From 4a42a4465c8ff5496229f8883b9d1532bf7c9cab Mon Sep 17 00:00:00 2001
From: GrailFinder <wohilas@gmail.com>
Date: Sun, 7 Apr 2024 09:53:04 +0300
Subject: Feat: db connection and migrations

---
 internal/database/sql/main.go | 141 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 internal/database/sql/main.go

(limited to 'internal/database/sql/main.go')

diff --git a/internal/database/sql/main.go b/internal/database/sql/main.go
new file mode 100644
index 0000000..80d5f5c
--- /dev/null
+++ b/internal/database/sql/main.go
@@ -0,0 +1,141 @@
+package database
+
+import (
+	"apjournal/internal/database/migrations"
+	"os"
+	"time"
+
+	"github.com/jmoiron/sqlx"
+
+	// driver postgres for migrations
+	"log/slog"
+
+	"github.com/golang-migrate/migrate"
+	_ "github.com/golang-migrate/migrate/database/postgres"
+	bindata "github.com/golang-migrate/migrate/source/go_bindata"
+	_ "github.com/jackc/pgx/v5/stdlib" // register pgx driver
+	"github.com/pkg/errors"
+)
+
+var log = slog.New(slog.NewJSONHandler(os.Stdout, nil))
+
+type DB struct {
+	Conn *sqlx.DB
+	URI  string
+}
+
+func (d *DB) CloseAll() error {
+	for _, conn := range []*sqlx.DB{d.Conn} {
+		if err := closeConn(conn); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func closeConn(conn *sqlx.DB) error {
+	return conn.Close()
+}
+
+func Init(DBURI string) (*DB, error) {
+	var result DB
+	var err error
+	result.Conn, err = openDBConnection(DBURI, "pgx")
+	if err != nil {
+		return nil, err
+	}
+	result.URI = DBURI
+
+	if err := testConnection(result.Conn); err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func InitWithMigrate(DBURI string, up bool) (*DB, error) {
+	var (
+		result DB
+		err    error
+	)
+	result.Conn, err = openDBConnection(DBURI, "pgx")
+	if err != nil {
+		return nil, err
+	}
+	result.URI = DBURI
+
+	if err = testConnection(result.Conn); err != nil {
+		return nil, err
+	}
+	if err = result.Migrate(DBURI, up); err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func openDBConnection(dbURI, driver string) (*sqlx.DB, error) {
+	conn, err := sqlx.Open(driver, dbURI)
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}
+
+func testConnection(conn *sqlx.DB) error {
+	err := conn.Ping()
+	if err != nil {
+		return errors.Wrap(err, "can't ping database")
+	}
+	return nil
+}
+
+func (db *DB) Migrate(url string, up bool) error {
+	source := bindata.Resource(migrations.AssetNames(), migrations.Asset)
+	driver, err := bindata.WithInstance(source)
+	if err != nil {
+		return errors.WithStack(errors.WithMessage(err,
+			"unable to instantiate driver from bindata"))
+	}
+	migration, err := migrate.NewWithSourceInstance("go-bindata",
+		driver, url)
+	if err != nil {
+		return errors.WithStack(errors.WithMessage(err,
+			"unable to start migration"))
+	}
+	if up {
+		if err = migration.Up(); err != nil && err.Error() != "no change" {
+			return errors.WithStack(errors.WithMessage(err,
+				"unable to migrate up"))
+		}
+	} else {
+		if err = migration.Down(); err != nil &&
+			err.Error() != "no change" {
+			return errors.WithStack(errors.WithMessage(err,
+				"unable to migrate down"))
+		}
+	}
+	return nil
+}
+
+func (d *DB) PingRoutine(interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	done := make(chan bool)
+
+	for {
+		select {
+		case <-done:
+			return
+		case t := <-ticker.C:
+			if err := testConnection(d.Conn); err != nil {
+				log.Error("failed to ping postrges db", "error", err, "ping_at", t)
+				// reconnect
+				if err := closeConn(d.Conn); err != nil {
+					log.Error("failed to close db connection", "error", err, "ping_at", t)
+				}
+				d.Conn, err = openDBConnection(d.URI, "pgx")
+				if err != nil {
+					log.Error("failed to reconnect", "error", err, "ping_at", t)
+				}
+			}
+		}
+	}
+}
-- 
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