Add helper scripts used by packages to validate site.conf

include/package.mk

+include $(INCLUDE_DIR)/package.mk
+
+# Annoyingly, make's shell function replaces all newlines with spaces, so we have to do some escaping work. Yuck.
+define GluonCheckSite
+[ -z "$$GLUONDIR" ] || sed -e 's/-@/\n/g' -e 's/+@/@/g' <<'END__GLUON__CHECK__SITE' | "$$GLUONDIR"/scripts/check_site.sh
+$(shell cat $(1) | sed -ne '1h; 1!H; $$ {g; s/@/+@/g; s/\n/-@/g; p}')
+END__GLUON__CHECK__SITE
+endef

scripts/check_site.sh

+#!/bin/sh
+
+export GLUON_SITE_CONFIG="$GLUONDIR/site/site.conf"
+
+SITE_CONFIG_LUA=packages/gluon/gluon/gluon-core/files/usr/lib/lua/gluon/site_config.lua
+CHECK_SITE_LIB=scripts/check_site_lib.lua
+
+"$GLUONDIR"/openwrt/staging_dir/host/bin/lua -e "site = dofile(os.getenv('GLUONDIR') .. '/${SITE_CONFIG_LUA}'); dofile(os.getenv('GLUONDIR') .. '/${CHECK_SITE_LIB}'); dofile()"

scripts/check_site_lib.lua

+local function loadvar(varname)
+   local ok, val = pcall(assert(loadstring('return site.' .. varname)))
+   if ok then
+      return val
+   else
+      return nil
+   end
+end
+
+local function assert_type(var, t, msg)
+   assert(type(var) == t, msg)
+end
+
+
+function need_string(varname, required)
+   local var = loadvar(varname)
+
+   if required == false and var == nil then
+      return nil
+   end
+
+   assert_type(var, 'string', "site.conf error: expected `" .. varname .. "' to be a string")
+   return var
+end
+
+function need_string_match(varname, pat, required)
+   local var = need_string(varname, required)
+
+   if not var then
+      return nil
+   end
+
+   assert(var:match(pat), "site.conf error: expected `" .. varname .. "' to match pattern `" .. pat .. "'")
+
+   return var
+end
+
+function need_number(varname, required)
+   local var = loadvar(varname)
+
+   if required == false and var == nil then
+      return nil
+   end
+
+   assert_type(var, 'number', "site.conf error: expected `" .. varname .. "' to be a number")
+
+   return var
+end
+
+function need_array(varname, subcheck, required)
+   local var = loadvar(varname)
+
+   if required == false and var == nil then
+      return nil
+   end
+
+   assert_type(var, 'table', "site.conf error: expected `" .. varname .. "' to be an array")
+
+   for _, e in ipairs(var) do
+      subcheck(e)
+   end
+
+   return var
+end
+
+function need_table(varname, subcheck, required)
+   local var = loadvar(varname)
+
+   if required == false and var == nil then
+      return nil
+   end
+
+   assert_type(var, 'table', "site.conf error: expected `" .. varname .. "' to be a table")
+
+   for k, v in pairs(var) do
+      subcheck(k, v)
+   end
+
+   return var
+end
+
+function need_string_array(varname, required)
+   return assert(pcall(need_array, varname, function(e) assert_type(e, 'string') end, required),
+		 "site.conf error: expected `" .. varname .. "' to be a string array")
+end