Merge pull request #852 from cloudwego/release/v0.5.0

chore: release v0.5.0

.github/CODEOWNERS

@@ -0,0 +1,3 @@
+# For more information, please refer to https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners
+
+*   @cloudwego/Kitex-reviewers @cloudwego/Kitex-approvers @cloudwego/Kitex-maintainers

.github/workflows/pr-check.yml

@@ -14,7 +14,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Check Spell
-        uses: crate-ci/typos@master
+        uses: crate-ci/typos@v1.13.14
 
   staticcheck:
     runs-on: [ self-hosted, X64 ]

.github/workflows/tests.yml

@@ -48,4 +48,4 @@ jobs:
         with:
           go-version: ${{ matrix.go }}
       - name: Unit Test
-        run: go test -gcflags=-l -race -covermode=atomic -coverprofile=coverage.txt ./...
+        run: go test -gcflags=-l -race -covermode=atomic ./...

CONTRIBUTING.md

@@ -31,7 +31,7 @@ Before you submit your Pull Request (PR) consider the following guidelines:
     ```
     git checkout -b my-fix-branch develop
     ```
-6. Create your patch, including appropriate test cases.
+6. Create your patch, including appropriate test cases. Please refer to [Go-UT](https://pkg.go.dev/testing#pkg-overview) for writing guides. [Go-Mock](https://github.com/golang/mock) is recommended to mock interface, please refer to internal/mocks/readme.md for more details, and [Mockey](https://github.com/bytedance/mockey) is recommended to mock functions, please refer to its readme doc for specific usage.
 7. Follow our [Style Guides](#code-style-guides).
 8. Commit your changes using a descriptive commit message that follows [AngularJS Git Commit Message Conventions](https://docs.google.com/document/d/1QrDFcIiPjSLDn3EL15IJygNPiHORgU1_OOAqWjiDU5Y/edit).
    Adherence to these conventions is necessary because release notes are automatically generated from these messages.

README.md

@@ -52,7 +52,7 @@ Kitex has built-in code generation tools that support generating **Thrift**, **P
 
   - **Basic Features**
 
-    Including Message Type, Supported Protocols, Directly Invoke, Connection Pool, Timeout Control, Request Retry, LoadBalancer, Circuit Breaker, Rate Limiting, Instrumentation Control, Logging and HttpResolver.[[more]](https://www.cloudwego.io/docs/tutorials/basic-feature/)
+    Including Message Type, Supported Protocols, Directly Invoke, Connection Pool, Timeout Control, Request Retry, LoadBalancer, Circuit Breaker, Rate Limiting, Instrumentation Control, Logging and HttpResolver.[[more]](https://www.cloudwego.io/docs/kitex/tutorials/basic-feature/)
 
   - **Governance Features**
 

client/callopt/options.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/cloudwego/kitex/internal/client"
 	"github.com/cloudwego/kitex/pkg/discovery"
+	"github.com/cloudwego/kitex/pkg/fallback"
 	"github.com/cloudwego/kitex/pkg/http"
 	"github.com/cloudwego/kitex/pkg/retry"
 	"github.com/cloudwego/kitex/pkg/rpcinfo"
@@ -45,6 +46,7 @@ type CallOptions struct {
 
 	// export field for using in client
 	RetryPolicy retry.Policy
+	Fallback    *fallback.Policy
 }
 
 func newOptions() interface{} {
@@ -63,6 +65,7 @@ func (co *CallOptions) Recycle() {
 	co.configs = nil
 	co.svr = nil
 	co.RetryPolicy = retry.Policy{}
+	co.Fallback = nil
 	co.locks.Zero()
 	callOptionsPool.Put(co)
 }
@@ -171,14 +174,14 @@ func WithTag(key, val string) Option {
 
 // WithRetryPolicy sets the retry policy for a RPC call.
 // Build retry.Policy with retry.BuildFailurePolicy or retry.BuildBackupRequest instead of building retry.Policy directly.
-// Below is use demo, eg:
+// Demos are provided below:
 //
 //	  demo1. call with failure retry policy, default retry error is Timeout
-//	  	resp, err := cli.Mock(ctx, req, callopt.WithRetryPolicy(retry.BuildFailurePolicy(retry.NewFailurePolicy())))
+//	  	`resp, err := cli.Mock(ctx, req, callopt.WithRetryPolicy(retry.BuildFailurePolicy(retry.NewFailurePolicy())))`
 //	  demo2. call with backup request policy
-//	  	bp := retry.NewBackupPolicy(10)
+//	  	`bp := retry.NewBackupPolicy(10)
 //		 	bp.WithMaxRetryTimes(1)
-//	  	resp, err := cli.Mock(ctx, req, callopt.WithRetryPolicy(retry.BuildBackupRequest(bp)))
+//	  	resp, err := cli.Mock(ctx, req, callopt.WithRetryPolicy(retry.BuildBackupRequest(bp)))`
 func WithRetryPolicy(p retry.Policy) Option {
 	return Option{f: func(o *CallOptions, di *strings.Builder) {
 		if !p.Enable {
@@ -193,6 +196,23 @@ func WithRetryPolicy(p retry.Policy) Option {
 	}}
 }
 
+// WithFallback is used to set the fallback policy for a RPC call.
+// Demos are provided below:
+//
+//	demo1. call with fallback for error
+//		`resp, err := cli.Mock(ctx, req, callopt.WithFallback(fallback.ErrorFallback(yourFBFunc))`
+//	demo2. call with fallback for error and enable reportAsFallback, which sets reportAsFallback to be true and will do report(metric) as Fallback result
+//		`resp, err := cli.Mock(ctx, req, callopt.WithFallback(fallback.ErrorFallback(yourFBFunc).EnableReportAsFallback())`
+func WithFallback(fb *fallback.Policy) Option {
+	return Option{f: func(o *CallOptions, di *strings.Builder) {
+		if !fallback.IsPolicyValid(fb) {
+			return
+		}
+		di.WriteString("WithFallback")
+		o.Fallback = fb
+	}}
+}
+
 // Apply applies call options to the rpcinfo.RPCConfig and internal.RemoteInfo of kitex client.
 // The return value records the name and arguments of each option.
 // This function is for internal purpose only.

client/callopt/options_test.go

@@ -17,13 +17,16 @@
 package callopt
 
 import (
+	"context"
 	"fmt"
 	"testing"
 	"time"
 
 	"github.com/cloudwego/kitex/internal/client"
 	"github.com/cloudwego/kitex/internal/test"
+	"github.com/cloudwego/kitex/pkg/fallback"
 	"github.com/cloudwego/kitex/pkg/http"
+	"github.com/cloudwego/kitex/pkg/retry"
 	"github.com/cloudwego/kitex/pkg/rpcinfo"
 	"github.com/cloudwego/kitex/pkg/rpcinfo/remoteinfo"
 )
@@ -89,4 +92,27 @@ func TestApply(t *testing.T) {
 	v, exist := remoteInfo.Tag(mockKey)
 	test.Assert(t, exist)
 	test.Assert(t, v == mockVal, v)
+
+	// WithRetryPolicy
+	option = WithRetryPolicy(retry.BuildFailurePolicy(retry.NewFailurePolicy()))
+	_, co := Apply([]Option{option}, rpcConfig, remoteInfo, client.NewConfigLocks(), http.NewDefaultResolver())
+	test.Assert(t, co.RetryPolicy.Enable)
+	test.Assert(t, co.RetryPolicy.FailurePolicy != nil)
+
+	// WithRetryPolicy pass empty struct
+	option = WithRetryPolicy(retry.Policy{})
+	_, co = Apply([]Option{option}, rpcConfig, remoteInfo, client.NewConfigLocks(), http.NewDefaultResolver())
+	test.Assert(t, !co.RetryPolicy.Enable)
+
+	// WithFallback
+	option = WithFallback(fallback.ErrorFallback(fallback.UnwrapHelper(func(ctx context.Context, req, resp interface{}, err error) (fbResp interface{}, fbErr error) {
+		return
+	})).EnableReportAsFallback())
+	_, co = Apply([]Option{option}, rpcConfig, remoteInfo, client.NewConfigLocks(), http.NewDefaultResolver())
+	test.Assert(t, co.Fallback != nil)
+
+	// WithFallback pass nil
+	option = WithFallback(nil)
+	_, co = Apply([]Option{option}, rpcConfig, remoteInfo, client.NewConfigLocks(), http.NewDefaultResolver())
+	test.Assert(t, co.Fallback == nil)
 }

client/client.go

@@ -21,6 +21,7 @@ import (
 	"errors"
 	"fmt"
 	"runtime"
+	"runtime/debug"
 	"strconv"
 	"sync/atomic"
 
@@ -34,6 +35,7 @@ import (
 	"github.com/cloudwego/kitex/pkg/discovery"
 	"github.com/cloudwego/kitex/pkg/endpoint"
 	"github.com/cloudwego/kitex/pkg/event"
+	"github.com/cloudwego/kitex/pkg/fallback"
 	"github.com/cloudwego/kitex/pkg/kerrors"
 	"github.com/cloudwego/kitex/pkg/klog"
 	"github.com/cloudwego/kitex/pkg/loadbalance"
@@ -244,11 +246,14 @@ func (kc *kClient) initLBCache() error {
 			NameFunc: func() string { return "no_resolver" },
 		}
 	}
+	// because we cannot ensure that user's custom loadbalancer is cacheable, we need to disable it here
+	cacheOpts := lbcache.Options{DiagnosisService: kc.opt.DebugService, Cacheable: false}
 	balancer := kc.opt.Balancer
 	if balancer == nil {
+		// default internal lb balancer is cacheable
+		cacheOpts.Cacheable = true
 		balancer = loadbalance.NewWeightedBalancer()
 	}
-	cacheOpts := lbcache.Options{DiagnosisService: kc.opt.DebugService}
 	if kc.opt.BalancerCacheOpt != nil {
 		cacheOpts = *kc.opt.BalancerCacheOpt
 	}
@@ -365,48 +370,67 @@ func (kc *kClient) Call(ctx context.Context, method string, request, response in
 	ctx = kc.opt.TracerCtl.DoStart(ctx, ri)
 
 	var callOptRetry retry.Policy
-	if callOpts != nil && callOpts.RetryPolicy.Enable {
-		callOptRetry = callOpts.RetryPolicy
-	}
-	if kc.opt.RetryContainer == nil {
-		if callOptRetry.Enable {
-			// setup retry in callopt
-			kc.opt.RetryContainer = retry.NewRetryContainer()
-		} else {
-			err := kc.eps(ctx, request, response)
-			kc.opt.TracerCtl.DoFinish(ctx, ri, err)
-			if err == nil {
-				err = ri.Invocation().BizStatusErr()
-				rpcinfo.PutRPCInfo(ri)
-			}
-			return err
+	var callOptFallback *fallback.Policy
+	if callOpts != nil {
+		callOptFallback = callOpts.Fallback
+		if callOpts.RetryPolicy.Enable {
+			callOptRetry = callOpts.RetryPolicy
 		}
 	}
+	if kc.opt.RetryContainer == nil && callOptRetry.Enable {
+		// setup retry in callopt
+		kc.opt.RetryContainer = retry.NewRetryContainer()
+	}
 
-	var callTimes int32
-	var prevRI rpcinfo.RPCInfo
-	recycleRI, err := kc.opt.RetryContainer.WithRetryIfNeeded(ctx, callOptRetry, func(ctx context.Context, r retry.Retryer) (rpcinfo.RPCInfo, interface{}, error) {
-		currCallTimes := int(atomic.AddInt32(&callTimes, 1))
-		retryCtx := ctx
-		cRI := ri
-		if currCallTimes > 1 {
-			retryCtx, cRI, _ = kc.initRPCInfo(ctx, method)
-			retryCtx = metainfo.WithPersistentValue(retryCtx, retry.TransitKey, strconv.Itoa(currCallTimes-1))
-			if prevRI == nil {
-				prevRI = ri
+	var err error
+	var recycleRI bool
+	if kc.opt.RetryContainer == nil {
+		err = kc.eps(ctx, request, response)
+		if err == nil {
+			recycleRI = true
+		}
+	} else {
+		var callTimes int32
+		// prevRI represents a value of rpcinfo.RPCInfo type.
+		var prevRI atomic.Value
+		recycleRI, err = kc.opt.RetryContainer.WithRetryIfNeeded(ctx, callOptRetry, func(ctx context.Context, r retry.Retryer) (rpcinfo.RPCInfo, interface{}, error) {
+			currCallTimes := int(atomic.AddInt32(&callTimes, 1))
+			retryCtx := ctx
+			cRI := ri
+			if currCallTimes > 1 {
+				retryCtx, cRI, _ = kc.initRPCInfo(ctx, method)
+				retryCtx = metainfo.WithPersistentValue(retryCtx, retry.TransitKey, strconv.Itoa(currCallTimes-1))
+				if prevRI.Load() == nil {
+					prevRI.Store(ri)
+				}
+				r.Prepare(retryCtx, prevRI.Load().(rpcinfo.RPCInfo), cRI)
+				prevRI.Store(cRI)
 			}
-			r.Prepare(retryCtx, prevRI, cRI)
-			prevRI = cRI
+			err := kc.eps(retryCtx, request, response)
+			return cRI, response, err
+		}, ri, request)
+	}
+
+	// do fallback if with setup
+	fallback, hasFallback := getFallbackPolicy(callOptFallback, kc.opt.Fallback)
+	var fbErr error
+	reportErr := err
+	if hasFallback {
+		reportAsFB := false
+		// Notice: If rpc err is nil, rpcStatAsFB will always be false, even if it's set to true by user.
+		fbErr, reportAsFB = fallback.DoIfNeeded(ctx, ri, request, response, err)
+		if reportAsFB {
+			reportErr = fbErr
 		}
-		err := kc.eps(retryCtx, request, response)
-		return cRI, response, err
-	}, ri, request)
+		err = fbErr
+	}
 
-	kc.opt.TracerCtl.DoFinish(ctx, ri, err)
+	kc.opt.TracerCtl.DoFinish(ctx, ri, reportErr)
 	callOpts.Recycle()
-	if err == nil {
+	if err == nil && !hasFallback {
 		err = ri.Invocation().BizStatusErr()
 	}
+
 	if recycleRI {
 		// why need check recycleRI to decide if recycle RPCInfo?
 		// 1. no retry, rpc timeout happen will cause panic when response return
@@ -503,6 +527,11 @@ func (kc *kClient) invokeHandleEndpoint() (endpoint.Endpoint, error) {
 
 // Close is not concurrency safe.
 func (kc *kClient) Close() error {
+	defer func() {
+		if err := recover(); err != nil {
+			klog.Warnf("KITEX: panic when close client, error=%s, stack=%s", err, string(debug.Stack()))
+		}
+	}()
 	if kc.closed {
 		return nil
 	}
@@ -631,3 +660,14 @@ func (kc *kClient) warmingUp() error {
 
 	return nil
 }
+
+// return fallback policy from call option and client option.
+func getFallbackPolicy(callOptFB, cliOptFB *fallback.Policy) (fb *fallback.Policy, hasFallback bool) {
+	if callOptFB != nil {
+		return callOptFB, true
+	}
+	if cliOptFB != nil {
+		return cliOptFB, true
+	}
+	return nil, false
+}