Extract out some database functionality to another module

scripts/guix-data-service-process-branch-updated-email.in

@@ -25,10 +25,12 @@
              (ice-9 textual-ports)
              (squee)
              (email email)
+             (guix-data-service database)
              (guix-data-service branch-updated-emails))
 
-(let ((conn (connect-to-postgres-paramstring "dbname=guix_data_service")))
-  (enqueue-job-for-email
-   conn
-   (parse-email
-    (get-string-all (current-input-port)))))
+(with-postgresql-connection
+ (lambda (conn)
+   (enqueue-job-for-email
+    conn
+    (parse-email
+     (get-string-all (current-input-port))))))

scripts/guix-data-service-process-jobs.in

@@ -27,6 +27,7 @@
              (squee)
              (guix-data-service jobs))
 
-(let ((conn (connect-to-postgres-paramstring "dbname=guix_data_service")))
-  (simple-format #t "Ready to process jobs...\n")
-  (process-jobs conn))
+(with-postgresql-connection
+ (lambda (conn)
+   (simple-format #t "Ready to process jobs...\n")
+   (process-jobs conn)))

scripts/guix-data-service-query-build-servers.in

@@ -25,5 +25,4 @@
              (squee)
              (guix-data-service builds))
 
-(let ((conn (connect-to-postgres-paramstring "dbname=guix_data_service")))
-  (query-build-servers conn))
+(with-postgresql-connection query-build-servers)