Add generated Bob database integration

database.go

@@ -0,0 +1,144 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"embed"
+	"errors"
+	"fmt"
+	"io/fs"
+	"log"
+	"sync"
+
+	//"github.com/georgysavva/scany/v2/pgxscan"
+	//"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/jackc/pgx/v5/stdlib"
+	_ "github.com/jackc/pgx/v5/stdlib"
+	"github.com/pressly/goose/v3"
+	"github.com/stephenafamo/bob"
+)
+
+//go:embed migrations/*.sql
+var embedMigrations embed.FS
+
+type postgres struct {
+	BobDB bob.DB
+}
+
+var (
+	PGInstance *postgres
+	pgOnce     sync.Once
+)
+
+func doMigrations(connection_string string) error {
+	log.Println("Connecting to database at", connection_string)
+	db, err := sql.Open("pgx", connection_string)
+	if err != nil {
+		return fmt.Errorf("Failed to open database connection: %w", err)
+	}
+	defer db.Close()
+	row := db.QueryRowContext(context.Background(), "SELECT version()")
+	var val string
+	if err := row.Scan(&val); err != nil {
+		return fmt.Errorf("Failed to get database version query result: %w", err)
+	}
+	log.Printf("Connected to: %s", val)
+
+	fsys, err := fs.Sub(embedMigrations, "migrations")
+	if err != nil {
+		return fmt.Errorf("Failed to get migrations embedded directory: %w", err)
+	}
+	provider, err := goose.NewProvider(goose.DialectPostgres, db, fsys)
+	if err != nil {
+		return fmt.Errorf("Failed to create goose provider: %w", err)
+	}
+	//goose.SetBaseFS(embedMigrations)
+
+	current, target, err := provider.GetVersions(context.Background())
+	if err != nil {
+		return fmt.Errorf("Faield to get goose versions: %w", err)
+	}
+	log.Printf("Current version %d, need to be at version %d", current, target)
+	results, err := provider.Up(context.Background())
+	if err != nil {
+		return fmt.Errorf("Failed to run migrations: %w", err)
+	}
+	if len(results) > 0 {
+		for _, r := range results {
+			log.Printf("Migration %d %s", r.Source.Version, r.Direction)
+		}
+	} else {
+		log.Println("No migrations necessary.")
+	}
+	return nil
+}
+
+func initializeDatabase(ctx context.Context, uri string) error {
+	needs, err := needsMigrations(uri)
+	if err != nil {
+		return fmt.Errorf("Failed to determine if migrations are needed: %v", err)
+	}
+	if needs == nil {
+		return errors.New("Can't read variable 'needs' - it's nil")
+	}
+	if *needs {
+		//return errors.New(fmt.Sprintf("Must migrate database before connecting: %t", *needs))
+		log.Println("Handling database migrations")
+		err = doMigrations(uri)
+		if err != nil {
+			return fmt.Errorf("Failed to handle migrations: %v", err)
+		}
+	} else {
+		log.Println("No database migrations necessary")
+	}
+
+	pgOnce.Do(func() {
+		db, e := pgxpool.New(ctx, uri)
+		bobDB := bob.NewDB(stdlib.OpenDBFromPool(db))
+		PGInstance = &postgres{bobDB}
+		err = e
+	})
+	if err != nil {
+		return fmt.Errorf("unable to create connection pool: %w", err)
+	}
+
+	var current string
+	query := `SELECT current_database()`
+	err = PGInstance.BobDB.QueryRow(query).Scan(&current)
+	if err != nil {
+		return fmt.Errorf("Failed to get database current: %w", err)
+	}
+	log.Println("Connected to", current)
+	return nil
+}
+
+func needsMigrations(connection_string string) (*bool, error) {
+	log.Println("Connecting to database at", connection_string)
+	db, err := sql.Open("pgx", connection_string)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to open database connection: %w", err)
+	}
+	defer db.Close()
+	row := db.QueryRowContext(context.Background(), "SELECT version()")
+	var val string
+	if err := row.Scan(&val); err != nil {
+		return nil, fmt.Errorf("Failed to get database version query result: %w", err)
+	}
+	log.Printf("Connected to: %s", val)
+
+	fsys, err := fs.Sub(embedMigrations, "migrations")
+	if err != nil {
+		return nil, fmt.Errorf("Failed to get migrations embedded directory: %w", err)
+	}
+	provider, err := goose.NewProvider(goose.DialectPostgres, db, fsys)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to create goose provider: %w", err)
+	}
+
+	hasPending, err := provider.HasPending(context.Background())
+	if err != nil {
+		return nil, err
+	}
+	return &hasPending, nil
+}