glloq

The simplest way to use glloq is by using a data source name (DSN). UseLocker will take care of opening and closing any connection or socket, will wait for the backend to be available and will hold the lock and release it when you're finished.

package main

import (
	"time"

	"github.com/gilbsgilbs/glloq"
	"github.com/gilbsgilbs/glloq/anylocker"
)

func main() {
	err := glloq.UseLocker(
		&anylocker.Locker{},
		&glloq.Options{
			// This is a connection string to your backend. For SQL-based backends,
			// dburl (https://github.com/xo/dburl) is used.
			DSN: "postgres://user:password@localhost:5432/db?sslmode=disable",
			// DSN: "mysql://user:password@localhost:3006/db",
			// DSN: "file://.lock",

			// Maximum time to wait for the backend and the lock. Defaults to 1 minute.
			Timeout: 1 * time.Hour,

			// An optional lock key, if supported by the backend.
			Key: "someUniqueKey",

			// backend-specific parameters.
			Params: map[string]string{},
		},
		func() error {
			// You can run any synchronized operation here, such as database migrations.
			// It won't run concurrently.
			return nil
		},
	)
	if err != nil {
		panic(err)
	}
}

Output:

The file locker allows you take a lock using a local file.

package main

import (
	"context"

	"github.com/gilbsgilbs/glloq"
	"github.com/gilbsgilbs/glloq/filelocker"
)

func main() {
	locker := filelocker.Locker{}
	err := locker.WithLock(
		context.Background(),
		&glloq.Options{
			DSN: "file:///tmp/myAppLockFile.lock",
		},
		func() error {
			// ...
			return nil
		},
	)
	if err != nil {
		panic(err)
	}
}

Output:

package main

import (
	"context"
	"database/sql"

	"github.com/gilbsgilbs/glloq"
	"github.com/gilbsgilbs/glloq/mysqllocker"
)

func main() {
	var db *sql.DB

	locker := mysqllocker.Locker{}
	locker.DB = db

	err := locker.WithLock(
		context.Background(),
		&glloq.Options{
			Params: map[string]string{
				// Name of the table that will be created to take locks.
				// Defaults to glloq.
				"table_name": "my_lock_table",
			},
		},
		func() error {
			// ...
			return nil
		},
	)
	if err != nil {
		panic(err)
	}
}

Output:

package main

import (
	"context"
	"database/sql"

	"github.com/gilbsgilbs/glloq"
	"github.com/gilbsgilbs/glloq/postgreslocker"
)

func main() {
	var db *sql.DB

	locker := postgreslocker.Locker{}
	locker.DB = db

	err := locker.WithLock(
		context.Background(),
		&glloq.Options{
			Params: map[string]string{
				// Name of the table that will be created to take locks.
				// Defaults to glloq.
				"table_name": "my_lock_table",
			},
		},
		func() error {
			// ...
			return nil
		},
	)
	if err != nil {
		panic(err)
	}
}

Output: