Feature/assignment logger interface (#13)

* Add README so that package info on pkg.go.dev will be shown more nicely

* Change logAssignment func to accept AssignmentEvent

* Fix

* Fix for readme

* Linter fix

Author: pavelflux

README.md

@@ -7,7 +7,7 @@ It is used to retrieve the experiments data and put it to in-memory cache, and t
 
 Refer to our [SDK documentation](https://docs.geteppo.com/prerequisites/feature-flagging/randomization-sdk/) for how to install and use the SDK.
 
-## Supported Python Versions
+## Supported Go Versions
 This version of the SDK is compatible with Go v1.18 and above.
 
 ## Example

eppoclient/assignmentlogger.go

@@ -3,7 +3,15 @@ package eppoclient
 import "fmt"
 
 type IAssignmentLogger interface {
-	LogAssignment(event map[string]string)
+	LogAssignment(event AssignmentEvent)
+}
+
+type AssignmentEvent struct {
+	Experiment        string
+	Variation         string
+	Subject           string
+	Timestamp         string
+	SubjectAttributes dictionary
 }
 
 type AssignmentLogger struct {
@@ -13,7 +21,7 @@ func NewAssignmentLogger() IAssignmentLogger {
 	return &AssignmentLogger{}
 }
 
-func (al *AssignmentLogger) LogAssignment(event map[string]string) {
+func (al *AssignmentLogger) LogAssignment(event AssignmentEvent) {
 	fmt.Println("Assignment Logged")
 	fmt.Println(event)
 }

eppoclient/client.go

@@ -17,14 +17,6 @@ type EppoClient struct {
 	logger          IAssignmentLogger
 }
 
-type assignmentEvent struct {
-	Experiment        string
-	Variation         string
-	Subject           string
-	Timestamp         string
-	SubjectAttributes dictionary
-}
-
 func newEppoClient(configRequestor iConfigRequestor, assignmentLogger IAssignmentLogger) *EppoClient {
 	var ec = &EppoClient{}
 
@@ -75,15 +67,19 @@ func (ec *EppoClient) GetAssignment(subjectKey string, experimentKey string, sub
 
 	assignedVariation := variationShard.Name
 
-	assignmentEvent := &assignmentEvent{
+	assignmentEvent := AssignmentEvent{
 		Experiment:        experimentKey,
 		Variation:         assignedVariation,
 		Subject:           subjectKey,
 		Timestamp:         time.Now().String(),
 		SubjectAttributes: subjectAttributes,
 	}
 
-	aeJson, _ := json.Marshal(assignmentEvent)
+	_, jsonErr := json.Marshal(assignmentEvent)
+
+	if jsonErr != nil {
+		panic("incorrect json")
+	}
 
 	func() {
 		// need to catch panics from Logger and continue
@@ -94,10 +90,7 @@ func (ec *EppoClient) GetAssignment(subjectKey string, experimentKey string, sub
 			}
 		}()
 
-		event := map[string]string{}
-		json.Unmarshal([]byte(aeJson), &event)
-
-		ec.logger.LogAssignment(event)
+		ec.logger.LogAssignment(assignmentEvent)
 	}()
 
 	return assignedVariation, nil

eppoclient/mocks.go

@@ -8,7 +8,7 @@ type mockLogger struct {
 	mock.Mock
 }
 
-func (ml *mockLogger) LogAssignment(event map[string]string) {
+func (ml *mockLogger) LogAssignment(event AssignmentEvent) {
 	ml.Called(event)
 }