diff options
| -rw-r--r-- | doc/guix.texi | 47 | ||||
| -rw-r--r-- | guix/scripts/system.scm | 72 |
2 files changed, 110 insertions, 9 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index 7715b72818..20bf28424e 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -5369,9 +5369,24 @@ information about the @code{nss-certs} package that is used here. Assuming the above snippet is stored in the @file{my-system-config.scm} file, the @command{guix system reconfigure my-system-config.scm} command instantiates that configuration, and makes it the default GRUB boot -entry (@pxref{Invoking guix system}). The normal way to change the -system's configuration is by updating this file and re-running the -@command{guix system} command. +entry (@pxref{Invoking guix system}). + +The normal way to change the system's configuration is by updating this +file and re-running @command{guix system reconfigure}. One should never +have to touch files in @command{/etc} or to run commands that modify the +system state such as @command{useradd} or @command{grub-install}. In +fact, you must avoid that since that would not only void your warranty +but also prevent you from rolling back to previous versions of your +system, should you ever need to. + +@cindex roll-back, of the operating system +Speaking of roll-back, each time you run @command{guix system +reconfigure}, a new @dfn{generation} of the system is created---without +modifying or deleting previous generations. Old system generations get +an entry in the GRUB boot menu, allowing you to boot them in case +something went wrong with the latest generation. Reassuring, no? The +@command{guix system list-generations} command lists the system +generations available on disk. At the Scheme level, the bulk of an @code{operating-system} declaration is instantiated with the following monadic procedure (@pxref{The Store @@ -7077,7 +7092,7 @@ supported: @item reconfigure Build the operating system described in @var{file}, activate it, and switch to it@footnote{This action is usable only on systems already -running GNU.}. +running GuixSD.}. This effects all the configuration specified in @var{file}: user accounts, system services, global package list, setuid programs, etc. @@ -7218,6 +7233,30 @@ KVM kernel module should be loaded, and the @file{/dev/kvm} device node must exist and be readable and writable by the user and by the daemon's build users. +Once you have built, configured, re-configured, and re-re-configured +your GuixSD installation, you may find it useful to list the operating +system generations available on disk---and that you can choose from the +GRUB boot menu: + +@table @code + +@item list-generations +List a summary of each generation of the operating system available on +disk, in a human-readable way. This is similar to the +@option{--list-generations} option of @command{guix package} +(@pxref{Invoking guix package}). + +Optionally, one can specify a pattern, with the same syntax that is used +in @command{guix package --list-generations}, to restrict the list of +generations displayed. For instance, the following command displays +generations up to 10-day old: + +@example +$ guix system list-generations 10d +@end example + +@end table + The @command{guix system} command has even more to offer! The following sub-commands allow you to visualize how your system services relate to each other: diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm index 6db6a01ac9..d847c75444 100644 --- a/guix/scripts/system.scm +++ b/guix/scripts/system.scm @@ -42,6 +42,8 @@ #: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) #:use-module (srfi srfi-37) #:use-module (ice-9 match) #:export (guix-system @@ -353,6 +355,48 @@ list of services." ;;; +;;; Generations. +;;; + +(define* (display-system-generation number + #:optional (profile %system-profile)) + "Display a summary of system generation NUMBER in a human-readable format." + (unless (zero? number) + (let* ((generation (generation-file-name profile number)) + (param-file (string-append generation "/parameters")) + (params (call-with-input-file param-file read-boot-parameters))) + (display-generation profile number) + (format #t (_ " file name: ~a~%") generation) + (format #t (_ " canonical file name: ~a~%") (readlink* generation)) + (match params + (($ <boot-parameters> label root kernel) + ;; TRANSLATORS: Please preserve the two-space indentation. + (format #t (_ " label: ~a~%") label) + (format #t (_ " root device: ~a~%") root) + (format #t (_ " kernel: ~a~%") kernel)) + (_ + #f))))) + +(define* (list-generations pattern #:optional (profile %system-profile)) + "Display in a human-readable format all the system generations matching +PATTERN, a string. When PATTERN is #f, display all the system generations." + (cond ((not (file-exists? profile)) ; XXX: race condition + (raise (condition (&profile-not-found-error + (profile profile))))) + ((string-null? pattern) + (for-each display-system-generation (profile-generations profile))) + ((matching-generations pattern profile) + => + (lambda (numbers) + (if (null-list? numbers) + (exit 1) + (leave-on-EPIPE + (for-each display-system-generation numbers))))) + (else + (leave (_ "invalid syntax: ~a~%") pattern)))) + + +;;; ;;; Action. ;;; @@ -468,7 +512,7 @@ building anything." ;;; (define (show-help) - (display (_ "Usage: guix system [OPTION] ACTION FILE + (display (_ "Usage: guix system [OPTION] ACTION [FILE] Build the operating system declared in FILE according to ACTION.\n")) (newline) (display (_ "The valid values for ACTION are:\n")) @@ -476,6 +520,8 @@ Build the operating system declared in FILE according to ACTION.\n")) (display (_ "\ reconfigure switch to a new operating system configuration\n")) (display (_ "\ + list-generations list the system generations\n")) + (display (_ "\ build build the operating system without installing anything\n")) (display (_ "\ vm build a virtual machine image that shares the host's store\n")) @@ -577,8 +623,10 @@ Build the operating system declared in FILE according to ACTION.\n")) ;;; (define (process-action action args opts) - "Process ACTION, a sub-command, whose arguments are listed in ARGS. OPTS is -the raw alist of options resulting from command-line parsing." + "Process ACTION, a sub-command, with the arguments are listed in ARGS. +ACTION must be one of the sub-commands that takes an operating system +declaration as an argument (a file name.) OPTS is the raw alist of options +resulting from command-line parsing." (let* ((file (match args (() #f) ((x . _) x))) @@ -625,6 +673,20 @@ the raw alist of options resulting from command-line parsing." #:target target #:device device)))) #:system system)))) +(define (process-command command args opts) + "Process COMMAND, one of the 'guix system' sub-commands. ARGS is its +argument list and OPTS is the option alist." + (case command + ((list-generations) + ;; List generations. No need to connect to the daemon, etc. + (let ((pattern (match args + (() "") + ((pattern) pattern) + (x (leave (_ "wrong number of arguments~%")))))) + (list-generations pattern))) + (else + (process-action command args opts)))) + (define (guix-system . args) (define (parse-sub-command arg result) ;; Parse sub-command ARG and augment RESULT accordingly. @@ -633,7 +695,7 @@ the raw alist of options resulting from command-line parsing." (let ((action (string->symbol arg))) (case action ((build vm vm-image disk-image reconfigure init - extension-graph dmd-graph) + extension-graph dmd-graph list-generations) (alist-cons 'action action result)) (else (leave (_ "~a: unknown action~%") action)))))) @@ -676,6 +738,6 @@ the raw alist of options resulting from command-line parsing." parse-sub-command)) (args (option-arguments opts)) (command (assoc-ref opts 'action))) - (process-action command args opts)))) + (process-command command args opts)))) ;;; system.scm ends here |