Merge pull request #59 from fabiante/feat/refactor-env-config

Author: fabiante

.gitignore

@@ -1,3 +1,9 @@
+# devtools
 .idea
+
+# config files
 /.env
+/app.*
+
+# other
 *.sqlite

README.md

@@ -2,6 +2,17 @@
 
 Application to manage and resolve [PURL](https://en.wikipedia.org/wiki/Persistent_uniform_resource_locator) links.
 
+## Usage
+
+### Configuration
+
+The application can be configured using:
+
+- env variables, prefixed with `PERSURL_` (example: `PERSURL_DB_DSN`)
+- config files (example: `app.yml`)
+
+Have a look at `example.config.yml` for an example configuration.
+
 ## Documentation
 
 Until the documentation becomes large enough, this README will be used to
@@ -32,7 +43,7 @@ test specifications ensure correct behaviour. Test drivers execute test specific
 
 #### Load Tests
 
-Load tests can enabled via the env variable `TEST_LOAD=1`.
+Load tests can enabled via the env variable `TEST_LOAD=1` or setting `test_load` to `1` in your config file.
 
 These run the application and generate load by running multiple agents simulating user behaviour.
 The motivation of these tests is to ensure that the application can be used for a large user base which

config/env.go

@@ -2,50 +2,16 @@ package config
 
 import (
 	"errors"
-	"fmt"
-	"log"
-	"os"
-	"strconv"
 
-	"github.com/joho/godotenv"
+	"github.com/spf13/viper"
 )
 
-func LoadEnv() {
-	path := ".env"
-
-	// check if .env file exists - if not, exit early.
-	_, err := os.Stat(path)
-	if errors.Is(err, os.ErrNotExist) {
-		return
-	}
-
-	err = godotenv.Load(path)
-	if err != nil {
-		panic(fmt.Errorf("loading env failed: %w", err))
-	}
-}
-
-func DbDSN() string {
-	dsn := os.Getenv("PERSURL_DB_DSN")
-	if dsn == "" {
-		dsn = os.Getenv("DATABASE_URL")
-	}
-	if dsn == "" {
-		log.Fatalf("persurl db dsn may not be empty")
-	}
-	return dsn
-}
-
-func DbMaxConnections() int {
-	val := os.Getenv("PERSURL_DB_MAX_CONNECTIONS")
-	if val == "" {
-		val = "10"
-	}
-
-	maxCon, err := strconv.ParseInt(val, 10, 32)
-	if err != nil {
-		log.Fatalf("invalid db max connection parameter %s", val)
+func setupEnv(v *viper.Viper) error {
+	errs := []error{
+		v.BindEnv("test_load", "TEST_LOAD"),
+		v.BindEnv("db.dsn", "PERSURL_DB_DSN", "DATABASE_URL"),
+		v.BindEnv("db.max_connections", "PERSURL_DB_MAX_CONNECTIONS"),
 	}
 
-	return int(maxCon)
+	return errors.Join(errs...)
 }

config/values.go

@@ -0,0 +1,23 @@
+package config
+
+import (
+	"errors"
+)
+
+func DbDSN() string {
+	dsn := vip.GetString("db.dsn")
+
+	if dsn == "" {
+		panic(errors.New("db dsn may not be empty"))
+	}
+
+	return dsn
+}
+
+func DbMaxConnections() int {
+	return vip.GetInt("db.max_connections")
+}
+
+func TestLoad() bool {
+	return vip.IsSet("test_load")
+}

config/viper.go

@@ -0,0 +1,44 @@
+package config
+
+import (
+	"errors"
+
+	"github.com/spf13/viper"
+)
+
+var vip *viper.Viper
+
+func init() {
+	vip = setupViper()
+}
+
+func setupViper() *viper.Viper {
+	v := viper.New()
+
+	// loading
+	v.AddConfigPath(".")
+	v.SetConfigName("app")
+
+	// helper to panic on any error
+	check := func(e error) {
+		if e != nil {
+			panic(e)
+		}
+	}
+
+	// defaults
+	v.SetDefault("db.max_connections", 10)
+
+	// env binding
+	check(setupEnv(v))
+
+	// trigger config parsing - optional
+	if err := v.ReadInConfig(); err != nil {
+		var configFileNotFoundError viper.ConfigFileNotFoundError
+		if !errors.As(err, &configFileNotFoundError) {
+			check(err)
+		}
+	}
+
+	return v
+}

example.config.yml

@@ -0,0 +1,8 @@
+# Example configuration - copy as app.yml and modify
+
+# Enable this if you want to run load tests
+# test_load: true
+
+db:
+  dsn: postgresql://persurl:persurl@localhost:5432/persurl?sslmode=disable
+  max_connections: 10

example.env

@@ -5,34 +5,41 @@ go 1.21
 require (
 	github.com/doug-martin/goqu/v9 v9.18.0
 	github.com/gin-gonic/gin v1.9.1
-	github.com/joho/godotenv v1.5.1
 	github.com/lib/pq v1.10.1
 	github.com/lopezator/migrator v0.3.1
 	github.com/spf13/cobra v1.7.0
+	github.com/spf13/viper v1.16.0
 	github.com/stretchr/testify v1.8.3
 )
 
 require (
 	github.com/bytedance/sonic v1.9.1 // indirect
 	github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/fsnotify/fsnotify v1.6.0 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.2 // indirect
 	github.com/gin-contrib/sse v0.1.0 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/go-playground/validator/v10 v10.14.0 // indirect
 	github.com/goccy/go-json v0.10.2 // indirect
-	github.com/google/go-cmp v0.5.9 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.4 // indirect
 	github.com/leodido/go-urn v1.2.4 // indirect
+	github.com/magiconair/properties v1.8.7 // indirect
 	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.8 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/spf13/afero v1.9.5 // indirect
+	github.com/spf13/cast v1.5.1 // indirect
+	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/subosito/gotenv v1.4.2 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.11 // indirect
 	golang.org/x/arch v0.3.0 // indirect
@@ -41,5 +48,6 @@ require (
 	golang.org/x/sys v0.8.0 // indirect
 	golang.org/x/text v0.9.0 // indirect
 	google.golang.org/protobuf v1.30.0 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )