config-file part degradation

README.md

@@ -316,7 +316,24 @@ Example：
     }
 }
 ```
+##### Degradation: Category=degradation
 
+[JSON Schema](https://github.com/cloudwego/kitex/blob/develop/pkg/#L30)
+
+|Variable|Introduction|
+|------------|----|
+| percentage | The percentage of dropped requests| 
+
+Example：
+default configuration(false,0)
+```json
+{
+   "degradation": {
+            "enabled": true,
+            "percentage": 30
+        }
+}
+```
 Note: The circuit breaker implementation of kitex does not currently support changing the global default configuration (see [initServiceCB](https://github.com/cloudwego/kitex/blob/v0.5.1/pkg/circuitbreak/cbsuite.go#L195) for details).
 ### More Info
 
@@ -374,6 +391,10 @@ For client configuration, you should write all their configurations in the same
                     }
                 }
             }
+        },
+        "degradation": {
+            "enabled": true,
+            "percentage": 30
         }
     }
 }

README_CN.md

@@ -315,6 +315,25 @@ echo 方法使用下面的配置（0.3、100），其他方法使用全局默认
 }
 ```
 注：kitex 的熔断实现目前不支持修改全局默认配置（详见 [initServiceCB](https://github.com/cloudwego/kitex/blob/v0.5.1/pkg/circuitbreak/cbsuite.go#L195)）
+
+##### 降级: Category=degradation
+
+[JSON Schema](https://github.com/cloudwego/kitex/blob/develop/pkg/#L30)
+
+|参数|说明|
+|----|----|
+| percentage | 丢弃比例 | 
+
+样例：
+默认配置(false,0)
+```json
+{
+   "degradation": {
+            "enabled": true,
+            "percentage": 30
+        }
+}
+```
 ### 更多信息
 
 更多示例请参考 [example](https://github.com/kitex-contrib/config-file/tree/main/example)
@@ -374,6 +393,10 @@ echo 方法使用下面的配置（0.3、100），其他方法使用全局默认
                     }
                 }
             }
+        },
+        "degradation": {
+            "enabled": true,
+            "percentage": 30
         }
     }
 }

client/degradation.go

@@ -0,0 +1,45 @@
+// Copyright 2024 CloudWeGo Authors
+//
+// 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.
+
+package client
+
+import (
+	kitexclient "github.com/cloudwego/kitex/client"
+	"github.com/kitex-contrib/config-file/monitor"
+	degradation "github.com/kitex-contrib/config-file/pkg"
+)
+
+func WithDegradation(watcher monitor.ConfigMonitor) []kitexclient.Option {
+	container, keyDegradation := initDegradationOptions(watcher)
+	return []kitexclient.Option{
+		kitexclient.WithACLRules(container.GetAclRule()),
+		kitexclient.WithCloseCallbacks(func() error {
+			watcher.DeregisterCallback(keyDegradation)
+			return nil
+		}),
+	}
+}
+
+func initDegradationOptions(watcher monitor.ConfigMonitor) (*degradation.Container, int64) {
+	degradationContainer := degradation.NewContainer()
+	onChangeCallback := func() {
+		config := getFileConfig(watcher)
+		if config == nil {
+			return // config is nil, do nothing, log will be printed in getFileConfig
+		}
+		degradationContainer.NotifyPolicyChange(config.Degradation)
+	}
+	keyDegradation := watcher.RegisterCallback(onChangeCallback)
+	return degradationContainer, keyDegradation
+}

client/suite.go

@@ -48,6 +48,7 @@ func (s *FileConfigClientSuite) Options() []kitexclient.Option {
 	opts = append(opts, WithRetryPolicy(s.watcher)...)
 	opts = append(opts, WithCircuitBreaker(s.service, s.watcher)...)
 	opts = append(opts, WithRPCTimeout(s.watcher)...)
+	opts = append(opts, WithDegradation(s.watcher)...)
 	opts = append(opts, kitexclient.WithCloseCallbacks(func() error {
 		s.watcher.Stop()
 		return nil

example/client/kitex_client.json

@@ -41,6 +41,10 @@
                     }
                 }
             }
+        },
+        "degradation": {
+            "enabled": true,
+            "percentage": 0
         }
     }
 }

parser/client.go

@@ -18,13 +18,15 @@ import (
 	"github.com/cloudwego/kitex/pkg/circuitbreak"
 	"github.com/cloudwego/kitex/pkg/retry"
 	"github.com/cloudwego/kitex/pkg/rpctimeout"
+	degradation "github.com/kitex-contrib/config-file/pkg"
 )
 
 // ClientFileConfig is config of a client/service pair
 type ClientFileConfig struct {
-	Timeout        map[string]*rpctimeout.RPCTimeout `mapstructure:"timeout"`        // key: method, "*" for default
-	Retry          map[string]*retry.Policy          `mapstructure:"retry"`          // key: method, "*" for default
-	Circuitbreaker map[string]*circuitbreak.CBConfig `mapstructure:"circuitbreaker"` // key: method
+	Timeout        map[string]*rpctimeout.RPCTimeout         `mapstructure:"timeout"`        // key: method, "*" for default
+	Retry          map[string]*retry.Policy                  `mapstructure:"retry"`          // key: method, "*" for default
+	Circuitbreaker map[string]*circuitbreak.CBConfig         `mapstructure:"circuitbreaker"` // key: method
+	Degradation    map[string]*degradation.DegradationConfig `mapstructure:"degradation"`
 }
 
 // ClientFileManager is a map of client/service pairs to ClientFileConfig

pkg/degradation.go

@@ -0,0 +1,93 @@
+// Copyright 2024 CloudWeGo Authors
+//
+// 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.
+
+package degradation
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+
+	"github.com/bytedance/gopkg/lang/fastrand"
+	"github.com/cloudwego/configmanager/iface"
+	"github.com/cloudwego/kitex/pkg/acl"
+)
+
+var errRejected = errors.New("rejected by client degradation config")
+
+var defaultConfig = &DegradationConfig{
+	Enable:     false,
+	Percentage: 0,
+}
+
+type DegradationConfig struct {
+	Enable     bool `json:"enabled"`
+	Percentage int  `json:"percentage"`
+}
+
+// DeepCopy returns a copy of the current Config
+func (c *DegradationConfig) DeepCopy() iface.ConfigValueItem {
+	result := &DegradationConfig{
+		Enable:     c.Enable,
+		Percentage: c.Percentage,
+	}
+	return result
+}
+
+// EqualsTo returns true if the current Config equals to the other Config
+func (c *DegradationConfig) EqualsTo(other iface.ConfigValueItem) bool {
+	o, ok := other.(*DegradationConfig)
+	if !ok {
+		return false
+	}
+	if c == nil {
+		return o == nil
+	}
+	return c.Enable == o.Enable && c.Percentage == o.Percentage
+}
+
+// Container is a wrapper for Config
+type Container struct {
+	config atomic.Value
+}
+
+func NewContainer() *Container {
+	c := &Container{}
+	c.config.Store(defaultConfig)
+	return c
+}
+
+// NotifyPolicyChange to receive policy when it changes
+func (c *Container) NotifyPolicyChange(cfg map[string]*DegradationConfig) {
+	for _, value := range cfg {
+		newConfig := &DegradationConfig{
+			Enable:     value.Enable,
+			Percentage: value.Percentage,
+		}
+		c.config.Store(newConfig)
+	}
+}
+
+func (c *Container) GetAclRule() acl.RejectFunc {
+	return func(ctx context.Context, request interface{}) (reason error) {
+		cfg := c.config.Load().(*DegradationConfig)
+		if !cfg.Enable {
+			return nil
+		}
+		if fastrand.Intn(100) < cfg.Percentage {
+			return errRejected
+		}
+		return nil
+	}
+}

pkg/degradation_test.go

@@ -0,0 +1,46 @@
+// Copyright 2024 CloudWeGo Authors
+//
+// 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.
+
+package degradation
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/cloudwego/kitex/pkg/acl"
+	"github.com/cloudwego/thriftgo/pkg/test"
+)
+
+var errFake = errors.New("fake error")
+
+func invoke(ctx context.Context, request, response interface{}) error {
+	return errFake
+}
+
+func TestNewContainer(t *testing.T) {
+	container := NewContainer()
+	cfg1 := map[string]*DegradationConfig{
+		"someMethod": {Enable: false, Percentage: 100}, // Example method and config
+	}
+	cfg2 := map[string]*DegradationConfig{
+		"someMethod": {Enable: true, Percentage: 100}, // Example method and config
+	}
+	aclMiddleware := acl.NewACLMiddleware([]acl.RejectFunc{container.GetAclRule()})
+	test.Assert(t, errors.Is(aclMiddleware(invoke)(context.Background(), nil, nil), errFake))
+	container.NotifyPolicyChange(cfg1)
+	test.Assert(t, errors.Is(aclMiddleware(invoke)(context.Background(), nil, nil), errFake))
+	container.NotifyPolicyChange(cfg2)
+	test.Assert(t, errors.Is(aclMiddleware(invoke)(context.Background(), nil, nil), errRejected))
+}