bunstore

README

bunstore

A Bun based session store for SCS.

Setup

You should have a working database containing a sessions table with the definition (for PostgreSQL):

CREATE TABLE sessions (
	token TEXT PRIMARY KEY,
	data BYTEA NOT NULL,
	expiry TIMESTAMPTZ NOT NULL
);

CREATE INDEX sessions_expiry_idx ON sessions (expiry);

For other stores you can find the setup here: MySQL, SQLite3.

If no table is present, a new one will be automatically created.

The database user for your application must have CREATE TABLE, SELECT, INSERT, UPDATE and DELETE permissions on this table.

Example

package main

import (
	"database/sql"
	"io"
	"log"
	"net/http"

	"github.com/alexedwards/scs/bunstore"
	"github.com/alexedwards/scs/v2"
	"github.com/uptrace/bun"
	"github.com/uptrace/bun/dialect/pgdialect"
	_ "github.com/uptrace/bun/driver/pgdriver"
)

var sessionManager *scs.SessionManager

func main() {
	// Establish connection to your store.
	sqldb, err := sql.Open("pg", "postgres://username:password@host/dbname") // PostgreSQL
	//sqldb, err := sql.Open("mysql", "username:password@tcp(host)/dbname?parseTime=true") // MySQL
	//sqldb, err := sql.Open(sqliteshim.ShimName, "sqlite3_database.db") // SQLite3
	if err != nil {
		log.Fatal(err)
	}

	db := bun.NewDB(sqldb, pgdialect.New()) // PostgreSQL
	//db := bun.NewDB(sqldb, mysqldialect.New()) // MySQL
	//db := bun.NewDB(sqldb, sqlitedialect.New()) // SQLite3
	defer db.Close()

	db.SetMaxOpenConns(1)
	db.SetMaxIdleConns(1000)
	db.SetConnMaxLifetime(0)

	// Initialize a new session manager and configure it to use bunstore as the session store.
	sessionManager = scs.New()
	if sessionManager.Store, err = bunstore.New(db); err != nil {
        log.Fatal(err)
    }

	mux := http.NewServeMux()
	mux.HandleFunc("/put", putHandler)
	mux.HandleFunc("/get", getHandler)

	http.ListenAndServe(":4000", sessionManager.LoadAndSave(mux))
}

func putHandler(w http.ResponseWriter, r *http.Request) {
	sessionManager.Put(r.Context(), "message", "Hello from a session!")
}

func getHandler(w http.ResponseWriter, r *http.Request) {
	msg := sessionManager.GetString(r.Context(), "message")
	io.WriteString(w, msg)
}

Expired Session Cleanup

This package provides a background 'cleanup' goroutine to delete expired session data. This stops the database table from holding on to invalid sessions indefinitely and growing unnecessarily large. By default the cleanup runs every 5 minutes. You can change this by using the NewWithCleanupInterval() function to initialize your session store. For example:

// Run a cleanup every 30 minutes.
bunstore.NewWithCleanupInterval(db, 30*time.Minute)

// Disable the cleanup goroutine by setting the cleanup interval to zero.
bunstore.NewWithCleanupInterval(db, 0)

Terminating the Cleanup Goroutine

It's rare that the cleanup goroutine needs to be terminated --- it is generally intended to be long-lived and run for the lifetime of your application.

However, there may be occasions when your use of a session store instance is transient. A common example would be using it in a short-lived test function. In this scenario, the cleanup goroutine (which will run forever) will prevent the session store instance from being garbage collected even after the test function has finished. You can prevent this by either disabling the cleanup goroutine altogether (as described above) or by stopping it using the StopCleanup() method. For example:

func TestExample(t *testing.T) {
	sqldb, err := sql.Open("pg", "postgres://username:password@host/dbname")
	if err != nil {
		log.Fatal(err)
	}
	
	db := bun.NewDB(sqldb, pgdialect.New())
	defer db.Close()

	db.SetMaxOpenConns(1)
	db.SetMaxIdleConns(1000)
	db.SetConnMaxLifetime(0)

    store, err := bunstore.New(db)
    if err != nil {
	    t.Fatal(err)
    }
	defer store.StopCleanup()

	sessionManager = scs.New()
	sessionManager.Store = store

	// Run test...
}

Documentation

Index

• type BunStore
  • func New(db *bun.DB) (*BunStore, error)
  • func NewWithCleanupInterval(db *bun.DB, cleanupInterval time.Duration) (*BunStore, error)
  • func (b *BunStore) AllCtx(ctx context.Context) (map[string][]byte, error)
  • func (b *BunStore) Commit(token string, bb []byte, expiry time.Time) error
  • func (b *BunStore) CommitCtx(ctx context.Context, token string, bb []byte, expiry time.Time) error
  • func (b *BunStore) Delete(token string) error
  • func (b *BunStore) DeleteCtx(ctx context.Context, token string) error
  • func (b *BunStore) Find(token string) ([]byte, bool, error)
  • func (b *BunStore) FindCtx(ctx context.Context, token string) (bb []byte, exists bool, err error)
  • func (b *BunStore) StopCleanup()

Types

type BunStore

type BunStore struct {
	// contains filtered or unexported fields
}

BunStore represents the session store.

func New

func New(db *bun.DB) (*BunStore, error)

New returns a new BunStore instance, with a background cleanup goroutine that runs every 5 minutes to remove expired session data.

func NewWithCleanupInterval

func NewWithCleanupInterval(db *bun.DB, cleanupInterval time.Duration) (*BunStore, error)

NewWithCleanupInterval returns a new BunStore instance. The cleanupInterval parameter controls how frequently expired session data is removed by the background cleanup goroutine. Setting it to 0 prevents the cleanup goroutine from running (i.e. expired sessions will not be removed).

func (*BunStore) AllCtx

func (b *BunStore) AllCtx(ctx context.Context) (map[string][]byte, error)

All returns a map containing the token and data for all active (i.e. not expired) sessions in the BunStore instance.

func (*BunStore) Commit

func (b *BunStore) Commit(token string, bb []byte, expiry time.Time) error

func (*BunStore) CommitCtx

func (b *BunStore) CommitCtx(ctx context.Context, token string, bb []byte, expiry time.Time) error

Commit adds a session token and data to the BunStore instance with the given expiry time. If the session token already exists, then the data and expiry time are updated.

func (*BunStore) Delete

func (b *BunStore) Delete(token string) error

func (*BunStore) DeleteCtx

func (b *BunStore) DeleteCtx(ctx context.Context, token string) error

Delete removes a session token and corresponding data from the BunStore instance.

func (*BunStore) Find

func (b *BunStore) Find(token string) ([]byte, bool, error)

func (*BunStore) FindCtx

func (b *BunStore) FindCtx(ctx context.Context, token string) (bb []byte, exists bool, err error)

Find returns the data for a given session token from the BunStore instance. If the session token is not found or is expired, the returned exists flag will be set to false.

func (*BunStore) StopCleanup

func (b *BunStore) StopCleanup()

StopCleanup terminates the background cleanup goroutine for the BunStore instance. It's rare to terminate this; generally BunStore instances and their cleanup goroutines are intended to be long-lived and run for the lifetime of your application.

There may be occasions though when your use of the BunStore is transient. An example is creating a new BunStore instance in a test function. In this scenario, the cleanup goroutine (which will run forever) will prevent the BunStore object from being garbage collected even after the test function has finished. You can prevent this by manually calling StopCleanup.