services: greetd: Improve greeter configurations.

This improvement focuses on providing common user session scripts
for use by multiple greeters. Now user session entry point is
factored out into '<greetd-user-session>', which can be reused
as is with different greeters. By default it uses 'bash' as
first user process. Then user normally starts additional programs
with '.profile' or '.bashrc'. Using 'command', 'command-args' and
'extra-env' one can specify something else, which could be
'dbus-session' wrapped process, some desktop environment or else.
While the above is possible, one is still encouraged to use
'.bashrc', '.profile' or similar.

It also fixes incorrect use of 'XDG_RUNTIME_DIR' for 'wlgreet'.
'wlgreet' requires a compositor to run. We provide common sway based
greeter script, which can be shared by other graphical greeters.

* gnu/services/base.scm (<greetd-user-session>): Common user session
factored out, for shared use by multiple greeters.
(<greetd-agreety-session>): Switch to common user session.
(<greetd-wlgreet-configuration>): Refactor 'wlgreet' configuration.
(<greetd-wlgreet-sway-session>): Switch to common user session.
(<greetd-terminal-configuration>): Add 'extra-shepherd-requirement'
for establishing configurable Shepherd service dependency.
* gnu/tests/desktop.scm (%minimal-services): Reflect configuration
changes.
* doc/guix.texi (Base Services): Document refactoring changes.

Change-Id: I9d45a592b355eb9c438be5b1d4d15555ce4956fa
Modified-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/gnu/tests/desktop.scm b/gnu/tests/desktop.scm
index 1c32076ccb2..3f861b253b0 100644
--- a/gnu/tests/desktop.scm
+++ b/gnu/tests/desktop.scm
@@ -141,13 +141,21 @@
                  (terminal-vt "2")
                  (default-session-command
                    (greetd-agreety-session
-                    (extra-env '(("MY_VAR" . "1")))
-                    (xdg-env? #f))))
+                    (command
+                     (greetd-user-session
+                      (extra-env '(("MY_VAR" . "1")))
+                      (xdg-env? #f))))))
                 ;; we can use different shell instead of default bash
                 (greetd-terminal-configuration
                  (terminal-vt "3")
                  (default-session-command
-                   (greetd-agreety-session (command (file-append zsh "/bin/zsh")))))
+                   (greetd-agreety-session
+                    (command
+                     (greetd-user-session
+                      (command (file-append zsh "/bin/zsh"))
+                      (command-args '("-l"))
+                      (extra-env '(("MY_VAR" . "1")))
+                      (xdg-env? #f))))))
                 ;; we can use any other executable command as greeter
                 (greetd-terminal-configuration
                  (terminal-vt "4")