[SERF-3458] Introduce Statsig package

README.md

@@ -32,6 +32,9 @@ SDK, the Go version.
         - [Kafka specific configuration](#kafka-specific-configuration)
     - [Cache](#cache)
         - [Redis](#redis-specific-configuration)
+    - [Experimentation](#experimentation)
+        - [Initialization of Statsig](#initialization-of-statsig)
+        - [Usage of Statsig](#usage-of-statsig)
     - [AWS configuration](#aws-configuration)
         - [AWS Common configuration](#aws-common-configuration)
         - [AWS Service configuration](#aws-service-configuration)
@@ -987,6 +990,77 @@ To secure the requests to Redis, Go SDK provides a configuration set for TLS:
 | Passphrase            | Passphrase is used in case the private key needs to be decrypted | `passphrase`           | `APP_CACHE_REDIS_TLS_PASSPHRASE`           | string | pass phrase         |
 | Skip TLS verification | Turn on / off TLS verification                                   | `insecure_skip_verify` | `APP_CACHE_REDIS_TLS_INSECURE_SKIP_VERIFY` | bool   | true, false         |
 
+### Experimentation
+
+`go-sdk` comes with an integration with [Statsig](https://statsig.com) to
+leverage its experimentation and feature flag functionality.
+
+#### Initialization of Statsig
+
+The respective configuration file is `statsig.yml` and it should include
+the following content:
+
+```yaml
+# config/statsig.yml
+common: &common
+  secret_key: ""
+  local_mode: false
+  config_sync_interval: 10s
+  id_list_sync_interval: 60s
+
+development:
+  <<: *common
+
+test:
+  <<: *common
+
+staging:
+  <<: *common
+
+production:
+  <<: *common
+```
+
+For more details on the configuration check the
+[Statsig Go Server SDK](https://docs.statsig.com/server/golangSDK).
+
+Using the configuration details, the statsig client can be initialized as
+follows:
+
+```go
+package main
+
+import (
+	sdkstatsig "github.com/scribd/go-sdk/pkg/statsig"
+)
+
+func main() {
+	// Loads the statsig configuration.
+	statsigConfig, err := sdkstatsig.NewConfig()
+
+	// Initialize statsig connection using the configuration.
+	sdkstatsig.Initialize(statsigConfig)
+}
+```
+
+#### Usage of Statsig
+
+After initializing the statsig client, one can start using experiments or
+feature flags using the following code:
+
+```go
+import (
+  sdkstatsig "github.com/scribd/go-sdk/pkg/statsig"
+  statsig "github.com/statsig-io/go-sdk"
+)
+
+func main() {
+  u := statsig.User{}
+
+  experiment := sdkstatsig.GetExperiment(u, "experiment_name")
+  featureFlag := sdkstatsig.GetFeatureFlag(u, "feature_flag_name")
+}
+```
 
 ### AWS configuration
 

go.mod

@@ -25,6 +25,7 @@ require (
 	github.com/rs/cors v1.7.0
 	github.com/sirupsen/logrus v1.9.3
 	github.com/spf13/viper v1.10.1
+	github.com/statsig-io/go-sdk v1.26.0
 	github.com/stretchr/testify v1.8.4
 	github.com/twmb/franz-go v1.17.0
 	github.com/twmb/franz-go/pkg/kmsg v1.8.0
@@ -99,8 +100,10 @@ require (
 	github.com/spf13/cast v1.4.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/statsig-io/ip3country-go v0.2.0 // indirect
 	github.com/subosito/gotenv v1.2.0 // indirect
 	github.com/tinylib/msgp v1.1.8 // indirect
+	github.com/ua-parser/uap-go v0.0.0-20211112212520-00c877edfe0f // indirect
 	go.uber.org/atomic v1.11.0 // indirect
 	golang.org/x/mod v0.12.0 // indirect
 	golang.org/x/net v0.20.0 // indirect

go.sum

@@ -1909,6 +1909,10 @@ github.com/spf13/viper v1.4.0/go.mod h1:PTJ7Z/lr49W6bUbkmS1V3by4uWynFiR9p7+dSq/y
 github.com/spf13/viper v1.7.0/go.mod h1:8WkrPz2fc9jxqZNCJI/76HCieCp4Q8HaLFoCha5qpdg=
 github.com/spf13/viper v1.10.1 h1:nuJZuYpG7gTj/XqiUwg8bA0cp1+M2mC3J4g5luUYBKk=
 github.com/spf13/viper v1.10.1/go.mod h1:IGlFPqhNAPKRxohIzWpI5QEy4kuI7tcl5WvR+8qy1rU=
+github.com/statsig-io/go-sdk v1.26.0 h1:HaPwN1+mDFdCnvqDbo8cr3obIlqmrShR9J2ogxw3kZs=
+github.com/statsig-io/go-sdk v1.26.0/go.mod h1:Pej0D6R75gTHj7FdS6pbXQ7ayF0HL1cwOgiz5zDNdyc=
+github.com/statsig-io/ip3country-go v0.2.0 h1:4z4ovVCx7GnQAKJC753bjcOgxLQJFsrDdcCKda4I2U8=
+github.com/statsig-io/ip3country-go v0.2.0/go.mod h1:PKuA/VSpe4puBXw3BNGAHyP8IOZOiXAh/xIz+iYYoMQ=
 github.com/stefanberger/go-pkcs11uri v0.0.0-20201008174630-78d3cae3a980/go.mod h1:AO3tvPzVZ/ayst6UlUKUv6rcPQInYe3IknH3jYhAKu8=
 github.com/stoewer/go-strcase v1.2.0/go.mod h1:IBiWB2sKIp3wVVQ3Y035++gc+knqhUQag1KpM8ahLw8=
 github.com/stretchr/objx v0.0.0-20180129172003-8a3f7159479f/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -1961,6 +1965,8 @@ github.com/twmb/franz-go v1.17.0 h1:hawgCx5ejDHkLe6IwAtFWwxi3OU4OztSTl7ZV5rwkYk=
 github.com/twmb/franz-go v1.17.0/go.mod h1:NreRdJ2F7dziDY/m6VyspWd6sNxHKXdMZI42UfQ3GXM=
 github.com/twmb/franz-go/pkg/kmsg v1.8.0 h1:lAQB9Z3aMrIP9qF9288XcFf/ccaSxEitNA1CDTEIeTA=
 github.com/twmb/franz-go/pkg/kmsg v1.8.0/go.mod h1:HzYEb8G3uu5XevZbtU0dVbkphaKTHk0X68N5ka4q6mU=
+github.com/ua-parser/uap-go v0.0.0-20211112212520-00c877edfe0f h1:A+MmlgpvrHLeUP8dkBVn4Pnf5Bp5Yk2OALm7SEJLLE8=
+github.com/ua-parser/uap-go v0.0.0-20211112212520-00c877edfe0f/go.mod h1:OBcG9bn7sHtXgarhUEb3OfCnNsgtGnkVf41ilSZ3K3E=
 github.com/ugorji/go v1.1.4/go.mod h1:uQMGLiO92mf5W77hV/PUCpI3pbzQx3CRekS0kk+RGrc=
 github.com/ugorji/go v1.1.7/go.mod h1:kZn38zHttfInRq0xu/PH0az30d+z6vm202qpg1oXVMw=
 github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=

pkg/configuration/configuration.go

@@ -11,6 +11,7 @@ import (
 	logger "github.com/scribd/go-sdk/pkg/logger"
 	"github.com/scribd/go-sdk/pkg/pubsub"
 	server "github.com/scribd/go-sdk/pkg/server"
+	"github.com/scribd/go-sdk/pkg/statsig"
 	tracking "github.com/scribd/go-sdk/pkg/tracking"
 )
 
@@ -25,6 +26,7 @@ type Config struct {
 	PubSub          *pubsub.Config
 	Cache           *cache.Config
 	AWS             *aws.Config
+	Statsig         *statsig.Config
 }
 
 // NewConfig returns a new Config instance
@@ -77,6 +79,11 @@ func NewConfig() (*Config, error) {
 		errGroup = wrapErrors(errGroup, fmt.Errorf("aws config err: %w", err))
 	}
 
+	statsigConfig, err := statsig.NewConfig()
+	if err != nil {
+		errGroup = wrapErrors(errGroup, fmt.Errorf("statsig config err: %w", err))
+	}
+
 	config.App = appConfig
 	config.Database = dbConfig
 	config.Instrumentation = instrumentationConfig
@@ -86,6 +93,7 @@ func NewConfig() (*Config, error) {
 	config.PubSub = pubsubConfig
 	config.Cache = cacheConfig
 	config.AWS = awsConfig
+	config.Statsig = statsigConfig
 
 	return config, errGroup
 }

pkg/statsig/config.go

@@ -0,0 +1,38 @@
+package statsig
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	cbuilder "github.com/scribd/go-sdk/internal/pkg/configuration/builder"
+)
+
+// Config stores the configuration for the statsig.
+type Config struct {
+	SecretKey          string        `mapstructure:"secret_key"`
+	LocalMode          bool          `mapstructure:"local_mode"`
+	ConfigSyncInterval time.Duration `mapstructure:"config_sync_interval"`
+	IDListSyncInterval time.Duration `mapstructure:"id_list_sync_interval"`
+
+	environment string
+}
+
+// NewConfig returns a new StatsigConfig instance.
+func NewConfig() (*Config, error) {
+	config := &Config{}
+	config.environment = os.Getenv("APP_ENV")
+
+	viperBuilder := cbuilder.New("statsig")
+
+	vConf, err := viperBuilder.Build()
+	if err != nil {
+		return config, err
+	}
+
+	if err = vConf.Unmarshal(config); err != nil {
+		return config, fmt.Errorf("unable to decode into struct: %s", err.Error())
+	}
+
+	return config, nil
+}

pkg/statsig/config_test.go

@@ -0,0 +1,49 @@
+package statsig
+
+import (
+	"os"
+	"testing"
+	"time"
+
+	assert "github.com/stretchr/testify/assert"
+)
+
+func TestNewConfig(t *testing.T) {
+	t.Run("RunningInTestEnvironment", func(t *testing.T) {
+		expected := "test"
+		actual := os.Getenv("APP_ENV")
+		assert.Equal(t, expected, actual)
+	})
+
+	testCases := []struct {
+		name               string
+		secretKey          string
+		localMode          bool
+		configSyncInterval time.Duration
+		idListSyncInterval time.Duration
+		wantError          bool
+	}{
+		{
+			name:               "default",
+			secretKey:          "",
+			localMode:          false,
+			configSyncInterval: 0,
+			idListSyncInterval: 0,
+			wantError:          true,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			c, err := NewConfig()
+			if tc.wantError {
+				assert.Error(t, err)
+			}
+
+			assert.Equal(t, c.SecretKey, tc.secretKey)
+			assert.Equal(t, c.LocalMode, tc.localMode)
+			assert.Equal(t, c.ConfigSyncInterval, tc.configSyncInterval)
+			assert.Equal(t, c.IDListSyncInterval, tc.idListSyncInterval)
+		})
+	}
+}

pkg/statsig/statsig.go

@@ -0,0 +1,37 @@
+package statsig
+
+import (
+	statsig "github.com/statsig-io/go-sdk"
+)
+
+func Initialize(c *Config) {
+	opts := &statsig.Options{
+		Environment: statsig.Environment{Tier: c.environment},
+	}
+
+	if c.LocalMode {
+		opts.LocalMode = true
+	}
+
+	if c.ConfigSyncInterval > 0 {
+		opts.ConfigSyncInterval = c.ConfigSyncInterval
+	}
+
+	if c.IDListSyncInterval > 0 {
+		opts.IDListSyncInterval = c.IDListSyncInterval
+	}
+
+	statsig.InitializeWithOptions(c.SecretKey, opts)
+}
+
+func GetExperiment(user statsig.User, experiment string) statsig.DynamicConfig {
+	return statsig.GetExperiment(user, experiment)
+}
+
+func GetFeatureFlag(user statsig.User, flag string) statsig.FeatureGate {
+	return statsig.GetGate(user, flag)
+}
+
+func Shutdown() {
+	statsig.Shutdown()
+}