11package eppoclient
22
33import (
4- "crypto/md5"
5- "encoding/hex"
6- "errors"
74 "fmt"
85)
96
7+ type SubjectAttributes map [string ]interface {}
8+
109// Client for eppo.cloud. Instance of this struct will be created on calling InitClient.
1110// EppoClient will then immediately start polling experiments data from Eppo.
1211type EppoClient struct {
@@ -15,43 +14,73 @@ type EppoClient struct {
1514 logger IAssignmentLogger
1615}
1716
18- func newEppoClient (configRequestor iConfigRequestor , assignmentLogger IAssignmentLogger ) * EppoClient {
17+ func newEppoClient (configRequestor iConfigRequestor , poller * poller , assignmentLogger IAssignmentLogger ) * EppoClient {
1918 var ec = & EppoClient {}
2019
21- var poller = newPoller (10 , configRequestor .FetchAndStoreConfigurations )
2220 ec .poller = * poller
2321 ec .configRequestor = configRequestor
2422 ec .logger = assignmentLogger
2523
2624 return ec
2725}
2826
29- // GetAssignment is maintained for backwards capability. It will return a string value for the assignment.
30- func (ec * EppoClient ) GetAssignment (subjectKey string , flagKey string , subjectAttributes dictionary ) (string , error ) {
31- return ec .GetStringAssignment (subjectKey , flagKey , subjectAttributes )
27+ func (ec * EppoClient ) GetBoolAssignment (subjectKey string , flagKey string , subjectAttributes SubjectAttributes , defaultValue bool ) (bool , error ) {
28+ variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , booleanVariation )
29+ if err != nil || variation == nil {
30+ return defaultValue , err
31+ }
32+ result , ok := variation .(bool )
33+ if ! ok {
34+ return defaultValue , fmt .Errorf ("failed to cast %v to bool" , variation )
35+ }
36+ return result , err
3237}
3338
34- func (ec * EppoClient ) GetBoolAssignment (subjectKey string , flagKey string , subjectAttributes dictionary ) (bool , error ) {
35- variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , BoolType )
36- return variation .BoolValue , err
39+ func (ec * EppoClient ) GetNumericAssignment (subjectKey string , flagKey string , subjectAttributes SubjectAttributes , defaultValue float64 ) (float64 , error ) {
40+ variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , numericVariation )
41+ if err != nil || variation == nil {
42+ return defaultValue , err
43+ }
44+ result , ok := variation .(float64 )
45+ if ! ok {
46+ return defaultValue , fmt .Errorf ("failed to cast %v to float64" , variation )
47+ }
48+ return result , err
3749}
3850
39- func (ec * EppoClient ) GetNumericAssignment (subjectKey string , flagKey string , subjectAttributes dictionary ) (float64 , error ) {
40- variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , NumericType )
41- return variation .NumericValue , err
51+ func (ec * EppoClient ) GetIntegerAssignment (subjectKey string , flagKey string , subjectAttributes SubjectAttributes , defaultValue int64 ) (int64 , error ) {
52+ variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , integerVariation )
53+ if err != nil || variation == nil {
54+ return defaultValue , err
55+ }
56+ result , ok := variation .(int64 )
57+ if ! ok {
58+ return defaultValue , fmt .Errorf ("failed to cast %v to int64" , variation )
59+ }
60+ return result , err
4261}
4362
44- func (ec * EppoClient ) GetStringAssignment (subjectKey string , flagKey string , subjectAttributes dictionary ) (string , error ) {
45- variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , StringType )
46- return variation .StringValue , err
63+ func (ec * EppoClient ) GetStringAssignment (subjectKey string , flagKey string , subjectAttributes SubjectAttributes , defaultValue string ) (string , error ) {
64+ variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , stringVariation )
65+ if err != nil || variation == nil {
66+ return defaultValue , err
67+ }
68+ result , ok := variation .(string )
69+ if ! ok {
70+ return defaultValue , fmt .Errorf ("failed to cast %v to string" , variation )
71+ }
72+ return result , err
4773}
4874
49- func (ec * EppoClient ) GetJSONStringAssignment (subjectKey string , flagKey string , subjectAttributes dictionary ) (string , error ) {
50- variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , StringType )
51- return variation .StringValue , err
75+ func (ec * EppoClient ) GetJSONAssignment (subjectKey string , flagKey string , subjectAttributes SubjectAttributes , defaultValue interface {}) (interface {}, error ) {
76+ variation , err := ec .getAssignment (subjectKey , flagKey , subjectAttributes , jsonVariation )
77+ if err != nil || variation == nil {
78+ return defaultValue , err
79+ }
80+ return variation , err
5281}
5382
54- func (ec * EppoClient ) getAssignment (subjectKey string , flagKey string , subjectAttributes dictionary , valueType ValueType ) (Value , error ) {
83+ func (ec * EppoClient ) getAssignment (subjectKey string , flagKey string , subjectAttributes SubjectAttributes , variationType variationType ) (interface {} , error ) {
5584 if subjectKey == "" {
5685 panic ("no subject key provided" )
5786 }
@@ -60,86 +89,35 @@ func (ec *EppoClient) getAssignment(subjectKey string, flagKey string, subjectAt
6089 panic ("no flag key provided" )
6190 }
6291
63- config , err := ec .configRequestor .GetConfiguration (flagKey )
92+ flag , err := ec .configRequestor .GetConfiguration (flagKey )
6493 if err != nil {
65- return Null (), err
66- }
67-
68- override := getSubjectVariationOverride (config , subjectKey , valueType )
69- if override != Null () {
70- return override , nil
71- }
72-
73- // Check if disabled
74- if ! config .Enabled {
75- return Null (), errors .New ("the experiment or flag is not enabled" )
94+ return nil , err
7695 }
7796
78- // Find matching rule
79- rule , err := findMatchingRule (subjectAttributes , config .Rules )
97+ err = flag .verifyType (variationType )
8098 if err != nil {
81- return Null (), err
82- }
83-
84- // Check if in sample population
85- allocation := config .Allocations [rule .AllocationKey ]
86- if ! isInExperimentSample (subjectKey , flagKey , config .SubjectShards , allocation .PercentExposure ) {
87- return Null (), errors .New ("subject not part of the sample population" )
99+ return nil , err
88100 }
89101
90- // Get assigned variation
91- assignmentKey := "assignment-" + subjectKey + "-" + flagKey
92- shard := getShard (assignmentKey , config .SubjectShards )
93- variations := allocation .Variations
94- var variationShard Variation
95-
96- for _ , variation := range variations {
97- if isShardInRange (shard , variation .ShardRange ) {
98- variationShard = variation
99- }
102+ assignmentValue , assignmentEvent , err := flag .eval (subjectKey , subjectAttributes )
103+ if err != nil {
104+ return nil , err
100105 }
101106
102- assignedVariation := variationShard .Value
103-
104- func () {
105- // need to catch panics from Logger and continue
106- defer func () {
107- r := recover ()
108- if r != nil {
109- fmt .Println ("panic occurred:" , r )
110- }
107+ if assignmentEvent != nil {
108+ func () {
109+ // need to catch panics from Logger and continue
110+ defer func () {
111+ r := recover ()
112+ if r != nil {
113+ fmt .Println ("panic occurred:" , r )
114+ }
115+ }()
116+
117+ // Log assignment
118+ ec .logger .LogAssignment (* assignmentEvent )
111119 }()
112-
113- // Log assignment
114- assignmentEvent := AssignmentEvent {
115- Experiment : flagKey + "-" + rule .AllocationKey ,
116- FeatureFlag : flagKey ,
117- Allocation : rule .AllocationKey ,
118- Variation : assignedVariation ,
119- Subject : subjectKey ,
120- Timestamp : TimeNow (),
121- SubjectAttributes : subjectAttributes ,
122- }
123- ec .logger .LogAssignment (assignmentEvent )
124- }()
125-
126- return assignedVariation , nil
127- }
128-
129- func getSubjectVariationOverride (experimentConfig experimentConfiguration , subject string , valueType ValueType ) Value {
130- hash := md5 .Sum ([]byte (subject ))
131- hashOutput := hex .EncodeToString (hash [:])
132-
133- if val , ok := experimentConfig .Overrides [hashOutput ]; ok {
134- return val
135120 }
136121
137- return Null ()
138- }
139-
140- func isInExperimentSample (subjectKey string , flagKey string , subjectShards int64 , percentExposure float32 ) bool {
141- shardKey := "exposure-" + subjectKey + "-" + flagKey
142- shard := getShard (shardKey , subjectShards )
143-
144- return float64 (shard ) <= float64 (percentExposure )* float64 (subjectShards )
122+ return assignmentValue , nil
145123}
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