solidify interfaces to match OF API & client

Signed-off-by: Kavindu Dodanduwa <kavindudodanduwa@gmail.com>

e2e/evaluation_fuzz_test.go

@@ -9,7 +9,7 @@ import (
 	"github.com/open-feature/go-sdk/openfeature/memprovider"
 )
 
-func setupFuzzClient(f *testing.F) *openfeature.Client {
+func setupFuzzClient(f *testing.F) openfeature.IClient {
 	f.Helper()
 
 	memoryProvider := memprovider.NewInMemoryProvider(map[string]memprovider.InMemoryFlag{})

openfeature/client.go

@@ -10,32 +10,6 @@ import (
 	"github.com/go-logr/logr"
 )
 
-// IClient defines the behaviour required of an openfeature client
-type IClient interface {
-	Metadata() ClientMetadata
-	AddHooks(hooks ...Hook)
-	AddHandler(eventType EventType, callback EventCallback)
-	RemoveHandler(eventType EventType, callback EventCallback)
-	SetEvaluationContext(evalCtx EvaluationContext)
-	EvaluationContext() EvaluationContext
-	BooleanValue(ctx context.Context, flag string, defaultValue bool, evalCtx EvaluationContext, options ...Option) (bool, error)
-	StringValue(ctx context.Context, flag string, defaultValue string, evalCtx EvaluationContext, options ...Option) (string, error)
-	FloatValue(ctx context.Context, flag string, defaultValue float64, evalCtx EvaluationContext, options ...Option) (float64, error)
-	IntValue(ctx context.Context, flag string, defaultValue int64, evalCtx EvaluationContext, options ...Option) (int64, error)
-	ObjectValue(ctx context.Context, flag string, defaultValue interface{}, evalCtx EvaluationContext, options ...Option) (interface{}, error)
-	BooleanValueDetails(ctx context.Context, flag string, defaultValue bool, evalCtx EvaluationContext, options ...Option) (BooleanEvaluationDetails, error)
-	StringValueDetails(ctx context.Context, flag string, defaultValue string, evalCtx EvaluationContext, options ...Option) (StringEvaluationDetails, error)
-	FloatValueDetails(ctx context.Context, flag string, defaultValue float64, evalCtx EvaluationContext, options ...Option) (FloatEvaluationDetails, error)
-	IntValueDetails(ctx context.Context, flag string, defaultValue int64, evalCtx EvaluationContext, options ...Option) (IntEvaluationDetails, error)
-	ObjectValueDetails(ctx context.Context, flag string, defaultValue interface{}, evalCtx EvaluationContext, options ...Option) (InterfaceEvaluationDetails, error)
-
-	Boolean(ctx context.Context, flag string, defaultValue bool, evalCtx EvaluationContext, options ...Option) bool
-	String(ctx context.Context, flag string, defaultValue string, evalCtx EvaluationContext, options ...Option) string
-	Float(ctx context.Context, flag string, defaultValue float64, evalCtx EvaluationContext, options ...Option) float64
-	Int(ctx context.Context, flag string, defaultValue int64, evalCtx EvaluationContext, options ...Option) int64
-	Object(ctx context.Context, flag string, defaultValue interface{}, evalCtx EvaluationContext, options ...Option) interface{}
-}
-
 // ClientMetadata provides a client's metadata
 type ClientMetadata struct {
 	name string
@@ -56,7 +30,7 @@ func (cm ClientMetadata) Name() string {
 
 // Client implements the behaviour required of an openfeature client
 type Client struct {
-	api               evalAPI
+	api               evalImpl
 	clientEventing    ClientEvent
 	metadata          ClientMetadata
 	hooks             []Hook
@@ -69,8 +43,8 @@ type Client struct {
 // interface guard to ensure that Client implements IClient
 var _ IClient = (*Client)(nil)
 
-// NewClient returns a new Client. Name is a unique identifier for this client
-func NewClient(name string) *Client {
+// NewClient returns a new IClient. Name is a unique identifier for this client
+func NewClient(name string) IClient {
 	return &Client{
 		api:            api,
 		clientEventing: eventing,

openfeature/client_test.go

@@ -22,7 +22,8 @@ func TestRequirement_1_2_1(t *testing.T) {
 	client.AddHooks(mockHook)
 	client.AddHooks(mockHook, mockHook)
 
-	if len(client.hooks) != 3 {
+	c := client.(*Client)
+	if len(c.hooks) != 3 {
 		t.Error("func client.AddHooks didn't append the list of hooks to the client's existing collection of hooks")
 	}
 }
@@ -360,7 +361,8 @@ func TestRequirement_1_4_7(t *testing.T) {
 		t.Errorf("error setting up provider %v", err)
 	}
 
-	res, err := client.evaluate(
+	c := client.(*Client)
+	res, err := c.evaluate(
 		context.Background(), "foo", Boolean, true, EvaluationContext{}, EvaluationOptions{},
 	)
 	if err == nil {
@@ -395,7 +397,8 @@ func TestRequirement_1_4_8(t *testing.T) {
 		t.Errorf("error setting up provider %v", err)
 	}
 
-	res, err := client.evaluate(
+	c := client.(*Client)
+	res, err := c.evaluate(
 		context.Background(), "foo", Boolean, true, EvaluationContext{}, EvaluationOptions{},
 	)
 	if err == nil {
@@ -659,7 +662,8 @@ func TestRequirement_1_4_12(t *testing.T) {
 		})
 
 	client := NewClient("test")
-	evalDetails, err := client.evaluate(
+	c := client.(*Client)
+	evalDetails, err := c.evaluate(
 		context.Background(), "foo", Boolean, true, EvaluationContext{}, EvaluationOptions{},
 	)
 	if err == nil {
@@ -895,7 +899,8 @@ func TestErrorCodeFromProviderReturnedInEvaluationDetails(t *testing.T) {
 		})
 
 	client := NewClient("test")
-	evalDetails, err := client.evaluate(
+	c := client.(*Client)
+	evalDetails, err := c.evaluate(
 		context.Background(), "foo", Boolean, true, EvaluationContext{}, EvaluationOptions{},
 	)
 	if err == nil {

openfeature/evaluation.go

@@ -9,8 +9,9 @@ import (
 	"golang.org/x/exp/maps"
 )
 
-type evalAPI interface {
-	API
+// evalImpl is an internal reference interface extending IOFApi
+type evalImpl interface {
+	IOFApi
 	GetProvider() FeatureProvider
 	GetNamedProviders() map[string]FeatureProvider
 	GetHooks() []Hook
@@ -68,12 +69,12 @@ func (api *EvaluationAPI) SetProvider(provider FeatureProvider, async bool) erro
 	return nil
 }
 
-// GetProvider returns the default FeatureProvider
-func (api *EvaluationAPI) GetProvider() FeatureProvider {
+// GetProviderMetadata returns the default FeatureProvider's metadata
+func (api *EvaluationAPI) GetProviderMetadata() Metadata {
 	api.mu.RLock()
 	defer api.mu.RUnlock()
 
-	return api.defaultProvider
+	return api.defaultProvider.Metadata()
 }
 
 // SetNamedProvider sets a provider with client name. Returns an error if FeatureProvider is nil
@@ -103,6 +104,19 @@ func (api *EvaluationAPI) SetNamedProvider(clientName string, provider FeaturePr
 	return nil
 }
 
+// GetNamedProviderMetadata returns the default FeatureProvider's metadata
+func (api *EvaluationAPI) GetNamedProviderMetadata(name string) Metadata {
+	api.mu.RLock()
+	defer api.mu.RUnlock()
+
+	provider, ok := api.namedProviders[name]
+	if !ok {
+		return ProviderMetadata()
+	}
+
+	return provider.Metadata()
+}
+
 // GetNamedProviders returns named providers map.
 func (api *EvaluationAPI) GetNamedProviders() map[string]FeatureProvider {
 	api.mu.RLock()
@@ -111,6 +125,14 @@ func (api *EvaluationAPI) GetNamedProviders() map[string]FeatureProvider {
 	return api.namedProviders
 }
 
+func (api *EvaluationAPI) GetClient() IClient {
+	return NewClient("")
+}
+
+func (api *EvaluationAPI) GetNamedClient(clientName string) IClient {
+	return NewClient(clientName)
+}
+
 func (api *EvaluationAPI) SetEvaluationContext(apiCtx EvaluationContext) {
 	api.mu.Lock()
 	defer api.mu.Unlock()
@@ -173,6 +195,14 @@ func (api *EvaluationAPI) ForEvaluation(clientName string) (FeatureProvider, []H
 	return provider, api.hks, api.apiCtx
 }
 
+// GetProvider returns the default FeatureProvider
+func (api *EvaluationAPI) GetProvider() FeatureProvider {
+	api.mu.RLock()
+	defer api.mu.RUnlock()
+
+	return api.defaultProvider
+}
+
 // initNewAndShutdownOld is a helper to initialise new FeatureProvider and Shutdown the old FeatureProvider.
 func (api *EvaluationAPI) initNewAndShutdownOld(newProvider FeatureProvider, oldProvider FeatureProvider, async bool) error {
 	if async {

openfeature/event_executor.go

@@ -10,8 +10,9 @@ import (
 	"golang.org/x/exp/maps"
 )
 
-type eventingAPI interface {
-	Eventing
+// eventingImpl is an internal reference interface extending IEventing
+type eventingImpl interface {
+	IEventing
 	GetAPIRegistry() map[EventType][]EventCallback
 	GetClientRegistry(client string) ScopedCallback
 }

openfeature/hooks_test.go

@@ -228,7 +228,7 @@ func TestRequirement_4_3_3(t *testing.T) {
 		flagKey:           flagKey,
 		flagType:          String,
 		defaultValue:      defaultValue,
-		clientMetadata:    client.metadata,
+		clientMetadata:    client.Metadata(),
 		providerMetadata:  mockProvider.Metadata(),
 		evaluationContext: evalCtx,
 	}

openfeature/interfaces.go

@@ -0,0 +1,58 @@
+package openfeature
+
+import "context"
+
+// IOFApi defines the OpenFeature API contract
+type IOFApi interface {
+	SetProvider(provider FeatureProvider, async bool) error
+	GetProviderMetadata() Metadata
+	SetNamedProvider(clientName string, provider FeatureProvider, async bool) error
+	GetNamedProviderMetadata(name string) Metadata
+	GetClient() IClient
+	GetNamedClient(clientName string) IClient
+	SetEvaluationContext(apiCtx EvaluationContext)
+	AddHooks(hooks ...Hook)
+	Shutdown()
+}
+
+// IClient defines the behaviour required of an OpenFeature client
+type IClient interface {
+	Metadata() ClientMetadata
+	AddHooks(hooks ...Hook)
+	AddHandler(eventType EventType, callback EventCallback)
+	RemoveHandler(eventType EventType, callback EventCallback)
+	SetEvaluationContext(evalCtx EvaluationContext)
+	EvaluationContext() EvaluationContext
+	BooleanValue(ctx context.Context, flag string, defaultValue bool, evalCtx EvaluationContext, options ...Option) (bool, error)
+	StringValue(ctx context.Context, flag string, defaultValue string, evalCtx EvaluationContext, options ...Option) (string, error)
+	FloatValue(ctx context.Context, flag string, defaultValue float64, evalCtx EvaluationContext, options ...Option) (float64, error)
+	IntValue(ctx context.Context, flag string, defaultValue int64, evalCtx EvaluationContext, options ...Option) (int64, error)
+	ObjectValue(ctx context.Context, flag string, defaultValue interface{}, evalCtx EvaluationContext, options ...Option) (interface{}, error)
+	BooleanValueDetails(ctx context.Context, flag string, defaultValue bool, evalCtx EvaluationContext, options ...Option) (BooleanEvaluationDetails, error)
+	StringValueDetails(ctx context.Context, flag string, defaultValue string, evalCtx EvaluationContext, options ...Option) (StringEvaluationDetails, error)
+	FloatValueDetails(ctx context.Context, flag string, defaultValue float64, evalCtx EvaluationContext, options ...Option) (FloatEvaluationDetails, error)
+	IntValueDetails(ctx context.Context, flag string, defaultValue int64, evalCtx EvaluationContext, options ...Option) (IntEvaluationDetails, error)
+	ObjectValueDetails(ctx context.Context, flag string, defaultValue interface{}, evalCtx EvaluationContext, options ...Option) (InterfaceEvaluationDetails, error)
+
+	Boolean(ctx context.Context, flag string, defaultValue bool, evalCtx EvaluationContext, options ...Option) bool
+	String(ctx context.Context, flag string, defaultValue string, evalCtx EvaluationContext, options ...Option) string
+	Float(ctx context.Context, flag string, defaultValue float64, evalCtx EvaluationContext, options ...Option) float64
+	Int(ctx context.Context, flag string, defaultValue int64, evalCtx EvaluationContext, options ...Option) int64
+	Object(ctx context.Context, flag string, defaultValue interface{}, evalCtx EvaluationContext, options ...Option) interface{}
+}
+
+// IEventing defines the OpenFeature eventing contract
+type IEventing interface {
+	APIEvent
+	ClientEvent
+}
+
+type APIEvent interface {
+	AddHandler(eventType EventType, callback EventCallback)
+	RemoveHandler(eventType EventType, callback EventCallback)
+}
+
+type ClientEvent interface {
+	RegisterClientHandler(clientName string, t EventType, c EventCallback)
+	RemoveClientHandler(name string, t EventType, c EventCallback)
+}

openfeature/openfeature.go

@@ -5,13 +5,13 @@ import (
 	"github.com/open-feature/go-sdk/openfeature/internal"
 )
 
-// api is the global EvaluationAPI implementation. This is a singleton and there can only be one instance.
-var api evalAPI
+// api is the global evalImpl implementation. This is a singleton and there can only be one instance.
+var api evalImpl
 
-// eventing is the global Eventing implementation. This is a singleton and there can only be one instance.
-var eventing eventingAPI
+// eventing is the global IEventing implementation. This is a singleton and there can only be one instance.
+var eventing eventingImpl
 
-// logger is the global logger instance. This is a singleton and there can only be one instance.
+// logger is the global Logger instance. This is a singleton and there can only be one instance.
 var logger logr.Logger
 
 // init initializes the OpenFeature evaluation API
@@ -52,6 +52,11 @@ func SetNamedProviderAndWait(clientName string, provider FeatureProvider) error
 	return api.SetNamedProvider(clientName, provider, false)
 }
 
+// GetClient returns an OpenFeature Client
+func GetClient() IClient {
+	return api.GetClient()
+}
+
 // SetEvaluationContext sets the global evaluation context.
 func SetEvaluationContext(evalCtx EvaluationContext) {
 	api.SetEvaluationContext(evalCtx)
@@ -64,7 +69,7 @@ func SetLogger(l logr.Logger) {
 
 // ProviderMetadata returns the default provider's metadata
 func ProviderMetadata() Metadata {
-	return api.GetProvider().Metadata()
+	return api.GetProviderMetadata()
 }
 
 // AddHooks appends to the collection of any previously added hooks

openfeature/openfeature_test.go

@@ -503,7 +503,7 @@ func TestRequirement_1_1_6(t *testing.T) {
 // The client creation function MUST NOT throw, or otherwise abnormally terminate.
 func TestRequirement_1_1_7(t *testing.T) {
 	defer t.Cleanup(initSingleton)
-	type clientCreationFunc func(name string) *Client
+	type clientCreationFunc func(name string) IClient
 
 	// asserting that our NewClient method matches this signature is enough to deduce that no error is returned
 	var f clientCreationFunc = NewClient

pkg/openfeature/client.go

@@ -33,7 +33,7 @@ type Client = openfeature.Client
 //
 // Deprecated: use github.com/open-feature/go-sdk/openfeature.NewClient,
 // instead.
-func NewClient(name string) *Client {
+func NewClient(name string) IClient {
 	return openfeature.NewClient(name)
 }