services: Add 'profile-service-type'.

* gnu/services.scm (packages->profile-entry): New procedure.
  (profile-service-type): New variable.
* gnu/system.scm (operating-system-directory-base-entries): Remove
  the "profile" entry.
  (essential-services): Add a PROFILE-SERVICE-TYPE instance.
  (operating-system-profile): Rewrite in terms of 'fold-services'.
* doc/guix.texi (Service Reference): Add 'profile-service-type'.
* doc/images/service-graph.dot: Likewise.

2 files changed, 8 insertions, 0 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 6ab98deef3..897675291e 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -7899,6 +7899,12 @@ executable file names, passed as gexps, and adds them to the set of
 setuid-root programs on the system (@pxref{Setuid Programs}).
 @end defvr
 
+@defvr {Scheme Variable} profile-service-type
+Type of the service that populates the @dfn{system profile}---i.e., the
+programs under @file{/run/current-system/profile}.  Other services can
+extend it by passing it lists of packages to add to the system profile.
+@end defvr
+
 
 @node dmd Services
 @subsubsection dmd Services
diff --git a/doc/images/service-graph.dot b/doc/images/service-graph.dot
index 04f231bb09..b084005984 100644
--- a/doc/images/service-graph.dot
+++ b/doc/images/service-graph.dot
@@ -2,6 +2,7 @@ digraph "Service Type Dependencies" {
   dmd [shape = box, fontname = Helvetica];
   pam [shape = box, fontname = Helvetica];
   etc [shape = box, fontname = Helvetica];
+  profile [shape = box, fontname = Helvetica];
   accounts [shape = box, fontname = Helvetica];
   activation [shape = box, fontname = Helvetica];
   boot [shape = box, fontname = Helvetica];
@@ -35,4 +36,5 @@ digraph "Service Type Dependencies" {
   guix -> accounts;
   boot -> system;
   etc -> system;
+  profile -> system;
 }