Second checkpoint

internal/config/config.go

@@ -0,0 +1,72 @@
+// Package config loads application configuration from the environment.
+package config
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/caarlos0/env/v11"
+	"github.com/joho/godotenv"
+)
+
+// Config holds all configuration for the application. Values are read from
+// environment variables; a local .env file (if present) is loaded first.
+type Config struct {
+	HTTP     HTTPConfig
+	DB       DBConfig
+	S3       S3Config
+	RabbitMQ RabbitMQConfig
+}
+
+// HTTPConfig configures the HTTP server.
+type HTTPConfig struct {
+	Port              int           `env:"PORT" envDefault:"8080"`
+	ReadHeaderTimeout time.Duration `env:"HTTP_READ_HEADER_TIMEOUT" envDefault:"5s"`
+	ReadTimeout       time.Duration `env:"HTTP_READ_TIMEOUT" envDefault:"120s"`
+	WriteTimeout      time.Duration `env:"HTTP_WRITE_TIMEOUT" envDefault:"120s"`
+	IdleTimeout       time.Duration `env:"HTTP_IDLE_TIMEOUT" envDefault:"60s"`
+	ShutdownTimeout   time.Duration `env:"HTTP_SHUTDOWN_TIMEOUT" envDefault:"10s"`
+}
+
+// Addr returns the listen address for the HTTP server.
+func (c HTTPConfig) Addr() string {
+	return fmt.Sprintf(":%d", c.Port)
+}
+
+// DBConfig configures the Postgres connection.
+type DBConfig struct {
+	URL string `env:"DB_URL,required"`
+	// Schema is the Postgres schema migrations operate on. It is used by
+	// `migrate fresh` to know which schema to drop and recreate; in production
+	// this may be something other than "public".
+	Schema string `env:"DB_SCHEMA" envDefault:"public"`
+}
+
+// S3Config configures the S3/MinIO object store.
+type S3Config struct {
+	Endpoint  string `env:"S3_ENDPOINT,required"`
+	AccessKey string `env:"S3_ACCESS_KEY,required"`
+	SecretKey string `env:"S3_SECRET_KEY,required"`
+	Bucket    string `env:"S3_BUCKET" envDefault:"geofiles"`
+	UseSSL    bool   `env:"S3_USE_SSL" envDefault:"false"`
+}
+
+// RabbitMQConfig configures the RabbitMQ connection and example topology.
+type RabbitMQConfig struct {
+	URL      string `env:"RABBITMQ_URL,required"`
+	Exchange string `env:"RABBITMQ_EXCHANGE" envDefault:"gis.events"`
+	Queue    string `env:"RABBITMQ_QUEUE" envDefault:"gis.events.example"`
+}
+
+// Load reads configuration from the environment, loading an optional .env file
+// from the current working directory first.
+func Load() (*Config, error) {
+	// A missing .env file is not an error: in production we rely on real env vars.
+	_ = godotenv.Load()
+
+	cfg := &Config{}
+	if err := env.Parse(cfg); err != nil {
+		return nil, fmt.Errorf("parse config: %w", err)
+	}
+	return cfg, nil
+}