add a configuration struct for runtime config options

internal/shareasecret/shareasecret.go

@@ -1,9 +1,13 @@
 package shareasecret
 
 import (
+	"errors"
 	"fmt"
 	"io/fs"
 	"net/http"
+	"os"
+
+	"github.com/joho/godotenv"
 )
 
 // deletionReasonExpired is a deletion reason used when secrets have exceeded their TTL (time to live)
@@ -16,6 +20,46 @@ const deletionReasonUserDeleted = "user_deleted"
 // hit or exceeded
 const deletionReasonMaximumViewCountHit = "maximum_view_count_hit"
 
+// Configuration contains all of the possible configuration options for the application.
+type Configuration struct {
+	Database struct {
+		Path string
+	}
+	Server struct {
+		BaseUrl       string
+		ListeningAddr string
+	}
+	SecretCreationRestrictions struct {
+		IPAddresses []string
+	}
+}
+
+// PopulateFromEnv populates all of the configuration values from environment variables, returning errors if this
+// cannot be achieved.
+func (c *Configuration) PopulateFromEnv() error {
+	err := godotenv.Load()
+	if err != nil && !errors.Is(err, os.ErrNotExist) {
+		return fmt.Errorf("loading env file: %w", err)
+	}
+
+	c.Database.Path = os.Getenv("SHAREASECRET_DB_PATH")
+	if c.Database.Path == "" {
+		return fmt.Errorf("SHAREASECRET_DB_PATH not set")
+	}
+
+	c.Server.BaseUrl = os.Getenv("SHAREASECRET_BASE_URL")
+	if c.Server.BaseUrl == "" {
+		return fmt.Errorf("SHAREASECRET_BASE_URL not set")
+	}
+
+	c.Server.ListeningAddr = os.Getenv("SHAREASECRET_LISTENING_ADDR")
+	if c.Server.ListeningAddr == "" {
+		c.Server.ListeningAddr = "127.0.0.1:8994"
+	}
+
+	return nil
+}
+
 // Application is a wrapper/container for the "ShareASecret" project. All jobs and entry points hang off of this
 // struct.
 type Application struct {
@@ -26,16 +70,16 @@ type Application struct {
 }
 
 // NewApplication initializes the Application struct which provides access to all available components of the project.
-func NewApplication(connectionString string, baseURL string, webAssets fs.FS) (*Application, error) {
-	db, err := newDatabase(connectionString)
+func NewApplication(config *Configuration, webAssets fs.FS) (*Application, error) {
+	db, err := newDatabase("file:" + config.Database.Path)
 	if err != nil {
 		return nil, fmt.Errorf("new db: %w", err)
 	}
 
 	application := &Application{
 		db:        db,
 		router:    http.NewServeMux(),
-		baseURL:   baseURL,
+		baseURL:   config.Server.BaseUrl,
 		webAssets: webAssets,
 	}
 	application.mapRoutes()

internal/shareasecret/shareasecret_test.go

@@ -11,7 +11,11 @@ import (
 var app *Application
 
 func TestMain(m *testing.M) {
-	a, err := NewApplication("file:shareasecret_test.db", "http://127.0.0.1:8999", os.DirFS("../web/"))
+	config := &Configuration{}
+	config.Database.Path = "shareasecret_test.db"
+	config.Server.BaseUrl = "http://127.0.0.1:8999"
+
+	a, err := NewApplication(config, os.DirFS("../web/"))
 	if err != nil {
 		panic(err)
 	}

shareasecret.go

@@ -2,12 +2,10 @@ package main
 
 import (
 	"embed"
-	"errors"
 	"io/fs"
 	"net/http"
 	"os"
 
-	"github.com/joho/godotenv"
 	"github.com/lsymds/shareasecret/internal/shareasecret"
 	"github.com/rs/zerolog/log"
 )
@@ -23,28 +21,11 @@ var version string = "0.0.1"
 func main() {
 	log.Info().Str("version", version).Msg("starting shareasecret")
 
-	// extract any required environment variables
-	err := godotenv.Load()
-	if err != nil && !errors.Is(err, os.ErrNotExist) {
-		log.Error().Err(err).Msg("loading .env file")
-		os.Exit(1)
-	}
-
-	dbPath := os.Getenv("SHAREASECRET_DB_PATH")
-	if dbPath == "" {
-		log.Error().Msg("SHAREASECRET_DB_PATH not set")
-		os.Exit(1)
-	}
+	config := &shareasecret.Configuration{}
 
-	baseUrl := os.Getenv("SHAREASECRET_BASE_URL")
-	if baseUrl == "" {
-		log.Error().Msg("SHAREASECRET_BASE_URL not set")
-		os.Exit(1)
-	}
-
-	listeningAddr := os.Getenv("SHAREASECRET_LISTENING_ADDR")
-	if listeningAddr == "" {
-		listeningAddr = "127.0.0.1:8994"
+	err := config.PopulateFromEnv()
+	if err != nil {
+		log.Error().Err(err).Msg("populating configuration")
 	}
 
 	webAssets, err := fs.Sub(embeddedWebAssets, "web")
@@ -54,7 +35,7 @@ func main() {
 	}
 
 	// initialize the wrapper application
-	application, err := shareasecret.NewApplication("file:"+dbPath, baseUrl, webAssets)
+	application, err := shareasecret.NewApplication(config, webAssets)
 	if err != nil {
 		log.Error().Err(err).Msg("initializing application")
 		os.Exit(1)
@@ -64,8 +45,8 @@ func main() {
 	application.RunDeleteExpiredSecretsJob()
 
 	// serve all HTTP endpoints
-	log.Info().Str("addr", listeningAddr).Msg("booting HTTP server")
-	err = http.ListenAndServe(listeningAddr, application)
+	log.Info().Str("addr", config.Server.ListeningAddr).Msg("booting HTTP server")
+	err = http.ListenAndServe(config.Server.ListeningAddr, application)
 	if err != nil {
 		log.Error().Err(err).Msg("listen and serve")
 		os.Exit(1)