Codex first iteration

internal/app/config.go

@@ -0,0 +1,42 @@
+package app
+
+import (
+	"errors"
+	"os"
+	"time"
+)
+
+type Config struct {
+	Environment, Address, PublicBaseURL, StudentPIN, InstructorPIN, SessionSecret, LogLevel, LogFormat string
+	SessionDuration, ReadHeaderTimeout, ReadTimeout, WriteTimeout, IdleTimeout, ShutdownTimeout        time.Duration
+}
+
+func LoadConfigFromEnv() (Config, error) {
+	c := Config{Environment: get("APP_ENV", "development"), Address: get("HTTP_ADDRESS", ":8080"), PublicBaseURL: os.Getenv("PUBLIC_BASE_URL"), StudentPIN: os.Getenv("STUDENT_PIN"), InstructorPIN: os.Getenv("INSTRUCTOR_PIN"), SessionSecret: os.Getenv("SESSION_SIGNING_SECRET"), LogLevel: get("LOG_LEVEL", "info"), LogFormat: get("LOG_FORMAT", "text")}
+	var err error
+	c.SessionDuration, err = duration("SESSION_DURATION", "4h")
+	if err != nil {
+		return c, err
+	}
+	values := []struct {
+		target        *time.Duration
+		key, fallback string
+	}{{&c.ReadHeaderTimeout, "HTTP_READ_HEADER_TIMEOUT", "5s"}, {&c.ReadTimeout, "HTTP_READ_TIMEOUT", "30s"}, {&c.WriteTimeout, "HTTP_WRITE_TIMEOUT", "30s"}, {&c.IdleTimeout, "HTTP_IDLE_TIMEOUT", "60s"}, {&c.ShutdownTimeout, "HTTP_SHUTDOWN_TIMEOUT", "10s"}}
+	for _, value := range values {
+		*value.target, err = duration(value.key, value.fallback)
+		if err != nil {
+			return c, err
+		}
+	}
+	if c.StudentPIN == "" || c.InstructorPIN == "" || len(c.SessionSecret) < 32 || c.PublicBaseURL == "" {
+		return c, errors.New("STUDENT_PIN, INSTRUCTOR_PIN, PUBLIC_BASE_URL, and a 32+ character SESSION_SIGNING_SECRET are required")
+	}
+	return c, nil
+}
+func get(k, d string) string {
+	if v := os.Getenv(k); v != "" {
+		return v
+	}
+	return d
+}
+func duration(k, d string) (time.Duration, error) { return time.ParseDuration(get(k, d)) }