88 lines
3.1 KiB
Go
88 lines
3.1 KiB
Go
// Package config is responsible for one thing only: reading configuration
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// from environment variables and handing back a single, typed Config struct
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// that the rest of the app can use.
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//
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// Why centralize this instead of calling os.Getenv() all over the codebase?
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// - One place to see every setting the app needs.
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// - One place to define sane defaults for local development.
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// - Easy to swap the *source* later (e.g. read from a file, from Vault,
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// from AWS Secrets Manager) without touching any other package.
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package config
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import (
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"os"
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"strings"
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)
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// Config holds every piece of runtime configuration the application needs.
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// It is built once, in main(), and then passed down (by value - it's a
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// small, read-only struct) into whichever package needs it: the router,
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// the database connector, the session manager, the OAuth config, etc.
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type Config struct {
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// Port is the TCP port the HTTP server listens on.
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Port string
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// Env distinguishes "development" from "production". Currently used
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// to decide whether the session cookie requires HTTPS (Secure flag).
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Env string
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// --- MySQL connection settings ---
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DBHost string
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DBPort string
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DBUser string
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DBPassword string
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DBName string
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// --- Redis connection settings (used for session storage) ---
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RedisAddr string
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// --- Google OAuth2 settings ---
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GoogleClientID string
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GoogleClientSecret string
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GoogleRedirectURL string
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// AllowedOrigins is the CORS allowlist: which frontend origins are
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// permitted to call this API from browser JavaScript.
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AllowedOrigins []string
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}
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// Load reads every setting from the process environment, falling back to
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// sensible local-development defaults when a variable isn't set. In
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// production you would set all of these explicitly (e.g. via
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// docker-compose "environment:", a systemd unit, or your orchestrator's
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// secret/config mechanism) rather than relying on the defaults.
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func Load() Config {
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return Config{
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Port: getEnv("PORT", "8080"),
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Env: getEnv("ENV", "development"),
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DBHost: getEnv("DB_HOST", "127.0.0.1"),
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DBPort: getEnv("DB_PORT", "3306"),
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DBUser: getEnv("DB_USER", "root"),
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DBPassword: getEnv("DB_PASSWORD", "devpass"),
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DBName: getEnv("DB_NAME", "go_simple_api"),
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RedisAddr: getEnv("REDIS_ADDR", "127.0.0.1:6379"),
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GoogleClientID: getEnv("GOOGLE_CLIENT_ID", ""),
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GoogleClientSecret: getEnv("GOOGLE_CLIENT_SECRET", ""),
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GoogleRedirectURL: getEnv("GOOGLE_REDIRECT_URL", "http://localhost:8080/auth/google/callback"),
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// ALLOWED_ORIGINS is a comma-separated list, e.g.:
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// ALLOWED_ORIGINS=http://localhost:3000,https://myapp.com
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// strings.Split on a single-value default still works fine and
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// yields a one-element slice.
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AllowedOrigins: strings.Split(getEnv("ALLOWED_ORIGINS", "http://localhost:3000"), ","),
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}
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}
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// getEnv reads a single environment variable, returning fallback if it's
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// unset or empty. It's unexported (lowercase) because nothing outside this
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// package needs to read raw env vars directly - everyone else should go
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// through the Config struct instead.
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func getEnv(key, fallback string) string {
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if v := os.Getenv(key); v != "" {
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return v
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}
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return fallback
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}
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