Expand env vars in Values/StringValues [#34]

internal/env/config.go

@@ -93,11 +93,31 @@ func NewConfig(stdout, stderr io.Writer) (*Config, error) {
 		cfg.logDebug()
 	}
 
+	cfg.loadValuesSecrets()
+
 	cfg.deprecationWarn()
 
 	return &cfg, nil
 }
 
+func (cfg *Config) loadValuesSecrets() {
+	findVar := regexp.MustCompile(`\$\{?(\w+)\}?`)
+
+	replacer := func(varName string) string {
+		sigils := regexp.MustCompile(`[${}]`)
+		varName = sigils.ReplaceAllString(varName, "")
+
+		if value, ok := os.LookupEnv(varName); ok {
+			return value
+		}
+
+		return ""
+	}
+
+	cfg.Values = findVar.ReplaceAllStringFunc(cfg.Values, replacer)
+	cfg.StringValues = findVar.ReplaceAllStringFunc(cfg.StringValues, replacer)
+}
+
 func (cfg Config) logDebug() {
 	if cfg.KubeToken != "" {
 		cfg.KubeToken = "(redacted)"

internal/env/config_test.go

@@ -183,6 +183,21 @@ func (suite *ConfigTestSuite) TestLogDebugCensorsKubeToken() {
 	suite.Equal(kubeToken, cfg.KubeToken) // The actual config value should be left unchanged
 }
 
+func (suite *ConfigTestSuite) TestNewConfigWithValuesSecrets() {
+	suite.unsetenv("VALUES")
+	suite.unsetenv("STRING_VALUES")
+	suite.setenv("SECRET_FIRE", "Eru_Ilúvatar")
+	suite.setenv("SECRET_RINGS", "1")
+	suite.setenv("PLUGIN_VALUES", "fire=$SECRET_FIRE,water=${SECRET_WATER}")
+	suite.setenv("PLUGIN_STRING_VALUES", "rings=${SECRET_RINGS}")
+
+	cfg, err := NewConfig(&strings.Builder{}, &strings.Builder{})
+	suite.Require().NoError(err)
+
+	suite.Equal("fire=Eru_Ilúvatar,water=", cfg.Values)
+	suite.Equal("rings=1", cfg.StringValues)
+}
+
 func (suite *ConfigTestSuite) setenv(key, val string) {
 	orig, ok := os.LookupEnv(key)
 	if ok {