diff options
Diffstat (limited to 'gnu')
| -rw-r--r-- | gnu/machine.scm | 27 | ||||
| -rw-r--r-- | gnu/machine/ssh.scm | 72 |
2 files changed, 95 insertions, 4 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 fb15d39e61..4b5d5fe3a2 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) @@ -34,6 +35,7 @@ #: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) @@ -341,6 +343,18 @@ 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." @@ -353,9 +367,60 @@ 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 %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))) + (remote-result (machine-remote-eval machine remote-exp))) + (when (eqv? 'error remote-result) + (raise roll-back-failure)))) ;;; @@ -366,6 +431,7 @@ 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 |