Put PGX and other future Postgres Drivers behind SQL package

This PR makes allows users to provide a config, along with a driver string. It will then provide the respective driver.

pkg/dbtools/sql/postgres/database.go

@@ -0,0 +1,51 @@
+package postgres
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/dbtools/sql"
+)
+
+var _ sql.Database = &DB{}
+
+// TODO: Make NewPostgresDB accept a string and Config. IT should
+// Create a driver of its own.
+// This will make sure that if you want a driver, it conforms to the interface.
+
+// NewPostgresDB returns a postgres.DB using the provided Config and driver type.
+func NewPostgresDB(c Config, driverName string) (*DB, error) {
+	var driver *pgxDriver
+
+	driverType, err := ResolveDriverType(driverName)
+	if err != nil {
+		return nil, err
+	}
+
+	driver, err = createDriver(c, driverType)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &DB{driver}, nil
+}
+
+func createDriver(c Config, driverType DriverType) (*pgxDriver, error) {
+	switch driverType {
+	case PGX:
+		driver, err := newPGXDriver(context.Background(), c)
+		if err != nil {
+			return nil, fmt.Errorf("Error Creating Driver, err: %e", err)
+		}
+		return driver, nil
+	default:
+		return nil, fmt.Errorf("Can't find a driver to create")
+	}
+
+}
+
+// DB implements sql.Database using a configured driver and Postgres statement syntax
+type DB struct {
+	sql.Driver
+}

pkg/dbtools/sql/postgres/pgx.go

@@ -11,16 +11,16 @@ import (
 	"github.com/vulcanize/ipld-ethcl-indexer/pkg/dbtools/sql"
 )
 
-// PGXDriver driver, implements sql.Driver
-type PGXDriver struct {
+// pgxDriver driver, implements sql.Driver
+type pgxDriver struct {
 	ctx  context.Context
 	pool *pgxpool.Pool
 }
 
-// NewPGXDriver returns a new pgx driver.
+// newPGXDriver returns a new pgx driver.
 // It initializes the connection pool.
-func NewPGXDriver(ctx context.Context, config Config) (*PGXDriver, error) {
-	pgConf, err := MakeConfig(config)
+func newPGXDriver(ctx context.Context, config Config) (*pgxDriver, error) {
+	pgConf, err := makeConfig(config)
 	if err != nil {
 		return nil, err
 	}
@@ -28,12 +28,12 @@ func NewPGXDriver(ctx context.Context, config Config) (*PGXDriver, error) {
 	if err != nil {
 		return nil, sql.ErrDBConnectionFailed(err)
 	}
-	pg := &PGXDriver{ctx: ctx, pool: dbPool}
+	pg := &pgxDriver{ctx: ctx, pool: dbPool}
 	return pg, nil
 }
 
-// MakeConfig creates a pgxpool.Config from the provided Config
-func MakeConfig(config Config) (*pgxpool.Config, error) {
+// makeConfig creates a pgxpool.Config from the provided Config
+func makeConfig(config Config) (*pgxpool.Config, error) {
 	conf, err := pgxpool.ParseConfig("")
 	if err != nil {
 		return nil, err
@@ -65,28 +65,28 @@ func MakeConfig(config Config) (*pgxpool.Config, error) {
 }
 
 // QueryRow satisfies sql.Database
-func (pgx *PGXDriver) QueryRow(ctx context.Context, sql string, args ...interface{}) sql.ScannableRow {
+func (pgx *pgxDriver) QueryRow(ctx context.Context, sql string, args ...interface{}) sql.ScannableRow {
 	return pgx.pool.QueryRow(ctx, sql, args...)
 }
 
 // Exec satisfies sql.Database
-func (pgx *PGXDriver) Exec(ctx context.Context, sql string, args ...interface{}) (sql.Result, error) {
+func (pgx *pgxDriver) Exec(ctx context.Context, sql string, args ...interface{}) (sql.Result, error) {
 	res, err := pgx.pool.Exec(ctx, sql, args...)
 	return resultWrapper{ct: res}, err
 }
 
 // Select satisfies sql.Database
-func (pgx *PGXDriver) Select(ctx context.Context, dest interface{}, query string, args ...interface{}) error {
+func (pgx *pgxDriver) Select(ctx context.Context, dest interface{}, query string, args ...interface{}) error {
 	return pgxscan.Select(ctx, pgx.pool, dest, query, args...)
 }
 
 // Get satisfies sql.Database
-func (pgx *PGXDriver) Get(ctx context.Context, dest interface{}, query string, args ...interface{}) error {
+func (pgx *pgxDriver) Get(ctx context.Context, dest interface{}, query string, args ...interface{}) error {
 	return pgxscan.Get(ctx, pgx.pool, dest, query, args...)
 }
 
 // Begin satisfies sql.Database
-func (pgx *PGXDriver) Begin(ctx context.Context) (sql.Tx, error) {
+func (pgx *pgxDriver) Begin(ctx context.Context) (sql.Tx, error) {
 	tx, err := pgx.pool.Begin(ctx)
 	if err != nil {
 		return nil, err
@@ -94,19 +94,19 @@ func (pgx *PGXDriver) Begin(ctx context.Context) (sql.Tx, error) {
 	return pgxTxWrapper{tx: tx}, nil
 }
 
-func (pgx *PGXDriver) Stats() sql.Stats {
+func (pgx *pgxDriver) Stats() sql.Stats {
 	stats := pgx.pool.Stat()
 	return pgxStatsWrapper{stats: stats}
 }
 
 // Close satisfies sql.Database/io.Closer
-func (pgx *PGXDriver) Close() error {
+func (pgx *pgxDriver) Close() error {
 	pgx.pool.Close()
 	return nil
 }
 
 // Context satisfies sql.Database
-func (pgx *PGXDriver) Context() context.Context {
+func (pgx *pgxDriver) Context() context.Context {
 	return pgx.ctx
 }
 

pkg/dbtools/sql/postgres/pgx_test.go

@@ -12,7 +12,7 @@ import (
 )
 
 var (
-	pgConfig, _ = MakeConfig(DefaultConfig)
+	pgConfig, _ = makeConfig(DefaultConfig)
 	ctx         = context.Background()
 )
 
@@ -79,11 +79,20 @@ func TestPostgresPGX(t *testing.T) {
 	})
 
 	t.Run("throws error when can't connect to the database", func(t *testing.T) {
-		_, err := NewPGXDriver(ctx, Config{})
+		_, err := NewPostgresDB(Config{}, "PGX")
 		if err == nil {
 			t.Fatal("Expected an error")
 		}
 
 		expectContainsSubstring(t, err.Error(), sql.DbConnectionFailedMsg)
 	})
+	t.Run("Connect to the database", func(t *testing.T) {
+		driver, err := NewPostgresDB(DefaultConfig, "pgx")
+		defer driver.Close()
+
+		if err != nil {
+			t.Fatal("Error creating the postgres driver")
+		}
+
+	})
 }