Use default database parameters.

* src/cuirass/parameters.scm (%cuirass-database, %cuirass-host): New
parameters.
* src/cuirass/database.scm (db-open): Use them.

src/cuirass/database.scm

@@ -25,6 +25,7 @@
   #:use-module (cuirass logging)
   #:use-module (cuirass config)
   #:use-module (cuirass notification)
+  #:use-module (cuirass parameters)
   #:use-module (cuirass remote)
   #:use-module (cuirass specification)
   #:use-module (cuirass utils)
@@ -356,8 +357,8 @@ upgrade-n.sql files."
 database object."
   (let* ((param (or database
                     (format #f "dbname=~a host=~a"
-                            (getenv "CUIRASS_DATABASE")
-                            (getenv "CUIRASS_HOST"))))
+                            (%cuirass-database)
+                            (%cuirass-host))))
          (db (connect-to-postgres-paramstring param)))
     (when (%create-database?)
       (match (db-schema-version db)

src/cuirass/parameters.scm

@@ -17,10 +17,14 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (cuirass parameters)
-  #:export (%cuirass-url
+  #:export (%cuirass-database
+            %cuirass-host
+            %cuirass-url
+
             %zabbix-url
             %zabbix-user
             %zabbix-password
+
             %mastodon-instance-name
             %mastodon-instance-url
             %mastodon-instance-token))
@@ -28,6 +32,14 @@
 ;; This variable is looked up by 'mu-message-send'.
 (define-public mu-debug 0)
 
+;; The Cuirass PostgreSQL database name.
+(define %cuirass-database
+  (make-parameter "cuirass"))
+
+;; The Cuirass PostgreSQL database host.
+(define %cuirass-host
+  (make-parameter "/var/run/postgresql"))
+
 ;; The URL of the Cuirass web server.  This is useful to send absolute links
 ;; within notifications.
 (define %cuirass-url