README.md

Go transaction manager

Transaction manager is an abstraction to coordinate database transaction boundaries.

Easiest way to get the perfect repository.

Supported implementations

• database/sql, docs ( Go 1.13)
• jmoiron/sqlx, docs ( Go 1.13)
• gorm, docs ( Go 1.18)
• mongo-go-driver, docs ( Go 1.13)
• go-redis/redis, docs ( Go 1.17)
• pgx_v4, docs ( Go 1.16)
• pgx_v5, docs ( Go 1.19)

Installation

go get github.com/avito-tech/go-transaction-manager/trm/v2

To install some support database use go get github.com/avito-tech/go-transaction-manager/drivers/{name}.

For example go get github.com/avito-tech/go-transaction-manager/drivers/sqlx/v2.

Backwards Compatibility

The library is compatible with the most recent two versions of Go. Compatibility beyond that is not guaranteed.

The critical bugs are firstly solved for the most recent two Golang versions and then for older ones if it is simple.

Disclaimer: Keep your dependencies up to date, even indirect ones.

go get -u && go mod tidy helps you.

Note: The go-transaction-manager uses some old dependencies to support backwards compatibility for old versions of Go.

Usage

To use multiple transactions from different databases, you need to set CtxKey in Settings by WithCtxKey (docs).

For nested transactions with different transaction managers, you need to use ChainedMW (docs).

To skip a transaction rollback due to an error, use ErrSkip or Skippable

Explanation of the approach English, Russian article and youtube.

Examples with an ideal repository and nested transactions.

• database/sql
• jmoiron/sqlx
• gorm
• mongo-go-driver
• go-redis/redis
• pgx_v4
• pgx_v5

Below is an example how to start usage.

package main

import (
	"context"
	"fmt"

	"github.com/jmoiron/sqlx"
	_ "github.com/mattn/go-sqlite3"

	trmsqlx "github.com/avito-tech/go-transaction-manager/drivers/sqlx/v2"
	"github.com/avito-tech/go-transaction-manager/trm/v2/manager"
)

func main() {
	db, err := sqlx.Open("sqlite3", "file:test?mode=memory")
	checkErr(err)
	defer db.Close()

	sqlStmt := `CREATE TABLE IF NOT EXISTS user (user_id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, username TEXT);`
	_, err = db.Exec(sqlStmt)
	checkErr(err, sqlStmt)

	r := newRepo(db, trmsqlx.DefaultCtxGetter)
	ctx := context.Background()
	trManager := manager.Must(trmsqlx.NewDefaultFactory(db))
	u := &user{Username: "username"}

	err = trManager.Do(ctx, func(ctx context.Context) error {
		checkErr(r.Save(ctx, u))

		// example of nested transactions
		return trManager.Do(ctx, func(ctx context.Context) error {
			u.Username = "new_username"
			return r.Save(ctx, u)
		})
	})
	checkErr(err)

	userFromDB, err := r.GetByID(ctx, u.ID)
	checkErr(err)

	fmt.Println(userFromDB)
}

func checkErr(err error, args ...interface{}) {
	if err != nil {
		panic(fmt.Sprint(append([]interface{}{err}, args...)...))
	}
}

type repo struct {
	db     *sqlx.DB
	getter *trmsqlx.CtxGetter
}

func newRepo(db *sqlx.DB, c *trmsqlx.CtxGetter) *repo {
	return &repo{db: db, getter: c}
}

type user struct {
	ID       int64  `db:"user_id"`
	Username string `db:"username"`
}

func (r *repo) GetByID(ctx context.Context, id int64) (*user, error) {
	query := "SELECT * FROM user WHERE user_id = ?;"
	u := user{}

	return &u, r.getter.DefaultTrOrDB(ctx, r.db).GetContext(ctx, &u, r.db.Rebind(query), id)
}

func (r *repo) Save(ctx context.Context, u *user) error {
	query := `UPDATE user SET username = :username WHERE user_id = :user_id;`
	if u.ID == 0 {
		query = `INSERT INTO user (username) VALUES (:username);`
	}

	res, err := sqlx.NamedExecContext(ctx, r.getter.DefaultTrOrDB(ctx, r.db), r.db.Rebind(query), u)
	if err != nil {
		return err
	} else if u.ID != 0 {
		return nil
	} else if u.ID, err = res.LastInsertId(); err != nil {
		return err
	}

	return err
}

Benchmark

Comparing examples with and without trm.

Contribution

Requirements

• golangci-lint
• make

Local Running

• To install all dependencies use make go.mod.tidy or make go.mod.vendor.
• To run all tests use make test or make test.with_real_db for integration tests.

To run database by docker, there is docker-compose.yaml.

docker compose -f trm/drivers/test/docker-compose.yaml up

For full GitHub Actions run, you can use act.

Running old go versions

To stop Golang upgrading set environment variable GOTOOLCHAIN=local .

go install go1.16 # or older version
go1.16 install

Use -mod=readonly to prevent go.mod modification.

To run tests

go1.16 test -race -mod=readonly ./...

How to bump up Golang version in CI/CD

1. Changes in .github/workflows/main.yaml.
   1. Add all old version of Go in go-version: for tests-units job.
   2. Update go-version: on current version of Go for lint and tests-integration jobs.
2. Update build tags by replacing build go1.xx on new version.

Resolve problems with old version of dependencies

To build go.mod compatible for old version use go mod tidy -compat=1.13 (docs).

However, --compat doesn't always work correct and we need to set some library versions manually.

1. go get go.uber.org/[email protected] in trm, sql, sqlx.
2. go get github.com/mattn/[email protected] in trm, sql, sqlx.
3. go get github.com/stretchr/[email protected] in trm, sql, sqlx, goredis8, mongo.
4. go get github.com/jackc/[email protected] in pgxv4. Golang version was bumped up from 1.12 to 1.17 in pgconn v1.14.3.
5. go get golang.org/x/[email protected] in pgxv4.