feat: added custom grpc resolver (#587)

Signed-off-by: Pradeep <[email protected]>

Author: pradeepbbl

providers/flagd/README.md

@@ -69,6 +69,7 @@ Configuration can be provided as constructor options or as environment variables
 |----------------------------------------------------------|--------------------------------|-----------------------------|-----------|---------------------|
 | WithHost                                                 | FLAGD_HOST                     | string                      | localhost | rpc & in-process    |
 | WithPort                                                 | FLAGD_PORT                     | number                      | 8013      | rpc & in-process    |
+| WithTargetUri                                            | FLAGD_TARGET_URI               | string                      | ""        | in-process          |
 | WithTLS                                                  | FLAGD_TLS                      | boolean                     | false     | rpc & in-process    |
 | WithSocketPath                                           | FLAGD_SOCKET_PATH              | string                      | ""        | rpc & in-process    |
 | WithCertificatePath                                      | FLAGD_SERVER_CERT_PATH         | string                      | ""        | rpc & in-process    |
@@ -100,6 +101,20 @@ On invocation of a flag evaluation (if caching is available) an attempt is made
 By default, the provider is configured to use LRU caching with up to 1000 entries.
 This can be changed through constructor option or environment variable `FLAGD_MAX_CACHE_SIZE`
 
+### Target URI Support (gRPC name resolution)
+
+The `TargetUri` is meant for gRPC custom name resolution (default is `dns`), this allows users to use different
+resolution method e.g. `xds`. Currently, we are supporting all [core resolver](https://grpc.io/docs/guides/custom-name-resolution/)
+and one custom resolver for `envoy` proxy resolution. For more details, please refer the
+[RFC](https://github.com/open-feature/flagd/blob/main/docs/reference/specifications/proposal/rfc-grpc-custom-name-resolver.md) document.
+
+```go
+openfeature.SetProvider(flagd.NewProvider(
+        flagd.WithInProcessResolver(),
+        flagd.WithTargetUri("envoy://localhost:9211/test.service"),
+    ))
+```
+
 ## Supported Events
 
 The flagd provider emits `PROVIDER_READY`, `PROVIDER_ERROR` and `PROVIDER_CONFIGURATION_CHANGED` events.

providers/flagd/go.mod

@@ -6,31 +6,32 @@ toolchain go1.22.3
 
 require (
 	buf.build/gen/go/open-feature/flagd/connectrpc/go v1.17.0-20240906125204-0a6a901b42e8.1
-	buf.build/gen/go/open-feature/flagd/grpc/go v1.5.1-20240215170432-1e611e2999cc.1
-	buf.build/gen/go/open-feature/flagd/protocolbuffers/go v1.34.2-20240906125204-0a6a901b42e8.2
+	buf.build/gen/go/open-feature/flagd/grpc/go v1.5.1-20240906125204-0a6a901b42e8.1
+	buf.build/gen/go/open-feature/flagd/protocolbuffers/go v1.35.1-20240906125204-0a6a901b42e8.1
 	connectrpc.com/connect v1.17.0
 	connectrpc.com/otelconnect v0.7.1
 	github.com/cucumber/godog v0.14.1
-	github.com/go-logr/logr v1.4.1
+	github.com/go-logr/logr v1.4.2
 	github.com/google/go-cmp v0.6.0
 	github.com/hashicorp/golang-lru/v2 v2.0.7
-	github.com/open-feature/flagd/core v0.9.1
+	github.com/open-feature/flagd/core v0.10.4
 	github.com/open-feature/go-sdk v1.11.0
 	github.com/open-feature/go-sdk-contrib/tests/flagd v1.4.1
-	go.uber.org/mock v0.4.0
-	golang.org/x/exp v0.0.0-20240416160154-fe59bbe5cc7f
-	golang.org/x/net v0.26.0
-	google.golang.org/grpc v1.64.1
-	google.golang.org/protobuf v1.34.2
-	sigs.k8s.io/controller-runtime v0.17.3
+	go.uber.org/mock v0.5.0
+	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842
+	golang.org/x/net v0.30.0
+	google.golang.org/grpc v1.67.1
+	google.golang.org/protobuf v1.35.1
+	sigs.k8s.io/controller-runtime v0.19.0
 )
 
 require (
 	github.com/barkimedes/go-deepcopy v0.0.0-20220514131651-17c30cfc62df // indirect
 	github.com/cucumber/gherkin/go/v26 v26.2.0 // indirect
 	github.com/cucumber/messages/go/v21 v21.0.1 // indirect
-	github.com/diegoholiveira/jsonlogic/v3 v3.5.2 // indirect
+	github.com/diegoholiveira/jsonlogic/v3 v3.5.3 // indirect
 	github.com/fsnotify/fsnotify v1.7.0 // indirect
+	github.com/fxamacker/cbor/v2 v2.7.0 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-logr/zapr v1.3.0 // indirect
 	github.com/gofrs/uuid v4.3.1+incompatible // indirect
@@ -43,29 +44,29 @@ require (
 	github.com/klauspost/cpuid/v2 v2.2.7 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
-	github.com/open-feature/flagd-schemas v0.2.9-0.20240408192555-ea4f119d2bd7 // indirect
-	github.com/rogpeppe/go-internal v1.11.0 // indirect
+	github.com/open-feature/flagd-schemas v0.2.9-0.20240708163558-2aa89b314322 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/twmb/murmur3 v1.1.8 // indirect
+	github.com/x448/float16 v0.8.4 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
 	github.com/xeipuuv/gojsonschema v1.2.0 // indirect
 	github.com/zeebo/xxh3 v1.0.2 // indirect
-	go.opentelemetry.io/otel v1.25.0 // indirect
-	go.opentelemetry.io/otel/metric v1.25.0 // indirect
-	go.opentelemetry.io/otel/trace v1.25.0 // indirect
+	go.opentelemetry.io/otel v1.31.0 // indirect
+	go.opentelemetry.io/otel/metric v1.31.0 // indirect
+	go.opentelemetry.io/otel/trace v1.31.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	go.uber.org/zap v1.27.0 // indirect
-	golang.org/x/mod v0.17.0 // indirect
-	golang.org/x/sys v0.21.0 // indirect
-	golang.org/x/text v0.16.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20240415180920-8c6c420018be // indirect
+	golang.org/x/mod v0.21.0 // indirect
+	golang.org/x/sys v0.26.0 // indirect
+	golang.org/x/text v0.19.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20241007155032-5fefd90f89a9 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-	k8s.io/apimachinery v0.29.3 // indirect
-	k8s.io/klog/v2 v2.120.1 // indirect
-	k8s.io/utils v0.0.0-20240310230437-4693a0247e57 // indirect
+	k8s.io/apimachinery v0.31.1 // indirect
+	k8s.io/klog/v2 v2.130.1 // indirect
+	k8s.io/utils v0.0.0-20240711033017-18e509b52bc8 // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/structured-merge-diff/v4 v4.4.1 // indirect
 )