services: Add oci-container-service-type.

* gnu/services/docker.scm (oci-container-configuration): New variable;
(oci-container-shepherd-service): new variable;
(oci-container-service-type): new variable.
* doc/guix.texi (Miscellaneous Services): Document it.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
Change-Id: I17cede1975051a9fdd0e0a13b2191d8055266f80

1 files changed, 131 insertions, 0 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 94903fb5e2..767133cd0f 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -39560,6 +39560,137 @@ setuid-root (@pxref{Setuid Programs}) such that unprivileged users can invoke
 @command{singularity run} and similar commands.
 @end defvar
 
+@cindex OCI-backed, Shepherd services
+@subsubheading OCI backed services
+
+Should you wish to manage your Docker containers with the same consistent
+interface you use for your other Shepherd services,
+@var{oci-container-service-type} is the tool to use: given an
+@acronym{Open Container Initiative, OCI} container image, it will run it in a
+Shepherd service.  One example where this is useful: it lets you run services
+that are available as Docker/OCI images but not yet packaged for Guix.
+
+@defvar oci-container-service-type
+
+This is a thin wrapper around Docker's CLI that executes OCI images backed
+processes as Shepherd Services.
+
+@lisp
+(service oci-container-service-type
+         (list
+          (oci-container-configuration
+           (image "prom/prometheus")
+           (network "host")
+           (ports
+             '(("9000" . "9000")
+               ("9090" . "9090"))))
+          (oci-container-configuration
+           (image "grafana/grafana:10.0.1")
+           (network "host")
+           (ports
+             '(("3000" . "3000")))
+           (volumes
+             '("/var/lib/grafana:/var/lib/grafana")))))
+@end lisp
+
+In this example two different Shepherd services are going be added to the
+system.  Each @code{oci-container-configuration} record translates to a
+@code{docker run} invocation and its fields directly map to options.  You can
+refer to the
+@url{https://docs.docker.com/engine/reference/commandline/run,upstream},
+documentation for the semantics of each value.  If the images are not found they
+will be
+@url{https://docs.docker.com/engine/reference/commandline/pull/,pulled}.  The
+spawned services are going to be attached to the host network and are supposed
+to behave like other processes.
+
+@end defvar
+
+@c %start of fragment
+
+@deftp {Data Type} oci-container-configuration
+Available @code{oci-container-configuration} fields are:
+
+@table @asis
+@item @code{user} (default: @code{"oci-container"}) (type: string)
+The user under whose authority docker commands will be run.
+
+@item @code{group} (default: @code{"docker"}) (type: string)
+The group under whose authority docker commands will be run.
+
+@item @code{command} (default: @code{()}) (type: list-of-strings)
+Overwrite the default command (@code{CMD}) of the image.
+
+@item @code{entrypoint} (default: @code{""}) (type: string)
+Overwrite the default entrypoint (@code{ENTRYPOINT}) of the image.
+
+@item @code{environment} (default: @code{()}) (type: list)
+Set environment variables. This can be a list of pairs or strings, even mixed:
+
+@lisp
+(list '("LANGUAGE" . "eo:ca:eu")
+      "JAVA_HOME=/opt/java")
+@end lisp
+
+String are passed directly to the Docker CLI. You can refer to the
+@uref{https://docs.docker.com/engine/reference/commandline/run/#env,upstream}
+documentation for semantics.
+
+@item @code{image} (type: string)
+The image used to build the container.  Images are resolved by the
+Docker Engine, and follow the usual format
+@code{myregistry.local:5000/testing/test-image:tag}.
+
+@item @code{provision} (default: @code{""}) (type: string)
+Set the name of the provisioned Shepherd service.
+
+@item @code{network} (default: @code{""}) (type: string)
+Set a Docker network for the spawned container.
+
+@item @code{ports} (default: @code{()}) (type: list)
+Set the port or port ranges to expose from the spawned container.  This can be a
+list of pairs or strings, even mixed:
+
+@lisp
+(list '("8080" . "80")
+      "10443:443")
+@end lisp
+
+String are passed directly to the Docker CLI.  You can refer to the
+@uref{https://docs.docker.com/engine/reference/commandline/run/#publish,upstream}
+documentation for semantics.
+
+@item @code{volumes} (default: @code{()}) (type: list)
+Set volume mappings for the spawned container.  This can be a
+list of pairs or strings, even mixed:
+
+@lisp
+(list '("/root/data/grafana" . "/var/lib/grafana")
+      "/gnu/store:/gnu/store")
+@end lisp
+
+String are passed directly to the Docker CLI.  You can refer to the
+@uref{https://docs.docker.com/engine/reference/commandline/run/#volume,upstream}
+documentation for semantics.
+
+@item @code{container-user} (default: @code{""}) (type: string)
+Set the current user inside the spawned container.  You can refer to the
+@url{https://docs.docker.com/engine/reference/run/#user,upstream}
+documentation for semantics.
+
+@item @code{workdir} (default: @code{""}) (type: string)
+Set the current working for the spawned Shepherd service.
+You can refer to the
+@url{https://docs.docker.com/engine/reference/run/#workdir,upstream}
+documentation for semantics.
+
+@end table
+
+@end deftp
+
+
+@c %end of fragment
+
 @cindex Audit
 @subsubheading Auditd Service