Extract out some database functionality to another module

Makefile.am

@@ -35,6 +35,7 @@ SOURCES =							\
   guix-data-service/builds.scm					\
   guix-data-service/comparison.scm				\
   guix-data-service/config.scm					\
+  guix-data-service/database.scm				\
   guix-data-service/jobs.scm					\
   guix-data-service/jobs/load-new-guix-revision.scm		\
   guix-data-service/model/build-server.scm			\

guix-data-service/database.scm

@@ -0,0 +1,40 @@
+;;; Guix Data Service -- Information about Guix over time
+;;; Copyright © 2019 Christopher Baines <mail@cbaines.net>
+;;;
+;;; This program is free software: you can redistribute it and/or
+;;; modify it under the terms of the GNU Affero General Public License
+;;; as published by the Free Software Foundation, either version 3 of
+;;; the License, or (at your option) any later version.
+;;;
+;;; This program is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; Affero General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Affero General Public
+;;; License along with this program.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+(define-module (guix-data-service database)
+  #:use-module (squee)
+  #:export (with-postgresql-connection))
+
+;; TODO This isn't exported for some reason
+(define pg-conn-finish
+  (@@ (squee) pg-conn-finish))
+
+(define (with-postgresql-connection f)
+  (define paramstring
+    (or (getenv "GUIX_DATA_SERVICE_DATABASE_PARAMSTRING")
+        "dbname=guix_data_service user=guix_data_service"))
+
+  (let* ((conn (connect-to-postgres-paramstring paramstring)))
+    (with-throw-handler
+      #t
+      (lambda ()
+        (let ((result (f conn)))
+          (pg-conn-finish conn)
+          result))
+      (lambda (key . args)
+        (pg-conn-finish conn)))))
+

guix-data-service/web/server.scm

@@ -21,30 +21,14 @@
   #:use-module (web http)
   #:use-module (web request)
   #:use-module (web uri)
-  #:use-module (squee)
   #:use-module (fibers web server)
+  #:use-module (guix-data-service database)
   #:use-module (guix-data-service web controller)
   #:use-module (guix-data-service web util)
   #:export (start-guix-data-service-web-server))
 
-;; TODO This isn't exported for some reason
-(define pg-conn-finish
-  (@@ (squee) pg-conn-finish))
-
-(define (with-postgresql-connection paramstring f)
-  (let* ((conn (connect-to-postgres-paramstring paramstring)))
-    (with-throw-handler
-      #t
-      (lambda ()
-        (let ((result (f conn)))
-          (pg-conn-finish conn)
-          result))
-      (lambda (key . args)
-        (pg-conn-finish conn)))))
-
 (define (run-controller controller request body)
   (with-postgresql-connection
-   "dbname=guix_data_service"
    (lambda (conn)
      ((controller request body conn)
       (cons (request-method request)

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")))
+(with-postgresql-connection
+ (lambda (conn)
    (enqueue-job-for-email
     conn
     (parse-email
-    (get-string-all (current-input-port)))))
+     (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")))
+(with-postgresql-connection
+ (lambda (conn)
    (simple-format #t "Ready to process jobs...\n")
-  (process-jobs conn))
+   (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")))
+(with-postgresql-connection query-build-servers)
-  (query-build-servers conn))