec->number %system-profile "-1")) Can we use “relative-generation” or “previous-generation-number” here? I think the stringified “-1” is kinda ugly, and the “*-spec” procedure only exists to handle user input, which is provided as a string. > + (mlet* %store-monad ((boot-parameters (machine-boot-parameters machine)) > + (_ -> (if (< (length boot-parameters) 2) > + (raise roll-back-failure))) > + (entries -> (map boot-parameters->menu-entry > + (list (second boot-parameters)))) > + (old-entries -> (map boot-parameters->menu-entry > + (drop boot-parameters 2))) > + (bootloader -> (operating-system-bootloader > + (machine-operating-system machine))) > + (bootcfg (lower-object > + ((bootloader-configuration-file-generator > + (bootloader-configuration-bootloader > + bootloader)) > + bootloader entries > + #:old-entries old-entries))) > + (eval -> (cut machine-remote-eval machine <>)) > + (remote-result (machine-remote-eval machine > + > remote-exp))) Is it on purpose that you aren’t using the previously defined “eval” here? -- Ricardo
Hi Ricardo, Ricardo Wurmus <rekado@elephly.net> writes: > Can we use “relative-generation” or “previous-generation-number” here? > I think the stringified “-1” is kinda ugly, and the “*-spec” procedure > only exists to handle user input, which is provided as a string. Oh yeah, definitely. I used '*-spec' here because I was using 'guix system' as a model -- didn't know it was meant for handling user input. > Is it on purpose that you aren’t using the previously defined “eval” > here? Whoops! Unused variable, nice catch! Thanks for the review! Regards, Jakob
diff --git a/gnu/machine.scm b/gnu/machine.scm index 30ae97f6ec..05b03b21d4 100644 --- a/gnu/machine.scm +++ b/gnu/machine.scm @@ -24,6 +24,7 @@ #:use-module (guix records) #:use-module (guix store) #:use-module ((guix utils) #:select (source-properties->location)) + #:use-module (srfi srfi-35) #:export (environment-type environment-type? environment-type-name @@ -40,7 +41,13 @@ machine-display-name deploy-machine - machine-remote-eval)) + roll-back-machine + machine-remote-eval + + &deploy-error + deploy-error? + deploy-error-should-roll-back + deploy-error-captured-args)) ;;; Commentary: ;;; @@ -66,6 +73,7 @@ ;; of the form '(machine-remote-eval machine exp)'. (machine-remote-eval environment-type-machine-remote-eval) ; procedure (deploy-machine environment-type-deploy-machine) ; procedure + (roll-back-machine environment-type-roll-back-machine) ; procedure ;; Metadata. (name environment-type-name) ; symbol @@ -105,3 +113,20 @@ are built and deployed to MACHINE beforehand." MACHINE, activating it on MACHINE and switching MACHINE to the new generation." (let ((environment (machine-environment machine))) ((environment-type-deploy-machine environment) machine))) + +(define (roll-back-machine machine) + "Monadic procedure rolling back to the previous system generation on +MACHINE. Return the number of the generation that was current before switching +and the new generation number." + (let ((environment (machine-environment machine))) + ((environment-type-roll-back-machine environment) machine))) + + +;;; +;;; Error types. +;;; + +(define-condition-type &deploy-error &error + deploy-error? + (should-roll-back deploy-error-should-roll-back) + (captured-args deploy-error-captured-args)) diff --git a/gnu/machine/ssh.scm b/gnu/machine/ssh.scm index 274d56db26..ae312597dd 100644 --- a/gnu/machine/ssh.scm +++ b/gnu/machine/ssh.scm @@ -17,6 +17,7 @@ ;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. (define-module (gnu machine ssh) + #:use-module (gnu bootloader) #:use-module (gnu machine) #:autoload (gnu packages gnupg) (guile-gcrypt) #:use-module (gnu system) @@ -34,8 +35,10 @@ #:use-module (guix store) #:use-module (guix utils) #:use-module (ice-9 match) + #:use-module (srfi srfi-1) #:use-module (srfi srfi-19) #:use-module (srfi srfi-26) + #:use-module (srfi srfi-34) #:use-module (srfi srfi-35) #:export (managed-host-environment-type @@ -304,6 +307,18 @@ of MACHINE's system profile, ordered from most recent to oldest." (boot-parameters-kernel-arguments params)))))))) generations)))) +(define-syntax-rule (with-roll-back should-roll-back? mbody ...) + "Catch exceptions that arise when binding MBODY, a monadic expression in +%STORE-MONAD, and collect their arguments in a &deploy-error condition, with +the 'should-roll-back' field set to SHOULD-ROLL-BACK?" + (catch #t + (lambda () + mbody ...) + (lambda args + (raise (condition (&deploy-error + (should-roll-back should-roll-back?) + (captured-args args))))))) + (define (deploy-managed-host machine) "Internal implementation of 'deploy-machine' for MACHINE instances with an environment type of 'managed-host." @@ -316,9 +331,62 @@ environment type of 'managed-host." (bootloader-configuration (operating-system-bootloader os)) (bootcfg (operating-system-bootcfg os menu-entries))) (mbegin %store-monad - (switch-to-system eval os) - (upgrade-shepherd-services eval os) - (install-bootloader eval bootloader-configuration bootcfg))))) + (with-roll-back #f + (switch-to-system eval os)) + (with-roll-back #t + (mbegin %store-monad + (upgrade-shepherd-services eval os) + (install-bootloader eval bootloader-configuration bootcfg))))))) + + +;;; +;;; Roll-back. +;;; + +(define (roll-back-managed-host machine) + "Internal implementation of 'roll-back-machine' for MACHINE instances with +an environment type of 'managed-host." + (define remote-exp + (with-extensions (list guile-gcrypt) + (with-imported-modules (source-module-closure '((guix config) + (guix profiles))) + #~(begin + (use-modules (guix config) + (guix profiles)) + + (define %system-profile + (string-append %state-directory "/profiles/system")) + + (define target-generation + (relative-generation-spec->number %system-profile "-1")) + + (if target-generation + (switch-to-generation %system-profile target-generation) + 'error))))) + + (define roll-back-failure + (condition (&message (message (G_ "could not roll-back machine"))))) + + (mlet* %store-monad ((boot-parameters (machine-boot-parameters machine)) + (_ -> (if (< (length boot-parameters) 2) + (raise roll-back-failure))) + (entries -> (map boot-parameters->menu-entry + (list (second boot-parameters)))) + (old-entries -> (map boot-parameters->menu-entry + (drop boot-parameters 2))) + (bootloader -> (operating-system-bootloader + (machine-operating-system machine))) + (bootcfg (lower-object + ((bootloader-configuration-file-generator + (bootloader-configuration-bootloader + bootloader)) + bootloader entries + #:old-entries old-entries))) + (eval -> (cut machine-remote-eval machine <>)) + (remote-result (machine-remote-eval machine + remote-exp))) + (when (eqv? 'error remote-result) + (raise roll-back-failure)))) ;;; @@ -329,6 +397,7 @@ environment type of 'managed-host." (environment-type (machine-remote-eval managed-host-remote-eval) (deploy-machine deploy-managed-host) + (roll-back-machine roll-back-managed-host) (name 'managed-host-environment-type) (description "Provisioning for machines that are accessible over SSH and have a known host-name. This entails little more than maintaining an SSH diff --git a/guix/remote.scm b/guix/remote.scm index 5fecd954e9..853029c54f 100644 --- a/guix/remote.scm +++ b/guix/remote.scm @@ -24,6 +24,7 @@ #:use-module (guix monads) #:use-module (guix modules) #:use-module (guix derivations) + #:use-module (guix utils) #:use-module (ssh popen) #:use-module (srfi srfi-1) #:use-module (ice-9 match) diff --git a/guix/scripts/deploy.scm b/guix/scripts/deploy.scm index ebc99e52cc..d16e7d7480 100644 --- a/guix/scripts/deploy.scm +++ b/guix/scripts/deploy.scm @@ -28,6 +28,8 @@ #:use-module (guix grafts) #:use-module (ice-9 format) #:use-module (srfi srfi-1) + #:use-module (srfi srfi-34) + #:use-module (srfi srfi-35) #:use-module (srfi srfi-37) #:export (guix-deploy)) @@ -91,8 +93,19 @@ Perform the deployment specified by FILE.\n")) (with-store store (set-build-options-from-command-line store opts) (for-each (lambda (machine) - (info (G_ "deploying to ~a...") (machine-display-name machine)) + (info (G_ "deploying to ~a...~%") + (machine-display-name machine)) (parameterize ((%current-system (assq-ref opts 'system)) (%graft? (assq-ref opts 'graft?))) - (run-with-store store (deploy-machine machine)))) + (guard (c ((message-condition? c) + (report-error (G_ "failed to deploy ~a: '~a'~%") + (machine-display-name machine) + (condition-message c))) + ((deploy-error? c) + (when (deploy-error-should-roll-back c) + (info (G_ "rolling back ~a...~%") + (machine-display-name machine)) + (run-with-store store (roll-back-machine machine))) + (apply throw (deploy-error-captured-args c)))) + (run-with-store store (deploy-machine machine))))) machines))))