Fix OpenResty race condition from global logging variable initialization

src/util/Log.lua

@@ -12,9 +12,6 @@
 --See the License for the specific language governing permissions and
 --limitations under the License.
 
-local Logging = require "logging"
-local fileLogging = require "logging.file"
-
 -- The logging module for logging to console or any file
 local Log = {
     enabled = true
@@ -23,6 +20,8 @@ Log.__index = Log
 
 -- returns logger function for logging to console
 function Log.getLogger()
+    -- Lazy load to avoid global variable issues in OpenResty
+    local Logging = require "logging"
     local o = {}
     setmetatable(o, Log)
     o.logger = Logging.new(function(self, level, message)
@@ -37,6 +36,8 @@ function Log:getFileLogger(filePath)
     if not filePath then
         error("no filePath for logger provided")
     end
+    -- Lazy load to avoid global variable issues in OpenResty
+    local fileLogging = require "logging.file"
     local o = {}
     self.__index = self
     setmetatable(o, self)

tests/main/multi_enforcer_spec.lua

@@ -0,0 +1,81 @@
+--Copyright 2021 The casbin Authors. All Rights Reserved.
+--
+--Licensed under the Apache License, Version 2.0 (the "License");
+--you may not use this file except in compliance with the License.
+--You may obtain a copy of the License at
+--
+--    http://www.apache.org/licenses/LICENSE-2.0
+--
+--Unless required by applicable law or agreed to in writing, software
+--distributed under the License is distributed on an "AS IS" BASIS,
+--WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+--See the License for the specific language governing permissions and
+--limitations under the License.
+
+local Enforcer = require("src.main.Enforcer")
+
+describe("Multiple Enforcers tests", function ()
+    it("multiple newEnforcerFromText test (issue: race condition)", function ()
+        -- This test simulates the issue from GitHub where creating multiple 
+        -- enforcers would cause race conditions with the global logging variable
+
+        local model1 = [[
+            [request_definition]
+            r = path, method
+
+            [policy_definition]
+            p = path, method, eft
+
+            [policy_effect]
+            e = some(where (p.eft == allow)) && !some(where (p.eft == deny))
+
+            [matchers]
+            m = regexMatch(r.path, p.path) && keyMatch(r.method, p.method)
+        ]]
+
+        local policy1 =[[
+            p, ^/cate/sample/gen_label_no,              POST, allow
+            p, ^/cate/sample/.*/[print|reprint],        PUT,  allow
+        ]]
+
+        local model2 = [[
+            [request_definition]
+            r = user, path, method
+
+            [policy_definition]
+            p = role, path, method
+
+            [role_definition]
+            g = _, _
+
+            [policy_effect]
+            e = some(where (p.eft == allow))
+
+            [matchers]
+            m = (g(r.user, p.role) || keyMatch(r.user, p.role)) && regexMatch(r.path, p.path) && keyMatch(r.method, p.method)
+        ]]
+
+        local policy2 =[[
+            p, *,          ^/$,                         GET
+            p, *,          ^/portal,                    GET
+            p, *,          ^/admin,                     GET
+
+            p, sys-admin,  *,                           *
+            g, sys-admin,       guests
+        ]]
+
+        -- Create first enforcer
+        local ex2 = Enforcer:newEnforcerFromText(model2, policy2)
+        local pass2 = ex2:enforce("guests", "/", "GET")
+        assert.is.True(pass2)
+
+        -- Create second enforcer
+        local ex1 = Enforcer:newEnforcerFromText(model1, policy1)
+        local pass1 = ex1:enforce("/cate/sample/gen_label_no", "POST")
+        assert.is.True(pass1)
+
+        -- Test first enforcer again
+        local pass3 = ex2:enforce("guests", "/", "GET")
+        assert.is.True(pass3)
+    end)
+end)