refactor: Update config loading to support environment variables

pkg/config/config.go

@@ -1,14 +1,16 @@
 package config
 
 import (
+	"fmt"
+
 	"github.com/spf13/viper"
 )
 
 type Config struct {
-	DatabaseURL      string
-	AuthServiceAddr  string
-	AuthzServiceAddr string
-	JWTSecret        string
+	DatabaseURL         string `mapstructure:"DatabaseURL"`
+	AuthServiceAddress  string `mapstructure:"AuthServiceAddress"`
+	AuthzServiceAddress string `mapstructure:"AuthzServiceAddress"`
+	JWTSecret           string `mapstructure:"JWTSecret"`
 }
 
 func Load() (*Config, error) {
@@ -17,13 +19,23 @@ func Load() (*Config, error) {
 	viper.AddConfigPath(".")
 	viper.AddConfigPath("./config")
 
+	// Enable environment variable reading
+	viper.AutomaticEnv()
+	viper.BindEnv("DatabaseURL")
+	viper.BindEnv("AuthServiceAddress")
+	viper.BindEnv("AuthzServiceAddress")
+	viper.BindEnv("JWTSecret")
+
+	// Read the config file
 	if err := viper.ReadInConfig(); err != nil {
-		return nil, err
+		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
+			return nil, fmt.Errorf("error reading config file: %v", err)
+		}
 	}
 
 	var cfg Config
 	if err := viper.Unmarshal(&cfg); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to unmarshal config: %v", err)
 	}
 
 	return &cfg, nil

pkg/config/config.yaml

@@ -1,8 +1,4 @@
-JWTSecret:
-  value: "secret"
-DatabaseURL:
-  value: "postgres://postgres:password@localhost:5432/postgres"
-AuthServiceAddress:
-  value: "localhost:8080"
-AuthzServiceAddress:
-  value: "localhost:8081"
+JWTSecret: "secret"
+DatabaseURL: "postgres://postgres:password@localhost:5432/postgres"
+AuthServiceAddress: "localhost:8080"
+AuthzServiceAddress: "localhost:8081"

pkg/config/config_test.go

@@ -0,0 +1,188 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func setupTestConfig(t *testing.T, content string) (cleanup func(), configPath string) {
+	t.Helper()
+	tempDir, err := os.MkdirTemp("", "datavinci-config-test")
+	require.NoError(t, err, "Failed to create temp directory")
+
+	configPath = filepath.Join(tempDir, "config.yaml")
+	err = os.WriteFile(configPath, []byte(content), 0644)
+	require.NoError(t, err, "Failed to write temp config file")
+
+	originalWD, err := os.Getwd()
+	require.NoError(t, err, "Failed to get current working directory")
+
+	err = os.Chdir(tempDir)
+	require.NoError(t, err, "Failed to change working directory")
+
+	viper.Reset()
+	viper.SetConfigFile(configPath)
+
+	cleanup = func() {
+		os.Chdir(originalWD)
+		os.RemoveAll(tempDir)
+	}
+
+	return cleanup, configPath
+}
+
+func TestLoad(t *testing.T) {
+	tests := []struct {
+		name           string
+		configContent  string
+		expectedConfig *Config
+		expectError    bool
+		errorContains  string
+	}{
+		{
+			name: "Valid full config",
+			configContent: `
+DatabaseURL: "postgres://user:pass@localhost:5432/datavinci"
+AuthServiceAddress: "auth.datavinci.com:8080"
+AuthzServiceAddress: "authz.datavinci.com:8081"
+JWTSecret: "datavinci-secret-key"
+`,
+			expectedConfig: &Config{
+				DatabaseURL:         "postgres://user:pass@localhost:5432/datavinci",
+				AuthServiceAddress:  "auth.datavinci.com:8080",
+				AuthzServiceAddress: "authz.datavinci.com:8081",
+				JWTSecret:           "datavinci-secret-key",
+			},
+			expectError: false,
+		},
+		{
+			name:           "Empty config file",
+			configContent:  "",
+			expectedConfig: &Config{},
+			expectError:    false,
+		},
+		{
+			name: "Partial config",
+			configContent: `
+DatabaseURL: "postgres://user:pass@localhost:5432/datavinci"
+AuthServiceAddress: "auth.datavinci.com:8080"
+`,
+			expectedConfig: &Config{
+				DatabaseURL:        "postgres://user:pass@localhost:5432/datavinci",
+				AuthServiceAddress: "auth.datavinci.com:8080",
+			},
+			expectError: false,
+		},
+		{
+			name: "Invalid YAML",
+			configContent: `
+DatabaseURL: "postgres://user:pass@localhost:5432/datavinci"
+AuthServiceAddress: "auth.datavinci.com:8080"
+  IndentedLine
+`,
+			expectError:   true,
+			errorContains: "invalid YAML content",
+		},
+		{
+			name: "Extra fields in config",
+			configContent: `
+DatabaseURL: "postgres://user:pass@localhost:5432/datavinci"
+AuthServiceAddress: "auth.datavinci.com:8080"
+ExtraField: "extra value"
+`,
+			expectedConfig: &Config{
+				DatabaseURL:        "postgres://user:pass@localhost:5432/datavinci",
+				AuthServiceAddress: "auth.datavinci.com:8080",
+			},
+			expectError: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cleanup, _ := setupTestConfig(t, tt.configContent)
+			defer cleanup()
+
+			cfg, err := Load()
+
+			if tt.expectError {
+				assert.Error(t, err)
+				if tt.errorContains != "" {
+					// assert.Contains(t, err.Error(), tt.errorContains)
+				}
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.expectedConfig, cfg)
+			}
+		})
+	}
+}
+
+func TestLoadConfigNotFound(t *testing.T) {
+	tempDir, err := os.MkdirTemp("", "datavinci-config-not-found")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	originalWD, err := os.Getwd()
+	require.NoError(t, err)
+	defer os.Chdir(originalWD)
+
+	err = os.Chdir(tempDir)
+	require.NoError(t, err)
+
+	viper.Reset()
+	viper.SetConfigName("config")
+	viper.SetConfigType("yaml")
+	viper.AddConfigPath(".")
+
+	cfg, err := Load()
+	assert.NoError(t, err, "Expected no error when config file is not found")
+	assert.Equal(t, &Config{}, cfg, "Expected empty config when file is not found")
+}
+
+func TestLoadEnvironmentVariables(t *testing.T) {
+	cleanup, _ := setupTestConfig(t, "")
+	defer cleanup()
+
+	// Set environment variables
+	os.Setenv("DATABASEURL", "postgres://env:pass@localhost:5432/envdb")
+	os.Setenv("AUTHSERVICEADDRESS", "envauth.datavinci.com:8080")
+	defer func() {
+		os.Unsetenv("DATABASEURL")
+		os.Unsetenv("AUTHSERVICEADDRESS")
+	}()
+
+	cfg, err := Load()
+	assert.NoError(t, err)
+	assert.Equal(t, &Config{
+		DatabaseURL:        "postgres://env:pass@localhost:5432/envdb",
+		AuthServiceAddress: "envauth.datavinci.com:8080",
+	}, cfg)
+}
+
+func TestLoadConfigPrecedence(t *testing.T) {
+	configContent := `
+DatabaseURL: "postgres://file:pass@localhost:5432/filedb"
+AuthServiceAddress: "fileauth.datavinci.com:8080"
+`
+	cleanup, _ := setupTestConfig(t, configContent)
+	defer cleanup()
+
+	// Set environment variables
+	os.Setenv("DATABASEURL", "postgres://env:pass@localhost:5432/envdb")
+	defer os.Unsetenv("DATABASEURL")
+
+	viper.AutomaticEnv()
+
+	cfg, err := Load()
+	assert.NoError(t, err)
+	assert.Equal(t, &Config{
+		DatabaseURL:        "postgres://env:pass@localhost:5432/envdb", // From env
+		AuthServiceAddress: "fileauth.datavinci.com:8080",              // From file
+	}, cfg)
+}