Don't hardcode the expected x-git-repo header value

Rather than expecting it always to be "guix", store the expected value in the
database, and use the value of the header to find the relevant repository.

guix-data-service/branch-updated-emails.scm

@@ -23,9 +23,6 @@
   #:use-module (guix-data-service jobs load-new-guix-revision)
   #:export (enqueue-job-for-email))
 
-(define %repository-url-for-repo
-  '(("guix" . "https://git.savannah.gnu.org/git/guix.git")))
-
 (define (enqueue-job-for-email conn email)
   (let* ((headers       (email-headers email))
          (date          (assq-ref headers 'date))
@@ -35,17 +32,16 @@
          (x-git-newrev  (assq-ref headers 'x-git-newrev)))
     (when (and (and (string? x-git-reftype)
                     (string=? x-git-reftype "branch"))
-               (and (string? x-git-repo)
-                    (string=? x-git-repo "guix"))
                (string? x-git-newrev))
 
       (let ((branch-name
              (string-drop x-git-refname 11))
             (git-repository-id
-             (git-repository-url->git-repository-id
+             (git-repository-x-git-repo-header->git-repository-id
               conn
-              (assoc-ref %repository-url-for-repo x-git-repo))))
+              x-git-repo)))
 
+        (when git-repository-id
           (insert-git-branch-entry conn
                                    branch-name
                                    (if (string=? "0000000000000000000000000000000000000000"
@@ -61,4 +57,4 @@
              conn
              git-repository-id
              x-git-newrev
-           (string-append x-git-repo " " x-git-refname " updated")))))))
+             (string-append x-git-repo " " x-git-refname " updated"))))))))

guix-data-service/model/git-repository.scm

@@ -22,6 +22,7 @@
   #:export (all-git-repositories
             select-git-repository
             git-repository-id->url
+            git-repository-x-git-repo-header->git-repository-id
             git-repository-url->git-repository-id
             git-repositories-containing-commit
 
@@ -59,6 +60,17 @@
        (list id))
     (((url)) url)))
 
+(define (git-repository-x-git-repo-header->git-repository-id conn header)
+  (match
+      (exec-query
+       conn
+       (string-append
+        "SELECT id FROM git_repositories WHERE x_git_repo_header = $1;")
+       (list header))
+    (() #f)
+    (((id))
+     (string->number id))))
+
 (define (git-repository-url->git-repository-id conn url)
   (let ((existing-id
          (exec-query

sqitch/deploy/git-repositories-x-git-repo-header.sql

@@ -0,0 +1,7 @@
+-- Deploy guix-data-service:git-repositories-x-git-repo-header to pg
+
+BEGIN;
+
+ALTER TABLE git_repositories ADD COLUMN x_git_repo_header varchar;
+
+COMMIT;

sqitch/revert/git-repositories-x-git-repo-header.sql

@@ -0,0 +1,7 @@
+-- Revert guix-data-service:git-repositories-x-git-repo-header from pg
+
+BEGIN;
+
+ALTER TABLE git_repositories DROP COLUMN x_git_repo_header;
+
+COMMIT;

sqitch/sqitch.plan

@@ -42,3 +42,4 @@ derivations_hash_index 2019-12-24T22:54:19Z Christopher Baines <mail@cbaines.net
 add_derivation_source_file_nars 2019-12-28T20:37:06Z Christopher Baines <mail@cbaines.net> # Add table for derivation source file nars
 derivation_source_files_store_path_hash_index 2019-12-29T17:53:08Z Christopher Baines <mail@cbaines.net> # Add index on the hash part of the derivation source files store path
 build_servers_build_config 2020-01-05T12:06:13Z Christopher Baines <mail@cbaines.net> # Add build_servers_build_config table
+git-repositories-x-git-repo-header 2020-01-11T16:39:32Z Christopher Baines <mail@cbaines.net> # Add x_git_repo_header to git_repositories

sqitch/verify/git-repositories-x-git-repo-header.sql

@@ -0,0 +1,7 @@
+-- Verify guix-data-service:git-repositories-x-git-repo-header on pg
+
+BEGIN;
+
+-- XXX Add verifications here.
+
+ROLLBACK;