Add DB connection configs (#60)

* Add DB connection config

* Add testdata file

* Add a small comment update for the treatment service

---------

Co-authored-by: Krithika Sundararajan <krithika.sundararajan@go-jek.com>

management-service/config/config.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"fmt"
+	"time"
 
 	"github.com/gojek/mlp/api/pkg/instrumentation/newrelic"
 	"github.com/gojek/mlp/api/pkg/instrumentation/sentry"
@@ -40,6 +41,11 @@ type DatabaseConfig struct {
 	Password       string `default:"xp"`
 	Database       string `default:"xp"`
 	MigrationsPath string `default:"file://database/db-migrations"`
+
+	ConnMaxIdleTime time.Duration `default:"0s"`
+	ConnMaxLifetime time.Duration `default:"0s"`
+	MaxIdleConns    int           `default:"0"`
+	MaxOpenConns    int           `default:"0"`
 }
 
 // MLPConfig captures the configuration used to connect to the MLP API server

management-service/config/config_test.go

@@ -3,6 +3,7 @@ package config
 import (
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/gojek/mlp/api/pkg/instrumentation/newrelic"
 	"github.com/gojek/mlp/api/pkg/instrumentation/sentry"
@@ -11,6 +12,7 @@ import (
 )
 
 func TestDefaultConfigs(t *testing.T) {
+	zeroSecond, _ := time.ParseDuration("0s")
 	emptyInterfaceMap := make(map[string]interface{})
 	emptyStringMap := make(map[string]string)
 	defaultCfg := Config{
@@ -21,12 +23,16 @@ func TestDefaultConfigs(t *testing.T) {
 			URL:     "",
 		},
 		DbConfig: &DatabaseConfig{
-			Host:           "localhost",
-			Port:           5432,
-			User:           "xp",
-			Password:       "xp",
-			Database:       "xp",
-			MigrationsPath: "file://database/db-migrations",
+			Host:            "localhost",
+			Port:            5432,
+			User:            "xp",
+			Password:        "xp",
+			Database:        "xp",
+			MigrationsPath:  "file://database/db-migrations",
+			ConnMaxIdleTime: zeroSecond,
+			ConnMaxLifetime: zeroSecond,
+			MaxIdleConns:    0,
+			MaxOpenConns:    0,
 		},
 		SegmenterConfig: make(map[string]interface{}),
 		MLPConfig: &MLPConfig{
@@ -64,6 +70,8 @@ func TestDefaultConfigs(t *testing.T) {
 // TestLoadConfigFiles verifies that when multiple configs are passed in
 // they are consumed in the correct order
 func TestLoadConfigFiles(t *testing.T) {
+	oneSecond, _ := time.ParseDuration("1s")
+	twoSecond, _ := time.ParseDuration("2s")
 	tests := []struct {
 		name        string
 		configFiles []string
@@ -81,12 +89,16 @@ func TestLoadConfigFiles(t *testing.T) {
 					URL:     "test-authz-server",
 				},
 				DbConfig: &DatabaseConfig{
-					Host:           "localhost",
-					Port:           5432,
-					User:           "admin",
-					Password:       "password",
-					Database:       "xp",
-					MigrationsPath: "file://test-db-migrations",
+					Host:            "localhost",
+					Port:            5432,
+					User:            "admin",
+					Password:        "password",
+					Database:        "xp",
+					MigrationsPath:  "file://test-db-migrations",
+					ConnMaxIdleTime: oneSecond,
+					ConnMaxLifetime: twoSecond,
+					MaxIdleConns:    3,
+					MaxOpenConns:    4,
 				},
 				SegmenterConfig: map[string]interface{}{
 					"s2_ids": map[string]interface{}{

management-service/database/database.go

@@ -27,10 +27,25 @@ func ConnectionString(cfg *config.DatabaseConfig) string {
 }
 
 func Open(cfg *config.DatabaseConfig) (*gorm.DB, error) {
-	return gorm.Open(pg.Open(ConnectionString(cfg)),
+	db, err := gorm.Open(pg.Open(ConnectionString(cfg)),
 		&gorm.Config{
 			Logger: logger.Default.LogMode(logger.Silent),
 		})
+	if err != nil {
+		return nil, err
+	}
+
+	// Get the underlying SQL DB and apply connection properties
+	sqlDB, err := db.DB()
+	if err != nil {
+		return nil, err
+	}
+	sqlDB.SetConnMaxIdleTime(cfg.ConnMaxIdleTime)
+	sqlDB.SetConnMaxLifetime(cfg.ConnMaxLifetime)
+	sqlDB.SetMaxIdleConns(cfg.MaxIdleConns)
+	sqlDB.SetMaxOpenConns(cfg.MaxOpenConns)
+
+	return db, nil
 }
 
 func Migrate(cfg *config.DatabaseConfig) error {

management-service/services/configuration_service.go

@@ -14,8 +14,7 @@ type configurationService struct {
 }
 
 func NewConfigurationService(cfg *config.Config) ConfigurationService {
-	var segmenterConfig schema.SegmenterConfig
-	segmenterConfig = cfg.SegmenterConfig
+	var segmenterConfig schema.SegmenterConfig = cfg.SegmenterConfig
 
 	return &configurationService{
 		treatmentServiceConfig: schema.TreatmentServiceConfig{

management-service/testdata/config1.yaml

@@ -12,6 +12,10 @@ DbConfig:
   User: user
   Password: password
   MigrationsPath: file://test-db-migrations
+  ConnMaxIdleTime: 1s
+  ConnMaxLifetime: 2s
+  MaxIdleConns: 3
+  MaxOpenConns: 4
 
 MLPConfig:
   URL: test-mlp-url

treatment-service/services/experiment_service.go

@@ -61,11 +61,13 @@ func (es *experimentService) GetExperiment(
 		func(matches []*models.ExperimentMatch) []*models.ExperimentMatch {
 			return es.filterByMatchStrength(matches, projectSettings.Segmenters.Names)
 		},
-		// Resolve granularity of Segmenters
+		// Resolve lookup order. At this point, comparing by each segmenter, we should be left with one or more
+		// experiments which are either all exact or all weak. Where there are multiple transformed values returned
+		// by the segmenter, we pick the first transformed value that has a match, to filter the pool of experiments.
 		func(matches []*models.ExperimentMatch) []*models.ExperimentMatch {
 			return es.filterByLookupOrder(matches, requestFilter, projectSettings.Segmenters.Names, segmentersTypeMapping)
 		},
-		// Resolve tiers - at this point, we should ideally only be left with 1 experiment or 2
+		// Resolve tiers. At this point, we should ideally only be left with 1 experiment or 2
 		// (in different tiers), based on the orthogonality rules enforced by the management service.
 		es.filterByTierPriority,
 	}