Start storing channel instance derivations

These are the ones that relate to Guix pull.

guix-data-service/jobs/load-new-guix-revision.scm

@@ -35,6 +35,7 @@
   #:use-module (guix-data-service config)
   #:use-module (guix-data-service database)
   #:use-module (guix-data-service model build)
+  #:use-module (guix-data-service model channel-instance)
   #:use-module (guix-data-service model channel-news)
   #:use-module (guix-data-service model package)
   #:use-module (guix-data-service model package-derivation-by-guix-revision-range)
@@ -1206,6 +1207,17 @@ ORDER BY packages.name, packages.version"
            guix-revision-id
            (extract-information-from conn guix-revision-id
                                      commit store-item)
+           (insert-channel-instances conn
+                                     guix-revision-id
+                                     (filter-map
+                                      (match-lambda
+                                        ((system . derivations)
+                                         (and=>
+                                          (assoc-ref derivations
+                                                     'manifest-entry-item)
+                                          (lambda (drv)
+                                            (cons system drv)))))
+                                      channel-derivations-by-system))
            (if (defined? 'channel-news-for-commit
                  (resolve-module '(guix channels)))
                (log-time

guix-data-service/model/channel-instance.scm

@@ -0,0 +1,52 @@
+;;; Guix Data Service -- Information about Guix over time
+;;; Copyright © 2020 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 model channel-instance)
+  #:use-module (srfi srfi-1)
+  #:use-module (ice-9 match)
+  #:use-module (squee)
+  #:use-module (json)
+  #:use-module (guix utils)
+  #:use-module (guix-data-service model utils)
+  #:use-module (guix-data-service model derivation)
+  #:export (insert-channel-instances))
+
+(define (insert-channel-instances conn
+                                  guix-revision-id
+                                  derivations-by-system)
+  (let ((derivation-ids
+         (derivation-file-names->derivation-ids
+          conn
+          (map cdr derivations-by-system))))
+
+    (exec-query
+     conn
+     (string-append
+      "
+INSERT INTO channel_instances
+  (guix_revision_id, system, derivation_id)
+VALUES "
+      (string-join
+       (map (lambda (system derivation-id)
+              (simple-format #f "(~A, '~A', ~A)"
+                             guix-revision-id
+                             system
+                             derivation-id))
+            (map car derivations-by-system)
+            derivation-ids)
+       ", "))))
+  #t)