feat: Add PostgreSQL Retriever

cmd/relayproxy/config/retriever.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/redis/go-redis/v9"
+	"golang.org/x/exp/slices"
 )
 
 // RetrieverConf contains all the field to configure a retriever
@@ -30,6 +31,9 @@ type RetrieverConf struct {
 	URI          string              `mapstructure:"uri" koanf:"uri"`
 	Database     string              `mapstructure:"database" koanf:"database"`
 	Collection   string              `mapstructure:"collection" koanf:"collection"`
+	Type         string              `mapstructure:"type" koanf:"type"`
+	Table        string              `mapstructure:"table" koanf:"table"`
+	Column       string              `mapstructure:"column" koanf:"column"`
 	RedisOptions *redis.Options      `mapstructure:"redisOptions" koanf:"redisOptions"`
 	RedisPrefix  string              `mapstructure:"redisPrefix" koanf:"redisPrefix"`
 	AccountName  string              `mapstructure:"accountName" koanf:"accountname"`
@@ -67,6 +71,9 @@ func (c *RetrieverConf) IsValid() error {
 	if c.Kind == MongoDBRetriever {
 		return c.validateMongoDBRetriever()
 	}
+	if c.Kind == PostgreSQLRetriever {
+		return c.validatePostgreSQLRetriever()
+	}
 	if c.Kind == RedisRetriever {
 		return c.validateRedisRetriever()
 	}
@@ -112,6 +119,24 @@ func (c *RetrieverConf) validateMongoDBRetriever() error {
 	return nil
 }
 
+func (c *RetrieverConf) validatePostgreSQLRetriever() error {
+	validTypes := []string{"json", "relational"}
+	if c.Type == "json" && c.Column == "" {
+		return fmt.Errorf("invalid retriever: no \"column\" property found for kind \"%s\"", c.Kind)
+	}
+	if c.Type == "json" && c.Table == "" {
+		return fmt.Errorf("invalid retriever: no \"table\" property found for kind \"%s\"", c.Kind)
+	}
+	if c.URI == "" {
+		return fmt.Errorf("invalid retriever: no \"uri\" property found for kind \"%s\"", c.Kind)
+	}
+	if c.Type == "" || !slices.Contains(validTypes, c.Type) {
+		return fmt.Errorf("invalid retriever: no \"type\" property or not a valid type in kind \"%s\"", c.Kind)
+	}
+
+	return nil
+}
+
 func (c *RetrieverConf) validateRedisRetriever() error {
 	if c.RedisOptions == nil {
 		return fmt.Errorf("invalid retriever: no \"redisOptions\" property found for kind \"%s\"", c.Kind)
@@ -144,6 +169,7 @@ const (
 	GoogleStorageRetriever RetrieverKind = "googleStorage"
 	KubernetesRetriever    RetrieverKind = "configmap"
 	MongoDBRetriever       RetrieverKind = "mongodb"
+	PostgreSQLRetriever    RetrieverKind = "postgresql"
 	RedisRetriever         RetrieverKind = "redis"
 	BitbucketRetriever     RetrieverKind = "bitbucket"
 	AzBlobStorageRetriever RetrieverKind = "azureBlobStorage"
@@ -154,7 +180,7 @@ func (r RetrieverKind) IsValid() error {
 	switch r {
 	case HTTPRetriever, GitHubRetriever, GitlabRetriever, S3Retriever, RedisRetriever,
 		FileRetriever, GoogleStorageRetriever, KubernetesRetriever, MongoDBRetriever,
-		BitbucketRetriever, AzBlobStorageRetriever:
+		PostgreSQLRetriever, BitbucketRetriever, AzBlobStorageRetriever:
 		return nil
 	}
 	return fmt.Errorf("invalid retriever: kind \"%s\" is not supported", r)

cmd/relayproxy/config/retriever_test.go

@@ -262,6 +262,80 @@ func TestRetrieverConf_IsValid(t *testing.T) {
 			wantErr:  true,
 			errValue: "invalid retriever: no \"redisOptions\" property found for kind \"redis\"",
 		},
+		{
+			name: "kind postgreSQL without Table",
+			fields: config.RetrieverConf{
+				Kind:   "postgresql",
+				URI:    "xxx",
+				Column: "xxx",
+				Type:   "json",
+			},
+			wantErr:  true,
+			errValue: "invalid retriever: no \"table\" property found for kind \"postgresql\"",
+		},
+		{
+			name: "kind postgreSQL without Column",
+			fields: config.RetrieverConf{
+				Kind:  "postgresql",
+				URI:   "xxx",
+				Table: "xxx",
+				Type:  "json",
+			},
+			wantErr:  true,
+			errValue: "invalid retriever: no \"column\" property found for kind \"postgresql\"",
+		},
+		{
+			name: "kind postgreSQL without URI",
+			fields: config.RetrieverConf{
+				Kind:   "postgresql",
+				Column: "xxx",
+				Table:  "xxx",
+				Type:   "json",
+			},
+			wantErr:  true,
+			errValue: "invalid retriever: no \"uri\" property found for kind \"postgresql\"",
+		},
+		{
+			name: "kind postgreSQL without Type",
+			fields: config.RetrieverConf{
+				Kind:   "postgresql",
+				Column: "xxx",
+				Table:  "xxx",
+				URI:    "xxx",
+			},
+			wantErr:  true,
+			errValue: "invalid retriever: no \"type\" property or not a valid type in kind \"postgresql\"",
+		},
+		{
+			name: "kind postgreSQL wrong Type",
+			fields: config.RetrieverConf{
+				Kind:   "postgresql",
+				Column: "xxx",
+				Table:  "xxx",
+				URI:    "xxx",
+				Type:   "wrong",
+			},
+			wantErr:  true,
+			errValue: "invalid retriever: no \"type\" property or not a valid type in kind \"postgresql\"",
+		},
+		{
+			name: "kind postgreSQL valid json type",
+			fields: config.RetrieverConf{
+				Kind:   "postgresql",
+				URI:    "xxx",
+				Table:  "xxx",
+				Type:   "json",
+				Column: "xxx",
+			},
+		},
+		{
+			name: "kind postgreSQL valid relational type",
+			fields: config.RetrieverConf{
+				Kind: "postgresql",
+				URI:  "xxx",
+				Type: "relational",
+			},
+		},
 		{
 			name: "kind mongoDB without Collection",
 			fields: config.RetrieverConf{

cmd/relayproxy/service/gofeatureflag.go

@@ -35,6 +35,7 @@ import (
 	"github.com/thomaspoignant/go-feature-flag/retriever/httpretriever"
 	"github.com/thomaspoignant/go-feature-flag/retriever/k8sretriever"
 	"github.com/thomaspoignant/go-feature-flag/retriever/mongodbretriever"
+	"github.com/thomaspoignant/go-feature-flag/retriever/postgresqlretriever"
 	"github.com/thomaspoignant/go-feature-flag/retriever/redisretriever"
 	"github.com/thomaspoignant/go-feature-flag/retriever/s3retrieverv2"
 	"go.uber.org/zap"
@@ -185,6 +186,8 @@ func initRetriever(c *config.RetrieverConf) (retriever.Retriever, error) {
 			ClientConfig: *client}, nil
 	case config.MongoDBRetriever:
 		return &mongodbretriever.Retriever{Database: c.Database, URI: c.URI, Collection: c.Collection}, nil
+	case config.PostgreSQLRetriever:
+		return &postgresqlretriever.Retriever{Type: c.Type, URI: c.URI, Table: c.Table, Column: c.Column}, nil
 	case config.RedisRetriever:
 		return &redisretriever.Retriever{Options: c.RedisOptions, Prefix: c.RedisPrefix}, nil
 	case config.AzBlobStorageRetriever:

examples/retriever_postgresql/README.md

@@ -0,0 +1,30 @@
+# PostgreSQL example
+
+This example contains everything you need to use **`PostgreSQL`** as the source for your flags.
+
+As you can see the `main.go` file contains a basic HTTP server that expose an API that use your flags.
+
+## How to setup the example
+_All commands should be run in the root level of the repository._
+
+1. Load all dependencies
+
+```shell
+make vendor
+```
+
+2. Run the PostgreSQL container provided in the `docker-compose.yml` file.
+
+```shell
+docker compose -f ./example/retriever_postgresql/docker-compose.yml up
+```
+
+The container will run an initialization script that populates the database with example flags
+
+3. Run the example app to visualize the flags being evaluated
+
+```shell
+go run ./examples/retriever_postgresql/main.go
+```
+
+4. Play with the values in the configured MongoDB documents to see different outputs

examples/retriever_postgresql/docker-compose.yml

@@ -0,0 +1,28 @@
+# Use root/example as user/password credentials
+version: '3.1'
+
+services:
+  postgres:
+    container_name: goff_postgres
+    hostname: postgres
+    image: postgres:16-alpine
+    environment:
+      - POSTGRES_USER=root
+      - POSTGRES_PASSWORD=example
+      - POSTGRES_DB=flags_db
+    ports:
+      - "5432:5432"
+    volumes:
+      - ./init-db.sh:/docker-entrypoint-initdb.d/init-db.sh:ro
+
+  pgadmin:
+    container_name: goff_pgadmin
+    image: dpage/pgadmin4
+    depends_on:
+      - postgres
+    environment:
+      - [email protected]
+      - PGADMIN_DEFAULT_PASSWORD=example
+    ports:
+      - "5050:80"
+