fix(bk-cache-fallback): enhance error messages for lock acquisition f…

…ailures and add tests for timeout scenarios

src/apisix/plugins/bk-cache-fallback/init.lua

@@ -139,7 +139,7 @@ function _M.get_with_fallback(self, ctx, key, version, create_obj_func, ...)
     local elapsed, lock_err = lock:lock(key_s)
     if not elapsed then
         if lock_err ~= "timeout" then
-            return nil, "failed to acquire the bk-cache-fallback lock, err: " .. lock_err
+            return nil, "failed to acquire the bk-cache-fallback lock, key: " .. key_s .. ", err: " .. lock_err
         end
 
         -- NOTE: 2024-11-11 we met some timeout here, in the same apisix pod, the same cache_key,
@@ -151,13 +151,14 @@ function _M.get_with_fallback(self, ctx, key, version, create_obj_func, ...)
             if sd ~= nil then
                 local obj_decoded, json_err = core.json.decode(sd)
                 if json_err == nil then
-                    log.error("failed to acquire the bk-cache-fallback lock, fallback to get the data from shared_dict")
+                    log.error("failed to acquire the bk-cache-fallback lock, key: " .. key_s ..
+                              ", fallback to get the data from shared_dict")
                     return obj_decoded, nil
                 end
             end
         end
 
-        return nil, "failed to acquire the bk-cache-fallback lock, error: timeout."
+        return nil, "failed to acquire the bk-cache-fallback lock, key: " .. key_s  .. ", error: timeout."
     end
 
     -- TODO: 函数过长, 需要考虑拆分, 特别是 unlock 特别多, 也容易出问题

src/apisix/tests/bk-cache-fallback/test-init.lua

@@ -19,6 +19,7 @@
 local cache_fallback = require("apisix.plugins.bk-cache-fallback.init")
 local ngx_shared = ngx.shared
 local ngx_sleep = ngx.sleep
+local core = require("apisix.core")
 
 describe(
     "bk-cache-fallback", function()
@@ -313,5 +314,124 @@ describe(
             end
         )
 
+        -- a new case here, to test the lock:lock timeout and other errors
+        describe("lock:lock timeout and other errors", function()
+            local key
+            local f
+
+            before_each(function ()
+                key = "foo"
+
+                f = {
+                    create_obj_func_ok = function() end,
+                    create_obj_func_fail = function() end,
+                }
+
+                stub(f, "create_obj_func_ok", function ()
+                    return {
+                        ["hello"] = "world",
+                    }, nil
+                end)
+                stub(f, "create_obj_func_fail", function ()
+                    return nil, "error"
+                end)
+
+            end)
+
+            after_each(function ()
+                f.create_obj_func_ok:revert()
+                f.create_obj_func_fail:revert()
+            end)
+
+            it("is not timeout error, should return the error", function ()
+                local ctx = {
+                    conf_id = 789,
+                    conf_type = "test",
+                }
+                local cache = cache_fallback.new(conf, "bk-cache-fallback-lock-error")
+                local cache_key = cache.key_prefix .. key
+
+                local shared_data_dict = ngx_shared[cache.plugin_shared_dict_name]
+                assert.is_not_nil(shared_data_dict)
+
+                -- Stub lock:lock to simulate an error (not timeout)
+                local lock = require("resty.lock")
+                stub(lock, "lock", function(self, key_s)
+                    if key_s == cache_key then
+                        return nil, "some error"
+                    else
+                        return 0, nil
+                    end
+                end)
+
+                local obj, err = cache:get_with_fallback(ctx, key, nil, f.create_obj_func_fail)
+                assert.is_nil(obj)
+                assert.is_not_nil(err)
+                assert.equal("failed to acquire the bk-cache-fallback lock, key: bk-cache-fallback-lock-error:foo, err: some error", err)
+
+                lock.lock:revert()
+            end)
+
+            it("is timeout, no data in shared_dict, return the error", function ()
+                local ctx = {
+                    conf_id = 789,
+                    conf_type = "test",
+                }
+                local cache = cache_fallback.new(conf, "bk-cache-fallback-lock-timeout")
+                local cache_key = cache.key_prefix .. key
+
+                local shared_data_dict = ngx_shared[cache.plugin_shared_dict_name]
+                assert.is_not_nil(shared_data_dict)
+
+                -- Stub lock:lock to simulate a timeout
+                local lock = require("resty.lock")
+                stub(lock, "lock", function(self, key_s)
+                    if key_s == cache_key then
+                        return nil, "timeout"
+                    else
+                        return 0, nil
+                    end
+                end)
+
+                local obj, err = cache:get_with_fallback(ctx, key, nil, f.create_obj_func_fail)
+                assert.is_nil(obj)
+                assert.is_not_nil(err)
+                assert.equal("failed to acquire the bk-cache-fallback lock, key: bk-cache-fallback-lock-timeout:foo, error: timeout.", err)
+
+                lock.lock:revert()
+            end)
+
+            it("is timeout, got the data in shared_dict, return data,nil", function ()
+                local ctx = {
+                    conf_id = 789,
+                    conf_type = "test",
+                }
+                local cache = cache_fallback.new(conf, "bk-cache-fallback-lock-timeout-data")
+                local cache_key = cache.key_prefix .. key
+
+                local shared_data_dict = ngx_shared[cache.plugin_shared_dict_name]
+                assert.is_not_nil(shared_data_dict)
+
+                -- set data in shared_dict
+                shared_data_dict:set(cache_key, '{"hello":"abc"}', 60 * 60)
+
+                -- Stub lock:lock to simulate a timeout
+                local lock = require("resty.lock")
+                stub(lock, "lock", function(self, key_s)
+                    if key_s == cache_key then
+                        return nil, "timeout"
+                    else
+                        return 0, nil
+                    end
+                end)
+
+                local obj, err = cache:get_with_fallback(ctx, key, nil, f.create_obj_func_ok)
+                assert.is_not_nil(obj)
+                assert.is_nil(err)
+                assert.equal("abc", obj["hello"])
+
+                lock.lock:revert()
+            end)
+        end)
     end
 )

src/apisix/tests/conf/nginx.conf

@@ -4,9 +4,12 @@ lua_shared_dict prometheus-metrics 1m;
 lua_shared_dict plugin-bk-permission 1m;
 lua_shared_dict plugin-bk-cache-fallback 1m;
 lua_shared_dict plugin-bk-cache-fallback-lock 1m;
-# for unittest, bk-cache-fallback/init.lua, case ok/fail/ok->fail
+# for unittest, bk-cache-fallback/init.lua, case ok/fail/ok->fail/lock fail
 lua_shared_dict plugin-bk-cache-fallback-ok 1m;
 lua_shared_dict plugin-bk-cache-fallback-fail 1m;
 lua_shared_dict plugin-bk-cache-fallback-ok-fail 1m;
+lua_shared_dict plugin-bk-cache-fallback-lock-error 1m;
+lua_shared_dict plugin-bk-cache-fallback-lock-timeout 1m;
+lua_shared_dict plugin-bk-cache-fallback-lock-timeout-data 1m;
 
-error_log /bkgateway/logs/error.log;
+error_log /bkgateway/logs/error.log;