DSNInjector

A tiny, zero-dependency Go library for parsing, building, and loading DSNs (Data Source Names / connection strings) of the form driver://login:password@host:port/database?opt=val. One generic parser serves databases (PostgreSQL, MySQL, MongoDB, Redis, SQLite, …) and any other scheme-shaped config — HTTP endpoints, message-bus URLs, API base URLs.

Features

• Parse a DSN into a map-backed value object with typed accessors (Driver, Host, Port, Login, Password, Database, Addr) and query options, including typed reads: OptionInt, OptionBool, OptionDuration.
• Build a DSN programmatically with New + WithHost/WithPort/… , rebuild any DSN with Marshal, and validate required fields with Require.
• Read a DSN straight from an environment variable (Unmarshal / UnmarshalOrEmpty, with fallback defaults) and load .env-style files with InitEnvFrom.
• Log safely with Redacted() (masks the password); MustParse for tests and init-time configuration.
• Standard library only — no third-party runtime dependencies, no CGO.

Install

go get github.com/prorochestvo/dsninjector

Usage

package main

import (
	"fmt"

	"github.com/prorochestvo/dsninjector"
)

func main() {
	ds, err := dsninjector.Parse("mysql://user:password@localhost:3306/dbname?charset=utf8")
	if err != nil {
		panic(err)
	}

	fmt.Println(ds.Driver())          // "mysql"
	fmt.Println(ds.Addr())            // "localhost:3306"
	fmt.Println(ds.Port())            // 3306
	fmt.Println(ds.Database())        // "dbname"
	fmt.Println(ds.Option("charset")) // "utf8"
}

Read a DSN from the environment, optionally loading a .env file first:

_ = dsninjector.InitEnvFrom(".env") // missing files are skipped

ds, err := dsninjector.Unmarshal("DATABASE_DSN", "postgres://localhost:5432/app")
if err != nil {
	panic(err)
}
_ = ds

Build one programmatically and log it without leaking the password:

ds := dsninjector.New(
	dsninjector.WithDriver("postgres"),
	dsninjector.WithHost("db.internal"),
	dsninjector.WithPort(5432),
	dsninjector.WithLogin("app"),
	dsninjector.WithPassword("s3cret"),
	dsninjector.WithDatabase("app"),
)
fmt.Println(ds.Redacted()) // postgres://app:xxxxx@db.internal:5432/app

Notes

• A scheme is optional: localhost:5432, example.com, and filesystem paths parse without a driver:// prefix.
• Reserved fields are driver, hostname, port, login, password, database; every other query-string key is a free-form option.
• Getters coerce on read and never panic — Port returns 0 for an empty or non-numeric port.
• Credentials without a colon are treated as password-only: redis://secret@host yields Password() == "secret" and Login() == "".
• Secrets: Marshal emits credentials in cleartext and Redacted() masks only the password field — never log a DSN whose secret rides in the host, port, or a query option (?apikey=…). AuthBasicBase64 is encoding, not secrecy.

License

MIT