common/database/connector.go
Ask Bjørn Hansen 96afb77844 database: create shared database package with configurable patterns
Extract ~200 lines of duplicate database connection code from api/ntpdb/
and monitor/ntpdb/ into common/database/ package. Creates foundation for
database consolidation while maintaining zero breaking changes.

Files added:
- config.go: Unified configuration with package-specific defaults
- connector.go: Dynamic connector pattern from Boostport
- pool.go: Configurable connection pool management
- metrics.go: Optional Prometheus metrics integration
- interfaces.go: Shared database interfaces for consistent patterns

Key features:
- Configuration-driven approach (API: 25/10 connections + metrics,
  Monitor: 10/5 connections, no metrics)
- Optional Prometheus metrics when registerer provided
- Backward compatibility via convenience functions
- Flexible config file loading (explicit paths + search-based)

Dependencies: Added mysql driver and yaml parsing for database configuration.
2025-07-12 16:54:24 -07:00

89 lines
2.0 KiB
Go

package database
import (
"context"
"database/sql/driver"
"errors"
"fmt"
"os"
"github.com/go-sql-driver/mysql"
"gopkg.in/yaml.v3"
)
// from https://github.com/Boostport/dynamic-database-config
// CreateConnectorFunc is a function that creates a database connector
type CreateConnectorFunc func() (driver.Connector, error)
// Driver implements the sql/driver interface with dynamic configuration
type Driver struct {
CreateConnectorFunc CreateConnectorFunc
}
// Driver returns the driver instance
func (d Driver) Driver() driver.Driver {
return d
}
// Connect creates a new database connection using the dynamic connector
func (d Driver) Connect(ctx context.Context) (driver.Conn, error) {
connector, err := d.CreateConnectorFunc()
if err != nil {
return nil, fmt.Errorf("error creating connector from function: %w", err)
}
return connector.Connect(ctx)
}
// Open is not supported for dynamic configuration
func (d Driver) Open(name string) (driver.Conn, error) {
return nil, errors.New("open is not supported")
}
// createConnector creates a connector function that reads configuration from a file
func createConnector(configFile string) CreateConnectorFunc {
return func() (driver.Connector, error) {
dbFile, err := os.Open(configFile)
if err != nil {
return nil, err
}
defer dbFile.Close()
dec := yaml.NewDecoder(dbFile)
cfg := Config{}
err = dec.Decode(&cfg)
if err != nil {
return nil, err
}
dsn := cfg.MySQL.DSN
if len(dsn) == 0 {
dsn = os.Getenv("DATABASE_DSN")
if len(dsn) == 0 {
return nil, fmt.Errorf("dsn config in database.yaml or DATABASE_DSN environment variable required")
}
}
dbcfg, err := mysql.ParseDSN(dsn)
if err != nil {
return nil, err
}
if user := cfg.MySQL.User; len(user) > 0 {
dbcfg.User = user
}
if pass := cfg.MySQL.Pass; len(pass) > 0 {
dbcfg.Passwd = pass
}
if name := cfg.MySQL.DBName; len(name) > 0 {
dbcfg.DBName = name
}
return mysql.NewConnector(dbcfg)
}
}