make server capable of migrating itself

crossfire/protocol.rkt

@@ -16,7 +16,8 @@
 ;; You should have received a copy of the GNU Affero General Public License
 ;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-(require db/base db/sqlite3 racket/path
+(require db/base db/sqlite3 racket/path racket/runtime-path
+         north/base north/adapter/base north/adapter/sqlite
          "comms.rkt" "not-crypto.rkt")
 
 ;; configuration
@@ -26,14 +27,29 @@
 (define SERVER-DATA-DIR (if PRODUCTION? "/var/lib/crossfire/" "lib/"))
 (define SERVER-DB-PATH (build-path SERVER-DATA-DIR "crossfire.sqlite"))
 
+;; north migrations
+(define-runtime-path migrations-dir "migrations/")
 
 ;; database
 
-(define (open-server-db)
-  (sqlite3-connect #:database SERVER-DB-PATH))
-
 (define current-db (make-parameter #f))
 
+(define (open-server-db [mode 'read/write])
+  (sqlite3-connect #:database SERVER-DB-PATH #:mode mode))
+
+;; this allows the server to be capable of migrating itself
+(define (migrate-server-db [db (current-db)])
+  (define base (path->migration migrations-dir))
+  (define adapter (sqlite-adapter db))
+  (adapter-init adapter)
+  (define current-revision (adapter-current-revision adapter))
+  (define target-revision (migration-revision (migration-most-recent base)))
+  (define plan (migration-plan base current-revision target-revision))
+  (for ([migration (in-list plan)])
+    (displayln (format "applying migration: ~a" (migration-revision migration)))
+    (adapter-apply! adapter (migration-revision migration) (migration-up migration)))
+  (void))
+
 (define (with-server-db proc)
   (parameterize ([current-db (open-server-db)])
     (proc)