fix bug with envloader when there are empty overwrites

Author: junedev

envloader/envloader.go

@@ -28,38 +28,51 @@ func LoadEnvs(folderPath string) error {
 	customConfigPath := path.Join(folderPath, stage+".env")
 	defaultConfigPath := path.Join(folderPath, DefaultEnvFile)
 
-	missingEnvs := []string{}
-	combinedEnvMap, err := createCombinedEnvMap(customConfigPath, defaultConfigPath)
+	err := checkForMissingEnvs(customConfigPath, defaultConfigPath)
 	if err != nil {
 		return err
 	}
 
-	for envName, value := range combinedEnvMap {
-		if value == "" && os.Getenv(envName) == "" {
-			missingEnvs = append(missingEnvs, envName)
-		}
-	}
-	if len(missingEnvs) > 0 {
-		return fmt.Errorf("environment variables missing: %v", missingEnvs)
-	}
 	return godotenv.Load(customConfigPath, defaultConfigPath)
 }
 
-func createCombinedEnvMap(customConfigPath string, defaultConfigPath string) (map[string]string, error) {
+// checkForMissingEnvs errors if an env was defined in the default but not set in
+// either the default file, custom config file or environment variables.
+// Returns nil otherwise.
+func checkForMissingEnvs(customConfigPath string, defaultConfigPath string) error {
 	envMapCustom, err := godotenv.Read(customConfigPath)
 	if err != nil {
-		return nil, err
+		return fmt.Errorf("error reading custom config file: %w", err)
 	}
 	envMapDefault, err := godotenv.Read(defaultConfigPath)
 	if err != nil {
-		return nil, err
+		return fmt.Errorf("error reading default config file: %w", err)
+	}
+
+	fmt.Println(envMapCustom)
+	fmt.Println(envMapDefault)
+
+	envMapCombined := map[string]string{}
+	for key, value := range envMapCustom {
+		envMapCombined[key] = value
 	}
 
-	envMapCombined := envMapCustom
 	for key, value := range envMapDefault {
 		if envMapCombined[key] == "" {
 			envMapCombined[key] = value
 		}
 	}
-	return envMapCombined, nil
+
+	missingEnvs := []string{}
+	for envName, value := range envMapCombined {
+		_, keyPresentInCustomEnvs := envMapCustom[envName]
+		if value == "" && os.Getenv(envName) == "" && !keyPresentInCustomEnvs {
+			missingEnvs = append(missingEnvs, envName)
+		}
+	}
+	if len(missingEnvs) > 0 {
+		return fmt.Errorf("environment variables missing: %v", missingEnvs)
+	}
+
+	return nil
 }

envloader/envloader_test.go

@@ -9,15 +9,16 @@ import (
 )
 
 func TestLoadingDefaults(t *testing.T) {
+	defer cleanup(t)
 	err := LoadEnvs("testdata")
 	if assert.NoError(t, err) {
 		assert.Equal(t, "defaultValue1", os.Getenv("ENVLOADER_TESTKEY1"))
 		assert.Equal(t, "defaultValue2", os.Getenv("ENVLOADER_TESTKEY2"))
 	}
-	assert.NoError(t, cleanup())
 }
 
 func TestOverwritingDefaultsWithCustomsSuccess(t *testing.T) {
+	defer cleanup(t)
 	DefaultEnvFile = "production_missing.env"
 	StageEnv = "ENVLOADER_APP_ENV"
 	err := os.Setenv("ENVLOADER_APP_ENV", "teststage_success")
@@ -28,10 +29,10 @@ func TestOverwritingDefaultsWithCustomsSuccess(t *testing.T) {
 		assert.Equal(t, "customValue2", os.Getenv("ENVLOADER_TESTKEY2"))
 		assert.Equal(t, "customValue3", os.Getenv("ENVLOADER_TESTKEY3"))
 	}
-	assert.NoError(t, cleanup())
 }
 
 func TestNotOverwritingExistingEnvs(t *testing.T) {
+	defer cleanup(t)
 	err := os.Setenv("ENVLOADER_TESTKEY1", "outerValue1")
 	assert.NoError(t, err)
 	err = os.Setenv("ENVLOADER_TESTKEY2", "outerValue2")
@@ -48,10 +49,10 @@ func TestNotOverwritingExistingEnvs(t *testing.T) {
 		assert.Equal(t, "outerValue2", os.Getenv("ENVLOADER_TESTKEY2"))
 		assert.Equal(t, "customValue3", os.Getenv("ENVLOADER_TESTKEY3"))
 	}
-	assert.NoError(t, cleanup())
 }
 
 func TestOverwritingDefaultsWithCustomsFail(t *testing.T) {
+	defer cleanup(t)
 	DefaultEnvFile = "production_missing.env"
 	StageEnv = "ENVLOADER_APP_ENV"
 	err := os.Setenv("ENVLOADER_APP_ENV", "teststage_fail")
@@ -60,27 +61,35 @@ func TestOverwritingDefaultsWithCustomsFail(t *testing.T) {
 	if assert.Error(t, err) {
 		assert.Equal(t, "environment variables missing: [ENVLOADER_TESTKEY3]", err.Error())
 	}
-	assert.NoError(t, cleanup())
+}
+
+func TestOverwriteEmptyDefaultWithEmptyValue(t *testing.T) {
+	defer cleanup(t)
+	DefaultEnvFile = "production_missing.env"
+	StageEnv = "ENVLOADER_APP_ENV"
+	err := os.Setenv("ENVLOADER_APP_ENV", "empty_overwrite")
+	assert.NoError(t, err)
+	err = LoadEnvs("testdata")
+	assert.NoError(t, err)
+	assert.Equal(t, "", os.Getenv("ENVLOADER_TESTKEY3"))
 }
 
 func TestMissingEnvsAreDetected(t *testing.T) {
+	defer cleanup(t)
+	DefaultEnvFile = "production_missing.env"
 	StageEnv = "ENVLOADER_APP_ENV"
 	err := os.Setenv("ENVLOADER_APP_ENV", "missing")
 	assert.NoError(t, err)
 	err = LoadEnvs("testdata")
-	assert.Equal(t, "environment variables missing: [ENVLOADER_TESTKEY4]", err.Error())
-	assert.NoError(t, cleanup())
+	assert.Error(t, err)
+	assert.Equal(t, "environment variables missing: [ENVLOADER_TESTKEY3]", err.Error())
 }
 
-func cleanup() error {
+func cleanup(t *testing.T) {
 	for _, line := range os.Environ() {
 		if strings.HasPrefix(line, "ENVLOADER") {
 			pair := strings.Split(line, "=")
-			err := os.Unsetenv(pair[0])
-			if err != nil {
-				return err
-			}
+			assert.NoError(t, os.Unsetenv(pair[0]))
 		}
 	}
-	return nil
 }

envloader/testdata/empty_overwrite.env

@@ -0,0 +1 @@
+ENVLOADER_TESTKEY3=""

envloader/testdata/missing.env

@@ -1,2 +1 @@
-ENVLOADER_TESTKEY4=
-ENVLOADER_TESTKEY3=customValue3
+ENVLOADER_TESTKEY4=customValue4