Defer driver search to Open() (#93)

No longer dependent on initialisation order, and also allows explicit
selection using option.

Author: undeconstructed

pgx_test.go

@@ -16,33 +16,29 @@ func init() {
 }
 
 func TestAdapterPgx_specs(t *testing.T) {
-	driverName = "pgx"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("pgx"))
 	defer adapter.Close()
 
 	repo := rel.New(adapter)
 	AdapterSpecs(t, repo)
 }
 
 func TestAdapterPgx_Transaction_commitError(t *testing.T) {
-	driverName = "pgx"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("pgx"))
 	defer adapter.Close()
 
 	assert.NotNil(t, adapter.Commit(ctx))
 }
 
 func TestAdapterPgx_Transaction_rollbackError(t *testing.T) {
-	driverName = "pgx"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("pgx"))
 	defer adapter.Close()
 
 	assert.NotNil(t, adapter.Rollback(ctx))
 }
 
 func TestAdapterPgx_Exec_error(t *testing.T) {
-	driverName = "pgx"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("pgx"))
 	defer adapter.Close()
 
 	_, _, err := adapter.Exec(ctx, "error", nil)
@@ -51,7 +47,6 @@ func TestAdapterPgx_Exec_error(t *testing.T) {
 
 func TestAdapterPgx_InvalidDriverPanic(t *testing.T) {
 	assert.Panics(t, func() {
-		driverName = "pgx/v4"
-		MustOpen("postgres://test:test@localhost:1111/test?sslmode=disable&timezone=Asia/Jakarta")
+		MustOpen("postgres://test:test@localhost:1111/test?sslmode=disable&timezone=Asia/Jakarta", WithDriver("pgx/v4"))
 	})
 }

postgres.go

@@ -16,6 +16,7 @@ package postgres
 import (
 	"context"
 	db "database/sql"
+	"slices"
 	"time"
 
 	"github.com/go-rel/rel"
@@ -31,8 +32,6 @@ type Postgres struct {
 // Name of database type this adapter implements.
 const Name string = "postgres"
 
-var driverName string = "postgres"
-
 // New postgres adapter using existing connection.
 func New(database *db.DB) rel.Adapter {
 	var (
@@ -65,15 +64,37 @@ func New(database *db.DB) rel.Adapter {
 	}
 }
 
+type OpenOpt struct {
+	driver string
+}
+
+func WithDriver(driver string) OpenOpt {
+	return OpenOpt{driver: driver}
+}
+
 // Open postgres connection using dsn.
-func Open(dsn string) (rel.Adapter, error) {
+func Open(dsn string, opts ...OpenOpt) (rel.Adapter, error) {
+	// Default to postgres driver
+	driverName := "postgres"
+
+	// Identify if pgx driver is available and default to that instead.
+	if slices.Contains(db.Drivers(), "pgx") {
+		driverName = "pgx"
+	}
+
+	for _, opts := range opts {
+		if opts.driver != "" {
+			driverName = opts.driver
+		}
+	}
+
 	database, err := db.Open(driverName, dsn)
 	return New(database), err
 }
 
 // MustOpen postgres connection using dsn.
-func MustOpen(dsn string) rel.Adapter {
-	adapter, err := Open(dsn)
+func MustOpen(dsn string, opts ...OpenOpt) rel.Adapter {
+	adapter, err := Open(dsn, opts...)
 	if err != nil {
 		panic(err)
 	}
@@ -195,13 +216,3 @@ func columnMapper(column *rel.Column) (string, int, int) {
 
 	return typ, m, n
 }
-
-func init() {
-	// Identify if pgx driver is available and default to that instead.
-	for _, drv := range db.Drivers() {
-		if drv == "pgx" {
-			driverName = "pgx"
-			break
-		}
-	}
-}

postgres_test.go

@@ -29,8 +29,7 @@ func dsn() string {
 }
 
 func TestAdapter_Name(t *testing.T) {
-	driverName = "postgres"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("postgres"))
 	defer adapter.Close()
 
 	assert.Equal(t, Name, adapter.Name())
@@ -115,8 +114,7 @@ func TestAdapter_specs(t *testing.T) {
 		return
 	}
 
-	driverName = "postgres"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("postgres"))
 	defer adapter.Close()
 
 	repo := rel.New(adapter)
@@ -129,7 +127,6 @@ func TestAdapter_PrimaryReplica_specs(t *testing.T) {
 		return
 	}
 
-	driverName = "postgres"
 	adapter := primaryreplica.New(
 		MustOpen("postgres://rel:rel@localhost:25432/rel_test?sslmode=disable&timezone=Asia/Jakarta"),
 		MustOpen("postgres://rel:rel@localhost:25433/rel_test?sslmode=disable&timezone=Asia/Jakarta"),
@@ -142,24 +139,21 @@ func TestAdapter_PrimaryReplica_specs(t *testing.T) {
 }
 
 func TestAdapter_Transaction_commitError(t *testing.T) {
-	driverName = "postgres"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("postgres"))
 	defer adapter.Close()
 
 	assert.NotNil(t, adapter.Commit(ctx))
 }
 
 func TestAdapter_Transaction_rollbackError(t *testing.T) {
-	driverName = "postgres"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("postgres"))
 	defer adapter.Close()
 
 	assert.NotNil(t, adapter.Rollback(ctx))
 }
 
 func TestAdapter_Exec_error(t *testing.T) {
-	driverName = "postgres"
-	adapter, err := Open(dsn())
+	adapter, err := Open(dsn(), WithDriver("postgres"))
 	assert.Nil(t, err)
 	defer adapter.Close()
 
@@ -168,8 +162,7 @@ func TestAdapter_Exec_error(t *testing.T) {
 }
 
 func TestAdapter_TableBuilder(t *testing.T) {
-	driverName = "postgres"
-	adapter := MustOpen(dsn())
+	adapter := MustOpen(dsn(), WithDriver("postgres"))
 	defer adapter.Close()
 
 	tests := []struct {