Initial MVP commit

internal/platform/datasource/postgres/factory.go

@@ -0,0 +1,71 @@
+package postgres
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"strings"
+
+	"gitea.maximumdirect.net/ejr/weatherapi/internal/platform/config"
+	"gitea.maximumdirect.net/ejr/weatherapi/internal/platform/datasource"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+type Factory struct{}
+
+func (Factory) Driver() string {
+	return "postgres"
+}
+
+func (Factory) Open(ctx context.Context, cfg config.DatabaseConfig) (datasource.DataSource, error) {
+	dsn, err := buildDSN(cfg.Params.URI, cfg.Params.Username, cfg.Params.Password)
+	if err != nil {
+		return nil, fmt.Errorf("open postgres datasource %q: %w", cfg.Name, err)
+	}
+
+	pool, err := pgxpool.New(ctx, dsn)
+	if err != nil {
+		return nil, fmt.Errorf("open postgres datasource %q: %w", cfg.Name, err)
+	}
+
+	if err := pool.Ping(ctx); err != nil {
+		pool.Close()
+		return nil, fmt.Errorf("open postgres datasource %q: ping: %w", cfg.Name, err)
+	}
+
+	return &DataSource{pool: pool}, nil
+}
+
+type DataSource struct {
+	pool *pgxpool.Pool
+}
+
+func (d *DataSource) Pool() *pgxpool.Pool {
+	if d == nil {
+		return nil
+	}
+	return d.pool
+}
+
+func (d *DataSource) Close() {
+	if d == nil || d.pool == nil {
+		return
+	}
+	d.pool.Close()
+}
+
+func buildDSN(uri, username, password string) (string, error) {
+	u, err := url.Parse(strings.TrimSpace(uri))
+	if err != nil {
+		return "", fmt.Errorf("invalid params.uri: %w", err)
+	}
+	if strings.TrimSpace(u.Scheme) == "" {
+		return "", fmt.Errorf("invalid params.uri: missing scheme")
+	}
+	if strings.TrimSpace(u.Host) == "" {
+		return "", fmt.Errorf("invalid params.uri: missing host")
+	}
+
+	u.User = url.UserPassword(strings.TrimSpace(username), strings.TrimSpace(password))
+	return u.String(), nil
+}