Split out querying of build servers and substitute servers

These are related things, but somewhat separate. This change should make it
easier to deal with changes regarding querying build servers, and querying
substitute servers.

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

@@ -0,0 +1,72 @@
+#!@GUILE@ --no-auto-compile
+-*- scheme -*-
+-*- geiser-scheme-implementation: guile -*-
+!#
+;;; Guix Data Service -- Information about Guix over time
+;;; Copyright © 2019, 2020 Christopher Baines <mail@cbaines.net>
+;;;
+;;; This file is part of guix-data-service.
+;;;
+;;; guix-data-service is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; guix-data-service 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
+;;; General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with the guix-data-service.  If not, see <http://www.gnu.org/licenses/>.
+
+(use-modules (srfi srfi-1)
+             (srfi srfi-37)
+             (squee)
+             (guix-data-service database)
+             (guix-data-service substitutes))
+
+(define %options
+  ;; Specifications of the command-line options
+  (list (option '("build-server-id") #t #f
+                (lambda (opt name arg result)
+                  (alist-cons
+                   'build-server-ids
+                   (cons (string->number arg)
+                         (or (assoc-ref result 'build-server-ids)
+                             '()))
+                   (alist-delete 'build-server-ids result))))
+        (option '("verbose") #f #f
+                (lambda (opt name _ result)
+                  (alist-cons 'verbose #t result)))))
+
+(define %default-options
+  ;; Alist of default option values
+  '((revision-commits . ())))
+
+(define (parse-options args)
+  (args-fold
+   args %options
+   (lambda (opt name arg result)
+     (error "unrecognized option" name))
+   (lambda (arg result)
+     (let ((type (if (string-prefix? "/gnu/store/" arg)
+                     'outputs
+                     'revision-commits)))
+       (alist-cons
+        type
+        (cons arg
+              (or (assoc-ref result type)
+                  '()))
+        (alist-delete type result))))
+   %default-options))
+
+(let ((opts (parse-options (cdr (program-arguments)))))
+  (with-postgresql-connection
+   "query-substitute-servers"
+   (lambda (conn)
+     (query-build-server-substitutes conn
+                                     (assq-ref opts 'build-server-ids)
+                                     (assq-ref opts 'revision-commits)
+                                     (assq-ref opts 'outputs)
+                                     #:verbose? (assq-ref opts 'verbose)))))