rails: Create a state directory where stateful files can live

This is necessary for files like the state file that tells the
migration script whether or not the schema needs to be loaded.

Fixes a bug where the migration script would try to load the schema on
a second deployment (since touching a file in the db directory fails
because it's in the nix store).

modules/services/web/rails/db-migrate.sh

@@ -9,6 +9,7 @@ set -u
 ################################################################################
 option_env=${RAILS_ENV:-production}
 option_root=$(pwd)
+option_statedir=$(pwd)/state
 
 ################################################################################
 usage () {
@@ -18,11 +19,12 @@ Usage: db-migrate.sh [options]
   -e NAME Set RAILS_ENV to NAME
   -h      This message
   -r DIR  The root directory of the Rails app
+  -s DIR  Directory where state files can be stored
 EOF
 }
 
 ################################################################################
-while getopts "he:r:" o; do
+while getopts "he:r:s:" o; do
   case "${o}" in
     e) option_env=$OPTARG
        ;;
@@ -34,6 +36,9 @@ while getopts "he:r:" o; do
     r) option_root=$OPTARG
        ;;
 
+    s) option_statedir=$OPTARG
+       ;;
+
     *) exit 1
        ;;
   esac
@@ -47,9 +52,9 @@ export RAILS_ENV=$option_env
 
 ################################################################################
 # If this is a new database, load the schema file:
-if [ ! -e config/database-loaded.flag ]; then
+if [ ! -e "$option_statedir/database-loaded.flag" ]; then
   rake db:schema:load
-  touch config/database-loaded.flag
+  touch "$option_statedir/database-loaded.flag"
 fi
 
 ################################################################################

modules/services/web/rails/default.nix

@@ -66,7 +66,7 @@ let
         DATABASE_PORT = toString app.database.port;
         DATABASE_NAME = app.database.name;
         DATABASE_USER = app.database.user;
-        DATABASE_PASSWORD_FILE = "${app.home}/config/database.password";
+        DATABASE_PASSWORD_FILE = "${app.home}/state/database.password";
       } // app.environment;
 
       wantedBy = [ "multi-user.target" ];
@@ -78,11 +78,12 @@ let
       preStart = ''
         # Prepare the config directory:
         rm -rf ${app.home}/config
-        mkdir -p ${app.home}/{config,log,tmp,db}
+        mkdir -p ${app.home}/{config,log,tmp,db,state}
+
         cp -rf ${app.package}/share/${app.name}/config.dist/* ${app.home}/config/
         cp ${app.package}/share/${app.name}/db/schema.rb.dist ${app.home}/db/schema.rb
         cp ${./database.yml} ${app.home}/config/database.yml
-        cp ${app.database.passwordFile} ${app.home}/config/database.password
+        cp ${app.database.passwordFile} ${app.home}/state/database.password
 
         mkdir -p ${app.home}/home
         ln -nfs ${app.package}/share/${app.name} ${app.home}/home/${app.name}
@@ -95,7 +96,9 @@ let
       '' + optionalString app.database.migrate ''
         # Migrate the database (use sudo so environment variables go through):
         ${pkgs.sudo}/bin/sudo -u rails-${app.name} -EH \
-          ${scripts}/bin/db-migrate.sh -r ${app.package}/share/${app.name}
+          ${scripts}/bin/db-migrate.sh \
+            -r ${app.package}/share/${app.name} \
+            -s ${app.home}/state
       '';
 
       serviceConfig = {