chore(nix): provide memcached

shell.nix

@@ -19,12 +19,22 @@ let
   '';
 
   override = oldAttrs: {
-    nativeBuildInputs = oldAttrs.nativeBuildInputs ++ (with pkgs; [ nodejs-13_x postgresql openldap google-chrome exiftool ]) ++ (with pkgs.haskellPackages; [ stack yesod-bin hlint cabal-install weeder ]);
+    nativeBuildInputs = oldAttrs.nativeBuildInputs ++ (with pkgs; [ nodejs-13_x postgresql openldap google-chrome exiftool memcached ]) ++ (with pkgs.haskellPackages; [ stack yesod-bin hlint cabal-install weeder profiteur ]);
     shellHook = ''
       export PROMPT_INFO="${oldAttrs.name}"
 
       export EDITOR=emacsclient
 
+      cleanup() {
+        set +e -x
+        type cleanup_postgres && cleanup_postgres
+        type cleanup_widget_memcached && cleanup_widget_memcached
+        type cleanup_session_memcached && cleanup_session_memcached
+        set +x
+      }
+
+      trap cleanup EXIT
+
       if [[ -z "$PGHOST" ]]; then
         set -xe
 
@@ -37,14 +47,42 @@ let
         psql -f ${postgresSchema} postgres
         printf "Postgres logfile is %s\nPostgres socket directory is %s\n" ''${pgLogFile} ''${pgSockDir}
 
-        cleanup() {
+        cleanup_postgres() {
             set +e -x
             pg_ctl stop -D ''${pgDir}
             rm -rvf ''${pgDir} ''${pgSockDir} ''${pgLogFile}
             set +x
         }
 
-        trap cleanup EXIT
+        set +xe
+      fi
+
+      if [[ -z "$WIDGET_MEMCACHED_HOST" ]]; then
+        set -xe
+
+        memcached -l localhost -p 11211 &>/dev/null &
+        widget_memcached_pid=$?
+
+        cleanup_widget_memcached() {
+          [[ -n "$widget_memcached_pid" ]] && kill $widget_memcached_pid
+        }
+
+        export WIDGET_MEMCACHED_HOST=localhost WIDGET_MEMCACHED_PORT=11211
+
+        set +xe
+      fi
+
+      if [[ -z "$SESSION_MEMCACHED_HOST" ]]; then
+        set -xe
+
+        memcached -l localhost -p 11212 &>/dev/null &
+        session_memcached_pid=$?
+
+        cleanup_session_memcached() {
+          [[ -n "$session_memcached_pid" ]] && kill $session_memcached_pid
+        }
+
+        export SESSION_MEMCACHED_HOST=localhost SESSION_MEMCACHED_PORT=11212
 
         set +xe
       fi