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fix: use executor when WithExecutor is set without SetDefaultExecutor #53

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Merged
ankurs merged 3 commits into from
Apr 24, 2026
Merged

fix: use executor when WithExecutor is set without SetDefaultExecutor #53

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94a483e
fix: use executor when WithExecutor is set without SetDefaultExecutor
ankurs Apr 23, 2026
51a1e29
fix: address review — qualify doc comment, deduplicate hystrix logic
ankurs Apr 24, 2026
f61330c
fix: update hystrixFallback doc to reflect shared usage
ankurs Apr 24, 2026
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20 changes: 10 additions & 10 deletions README.md
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Expand Up @@ -156,7 +156,7 @@ func DebugLoggingInterceptor() grpc.UnaryServerInterceptor
DebugLoggingInterceptor is the interceptor that logs all request/response from a handler

<a name="DefaultClientInterceptor"></a>
## func [DefaultClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L66>)
## func [DefaultClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L62>)

```go
func DefaultClientInterceptor(defaultOpts ...any) grpc.UnaryClientInterceptor
Expand All @@ -174,7 +174,7 @@ func DefaultClientInterceptors(defaultOpts ...any) []grpc.UnaryClientInterceptor
DefaultClientInterceptors are the set of default interceptors that should be applied to all client calls

<a name="DefaultClientStreamInterceptor"></a>
## func [DefaultClientStreamInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L71>)
## func [DefaultClientStreamInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L67>)

```go
func DefaultClientStreamInterceptor(defaultOpts ...any) grpc.StreamClientInterceptor
Expand All @@ -183,7 +183,7 @@ func DefaultClientStreamInterceptor(defaultOpts ...any) grpc.StreamClientInterce
DefaultClientStreamInterceptor are the set of default interceptors that should be applied to all stream client calls

<a name="DefaultClientStreamInterceptors"></a>
## func [DefaultClientStreamInterceptors](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L51>)
## func [DefaultClientStreamInterceptors](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L47>)

```go
func DefaultClientStreamInterceptors(defaultOpts ...any) []grpc.StreamClientInterceptor
Expand Down Expand Up @@ -245,15 +245,15 @@ func (s *svc) echo(ctx context.Context, req *proto.EchoRequest) (*proto.EchoResp
```

<a name="ExecutorClientInterceptor"></a>
## func [ExecutorClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L114>)
## func [ExecutorClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L113>)

```go
func ExecutorClientInterceptor(defaultOpts ...grpc.CallOption) grpc.UnaryClientInterceptor
```

ExecutorClientInterceptor returns a unary client interceptor that wraps each RPC in an [Executor](<#Executor>). The executor provides resilience logic such as circuit breaking, retries, or bulkheading.

If no executor is configured \(neither via [SetDefaultExecutor](<#SetDefaultExecutor>) nor per\-call \[WithExecutor\]\), the RPC is invoked directly as a passthrough.
Executor resolution order: per\-call \[WithExecutor\] \> global [SetDefaultExecutor](<#SetDefaultExecutor>). When no executor is configured, the interceptor falls back to [HystrixClientInterceptor](<#HystrixClientInterceptor>) for backward compatibility. When the caller explicitly opts out via \[WithoutExecutor\] or \[WithoutHystrix\], the RPC is invoked directly as a passthrough.

Excluded errors and codes \(set via \[WithExcludedErrors\] / \[WithExcludedCodes\]\) are reported as nil to the executor, preventing them from tripping circuit breakers or retry logic. The original error is still returned to the caller.

Expand All @@ -267,7 +267,7 @@ func FilterMethodsFunc(ctx context.Context, fullMethodName string) bool
FilterMethodsFunc is the default implementation of Filter function

<a name="GRPCClientInterceptor"></a>
## func [GRPCClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L98>)
## func [GRPCClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L94>)

```go
func GRPCClientInterceptor(_ ...any) grpc.UnaryClientInterceptor
Expand All @@ -285,7 +285,7 @@ func GetDebugLogHeaderName() string
GetDebugLogHeaderName returns the current debug log header name.

<a name="HystrixClientInterceptor"></a>
## func [HystrixClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L174>)
## func [HystrixClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L220>)

```go
func HystrixClientInterceptor(defaultOpts ...grpc.CallOption) grpc.UnaryClientInterceptor
Expand All @@ -305,7 +305,7 @@ func NRHttpTracer(pattern string, h http.HandlerFunc) (string, http.HandlerFunc)
NRHttpTracer wraps an HTTP handler with New Relic tracing. The configured filterFunc \(see SetFilterFunc\) is consulted on every request: paths it rejects run the underlying handler without starting a New Relic transaction. When pattern is non\-empty, newrelic.WrapHandleFunc is used so its route\-level instrumentation stays intact for non\-filtered paths.

<a name="NewRelicClientInterceptor"></a>
## func [NewRelicClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L78>)
## func [NewRelicClientInterceptor](<https://github.com/go-coldbrew/interceptors/blob/main/client.go#L74>)

```go
func NewRelicClientInterceptor() grpc.UnaryClientInterceptor
Expand Down Expand Up @@ -422,13 +422,13 @@ func SetDebugLogHeaderName(name string)
SetDebugLogHeaderName sets the gRPC metadata header name that triggers per\-request log level override. Default is "x\-debug\-log\-level". The header value should be a valid log level \(e.g., "debug"\). Empty names are ignored. Must be called during initialization.

<a name="SetDefaultExecutor"></a>
## func [SetDefaultExecutor](<https://github.com/go-coldbrew/interceptors/blob/main/config.go#L243>)
## func [SetDefaultExecutor](<https://github.com/go-coldbrew/interceptors/blob/main/config.go#L245>)

```go
func SetDefaultExecutor(e Executor)
```

SetDefaultExecutor sets the default [Executor](<#Executor>) used by [ExecutorClientInterceptor](<#ExecutorClientInterceptor>) for all outbound unary RPCs. When set, ExecutorClientInterceptor replaces [HystrixClientInterceptor](<#HystrixClientInterceptor>) in the default client interceptor chain. Must be called during initialization, before any RPCs are made. Not safe for concurrent use.
SetDefaultExecutor sets the default [Executor](<#Executor>) used by [ExecutorClientInterceptor](<#ExecutorClientInterceptor>) for outbound unary RPCs when ColdBrew client interceptors are enabled \(the default\). In that configuration, when no executor is configured \(neither global via SetDefaultExecutor nor per\-call via \[WithExecutor\]\), [ExecutorClientInterceptor](<#ExecutorClientInterceptor>) falls back to [HystrixClientInterceptor](<#HystrixClientInterceptor>) for backward compatibility. Must be called during initialization, before any RPCs are made. Not safe for concurrent use.

<a name="SetDefaultRateLimit"></a>
## func [SetDefaultRateLimit](<https://github.com/go-coldbrew/interceptors/blob/main/config.go#L231>)
Expand Down
112 changes: 63 additions & 49 deletions client.go
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Original file line number Diff line number Diff line change
Expand Up @@ -33,11 +33,7 @@ func DefaultClientInterceptors(defaultOpts ...any) []grpc.UnaryClientInterceptor
callOptions = append(callOptions, o)
}
}
if defaultConfig.defaultExecutor != nil {
ints = append(ints, ExecutorClientInterceptor(callOptions...))
} else {
ints = append(ints, HystrixClientInterceptor(callOptions...))
}
ints = append(ints, ExecutorClientInterceptor(callOptions...))
ints = append(ints,
grpc_retry.UnaryClientInterceptor(),
NewRelicClientInterceptor(),
Expand Down Expand Up @@ -105,8 +101,11 @@ func GRPCClientInterceptor(_ ...any) grpc.UnaryClientInterceptor {
// RPC in an [Executor]. The executor provides resilience logic such as circuit
// breaking, retries, or bulkheading.
//
// If no executor is configured (neither via [SetDefaultExecutor] nor per-call
// [WithExecutor]), the RPC is invoked directly as a passthrough.
// Executor resolution order: per-call [WithExecutor] > global [SetDefaultExecutor].
// When no executor is configured, the interceptor falls back to
// [HystrixClientInterceptor] for backward compatibility. When the caller
// explicitly opts out via [WithoutExecutor] or [WithoutHystrix], the RPC is
// invoked directly as a passthrough.
//
// Excluded errors and codes (set via [WithExcludedErrors] / [WithExcludedCodes])
// are reported as nil to the executor, preventing them from tripping circuit
Expand All @@ -129,13 +128,18 @@ func ExecutorClientInterceptor(defaultOpts ...grpc.CallOption) grpc.UnaryClientI
}
}

// Resolve executor: per-call > global > nil (passthrough)
// Resolve executor: per-call > global > hystrix fallback
exec := defaultConfig.defaultExecutor
if o.hasExecutor {
exec = o.executor
}
if exec == nil {
return invoker(ctx, method, req, reply, cc, opts...)
if o.hasExecutor {
// Caller explicitly opted out (WithoutExecutor / WithoutHystrix).
return invoker(ctx, method, req, reply, cc, opts...)
}
// No executor configured; fall back to Hystrix for backward compat.
return hystrixFallback(ctx, method, req, reply, cc, invoker, opts, o)
}

var invokerErr error
Expand Down Expand Up @@ -167,61 +171,71 @@ func ExecutorClientInterceptor(defaultOpts ...grpc.CallOption) grpc.UnaryClientI
}
}

// hystrixFallback runs the RPC through the deprecated Hystrix circuit breaker.
// It is the shared Hystrix implementation used both as the executor fallback
// when no executor is configured (neither global nor per-call) and by
// [HystrixClientInterceptor], preserving backward compatibility for services
// that have not migrated.
func hystrixFallback(ctx context.Context, method string, req, reply any, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts []grpc.CallOption, o clientOptions) error {
if o.disableHystrix {
return invoker(ctx, method, req, reply, cc, opts...)
}
hystrixCmd := o.hystrixName
if hystrixCmd == "" {
hystrixCmd = method
}
newCtx, cancel := context.WithCancel(ctx)
defer cancel()

var invokerErr error
hystrixErr := hystrix.Do(hystrixCmd, func() (err error) {
defer func() {
if r := recover(); r != nil {
err = errors.Wrap(fmt.Errorf("panic inside hystrix method: %s, req: %v, reply: %v", method, req, reply), "Hystrix")
log.Error(ctx, "panic", r, "method", method, "req", req, "reply", reply)
}
}()
defer notifier.NotifyOnPanic(newCtx, method)
invokerErr = invoker(newCtx, method, req, reply, cc, opts...)
for _, excludedErr := range o.excludedErrors {
if stdError.Is(invokerErr, excludedErr) {
return nil
}
}
if st, ok := status.FromError(invokerErr); ok {
if slices.Contains(o.excludedCodes, st.Code()) {
return nil
}
}
return invokerErr
}, nil)
if invokerErr != nil {
return invokerErr
}
return hystrixErr
}
Comment thread
ankurs marked this conversation as resolved.

// Deprecated: HystrixClientInterceptor wraps the unmaintained hystrix-go library.
// Use [SetDefaultExecutor] with a failsafe-go executor instead. Will be removed in v1.
//
// See [ExecutorClientInterceptor] for the replacement.
func HystrixClientInterceptor(defaultOpts ...grpc.CallOption) grpc.UnaryClientInterceptor {
return func(ctx context.Context, method string, req, reply any, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
options := clientOptions{
hystrixName: method,
}
o := clientOptions{}
for _, opt := range defaultOpts {
if opt != nil {
if o, ok := opt.(clientOption); ok {
o.process(&options)
if co, ok := opt.(clientOption); ok {
co.process(&o)
}
}
}
for _, opt := range opts {
if opt != nil {
if o, ok := opt.(clientOption); ok {
o.process(&options)
}
}
}
if options.disableHystrix {
// short circuit if hystrix is disabled
return invoker(ctx, method, req, reply, cc, opts...)
}
newCtx, cancel := context.WithCancel(ctx)
defer cancel()

var invokerErr error
hystrixErr := hystrix.Do(options.hystrixName, func() (err error) {
defer func() {
if r := recover(); r != nil {
err = errors.Wrap(fmt.Errorf("panic inside hystrix method: %s, req: %v, reply: %v", method, req, reply), "Hystrix")
log.Error(ctx, "panic", r, "method", method, "req", req, "reply", reply)
}
}()
defer notifier.NotifyOnPanic(newCtx, method)
invokerErr = invoker(newCtx, method, req, reply, cc, opts...)
for _, excludedErr := range options.excludedErrors {
if stdError.Is(invokerErr, excludedErr) {
return nil
}
}
if st, ok := status.FromError(invokerErr); ok {
if slices.Contains(options.excludedCodes, st.Code()) {
return nil
if co, ok := opt.(clientOption); ok {
co.process(&o)
}
}
return invokerErr
}, nil)
if invokerErr != nil {
return invokerErr
}
return hystrixErr
return hystrixFallback(ctx, method, req, reply, cc, invoker, opts, o)
}
}
6 changes: 4 additions & 2 deletions config.go
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Original file line number Diff line number Diff line change
Expand Up @@ -237,8 +237,10 @@ func SetDefaultRateLimit(rps float64, burst int) {
}

// SetDefaultExecutor sets the default [Executor] used by [ExecutorClientInterceptor]
// for all outbound unary RPCs. When set, ExecutorClientInterceptor replaces
// [HystrixClientInterceptor] in the default client interceptor chain.
// for outbound unary RPCs when ColdBrew client interceptors are enabled (the
// default). In that configuration, when no executor is configured (neither global
// via SetDefaultExecutor nor per-call via [WithExecutor]), [ExecutorClientInterceptor]
// falls back to [HystrixClientInterceptor] for backward compatibility.
// Must be called during initialization, before any RPCs are made. Not safe for concurrent use.
func SetDefaultExecutor(e Executor) {
defaultConfig.defaultExecutor = e
Expand Down
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