services: cuirass: Improve simple-cuirass-services.

Instead of returning multiple services in simple-cuirass-services, rely on the
instantiate-missing-services procedure to instantiate postgresql and
postgresql-role-service-type when missing.

Turn simple-cuirass-services procedure into
simple-cuirass-configuration->specs, that takes a simple-cuirass-configuration
record and returns a Cuirass specification.

Suggested-by: Ludovic Courtès <ludo@gnu.org>

* gnu/services/cuirass.scm (%default-cuirass-config): Remove it.
(simple-cuirass-services): Rename it to ...
(simple-cuirass-configuration->specs): ... this procedure.
* gnu/tests/cuirass.scm (cuirass-services): Remove postgresql and
postgresql-role services that are automatically instantiated.
(simple-cuirass-service): New variable.
(%cuirass-simple-test): Adapt it to use simple-cuirass-configuration->specs
instead of simple-cuirass-services.
* doc/guix.texi (Simple Cuirass): Update it.

1 files changed, 3 insertions, 19 deletions

diff --git a/gnu/services/cuirass.scm b/gnu/services/cuirass.scm
index 18163b59e2..b962f2f80a 100644
--- a/gnu/services/cuirass.scm
+++ b/gnu/services/cuirass.scm
@@ -60,8 +60,7 @@
             simple-cuirass-configuration
             simple-cuirass-configuration?
 
-            %default-cuirass-config
-            simple-cuirass-services))
+            simple-cuirass-configuration->specs))
 
 ;;;; Commentary:
 ;;;
@@ -419,13 +418,7 @@ CONFIG."
   (systems               simple-cuirass-configuration-systems
                          (default (list (%current-system))))) ;list of strings
 
-(define %default-cuirass-config
-  (cuirass-configuration
-   (specifications #~())))
-
-(define* (simple-cuirass-services config
-                                  #:optional
-                                  (cuirass %default-cuirass-config))
+(define* (simple-cuirass-configuration->specs config)
   (define (format-name name)
     (if (string? name)
         name
@@ -475,13 +468,4 @@ CONFIG."
         (#:build-outputs . ())
         (#:priority . 1))))
 
-  (list
-   (service cuirass-service-type
-            (cuirass-configuration
-             (inherit cuirass)
-             (specifications #~(list
-                                '#$(config->spec config)))))
-   (service postgresql-service-type
-            (postgresql-configuration
-             (postgresql postgresql-10)))
-   (service postgresql-role-service-type)))
+  #~(list '#$(config->spec config)))