[bug#42634] [PATCH 0/3] Add image-type support.

[bug#42634] [PATCH 0/3] Add image-type support.

[Mathieu Othacehe]

Hello,

This is the missing piece for the new image API. It has been previously
discussed here[1].

I think this is close to what Ludo suggested and it addresses janneke concerns
about composability.

The idea is to introduce the concept of "image-type". An image type is a
converter from an <operating-system> record to an <image> record.

I have created in this serie 4 new image type records:
- raw
- iso9660
- uncompressed-iso9660
- hurd-raw

I also adapted the "guix system" command by removing the "file-system-type"
argument and replaced it by the "image-type" argument.

The default is still to create a raw disk-image, but one can now call:

guix system disk-image -t iso9660 my-config.scm
guix system disk-image -t uncompressed-iso9660 my-config.scm
guix system disk-image -t hurd-raw my-config.scm

and so on. Maybe we should also rename "disk-image" command to "image" that
would be somehow more accurate.

The only missing bit is the documentation update, as I prefer to wait for this
change to be approved first.

WDYT?

Thanks,

Mathieu

[1]: https://lists.gnu.org/archive/html/guix-devel/2020-05/msg00417.html

Mathieu Othacehe (3):
  image: Add image-type support.
  system: image: Add image-type support.
  scripts: system: Add support for image-type.

 gnu/image.scm              | 29 ++++++++++++++-
 gnu/system/image.scm       | 75 ++++++++++++++++++++++++++++++++++++--
 gnu/system/images/hurd.scm | 13 +++++--
 guix/scripts/system.scm    | 56 +++++++++++++++++-----------
 4 files changed, 145 insertions(+), 28 deletions(-)

-- 
2.26.2

[bug#42634] [PATCH 1/3] image: Add image-type support.

[Mathieu Othacehe]

* gnu/image.scm (<image-type>): New record,
(image-type, image-type?, image-type-name,
image-type-constructor, os->image): new procedures.
---
 gnu/image.scm | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/gnu/image.scm b/gnu/image.scm
index dc66f2c533..6f8f4828ac 100644
--- a/gnu/image.scm
+++ b/gnu/image.scm
@@ -39,7 +39,14 @@
             image-partitions
             image-compression?
             image-volatile-root?
-            image-substitutable?))
+            image-substitutable?
+
+            image-type
+            image-type?
+            image-type-name
+            image-type-constructor
+
+            os->image))
 
 \f
 ;;;
@@ -84,3 +91,23 @@
                       (default #t))
   (substitutable?     image-substitutable? ;boolean
                       (default #t)))
+
+\f
+;;;
+;;; Image type.
+;;;
+
+(define-record-type* <image-type>
+  image-type make-image-type
+  image-type?
+  (name           image-type-name) ;string
+  (constructor    image-type-constructor)) ;<operating-system> -> <image>
+
+\f
+;;;
+;;; Image creation.
+;;;
+
+(define* (os->image os #:key type)
+  (let ((constructor (image-type-constructor type)))
+    (constructor os)))
-- 
2.26.2

[bug#42634] [PATCH 2/3] system: image: Add image-type support.

[Mathieu Othacehe]

* gnu/system/image.scm (image-with-os): New macro. Rename the old
"image-with-os" procedure to ...
(image-with-os*): ... this new procedure,
(system-image): adapt according,
(raw-image-type, iso-image-type, uncompressed-iso-image-type
%image-types): new variables,
(lookup-image-type-by-name): new procedure.
(find-image): remove it.
* gnu/system/images/hurd.scm (hurd-image-type): New variable,
use it to define ...
(hurd-disk-image): ... this variable, using "os->image" procedure.
* gnu/tests/install.scm (run-install): Rename
installation-disk-image-file-system-type parameter to installation-image-type,
use os->config instead of find-image to compute the image passed to system-image,
(%test-iso-image-installer) adapt accordingly,
(guided-installation-test): ditto.
---
 gnu/system/image.scm       | 88 ++++++++++++++++++++++++++++++--------
 gnu/system/images/hurd.scm | 13 ++++--
 gnu/tests/install.scm      | 46 ++++++++++----------
 3 files changed, 103 insertions(+), 44 deletions(-)

diff --git a/gnu/system/image.scm b/gnu/system/image.scm
index 36f56e237d..deee8a6412 100644
--- a/gnu/system/image.scm
+++ b/gnu/system/image.scm
@@ -18,6 +18,7 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (gnu system image)
+  #:use-module (guix discovery)
   #:use-module (guix gexp)
   #:use-module (guix modules)
   #:use-module (guix monads)
@@ -62,8 +63,15 @@
             efi-disk-image
             iso9660-image
 
-            find-image
-            system-image))
+            image-with-os
+            raw-image-type
+            iso-image-type
+            uncompressed-iso-image-type
+
+            system-image
+
+            %image-types
+            lookup-image-type-by-name))
 
 \f
 ;;;
@@ -110,6 +118,37 @@
            (label "GUIX_IMAGE")
            (flags '(boot)))))))
 
+\f
+;;;
+;;; Images types.
+;;;
+
+(define-syntax-rule (image-with-os base-image os)
+  "Return an image inheriting from BASE-IMAGE, with the operating-system field
+set to the given OS."
+  (image
+   (inherit base-image)
+   (operating-system os)))
+
+(define raw-image-type
+  (image-type
+   (name "raw")
+   (constructor (cut image-with-os efi-disk-image <>))))
+
+(define iso-image-type
+  (image-type
+   (name "iso9660")
+   (constructor (cut image-with-os iso9660-image <>))))
+
+(define uncompressed-iso-image-type
+  (image-type
+   (name "uncompressed-iso9660")
+   (constructor (cut image-with-os
+                 (image
+                  (inherit iso9660-image)
+                  (compression? #f))
+                 <>))))
+
 \f
 ;;
 ;; Helpers.
@@ -426,7 +465,7 @@ used in the image. "
       image-size)
      (else root-size))))
 
-(define* (image-with-os base-image os)
+(define* (image-with-os* base-image os)
   "Return an image based on BASE-IMAGE but with the operating-system field set
 to OS.  Also set the UUID and the size of the root partition."
   (define root-file-system
@@ -507,7 +546,7 @@ image, depending on IMAGE format."
 
   (with-parameters ((%current-target-system target))
     (let* ((os (operating-system-for-image image))
-           (image* (image-with-os image os))
+           (image* (image-with-os* image os))
            (register-closures? (has-guix-service-type? os))
            (bootcfg (operating-system-bootcfg os))
            (bootloader (bootloader-configuration-bootloader
@@ -539,18 +578,33 @@ image, depending on IMAGE format."
           #:grub-mkrescue-environment
           '(("MKRESCUE_SED_MODE" . "mbr_only"))))))))
 
-(define (find-image file-system-type target)
-  "Find and return an image built that could match the given FILE-SYSTEM-TYPE,
-built for TARGET.  This is useful to adapt to interfaces written before the
-addition of the <image> record."
-  (match file-system-type
-    ("iso9660" iso9660-image)
-    (_ (cond
-        ((and target
-              (hurd-triplet? target))
-         (module-ref (resolve-interface '(gnu system images hurd))
-                     'hurd-disk-image))
-        (else
-         efi-disk-image)))))
+\f
+;;
+;; Image detection.
+;;
+
+(define (image-modules)
+  "Return the list of image modules."
+  (cons (resolve-interface '(gnu system image))
+        (all-modules (map (lambda (entry)
+                            `(,entry . "gnu/system/images/"))
+                          %load-path)
+                     #:warn warn-about-load-error)))
+
+(define %image-types
+  ;; The list of publically-known image types.
+  (delay (fold-module-public-variables (lambda (obj result)
+                                         (if (image-type? obj)
+                                             (cons obj result)
+                                             result))
+                                       '()
+                                       (image-modules))))
+
+(define (lookup-image-type-by-name name)
+  "Return the image type called NAME."
+  (or (srfi-1:find (lambda (image-type)
+                     (string=? name (image-type-name image-type)))
+                   (force %image-types))
+      (leave (G_ "~a: no such image type.~%") name)))
 
 ;;; image.scm ends here
diff --git a/gnu/system/images/hurd.scm b/gnu/system/images/hurd.scm
index d87640e8e3..67f657d289 100644
--- a/gnu/system/images/hurd.scm
+++ b/gnu/system/images/hurd.scm
@@ -29,8 +29,10 @@
   #:use-module (gnu system file-systems)
   #:use-module (gnu system hurd)
   #:use-module (gnu system image)
+  #:use-module (srfi srfi-26)
   #:export (hurd-barebones-os
             hurd-disk-image
+            hurd-image-type
             hurd-barebones-disk-image))
 
 (define hurd-barebones-os
@@ -82,8 +84,13 @@
            (flags '(boot))
            (initializer hurd-initialize-root-partition))))))
 
+(define hurd-image-type
+  (image-type
+   (name "hurd-raw")
+   (constructor (cut image-with-os hurd-disk-image <>))))
+
 (define hurd-barebones-disk-image
   (image
-   (inherit hurd-disk-image)
-   (name 'hurd-barebones-disk-image)
-   (operating-system hurd-barebones-os)))
+   (inherit
+    (os->image hurd-barebones-os #:type hurd-image-type))
+   (name 'hurd-barebones-disk-image)))
diff --git a/gnu/tests/install.scm b/gnu/tests/install.scm
index 9656e5f41f..0be9ee2892 100644
--- a/gnu/tests/install.scm
+++ b/gnu/tests/install.scm
@@ -218,7 +218,7 @@ reboot\n")
                            #:imported-modules '((gnu services herd)
                                                 (gnu installer tests)
                                                 (guix combinators))))
-                      (installation-disk-image-file-system-type "ext4")
+                      (installation-image-type "raw")
                       (install-size 'guess)
                       (target-size (* 2200 MiB)))
   "Run SCRIPT (a shell script following the system installation procedure) in
@@ -228,10 +228,6 @@ packages defined in installation-os."
 
   (mlet* %store-monad ((_      (set-grafting #f))
                        (system (current-system))
-                       (target (current-target-system))
-                       (base-image -> (find-image
-                                       installation-disk-image-file-system-type
-                                       target))
 
                        ;; Since the installation system has no network access,
                        ;; we cheat a little bit by adding TARGET to its GC
@@ -239,18 +235,20 @@ packages defined in installation-os."
                        ;; succeed.  Also add guile-final, which is pulled in
                        ;; through provenance.drv and may not always be present.
                        (target (operating-system-derivation target-os))
+                       (base-image ->
+                                   (os->image
+                                    (operating-system-with-gc-roots
+                                     os (list target guile-final))
+                                    #:type (lookup-image-type-by-name
+                                            installation-image-type)))
                        (image ->
-                        (system-image
-                         (image
-                          (inherit base-image)
-                          (size install-size)
-                          (operating-system
-                            (operating-system-with-gc-roots
-                             os (list target guile-final)))
-                          ;; Do not compress to speed-up the tests.
-                          (compression? #f)
-                          ;; Don't provide substitutes; too big.
-                          (substitutable? #f)))))
+                              (system-image
+                               (image
+                                (inherit base-image)
+                                (size install-size)
+
+                                ;; Don't provide substitutes; too big.
+                                (substitutable? #f)))))
     (define install
       (with-imported-modules '((guix build utils)
                                (gnu build marionette))
@@ -270,16 +268,16 @@ packages defined in installation-os."
                  "-no-reboot"
                  "-m" "1200"
                  #$@(cond
-                     ((string=? "ext4" installation-disk-image-file-system-type)
+                     ((string=? "raw" installation-image-type)
                       #~("-drive"
                          ,(string-append "file=" #$image
                                          ",if=virtio,readonly")))
-                     ((string=? "iso9660" installation-disk-image-file-system-type)
+                     ((string-contains installation-image-type "iso9660")
                       #~("-cdrom" #$image))
                      (else
                       (error
-                       "unsupported installation-disk-image-file-system-type:"
-                       installation-disk-image-file-system-type)))
+                       "unsupported installation-image-type:"
+                       installation-image-type)))
                  "-drive"
                  ,(string-append "file=" #$output ",if=virtio")
                  ,@(if (file-exists? "/dev/kvm")
@@ -443,8 +441,8 @@ reboot\n")
                                    %minimal-os-on-vda-source
                                    #:script
                                    %simple-installation-script-for-/dev/vda
-                                   #:installation-disk-image-file-system-type
-                                   "iso9660"))
+                                   #:installation-image-type
+                                   "uncompressed-iso9660"))
                          (command (qemu-command/writable-image image)))
       (run-basic-test %minimal-os-on-vda command name)))))
 
@@ -1309,8 +1307,8 @@ build (current-guix) and then store a couple of full system images.")
                                #:os installation-os-for-gui-tests
                                #:install-size install-size
                                #:target-size target-size
-                               #:installation-disk-image-file-system-type
-                               "iso9660"
+                               #:installation-image-type
+                               "uncompressed-iso9660"
                                #:gui-test
                                (lambda (marionette)
                                  (gui-test-program
-- 
2.26.2

[bug#42634] [PATCH 3/3] scripts: system: Add support for image-type.

[Mathieu Othacehe]

* guix/scripts/system.scm (list-image-types): New procedure,
(%options): add "image-type" and "list-image-types" options, remove
"file-system-type" option,
(show-help): adapt accordingly,
(%default-options): also adapt, and set the default "image-type" to "raw",
(perform-action): add image-type argument and remove file-system-type argument,
(process-action):  adapt perform-action call,
(system-derivation-for-action): remove base-image
argument, add image-type argument, and use it to create the image passed to
"system-image".
---
 guix/scripts/system.scm | 56 +++++++++++++++++++++++++----------------
 1 file changed, 35 insertions(+), 21 deletions(-)

diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm
index bfd50c7a79..4962401f36 100644
--- a/guix/scripts/system.scm
+++ b/guix/scripts/system.scm
@@ -659,8 +659,8 @@ checking this by themselves in their 'check' procedure."
 ;;; Action.
 ;;;
 
-(define* (system-derivation-for-action os base-image action
-                                       #:key image-size file-system-type
+(define* (system-derivation-for-action os action
+                                       #:key image-size image-type
                                        full-boot? container-shared-network?
                                        mappings)
   "Return as a monadic value the derivation for OS according to ACTION."
@@ -686,9 +686,8 @@ checking this by themselves in their 'check' procedure."
      (lower-object
       (system-image
        (image
-        (inherit base-image)
-        (size image-size)
-        (operating-system os)))))
+        (inherit (os->image os #:type image-type))
+        (size image-size)))))
     ((docker-image)
      (system-docker-image os #:shared-network? container-shared-network?))))
 
@@ -741,16 +740,17 @@ and TARGET arguments."
                          install-bootloader?
                          dry-run? derivations-only?
                          use-substitutes? bootloader-target target
-                         image-size file-system-type full-boot?
-                         container-shared-network?
+                         image-size image-type
+                         full-boot? container-shared-network?
                          (mappings '())
                          (gc-root #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
-the 'vm-image' and 'disk-image' actions.  The root file system is created as a
-FILE-SYSTEM-TYPE file system.  FULL-BOOT? is used for the 'vm' action; it
-determines whether to boot directly to the kernel or to the bootloader.
+the 'vm-image' and 'disk-image' actions.  IMAGE-TYPE is the type of image to
+be built.
+FULL-BOOT? is used for the 'vm' action; it determines whether to boot directly
+to the kernel or to the bootloader.
 CONTAINER-SHARED-NETWORK? determines if the container will use a separate
 network namespace.
 
@@ -792,10 +792,8 @@ static checks."
       (check-initrd-modules os)))
 
   (mlet* %store-monad
-      ((target*   (current-target-system))
-       (image ->  (find-image file-system-type target*))
-       (sys       (system-derivation-for-action os image action
-                                                #:file-system-type file-system-type
+       ((sys       (system-derivation-for-action os action
+                                                #:image-type image-type
                                                 #:image-size image-size
                                                 #:full-boot? full-boot?
                                                 #:container-shared-network? container-shared-network?
@@ -876,6 +874,17 @@ upgrade, and restart each service that was not automatically restarted.\n"))))))
                   #:node-type (shepherd-service-node-type shepherds)
                   #:reverse-edges? #t)))
 
+\f
+;;;
+;;; Images.
+;;;
+
+(define (list-image-types)
+  "Print the available image types."
+  (display (G_ "The available image types are:\n"))
+  (newline)
+  (format #t "~{   - ~a ~%~}" (map image-type-name (force %image-types))))
+
 \f
 ;;;
 ;;; Options.
@@ -935,9 +944,9 @@ Some ACTIONS support additional ARGS.\n"))
                          apply STRATEGY (one of nothing-special, backtrace,
                          or debug) when an error occurs while reading FILE"))
   (display (G_ "
-      --file-system-type=TYPE
-                         for 'disk-image', produce a root file system of TYPE
-                         (one of 'ext4', 'iso9660')"))
+      --list-image-types list available image types"))
+  (display (G_ "
+  -t, --image-type=TYPE  for 'disk-image', produce an image of TYPE"))
   (display (G_ "
       --image-size=SIZE  for 'vm-image', produce an image of SIZE"))
   (display (G_ "
@@ -994,10 +1003,14 @@ Some ACTIONS support additional ARGS.\n"))
                  (lambda (opt name arg result)
                    (alist-cons 'on-error (string->symbol arg)
                                result)))
-         (option '(#\t "file-system-type") #t #f
+         (option '(#\t "image-type") #t #f
                  (lambda (opt name arg result)
-                   (alist-cons 'file-system-type arg
+                   (alist-cons 'image-type arg
                                result)))
+         (option '("list-image-types") #f #f
+                 (lambda (opt name arg result)
+                   (list-image-types)
+                   (exit 0)))
          (option '("image-size") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'image-size (size->number arg)
@@ -1063,7 +1076,7 @@ Some ACTIONS support additional ARGS.\n"))
     (debug . 0)
     (verbosity . #f)                              ;default
     (validate-reconfigure . ,ensure-forward-reconfigure)
-    (file-system-type . "ext4")
+    (image-type . "raw")
     (image-size . guess)
     (install-bootloader? . #t)))
 
@@ -1150,7 +1163,8 @@ resulting from command-line parsing."
                                (assoc-ref opts 'skip-safety-checks?)
                                #:validate-reconfigure
                                (assoc-ref opts 'validate-reconfigure)
-                               #:file-system-type (assoc-ref opts 'file-system-type)
+                               #:image-type (lookup-image-type-by-name
+                                             (assoc-ref opts 'image-type))
                                #:image-size (assoc-ref opts 'image-size)
                                #:full-boot? (assoc-ref opts 'full-boot?)
                                #:container-shared-network?
-- 
2.26.2

[bug#42634] [PATCH 0/3] Add image-type support.

[Ludovic Courtès]

Hi!

Mathieu Othacehe <m.othacehe@gmail.com> skribis:

> I think this is close to what Ludo suggested and it addresses janneke concerns
> about composability.
>
> The idea is to introduce the concept of "image-type". An image type is a
> converter from an <operating-system> record to an <image> record.
>
> I have created in this serie 4 new image type records:
> - raw
> - iso9660
> - uncompressed-iso9660
> - hurd-raw
>
> I also adapted the "guix system" command by removing the "file-system-type"
> argument and replaced it by the "image-type" argument.
>
> The default is still to create a raw disk-image, but one can now call:
>
> guix system disk-image -t iso9660 my-config.scm
> guix system disk-image -t uncompressed-iso9660 my-config.scm
> guix system disk-image -t hurd-raw my-config.scm

Neat!

> and so on. Maybe we should also rename "disk-image" command to "image" that
> would be somehow more accurate.

Yes.  We can do that separately, but I agree that it would make sense.

I wonder if ‘docker-image’ could also fit in there.

Apologies for taking so long to reply!

Ludo’.

[bug#42634] [PATCH 1/3] image: Add image-type support.

[Ludovic Courtès]

Mathieu Othacehe <m.othacehe@gmail.com> skribis:

> * gnu/image.scm (<image-type>): New record,
> (image-type, image-type?, image-type-name,
> image-type-constructor, os->image): new procedures.

[...]

> +(define-record-type* <image-type>
> +  image-type make-image-type
> +  image-type?
> +  (name           image-type-name) ;string

It’s subjective, but I’d make it a symbol, like we do for service types
for instance.

Ludo’.

[bug#42634] [PATCH 2/3] system: image: Add image-type support.

[Ludovic Courtès]

Mathieu Othacehe <m.othacehe@gmail.com> skribis:

> * gnu/system/image.scm (image-with-os): New macro. Rename the old
> "image-with-os" procedure to ...
> (image-with-os*): ... this new procedure,
> (system-image): adapt according,
> (raw-image-type, iso-image-type, uncompressed-iso-image-type
> %image-types): new variables,
> (lookup-image-type-by-name): new procedure.
> (find-image): remove it.
> * gnu/system/images/hurd.scm (hurd-image-type): New variable,
> use it to define ...
> (hurd-disk-image): ... this variable, using "os->image" procedure.
> * gnu/tests/install.scm (run-install): Rename
> installation-disk-image-file-system-type parameter to installation-image-type,
> use os->config instead of find-image to compute the image passed to system-image,
> (%test-iso-image-installer) adapt accordingly,
> (guided-installation-test): ditto.

[...]

> +(define (lookup-image-type-by-name name)
> +  "Return the image type called NAME."
> +  (or (srfi-1:find (lambda (image-type)
> +                     (string=? name (image-type-name image-type)))
> +                   (force %image-types))
> +      (leave (G_ "~a: no such image type.~%") name)))

I’d raise a ‘&formatted-message’ condition instead.  That allows you to
remove (guix ui) from the loop.

You can also remove the period from the message here sine it’s not a
sentence.

Otherwise LGTM!

Ludo’.

[bug#42634] [PATCH 3/3] scripts: system: Add support for image-type.

[Ludovic Courtès]

Mathieu Othacehe <m.othacehe@gmail.com> skribis:

> * guix/scripts/system.scm (list-image-types): New procedure,
> (%options): add "image-type" and "list-image-types" options, remove
> "file-system-type" option,
> (show-help): adapt accordingly,
> (%default-options): also adapt, and set the default "image-type" to "raw",
> (perform-action): add image-type argument and remove file-system-type argument,
> (process-action):  adapt perform-action call,
> (system-derivation-for-action): remove base-image
> argument, add image-type argument, and use it to create the image passed to
> "system-image".

LGTM (with corresponding doc)!

Perhaps you can also add a ‘guix system list-image-types’ command to
tests/guix-system.sh for good measure.  That’d at least catch broken
modules and similar.

Thanks,
Ludo’.

[bug#42634] [PATCH 0/3] Add image-type support.

[Mathieu Othacehe]

Hey Ludo,

> I wonder if ‘docker-image’ could also fit in there.

Yes I think that 'docker-image' and 'vm-image' can both be absorbed by
the upcoming 'image' option.  Turns out, 'hurd-qcow2' image type already
produces what would be expected from 'vm-image'.

Thanks for reviewing :)

Mathieu

bug#42634: [PATCH 3/3] scripts: system: Add support for image-type.

[Mathieu Othacehe]

> Perhaps you can also add a ‘guix system list-image-types’ command to
> tests/guix-system.sh for good measure.  That’d at least catch broken
> modules and similar.

Sure, fixed. I pushed this serie with the according documentation
update.

Thanks,

Mathieu