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03/05: services: Missing services are automatically instantiated.
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From: |
Ludovic Courtès |
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Subject: |
03/05: services: Missing services are automatically instantiated. |
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Date: |
Sat, 20 Jan 2018 18:24:11 -0500 (EST) |
civodul pushed a commit to branch master
in repository guix.
commit d466b1fc8221a6224fe7ded53a828f9c29ed9457
Author: Ludovic Courtès <address@hidden>
Date: Sun Jan 21 00:05:09 2018 +0100
services: Missing services are automatically instantiated.
This simplifies OS configuration: users no longer need to be aware of
what a given service depends on.
See the discussion at
<https://lists.gnu.org/archive/html/guix-devel/2018-01/msg00114.html>.
* gnu/services.scm (missing-target-error): New procedure.
(service-back-edges): Use it.
(instantiate-missing-services): New procedure.
* gnu/system.scm (operating-system-services): Call
'instantiate-missing-services'.
* tests/services.scm ("instantiate-missing-services")
("instantiate-missing-services, no default value"): New tests.
* gnu/services/version-control.scm (cgit-service-type)[extensions]: Add
FCGIWRAP-SERVICE-TYPE.
* gnu/tests/version-control.scm (%cgit-os): Remove NGINX-SERVICE-TYPE
and FCGIWRAP-SERVICE-TYPE instances.
* doc/guix.texi (Log Rotation): Remove 'mcron-service-type' in example.
(Miscellaneous Services): Remove 'nginx-service-type' and
'fcgiwrap-service-type' in Cgit example.
---
doc/guix.texi | 7 ++---
gnu/services.scm | 59 ++++++++++++++++++++++++++++++++--------
gnu/services/version-control.scm | 6 +++-
gnu/system.scm | 7 +++--
gnu/tests/version-control.scm | 2 --
tests/services.scm | 32 +++++++++++++++++++++-
6 files changed, 90 insertions(+), 23 deletions(-)
diff --git a/doc/guix.texi b/doc/guix.texi
index 1ecdcd2..58b9675 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -10342,9 +10342,8 @@ with the default settings, for commonly encountered log
files.
(operating-system
;; @dots{}
- (services (cons* (service mcron-service-type)
- (service rottlog-service-type)
- %base-services)))
+ (services (cons (service rottlog-service-type)
+ %base-services)))
@end lisp
@defvr {Scheme Variable} rottlog-service-type
@@ -18269,8 +18268,6 @@ The following example will configure the service with
default values.
By default, Cgit can be accessed on port 80 (@code{http://localhost:80}).
@example
-(service nginx-service-type)
-(service fcgiwrap-service-type)
(service cgit-service-type)
@end example
diff --git a/gnu/services.scm b/gnu/services.scm
index 15fc6dc..b020d97 100644
--- a/gnu/services.scm
+++ b/gnu/services.scm
@@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <address@hidden>
+;;; Copyright © 2015, 2016, 2017, 2018 Ludovic Courtès <address@hidden>
;;; Copyright © 2016 Chris Marusich <address@hidden>
;;;
;;; This file is part of GNU Guix.
@@ -24,6 +24,7 @@
#:use-module (guix records)
#:use-module (guix profiles)
#:use-module (guix discovery)
+ #:use-module (guix combinators)
#:use-module (guix sets)
#:use-module (guix ui)
#:use-module ((guix utils) #:select (source-properties->location))
@@ -66,6 +67,7 @@
simple-service
modify-services
service-back-edges
+ instantiate-missing-services
fold-services
service-error?
@@ -630,6 +632,18 @@ kernel."
(service ambiguous-target-service-error-service)
(target-type ambiguous-target-service-error-target-type))
+(define (missing-target-error service target-type)
+ (raise
+ (condition (&missing-target-service-error
+ (service service)
+ (target-type target-type))
+ (&message
+ (message
+ (format #f (G_ "no target of type '~a' for service '~a'")
+ (service-type-name target-type)
+ (service-type-name
+ (service-kind service))))))))
+
(define (service-back-edges services)
"Return a procedure that, when passed a <service>, returns the list of
<service> objects that depend on it."
@@ -642,16 +656,7 @@ kernel."
((target)
(vhash-consq target service edges))
(()
- (raise
- (condition (&missing-target-service-error
- (service service)
- (target-type target-type))
- (&message
- (message
- (format #f (G_ "no target of type '~a' for service
'~a'")
- (service-type-name target-type)
- (service-type-name
- (service-kind service))))))))
+ (missing-target-error service target-type))
(x
(raise
(condition (&ambiguous-target-service-error
@@ -669,6 +674,38 @@ kernel."
(lambda (node)
(reverse (vhash-foldq* cons '() node edges)))))
+(define (instantiate-missing-services services)
+ "Return SERVICES, a list, augmented with any services targeted by extensions
+and missing from SERVICES. Only service types with a default value can be
+instantiated; other missing services lead to a
+'&missing-target-service-error'."
+ (define (adjust-service-list svc result instances)
+ (fold2 (lambda (extension result instances)
+ (define target-type
+ (service-extension-target extension))
+
+ (match (vhash-assq target-type instances)
+ (#f
+ (let ((default (service-type-default-value target-type)))
+ (if (eq? &no-default-value default)
+ (missing-target-error svc target-type)
+ (let ((new (service target-type)))
+ (values (cons new result)
+ (vhash-consq target-type new instances))))))
+ (_
+ (values result instances))))
+ result
+ instances
+ (service-type-extensions (service-kind svc))))
+
+ (let ((instances (fold (lambda (service result)
+ (vhash-consq (service-kind service) service
+ result))
+ vlist-null services)))
+ (fold2 adjust-service-list
+ services instances
+ services)))
+
(define* (fold-services services
#:key (target-type system-service-type))
"Fold SERVICES by propagating their extensions down to the root of type
diff --git a/gnu/services/version-control.scm b/gnu/services/version-control.scm
index 6bf6569..7166ed3 100644
--- a/gnu/services/version-control.scm
+++ b/gnu/services/version-control.scm
@@ -263,7 +263,11 @@ access to exported repositories under @file{/srv/git}."
(list (service-extension activation-service-type
cgit-activation)
(service-extension nginx-service-type
- cgit-configuration-nginx-config)))
+ cgit-configuration-nginx-config)
+
+ ;; Make sure fcgiwrap is instantiated.
+ (service-extension fcgiwrap-service-type
+ (const #t))))
(default-value (cgit-configuration))
(description
"Run the Cgit web interface, which allows users to browse Git
diff --git a/gnu/system.scm b/gnu/system.scm
index 40e259f..3945230 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <address@hidden>
+;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès
<address@hidden>
;;; Copyright © 2015 Mark H Weaver <address@hidden>
;;; Copyright © 2015, 2016 Alex Kost <address@hidden>
;;; Copyright © 2016 Chris Marusich <address@hidden>
@@ -492,8 +492,9 @@ a container or that of a \"bare metal\" system."
(define* (operating-system-services os #:key container?)
"Return all the services of OS, including \"internal\" services that do not
explicitly appear in OS."
- (append (operating-system-user-services os)
- (essential-services os #:container? container?)))
+ (instantiate-missing-services
+ (append (operating-system-user-services os)
+ (essential-services os #:container? container?))))
;;;
diff --git a/gnu/tests/version-control.scm b/gnu/tests/version-control.scm
index c20e599..9882cdb 100644
--- a/gnu/tests/version-control.scm
+++ b/gnu/tests/version-control.scm
@@ -88,8 +88,6 @@
(let ((base-os
(simple-operating-system
(dhcp-client-service)
- (service nginx-service-type)
- (service fcgiwrap-service-type)
(service cgit-service-type
(cgit-configuration
(nginx %cgit-configuration-nginx)))
diff --git a/tests/services.scm b/tests/services.scm
index ca32b56..b146a0d 100644
--- a/tests/services.scm
+++ b/tests/services.scm
@@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <address@hidden>
+;;; Copyright © 2015, 2016, 2017, 2018 Ludovic Courtès <address@hidden>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -122,6 +122,36 @@
(fold-services (list s) #:target-type t1)
#f)))
+(test-assert "instantiate-missing-services"
+ (let* ((t1 (service-type (name 't1) (extensions '())
+ (default-value 'dflt)
+ (compose concatenate)
+ (extend cons)))
+ (t2 (service-type (name 't2)
+ (extensions
+ (list (service-extension t1 list)))))
+ (s1 (service t1 'hey!))
+ (s2 (service t2 42)))
+ (and (lset= equal?
+ (list (service t1) s2)
+ (instantiate-missing-services (list s2)))
+ (equal? (list s1 s2)
+ (instantiate-missing-services (list s1 s2))))))
+
+(test-assert "instantiate-missing-services, no default value"
+ (let* ((t1 (service-type (name 't1) (extensions '())))
+ (t2 (service-type (name 't2)
+ (extensions
+ (list (service-extension t1 list)))))
+ (s (service t2 42)))
+ (guard (c ((missing-target-service-error? c)
+ (and (eq? (missing-target-service-error-target-type c)
+ t1)
+ (eq? (missing-target-service-error-service c)
+ s))))
+ (instantiate-missing-services (list s))
+ #f)))
+
(test-assert "shepherd-service-lookup-procedure"
(let* ((s1 (shepherd-service (provision '(s1 s1b)) (start #f)))
(s2 (shepherd-service (provision '(s2 s2b)) (start #f)))