feat(decide): Adding support for decide options and decision reasons. (#298)

A part of multiple PRs for Decide API:

- added DecideOptions.
- added DecisionReasons.
- Refactored interfaces with additional parameter of reasons and options.
- Fixed unit tests throughout the sdk.

Author: yasirfolio3

pkg/client/client.go

@@ -657,7 +657,8 @@ func (o *OptimizelyClient) getFeatureDecision(featureKey, variableKey string, us
 	}
 
 	decisionContext.Variable = variable
-	featureDecision, err = o.DecisionService.GetFeatureDecision(decisionContext, userContext)
+	options := decide.OptimizelyDecideOptions{}
+	featureDecision, err = o.DecisionService.GetFeatureDecision(decisionContext, userContext, options, decide.NewDecisionReasons(options))
 	if err != nil {
 		o.logger.Warning(fmt.Sprintf(`Received error while making a decision for feature "%s": %s`, featureKey, err))
 		return decisionContext, featureDecision, nil
@@ -687,7 +688,8 @@ func (o *OptimizelyClient) getExperimentDecision(experimentKey string, userConte
 		ProjectConfig: projectConfig,
 	}
 
-	experimentDecision, err = o.DecisionService.GetExperimentDecision(decisionContext, userContext)
+	options := decide.OptimizelyDecideOptions{}
+	experimentDecision, err = o.DecisionService.GetExperimentDecision(decisionContext, userContext, options, decide.NewDecisionReasons(options))
 	if err != nil {
 		o.logger.Warning(fmt.Sprintf(`Received error while making a decision for experiment "%s": %s`, experimentKey, err))
 		return decisionContext, experimentDecision, nil

pkg/client/client_test.go

@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright 2019, Optimizely, Inc. and contributors                        *
+ * Copyright 2019-2020, Optimizely, Inc. and contributors                   *
  *                                                                          *
  * Licensed under the Apache License, Version 2.0 (the "License");          *
  * you may not use this file except in compliance with the License.         *
@@ -21,6 +21,7 @@ import (
 	"fmt"
 
 	"github.com/optimizely/go-sdk/pkg/config"
+	"github.com/optimizely/go-sdk/pkg/decide"
 	"github.com/optimizely/go-sdk/pkg/decision"
 	"github.com/optimizely/go-sdk/pkg/entities"
 	"github.com/optimizely/go-sdk/pkg/event"
@@ -116,13 +117,13 @@ type MockDecisionService struct {
 	mock.Mock
 }
 
-func (m *MockDecisionService) GetFeatureDecision(decisionContext decision.FeatureDecisionContext, userContext entities.UserContext) (decision.FeatureDecision, error) {
-	args := m.Called(decisionContext, userContext)
+func (m *MockDecisionService) GetFeatureDecision(decisionContext decision.FeatureDecisionContext, userContext entities.UserContext, options decide.OptimizelyDecideOptions, reasons decide.DecisionReasons) (decision.FeatureDecision, error) {
+	args := m.Called(decisionContext, userContext, options, reasons)
 	return args.Get(0).(decision.FeatureDecision), args.Error(1)
 }
 
-func (m *MockDecisionService) GetExperimentDecision(decisionContext decision.ExperimentDecisionContext, userContext entities.UserContext) (decision.ExperimentDecision, error) {
-	args := m.Called(decisionContext, userContext)
+func (m *MockDecisionService) GetExperimentDecision(decisionContext decision.ExperimentDecisionContext, userContext entities.UserContext, options decide.OptimizelyDecideOptions, reasons decide.DecisionReasons) (decision.ExperimentDecision, error) {
+	args := m.Called(decisionContext, userContext, options, reasons)
 	return args.Get(0).(decision.ExperimentDecision), args.Error(1)
 }
 
@@ -159,11 +160,11 @@ func (m *PanickingConfigManager) GetConfig() (config.ProjectConfig, error) {
 type PanickingDecisionService struct {
 }
 
-func (m *PanickingDecisionService) GetFeatureDecision(decisionContext decision.FeatureDecisionContext, userContext entities.UserContext) (decision.FeatureDecision, error) {
+func (m *PanickingDecisionService) GetFeatureDecision(decisionContext decision.FeatureDecisionContext, userContext entities.UserContext, options decide.OptimizelyDecideOptions, reasons decide.DecisionReasons) (decision.FeatureDecision, error) {
 	panic("I'm panicking")
 }
 
-func (m *PanickingDecisionService) GetExperimentDecision(decisionContext decision.ExperimentDecisionContext, userContext entities.UserContext) (decision.ExperimentDecision, error) {
+func (m *PanickingDecisionService) GetExperimentDecision(decisionContext decision.ExperimentDecisionContext, userContext entities.UserContext, options decide.OptimizelyDecideOptions, reasons decide.DecisionReasons) (decision.ExperimentDecision, error) {
 	panic("I'm panicking")
 }
 

pkg/client/fixtures_test.go

@@ -24,6 +24,10 @@ type decideError string
 const (
 	// SDKNotReady when sdk is not ready
 	SDKNotReady decideError = "Optimizely SDK not configured properly yet"
+	// FlagKeyInvalid when invalid flag key is provided
+	FlagKeyInvalid decideError = `No flag was found for key "%s".`
+	// VariableValueInvalid when invalid variable value is provided
+	VariableValueInvalid decideError = `Variable value for key "%s" is invalid or wrong type.`
 )
 
 // GetError returns error for decide error type

pkg/decide/decide_errors.go

@@ -0,0 +1,25 @@
+/****************************************************************************
+ * Copyright 2020, Optimizely, Inc. and contributors                        *
+ *                                                                          *
+ * 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 decide //
+package decide
+
+// DecisionReasons defines the reasons for which the decision was made.
+type DecisionReasons interface {
+	AddError(format string, arguments ...interface{})
+	AddInfo(format string, arguments ...interface{}) string
+	ToReport() []string
+}

pkg/decide/decision_reasons.go

@@ -0,0 +1,77 @@
+/****************************************************************************
+ * Copyright 2020, Optimizely, Inc. and contributors                        *
+ *                                                                          *
+ * 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 decide
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewDecisionReasonsWithEmptyOptions(t *testing.T) {
+	reasons := NewDecisionReasons(OptimizelyDecideOptions{})
+	assert.Equal(t, 0, len(reasons.ToReport()))
+}
+
+func TestAddErrorWorksWithEveryOption(t *testing.T) {
+	options := OptimizelyDecideOptions{
+		DisableDecisionEvent:     true,
+		EnabledFlagsOnly:         true,
+		IgnoreUserProfileService: true,
+		ExcludeVariables:         true,
+		IncludeReasons:           true,
+	}
+	reasons := NewDecisionReasons(options)
+	reasons.AddError("error message")
+
+	reportedReasons := reasons.ToReport()
+	assert.Equal(t, 1, len(reportedReasons))
+	assert.Equal(t, "error message", reportedReasons[0])
+}
+
+func TestInfoLogsAreOnlyReportedWhenIncludeReasonsOptionIsSet(t *testing.T) {
+	options := OptimizelyDecideOptions{
+		DisableDecisionEvent:     true,
+		EnabledFlagsOnly:         true,
+		IgnoreUserProfileService: true,
+		ExcludeVariables:         true,
+	}
+	reasons := NewDecisionReasons(options)
+	reasons.AddError("error message")
+	reasons.AddError("error message: code %d", 121)
+	reasons.AddInfo("info message")
+	reasons.AddInfo("info message: %s", "unexpected string")
+
+	reportedReasons := reasons.ToReport()
+	assert.Equal(t, 2, len(reportedReasons))
+	assert.Equal(t, "error message", reportedReasons[0])
+	assert.Equal(t, "error message: code 121", reportedReasons[1])
+
+	options.IncludeReasons = true
+	reasons = NewDecisionReasons(options)
+	reasons.AddError("error message")
+	reasons.AddError("error message: code %d", 121)
+	reasons.AddInfo("info message")
+	reasons.AddInfo("info message: %s", "unexpected string")
+
+	reportedReasons = reasons.ToReport()
+	assert.Equal(t, 4, len(reportedReasons))
+	assert.Equal(t, "error message", reportedReasons[0])
+	assert.Equal(t, "error message: code 121", reportedReasons[1])
+	assert.Equal(t, "info message", reportedReasons[2])
+	assert.Equal(t, "info message: unexpected string", reportedReasons[3])
+}

pkg/decide/decision_reasons_test.go

@@ -0,0 +1,61 @@
+/****************************************************************************
+ * Copyright 2020, Optimizely, Inc. and contributors                        *
+ *                                                                          *
+ * 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 decide //
+package decide
+
+import (
+	"fmt"
+)
+
+// DefaultDecisionReasons provides the default implementation of DecisionReasons.
+type DefaultDecisionReasons struct {
+	errors, logs   []string
+	includeReasons bool
+}
+
+// NewDecisionReasons returns a new instance of DecisionReasons.
+func NewDecisionReasons(options OptimizelyDecideOptions) *DefaultDecisionReasons {
+	return &DefaultDecisionReasons{
+		errors:         []string{},
+		logs:           []string{},
+		includeReasons: options.IncludeReasons,
+	}
+}
+
+// AddError appends given message to the error list.
+func (o *DefaultDecisionReasons) AddError(format string, arguments ...interface{}) {
+	o.errors = append(o.errors, fmt.Sprintf(format, arguments...))
+}
+
+// AddInfo appends given info message to the info list after formatting.
+func (o *DefaultDecisionReasons) AddInfo(format string, arguments ...interface{}) string {
+	message := fmt.Sprintf(format, arguments...)
+	if !o.includeReasons {
+		return message
+	}
+	o.logs = append(o.logs, message)
+	return message
+}
+
+// ToReport returns reasons to be reported.
+func (o *DefaultDecisionReasons) ToReport() []string {
+	reasons := o.errors
+	if !o.includeReasons {
+		return reasons
+	}
+	return append(reasons, o.logs...)
+}

pkg/decide/default_decision_reasons.go

@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright 2019, Optimizely, Inc. and contributors                        *
+ * Copyright 2019-2020, Optimizely, Inc. and contributors                   *
  *                                                                          *
  * Licensed under the Apache License, Version 2.0 (the "License");          *
  * you may not use this file except in compliance with the License.         *
@@ -19,6 +19,8 @@ package decision
 
 import (
 	"fmt"
+
+	"github.com/optimizely/go-sdk/pkg/decide"
 	"github.com/optimizely/go-sdk/pkg/entities"
 	"github.com/optimizely/go-sdk/pkg/logging"
 )
@@ -54,7 +56,7 @@ func NewCompositeExperimentService(sdkKey string, options ...CESOptionFunc) *Com
 	// 1. Overrides (if supplied)
 	// 2. Whitelist
 	// 3. Bucketing (with User profile integration if supplied)
-	compositeExperimentService := &CompositeExperimentService{logger:logging.GetLogger(sdkKey, "CompositeExperimentService")}
+	compositeExperimentService := &CompositeExperimentService{logger: logging.GetLogger(sdkKey, "CompositeExperimentService")}
 	for _, opt := range options {
 		opt(compositeExperimentService)
 	}
@@ -81,11 +83,10 @@ func NewCompositeExperimentService(sdkKey string, options ...CESOptionFunc) *Com
 }
 
 // GetDecision returns a decision for the given experiment and user context
-func (s CompositeExperimentService) GetDecision(decisionContext ExperimentDecisionContext, userContext entities.UserContext) (decision ExperimentDecision, err error) {
-
+func (s CompositeExperimentService) GetDecision(decisionContext ExperimentDecisionContext, userContext entities.UserContext, options decide.OptimizelyDecideOptions, reasons decide.DecisionReasons) (decision ExperimentDecision, err error) {
 	// Run through the various decision services until we get a decision
 	for _, experimentService := range s.experimentServices {
-		decision, err = experimentService.GetDecision(decisionContext, userContext)
+		decision, err = experimentService.GetDecision(decisionContext, userContext, options, reasons)
 		if err != nil {
 			s.logger.Debug(fmt.Sprintf("%v", err))
 		}