services: Add oci-service-type.

This patch implements a generalization of the
oci-container-service-type, which consequently is made deprecated.  The
oci-service-type, in addition to all the features from the
oci-container-service-type, can now provision OCI networks and volumes.
It only handles OCI objects creation, the user is supposed to handle
state once the objects are provsioned.

It currently supports two different OCI runtimes: Docker and rootless
Podman.  Both runtimes are tested to make sure provisioned containers
can connect to each other through provisioned networks and can
read/write data with provisioned volumes.

At last the Scheme API is thought to facilitate the implementation of a
Guix Home service in the future.

* gnu/build/oci-containers.scm: New file containg OCI runtime business
logic used in OCI backed Shepherd services.
oci-read-lines
(oci-system*,oci-object-exists?,oci-object-service-available?
oci-image-load,oci-log-verbose,oci-container-execlp,oci-object-create):
New procedures.
* gnu/local.mk: Add it.
* gnu/services/containers.scm (list-of-oci-containers?,
list-of-oci-networks?,list-of-oci-volumes?,%oci-supported-runtimes,
oci-runtime?,oci-runtime-system-environment,oci-runtime-system-extra-arguments,
oci-runtime-system-requirement,oci-runtime-cli,oci-runtime-system-cli,
oci-runtime-home-cli,oci-runtime-name,oci-runtime-group,
oci-container-shepherd-name,oci-networks-shepherd-name,
oci-networks-home-shepherd-name,oci-volumes-shepherd-name,
oci-volumes-home-shepherd-name,oci-container-configuration->options,
oci-network-configuration->options,oci-volume-configuration->options,
oci-container-shepherd-service,oci-objects-merge-lst,oci-extension-merge,
oci-service-accounts,oci-service-profile,oci-service-subids,
oci-configuration->shepherd-services,oci-configuration-extend): New
procedures.
(image-reference): Implement unambiguous naming convention, that paired
with the new implementation for listing caches images with docker ls or
podman ls, allows for more efficient image caching.
(oci-container-configuration)[user,group]: Change default-type to
maybe-string, since by default containers will run under the user and
group declared in oci-configuration records. When unset the
oci-service-type will derive their value from the OCI runtime state.
[runtime,host-environment,environment,shepherd-actions,ports,extra-arguments]:
define a predicate and use it as a type in the configuration.  This
way errors are reported with source location information.
(lower-manifest): Defer to caller the logic of setting up an image tag.
(lower-oci-image): Rename to load-oci-image-state.
(oci-runtime-state): Intermediate representation of the OCI runtime
details. It is supposed to be an internal API.
(oci-state): Intermediate representation of the OCI provisioning state,
such as containers and networks. It is supposed to be an internal API.
(oci-container-invocation): Intermediate representation of the OCI
runtime run command to start a container. It is supposed to be an
internal API.
(%oci-image-loader): Rename to oci-image-loader and use
oci-runtime-state and (gnu build oci-containers).
(oci-container-shepherd-service): Use oci-state and oci-runtime-state,
add command-line action.
(oci-network-configuration,oci-volume-configuration,oci-configuration,
oci-extension): New record types.
(oci-service-type): New service-type.
* doc/guix.texi: Document it.
* gnu/tests/containers.scm: Test it.
* gnu/services/docker.scm: Deprecate the oci-container-service-type.

Change-Id: I656b3db85832e42d53072fcbfb91d1226f39ef38
Modified-by: Maxim Cournoyer <maxim@guixotic.coop>
Signed-off-by: Maxim Cournoyer <maxim@guixotic.coop>

1 files changed, 26 insertions, 12 deletions

diff --git a/gnu/services/docker.scm b/gnu/services/docker.scm
index 828ceea313a..6abfbc49a0b 100644
--- a/gnu/services/docker.scm
+++ b/gnu/services/docker.scm
@@ -31,7 +31,10 @@
   #:use-module (gnu system shadow)
   #:use-module (gnu packages docker)
   #:use-module (gnu packages linux)               ;singularity
+  #:use-module (guix deprecation)
+  #:use-module (guix diagnostics)
   #:use-module (guix gexp)
+  #:use-module (guix i18n)
   #:use-module (guix records)
   #:use-module (srfi srfi-1)
   #:use-module (ice-9 format)
@@ -67,16 +70,18 @@
                oci-container-configuration-volumes
                oci-container-configuration-container-user
                oci-container-configuration-workdir
-               oci-container-configuration-extra-arguments
-               oci-container-shepherd-service
-               %oci-container-accounts)
+               oci-container-configuration-extra-arguments)
 
   #:export (containerd-configuration
             containerd-service-type
             docker-configuration
             docker-service-type
             singularity-service-type
-            oci-container-service-type))
+            ;; For backwards compatibility, until the
+            ;; oci-container-service-type is fully deprecated.
+            oci-container-shepherd-service
+            oci-container-service-type
+            %oci-container-accounts))
 
 (define-maybe file-like)
 
@@ -297,17 +302,26 @@ bundles in Docker containers.")
 ;;; OCI container.
 ;;;
 
-(define (configs->shepherd-services configs)
-  (map oci-container-shepherd-service configs))
+;; For backwards compatibility, until the
+;; oci-container-service-type is fully deprecated.
+(define-deprecated (oci-container-shepherd-service config)
+  oci-service-type
+  ((@ (gnu services containers) oci-container-shepherd-service)
+   'docker config))
+(define %oci-container-accounts
+  (filter user-account? (oci-service-accounts (oci-configuration))))
 
 (define oci-container-service-type
   (service-type (name 'oci-container)
-                (extensions (list (service-extension profile-service-type
-                                                     (lambda _ (list docker-cli)))
-                                  (service-extension account-service-type
-                                                     (const %oci-container-accounts))
-                                  (service-extension shepherd-root-service-type
-                                                     configs->shepherd-services)))
+                (extensions
+                 (list (service-extension oci-service-type
+                                          (lambda (containers)
+                                            (warning
+                                             (G_
+                                              "'oci-container-service-type' is\
+ deprecated, use 'oci-service-type' instead~%"))
+                                            (oci-extension
+                                             (containers containers))))))
                 (default-value '())
                 (extend append)
                 (compose concatenate)