initial commit

datastores/sql/postgres/config.go

@@ -0,0 +1,80 @@
+package postgres
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// Config holds the database configuration.
+type Config struct {
+	ctx      context.Context
+	Host     string
+	Port     string
+	User     string
+	Password string
+	DBName   string
+	SSLMode  string
+}
+
+// ConfigOption is a functional option for Config.
+type ConfigOption func(*Config)
+
+// WithContext sets the context on the config.
+func WithContext(ctx context.Context) ConfigOption {
+	return func(c *Config) {
+		c.ctx = ctx
+	}
+}
+
+// NewConfig creates a new database configuration from environment variables.
+// DB_HOST, DB_PORT, DB_USER, DB_PASSWORD, DB_SSL_MODE fall back to sensible
+// defaults. DB_NAME is required and must be set in the environment.
+func NewConfig(opts ...ConfigOption) *Config {
+	c := &Config{
+		Host:     getEnvOrDefault("DB_HOST", "localhost"),
+		Port:     getEnvOrDefault("DB_PORT", "5432"),
+		User:     getEnvOrDefault("DB_USER", "postgres"),
+		Password: getEnvOrDefault("DB_PASSWORD", "postgres"),
+		DBName:   os.Getenv("DB_NAME"),
+		SSLMode:  getEnvOrDefault("DB_SSL_MODE", "disable"),
+	}
+	for _, opt := range opts {
+		opt(c)
+	}
+	return c
+}
+
+// DSN returns the database connection string in key=value format.
+func (c *Config) DSN() string {
+	return fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=%s",
+		c.Host, c.Port, c.User, c.Password, c.DBName, c.SSLMode)
+}
+
+// Connect creates a new single database connection using pgx.
+func (c *Config) Connect() (*pgx.Conn, error) {
+	conn, err := pgx.Connect(c.Context(), c.DSN())
+	if err != nil {
+		return nil, fmt.Errorf("failed to connect to database: %w", err)
+	}
+	return conn, nil
+}
+
+// Context returns the context associated with this config, defaulting to
+// context.Background() if none was set.
+func (c *Config) Context() context.Context {
+	if c.ctx == nil {
+		c.ctx = context.Background()
+	}
+	return c.ctx
+}
+
+// getEnvOrDefault returns the value of an environment variable or a fallback.
+func getEnvOrDefault(key, fallback string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+	return fallback
+}