Pgxmock batch example in Go

examples/batch/batch.go

@@ -0,0 +1,155 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	pgx "github.com/jackc/pgx/v5"
+	pgconn "github.com/jackc/pgx/v5/pgconn"
+	pgxpool "github.com/jackc/pgx/v5/pgxpool"
+)
+
+type PgxPoolInterface interface {
+	Exec(context.Context, string, ...interface{}) (pgconn.CommandTag, error)
+	SendBatch(context.Context, *pgx.Batch) pgx.BatchResults
+	Close()
+}
+
+type exampleBatch struct {
+	batch   *pgx.Batch       // batch pointer
+	results pgx.BatchResults // query results
+	db      PgxPoolInterface // database connection
+}
+
+type metadata struct {
+	title       string
+	authors     string
+	subject     string
+	description string
+}
+
+func NewExample(db PgxPoolInterface) (example exampleBatch, err error) {
+
+	example = exampleBatch{
+		db:    db,           // database
+		batch: &pgx.Batch{}, // batch struct address
+	}
+
+	sql := `CREATE TABLE IF NOT EXISTS metadata (
+	id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
+	title TEXT NOT NULL,
+	authors TEXT NOT NULL,
+	subject TEXT NOT NULL,
+	description TEXT NOT NULL);
+	DELETE FROM metadata ;`
+	_, err = example.db.Exec(context.Background(), sql) // Execute sql
+
+	return example, err
+}
+
+func (ex *exampleBatch) BulkInsertMetadata(data []metadata) error {
+	query := `INSERT INTO metadata (title, authors, subject, description)
+	VALUES
+		(@title, @authors, @subject, @description)
+	`
+	batch := &pgx.Batch{}
+	for _, m := range data {
+		args := pgx.NamedArgs{
+			"title":       m.title,
+			"authors":     m.authors,
+			"subject":     m.subject,
+			"description": m.description,
+		}
+		batch.Queue(query, args)
+	}
+
+	results := ex.db.SendBatch(context.Background(), batch)
+	defer results.Close()
+
+	for index := range data {
+		_, err := results.Exec()
+		if err != nil {
+			return fmt.Errorf("unable to insert row %d: %w", index, err)
+		}
+	}
+
+	return results.Close()
+}
+
+func (ex *exampleBatch) SendCustomBatch(queries []string) (err error) {
+
+	// Add SQL queries to the queue for a custom batch
+	for _, query := range queries {
+		ex.batch.Queue(query)
+	}
+
+	// Efficiently transmits queued queries as a single transaction.
+	// After the queries are run, a BatchResults object is returned.
+	ex.results = ex.db.SendBatch(context.Background(), ex.batch)
+	if ex.results == nil {
+		return errors.New("SendBatch returns a NIL object")
+	}
+
+	return err
+}
+
+func (ex *exampleBatch) TestCustomResults() (err error) {
+
+	for index := range ex.batch.QueuedQueries {
+		_, err := ex.results.Exec()
+		if err != nil {
+			return fmt.Errorf("unable to run query %d: %w", index, err)
+		}
+	}
+
+	return ex.results.Close()
+}
+
+func (ex *exampleBatch) Close() (err error) {
+
+	// Close batch results object
+	ex.results.Close()
+
+	// Close connection to database
+	ex.db.Close()
+
+	return err
+}
+
+func main() {
+
+	// @NOTE: the real connection is not required for tests
+	db, _ := pgxpool.New(context.Background(), "postgres://postgres:password@localhost/batch")
+
+	// Create a new instance of example struct
+	example, err := NewExample(db)
+	if err != nil {
+		panic(err)
+	}
+	defer example.Close()
+
+	// Insert multiple rows into the database
+	example.BulkInsertMetadata([]metadata{
+		{`A Journey Through the Alps`, `John Doe, Jane Smith`, `Hiking, Nature, Travel`, `Explore the breathtaking beauty of the Alps on a scenic hiking adventure. Discover hidden trails, alpine lakes, and charming mountain villages.`},
+		{`The Art of Baking: A Beginner's Guide`, `Emily Baker`, `Cooking, Baking, Food`, `Learn the fundamentals of baking and create delicious treats from scratch. Master techniques like kneading dough, frosting cakes, and piping cookies.`},
+		{`The History of Ancient Rome`, `David Johnson`, `History, Ancient Rome, Civilization`, `Delve into the fascinating history of the Roman Empire. Explore its rise to power, its cultural achievements, and its eventual decline.`},
+	})
+
+	// Send a custom batch operation to database
+	example.SendCustomBatch([]string{
+		"SELECT title FROM metadata",
+		"SELECT authors FROM metadata",
+		"SELECT subject, description FROM metadata",
+	})
+
+	// Print batch results
+	for _, query := range example.batch.QueuedQueries {
+		fmt.Println(query.SQL)
+		rows, _ := example.results.Query()
+		for rows.Next() {
+			values, _ := rows.Values()
+			fmt.Println(values)
+		}
+	}
+}

examples/batch/batch_test.go

@@ -0,0 +1,96 @@
+package main
+
+import (
+	"testing"
+
+	pgxmock "github.com/pashagolub/pgxmock/v4"
+)
+
+func TestNewExample(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer mock.Close()
+
+	// Expect a call to Exec
+	mock.ExpectExec(`^CREATE TABLE IF NOT EXISTS (.+)`).
+		WillReturnResult(pgxmock.NewResult("CREATE TABLE", 0))
+
+	_, err = NewExample(mock)
+	if err != nil {
+		t.Errorf("creating new example error: %s", err)
+	}
+
+	// We make sure that all expectations were met
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expectations: %s", err)
+	}
+}
+
+func TestSendCustomBatch(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer mock.Close()
+
+	// Expect a call to Exec and pgx.Batch
+	mock.ExpectExec(`^CREATE TABLE IF NOT EXISTS (.+)`).
+		WillReturnResult(pgxmock.NewResult("CREATE TABLE", 0))
+	mock.ExpectBatch()
+
+	example, err := NewExample(mock)
+	if err != nil {
+		t.Errorf("creating new example error: %s", err)
+	}
+
+	err = example.SendCustomBatch([]string{
+		"SELECT title FROM metadata",
+		"SELECT authors FROM metadata",
+		"SELECT subject, description FROM metadata",
+	})
+	if err != nil {
+		t.Errorf("SendCustomBatch error: %s", err)
+	}
+
+	err = example.TestCustomResults()
+	if err != nil {
+		t.Errorf("TestCustomResults error: %s", err)
+	}
+
+	// We make sure that all expectations were met
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expectations: %s", err)
+	}
+}
+func TestBulkInsert(t *testing.T) {
+	mock, err := pgxmock.NewPool()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer mock.Close()
+
+	// Expect a call to Exec and pgx.Batch
+	mock.ExpectExec(`^CREATE TABLE IF NOT EXISTS (.+)`).
+		WillReturnResult(pgxmock.NewResult("CREATE TABLE", 0))
+	mock.ExpectBatch()
+
+	example, err := NewExample(mock)
+	if err != nil {
+		t.Errorf("creating new example error: %s", err)
+	}
+
+	// Insert multiple rows into the database
+	err = example.BulkInsertMetadata([]metadata{
+		{`title`, `author`, `subject`, `description`},
+	})
+	if err != nil {
+		t.Errorf("bulk insert error: %s", err)
+	}
+
+	// We make sure that all expectations were met
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("there were unfulfilled expectations: %s", err)
+	}
+}