init: rapid_dashboards app from fn_registry

connections.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"path/filepath"
+
+	"fn-registry/functions/infra"
+)
+
+// OpenConnections opens all database connections defined in the config.
+// basePath is the directory of the YAML file — file-based drivers (sqlite, duckdb)
+// resolve relative paths from there.
+func OpenConnections(conns map[string]ConnConfig, basePath string) (map[string]*sql.DB, error) {
+	pool := make(map[string]*sql.DB, len(conns))
+
+	for name, cfg := range conns {
+		db, err := openOne(name, cfg, basePath)
+		if err != nil {
+			// Close already opened connections on failure.
+			CloseConnections(pool)
+			return nil, err
+		}
+		pool[name] = db
+	}
+
+	return pool, nil
+}
+
+func openOne(name string, cfg ConnConfig, basePath string) (*sql.DB, error) {
+	switch cfg.Driver {
+	case "sqlite":
+		return infra.SQLiteOpen(cfg.Path, basePath)
+	case "postgres":
+		port := cfg.Port
+		if port == 0 {
+			port = 5432
+		}
+		return infra.PostgresOpen(cfg.Host, port, cfg.User, cfg.Password, cfg.Database, cfg.SSLMode)
+	case "duckdb":
+		p := cfg.Path
+		if basePath != "" && p != "" && p != ":memory:" && !filepath.IsAbs(p) {
+			p = filepath.Join(basePath, p)
+		}
+		return infra.DuckDBOpen(p)
+	case "clickhouse":
+		port := cfg.Port
+		if port == 0 {
+			port = 9000
+		}
+		return infra.ClickHouseOpen(cfg.Host, port, cfg.User, cfg.Password, cfg.Database)
+	default:
+		return nil, fmt.Errorf("connection %q: unsupported driver %q", name, cfg.Driver)
+	}
+}
+
+// CloseConnections closes all database connections.
+func CloseConnections(pool map[string]*sql.DB) {
+	for _, db := range pool {
+		infra.DBClose(db)
+	}
+}