[utils] append the original error to the error string

gateway/src/apicast/threescale_utils.lua

@@ -152,22 +152,22 @@ function _M.connect_redis(options)
 
   local ok, err = red:connect(_M.resolve(host, port))
   if not ok then
-    return nil, _M.error("failed to connect to redis on " .. host .. ":" .. port .. ":", err)
+    return nil, _M.error("failed to connect to redis on ", host, ":", port, ": ", err)
   end
 
   if opts.password then
     ok = red:auth(opts.password)
 
     if not ok then
-      return nil, _M.error("failed to auth on redis " .. host .. ":" .. port)
+      return nil, _M.error("failed to auth on redis ", host, ":", port)
     end
   end
 
   if opts.db then
     ok = red:select(opts.db)
 
     if not ok then
-      return nil, _M.error("failed to select db " .. opts.db .. " on redis " .. host .. ":" .. port)
+      return nil, _M.error("failed to select db ", opts.db, " on redis ", host, ":", port)
     end
   end
 
@@ -187,10 +187,10 @@ function _M.match_xml_element(xml, element, value)
   return string.find(xml, pattern, xml_header_len, xml_header_len, true)
 end
 
--- error and exist
+-- error and exit
 function _M.error(...)
   if ngx.get_phase() == 'timer' then
-    return ...
+    return table.concat(table.pack(...))
   else
     ngx.status = ngx.HTTP_INTERNAL_SERVER_ERROR
     ngx.say(...)

spec/threescale_utils_spec.lua

@@ -0,0 +1,14 @@
+local _M = require('apicast.threescale_utils')
+
+describe('3scale utils', function()
+    describe('.error', function()
+        it('returns concatenated error in timer phase', function()
+            local get_phase = spy.on(ngx, 'get_phase', function() return 'timer' end)
+            local error = _M.error('one', ' two', ' three')
+
+            assert.spy(get_phase).was_called(1)
+
+            assert.equal('one two three', error)
+        end)
+    end)
+end)