Add minimal web interface

config/config.go

@@ -0,0 +1,98 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/pelletier/go-toml"
+)
+
+var ErrNotFound = errors.New("no config file found")
+
+type Config struct {
+	ListenAddr string `toml:"ListenAddr"`
+	LogLevel   string `toml:"LogLevel"`
+}
+
+type InvalidValueError struct {
+	Key string
+}
+
+func (ive *InvalidValueError) Error() string {
+	return fmt.Sprintf("invalid value: config key %s has invalid value", ive.Key)
+}
+
+func FromReader(r io.Reader) (*Config, error) {
+	var c Config
+	// Set some defaults
+	c.ListenAddr = ":5566"
+	c.LogLevel = "INFO"
+
+	decoder := toml.NewDecoder(r)
+	if err := decoder.Decode(&c); err != nil {
+		return nil, fmt.Errorf("error parsing config file: %w", err)
+	}
+
+	return &c, c.Verify()
+}
+
+func (c *Config) Verify() error {
+	// Check that LogLevel is valid
+	switch c.LogLevel {
+	case "DEBUG", "INFO", "WARN", "ERROR":
+	default:
+		return &InvalidValueError{Key: "LogLevel"}
+	}
+	return nil
+}
+
+func (c *Config) UpdateFromEnv() error {
+	if loglevel, found := os.LookupEnv("DOGTAMER_LOGLEVEL"); found {
+		c.LogLevel = loglevel
+	}
+	if listenAddr, found := os.LookupEnv("DOGTAMER_LISTENADDR"); found {
+		c.ListenAddr = listenAddr
+	}
+
+	return c.Verify()
+}
+
+func FromFile(path string) (*Config, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("Error opening config file: %w", err)
+	}
+
+	return FromReader(f)
+}
+
+func FromDefaultLocations(path string) (*Config, error) {
+	defaultLocations := []string{
+		"dogtamer.toml",
+		"/etc/dogtamer.toml",
+	}
+	baseConfigDir, err := os.UserConfigDir()
+	if err == nil {
+		userConfigFile := filepath.Join(baseConfigDir, "dogtamer", "dogtamer.toml")
+		defaultLocations = append(defaultLocations, userConfigFile)
+	}
+
+	for _, fname := range defaultLocations {
+		if _, err := os.Stat(fname); os.IsNotExist(err) {
+			continue
+		}
+
+		cfg, err := FromFile(fname)
+		if err != nil {
+			continue
+
+		}
+
+		return cfg, cfg.UpdateFromEnv()
+	}
+
+	return nil, ErrNotFound
+}

config/config_test.go

@@ -0,0 +1,126 @@
+package config_test
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.uio.no/torjus/dogtamer/config"
+)
+
+func TestConfig(t *testing.T) {
+	t.Run("TestEmpty", func(t *testing.T) {
+		emptyConfig := ""
+		sr := strings.NewReader(emptyConfig)
+
+		c, err := config.FromReader(sr)
+		if err != nil {
+			t.Fatalf("Error reading empty config: %s", err)
+		}
+
+		// Ensure proper defaults are set
+		if c.ListenAddr != ":5566" {
+			t.Errorf("Unexpected ListenAddr: %s", c.ListenAddr)
+		}
+		if c.LogLevel != "INFO" {
+			t.Errorf("Unexpected LogLevel: %s", c.LogLevel)
+		}
+	})
+
+	t.Run("TestWithValidValues", func(t *testing.T) {
+		configString := `
+		# Random comment
+		LogLevel = "DEBUG"
+		
+		ListenAddr = ":5555"
+		`
+		sr := strings.NewReader(configString)
+
+		c, err := config.FromReader(sr)
+		if err != nil {
+			t.Fatalf("Error reading config: %s", err)
+		}
+
+		if c.ListenAddr != ":5555" {
+			t.Errorf("Unexpected ListenAddr: %s", c.ListenAddr)
+		}
+
+		if c.LogLevel != "DEBUG" {
+			t.Errorf("Unexpected LogLevel: %s", c.LogLevel)
+		}
+	})
+	t.Run("TestWithInValidValues", func(t *testing.T) {
+		configString := `
+		# Random comment
+		LogLevel = "INVALID"
+		
+		ListenAddr = ":5555"
+		`
+		sr := strings.NewReader(configString)
+
+		_, err := config.FromReader(sr)
+		ive, ok := err.(*config.InvalidValueError)
+		if !ok {
+			t.Fatalf("Error is of wrong type: %T", ive)
+		}
+		if ive.Key != "LogLevel" {
+			t.Errorf("Error has wrong key: %s", ive.Key)
+		}
+	})
+	t.Run("TestFromEnv", func(t *testing.T) {
+		os.Clearenv()
+
+		envValues := map[string]string{
+			"DOGTAMER_LOGLEVEL":   "DEBUG",
+			"DOGTAMER_LISTENADDR": ":3333",
+		}
+
+		for k, v := range envValues {
+			if err := os.Setenv(k, v); err != nil {
+				t.Fatalf("Unable to set env values: %s", err)
+			}
+		}
+
+		emptyCfg := ""
+		sr := strings.NewReader(emptyCfg)
+
+		c, err := config.FromReader(sr)
+		if err != nil {
+			t.Fatalf("Error parsing config string: %s", err)
+		}
+		if err := c.UpdateFromEnv(); err != nil {
+			t.Errorf("Error updating config with environment")
+		}
+
+		if c.ListenAddr != envValues["DOGTAMER_LISTENADDR"] {
+			t.Errorf("ListenAddr has wrong value: %s", c.ListenAddr)
+		}
+		if c.LogLevel != envValues["DOGTAMER_LOGLEVEL"] {
+			t.Errorf("LogLevel has wrong value: %s", c.LogLevel)
+		}
+	})
+	t.Run("TestFromEnvInvalid", func(t *testing.T) {
+		os.Clearenv()
+
+		envValues := map[string]string{
+			"DOGTAMER_LOGLEVEL":   "TEST",
+			"DOGTAMER_LISTENADDR": ":3333",
+		}
+
+		for k, v := range envValues {
+			if err := os.Setenv(k, v); err != nil {
+				t.Fatalf("Unable to set env values: %s", err)
+			}
+		}
+		emptyCfg := ""
+		sr := strings.NewReader(emptyCfg)
+
+		c, err := config.FromReader(sr)
+		if err != nil {
+			t.Fatalf("Error parsing config string: %s", err)
+		}
+		if err := c.UpdateFromEnv(); err == nil {
+			t.Errorf("No error when parsing invalid env values")
+		}
+	})
+}