[bug#32998] [PATCH 0/2] Turn ~/.config/guix/current into a symlink to /var/guix/profiles

[bug#32998] [PATCH 0/2] Turn ~/.config/guix/current into a symlink to /var/guix/profiles

[Ludovic Courtès]

Hi there!

The following patches turn ~/.config/guix/current into a symlink to
/var/guix/profiles/per-user/$USER/current-guix, in a way that is
consistent with what ‘guix package’ does.

Note that ‘guix pull’ will automatically move your generations from
~/.config/guix to /var/guix/profiles/per-user/$USER the first time
you run it.

This will allow us to fix <https://bugs.gnu.org/32183> nicely.

Objections?

Ludo’.

Ludovic Courtès (2):
  profiles: Generalize 'canonicalize-profile'.
  pull: Turn ~/.config/guix/current into a symlink to
    /var/guix/profiles.

 doc/guix.texi         |  2 +-
 guix/profiles.scm     | 23 ++++++++-------
 guix/scripts/pull.scm | 65 +++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 74 insertions(+), 16 deletions(-)

-- 
2.19.0

[bug#32998] [PATCH 1/2] profiles: Generalize 'canonicalize-profile'.

[Ludovic Courtès]

* guix/profiles.scm (canonicalize-profile): Rewrite to work with any
profile that lives under %PROFILE-DIRECTORY.
---
 guix/profiles.scm | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/guix/profiles.scm b/guix/profiles.scm
index de3a04464..6b911b3fe 100644
--- a/guix/profiles.scm
+++ b/guix/profiles.scm
@@ -1611,19 +1611,18 @@ because the NUMBER is zero.)"
   (string-append %profile-directory "/guix-profile"))
 
 (define (canonicalize-profile profile)
-  "If PROFILE is %USER-PROFILE-DIRECTORY, return %CURRENT-PROFILE.  Otherwise
-return PROFILE unchanged.  The goal is to treat '-p ~/.guix-profile' as if
-'-p' was omitted."                           ; see <http://bugs.gnu.org/17939>
-
-  ;; Trim trailing slashes so that the basename comparison below works as
-  ;; intended.
+  "If PROFILE points to a profile in %PROFILE-DIRECTORY, return that.
+Otherwise return PROFILE unchanged.  The goal is to treat '-p ~/.guix-profile'
+as if '-p' was omitted."  ; see <http://bugs.gnu.org/17939>
+  ;; Trim trailing slashes so 'readlink' can do its job.
   (let ((profile (string-trim-right profile #\/)))
-    (if (and %user-profile-directory
-             (string=? (canonicalize-path (dirname profile))
-                       (dirname %user-profile-directory))
-             (string=? (basename profile) (basename %user-profile-directory)))
-        %current-profile
-        profile)))
+    (catch 'system-error
+      (lambda ()
+        (let ((target (readlink profile)))
+          (if (string=? (dirname target) %profile-directory)
+              target
+              profile)))
+      (const profile))))
 
 (define (user-friendly-profile profile)
   "Return either ~/.guix-profile if that's what PROFILE refers to, directly or
-- 
2.19.0

[bug#32998] [PATCH 2/2] pull: Turn ~/.config/guix/current into a symlink to /var/guix/profiles.

[Ludovic Courtès]

This is more consistent with what 'guix package' does, more pleasant for
users (we no longer clobber ~/.config/guix), and more
cluster-friendly (since /var/guix/profiles is usually an NFS share
already.)

* guix/scripts/pull.scm (%current-profile, %user-profile-directory): New
variables.
(migrate-generations, ensure-default-profile): New procedures.
(guix-pull): Use %CURRENT-PROFILE by default.  Call
'ensure-default-profile'.
* doc/guix.texi (Invoking guix pull): Adjust 'guix package -p
~/.config/guix/current' example.
---
 doc/guix.texi         |  2 +-
 guix/scripts/pull.scm | 65 +++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 3c116fc0b..c6e474955 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -2831,7 +2831,7 @@ generation---i.e., the previous Guix---and so on:
 $ guix package -p ~/.config/guix/current --roll-back
 switched from generation 3 to 2
 $ guix package -p ~/.config/guix/current --delete-generations=1
-deleting /home/charlie/.config/guix/current-1-link
+deleting /var/guix/profiles/per-user/charlie/current-guix-1-link
 @end example
 
 The @command{guix pull} command is usually invoked with no arguments,
diff --git a/guix/scripts/pull.scm b/guix/scripts/pull.scm
index 0d65857be..042b493ae 100644
--- a/guix/scripts/pull.scm
+++ b/guix/scripts/pull.scm
@@ -226,6 +226,66 @@ Download and deploy the latest version of Guix.\n"))
       (report-git-error err))))
 
 \f
+;;;
+;;; Profile.
+;;;
+
+(define %current-profile
+  ;; The "real" profile under /var/guix.
+  (string-append %profile-directory "/current-guix"))
+
+(define %user-profile-directory
+  ;; The user-friendly name of %CURRENT-PROFILE.
+  (string-append (config-directory #:ensure? #f) "/current"))
+
+(define (migrate-generations profile directory)
+  "Migration the generations of PROFILE to DIRECTORY."
+  (format (current-error-port)
+          (G_ "Migrating profile generations to '~a'...~%")
+          %profile-directory)
+  (for-each (lambda (generation)
+              (let ((source (generation-file-name profile generation))
+                    (target (string-append directory "/current-guix-"
+                                           (number->string generation)
+                                           "-link")))
+                (rename-file source target)))
+            (profile-generations profile)))
+
+(define (ensure-default-profile)
+  (catch 'system-error
+    (lambda ()
+      ;; Note: The /per-user directory, parent of %PROFILE-DIRECTORY, is
+      ;; created by the daemon.  Assume it already exists.
+      (mkdir %profile-directory))
+    (lambda args
+      (unless (= EEXIST (system-error-errno args))
+        (format (current-error-port)
+                (G_ "error: while creating directory `~a': ~a~%")
+                %profile-directory
+                (strerror (system-error-errno args)))
+        (format (current-error-port)
+                (G_ "Please create the `~a' directory, with you as the owner.~%")
+                %profile-directory))))
+
+  ;; In 0.15.0+ we'd create ~/.config/guix/current-[0-9]*-link symlinks.  Move
+  ;; them to %PROFILE-DIRECTORY.
+  (unless (string=? %profile-directory
+                    (dirname (canonicalize-profile %user-profile-directory)))
+    (migrate-generations %user-profile-directory %profile-directory))
+
+  ;; Recreate ~/.config/guix/current.  Recreating it is a way to have an
+  ;; up-to-date mtime on the link, which we can then use to determine the time
+  ;; of the last update (XXX: we could do better...).
+  (let ((link %user-profile-directory))
+    (false-if-exception (delete-file link))
+    (catch 'system-error
+      (lambda ()
+        (symlink %current-profile link))
+      (lambda args
+        (leave (G_ "while creating symlink '~a': ~a~%")
+               link (strerror (system-error-errno args)))))))
+
+\f
 ;;;
 ;;; Queries.
 ;;;
@@ -438,9 +498,8 @@ Use '~/.config/guix/channels.scm' instead."))
                                           (list %default-options)))
             (cache    (string-append (cache-directory) "/pull"))
             (channels (channel-list opts))
-            (profile  (or (assoc-ref opts 'profile)
-                          (string-append (config-directory) "/current"))))
-
+            (profile  (or (assoc-ref opts 'profile) %current-profile)))
+       (ensure-default-profile)
        (cond ((assoc-ref opts 'query)
               (process-query opts profile))
              ((assoc-ref opts 'dry-run?)
-- 
2.19.0

bug#32998: [PATCH 0/2] Turn ~/.config/guix/current into a symlink to /var/guix/profiles

[Ludovic Courtès]

Hello,

Ludovic Courtès <ludo@gnu.org> skribis:

> The following patches turn ~/.config/guix/current into a symlink to
> /var/guix/profiles/per-user/$USER/current-guix, in a way that is
> consistent with what ‘guix package’ does.
>
> Note that ‘guix pull’ will automatically move your generations from
> ~/.config/guix to /var/guix/profiles/per-user/$USER the first time
> you run it.

Applied with minor refactoring (the ‘ensure-profile-directory’ thing.)

Ludo’.