Allow to connect with gocloud to AWS/GCP instances.

Author: cyrilgdn

go.mod

@@ -5,6 +5,7 @@ go 1.14
 require (
 	github.com/blang/semver v3.5.1+incompatible
 	github.com/hashicorp/terraform-plugin-sdk v1.0.0
-	github.com/lib/pq v1.3.0
+	github.com/lib/pq v1.9.0
 	github.com/sean-/postgresql-acl v0.0.0-20161225120419-d10489e5d217
+	gocloud.dev v0.21.0
 )

go.sum

@@ -1,6 +1,7 @@
 package postgresql
 
 import (
+	"context"
 	"database/sql"
 	"fmt"
 	"net/url"
@@ -11,6 +12,9 @@ import (
 
 	"github.com/blang/semver"
 	_ "github.com/lib/pq" //PostgreSQL db
+	"gocloud.dev/postgres"
+	_ "gocloud.dev/postgres/awspostgres"
+	_ "gocloud.dev/postgres/gcppostgres"
 )
 
 type featureName uint
@@ -114,6 +118,7 @@ type ClientCertificateConfig struct {
 
 // Config - provider config
 type Config struct {
+	Scheme            string
 	Host              string
 	Port              int
 	Username          string
@@ -166,14 +171,17 @@ func (c *Config) featureSupported(name featureName) bool {
 	return fn(c.ExpectedVersion)
 }
 
-func (c *Config) connStr(database string) string {
-	// NOTE: dbname must come before user otherwise dbname will be set to
-	// user.
+func (c *Config) connParams() []string {
 	params := map[string]string{
-		"sslmode":         c.SSLMode,
 		"connect_timeout": strconv.Itoa(c.ConnectTimeoutSec),
 	}
 
+	// sslmode is not allowed with gocloud
+	// (TLS is provided by gocloud directly)
+	if c.Scheme == "postgres" {
+		params["sslmode"] = c.SSLMode
+	}
+
 	if c.featureSupported(featureFallbackApplicationName) {
 		params["fallback_application_name"] = c.ApplicationName
 	}
@@ -191,14 +199,19 @@ func (c *Config) connStr(database string) string {
 		paramsArray = append(paramsArray, "%s=%s", key, url.QueryEscape(value))
 	}
 
+	return paramsArray
+}
+
+func (c *Config) connStr(database string) string {
 	connStr := fmt.Sprintf(
-		"postgres://%s:%s@%s:%d/%s?%s",
+		"%s://%s:%s@%s:%d/%s?%s",
+		c.Scheme,
 		url.QueryEscape(c.Username),
 		url.QueryEscape(c.Password),
-		url.QueryEscape(c.Host),
+		c.Host,
 		c.Port,
 		database,
-		strings.Join(paramsArray, "&"),
+		strings.Join(c.connParams(), "&"),
 	)
 
 	return connStr
@@ -221,9 +234,16 @@ func (c *Client) Connect() (*DBConnection, error) {
 	dsn := c.config.connStr(c.databaseName)
 	conn, found := dbRegistry[dsn]
 	if !found {
-		db, err := sql.Open("postgres", dsn)
+
+		var db *sql.DB
+		var err error
+		if c.config.Scheme == "postgres" {
+			db, err = sql.Open("postgres", dsn)
+		} else {
+			db, err = postgres.Open(context.Background(), dsn)
+		}
 		if err != nil {
-			return nil, fmt.Errorf("Error connecting to PostgreSQL server: %w", err)
+			return nil, fmt.Errorf("Error connecting to PostgreSQL server %s (scheme: %s): %w", c.config.Host, c.config.Scheme, err)
 		}
 
 		// We don't want to retain connection

postgresql/config.go

@@ -18,6 +18,16 @@ const (
 func Provider() terraform.ResourceProvider {
 	return &schema.Provider{
 		Schema: map[string]*schema.Schema{
+			"scheme": {
+				Type:     schema.TypeString,
+				Optional: true,
+				Default:  "postgres",
+				ValidateFunc: validation.StringInSlice([]string{
+					"postgres",
+					"awspostgres",
+					"gcppostgres",
+				}, false),
+			},
 			"host": {
 				Type:        schema.TypeString,
 				Optional:    true,
@@ -160,6 +170,7 @@ func providerConfigure(d *schema.ResourceData) (interface{}, error) {
 	version, _ := semver.ParseTolerant(versionStr)
 
 	config := Config{
+		Scheme:            d.Get("scheme").(string),
 		Host:              d.Get("host").(string),
 		Port:              d.Get("port").(int),
 		Username:          d.Get("username").(string),