Load schemas in init()

Issue Observed
--------------
When multiple goroutines uses different `Project` instances concurrently,
Go's race detector complains data races.

Issue Detail
------------
`schema_helpers.go` have some global variables and they are initialized
by `setupSchemaLoaders()` when `validate()` and other schema functions
are called for the first time.
However, `setupSchemaLoaders()` does not have mutex, so some times
multiple gorutines proceed into this function, then a race happens.

Suggested Resolution
--------------------
We can add a mutex to `setupSchemaLoader()` to avoid the race condition.
However, the function is supposed to cache results and called not so
many times. Therefore, in this patch, we simply initialize schemas in
`init()`.

Signed-off-by: Iwasaki Yudai <yudai@arielworks.com>

Author: yudai

config/schema_helpers.go

@@ -17,6 +17,16 @@ var (
 	schemaV2                 map[string]interface{}
 )
 
+func init() {
+	if err := setupSchemaLoaders(schemaDataV1, &schemaV1, &schemaLoaderV1, &constraintSchemaLoaderV1); err != nil {
+		panic(err)
+	}
+
+	if err := setupSchemaLoaders(servicesSchemaDataV2, &schemaV2, &schemaLoaderV2, &constraintSchemaLoaderV2); err != nil {
+		panic(err)
+	}
+}
+
 type (
 	environmentFormatChecker struct{}
 	portsFormatChecker       struct{}

config/validation.go

@@ -157,10 +157,6 @@ func invalidTypeMessage(service, key string, err gojsonschema.ResultError) strin
 }
 
 func validate(serviceMap RawServiceMap) error {
-	if err := setupSchemaLoaders(schemaDataV1, &schemaV1, &schemaLoaderV1, &constraintSchemaLoaderV1); err != nil {
-		return err
-	}
-
 	serviceMap = convertServiceMapKeysToStrings(serviceMap)
 
 	dataLoader := gojsonschema.NewGoLoader(serviceMap)
@@ -174,10 +170,6 @@ func validate(serviceMap RawServiceMap) error {
 }
 
 func validateV2(serviceMap RawServiceMap) error {
-	if err := setupSchemaLoaders(servicesSchemaDataV2, &schemaV2, &schemaLoaderV2, &constraintSchemaLoaderV2); err != nil {
-		return err
-	}
-
 	serviceMap = convertServiceMapKeysToStrings(serviceMap)
 
 	dataLoader := gojsonschema.NewGoLoader(serviceMap)
@@ -250,10 +242,6 @@ func generateErrorMessages(serviceMap RawServiceMap, schema map[string]interface
 }
 
 func validateServiceConstraints(service RawService, serviceName string) error {
-	if err := setupSchemaLoaders(schemaDataV1, &schemaV1, &schemaLoaderV1, &constraintSchemaLoaderV1); err != nil {
-		return err
-	}
-
 	service = convertServiceKeysToStrings(service)
 
 	var validationErrors []string
@@ -289,10 +277,6 @@ func validateServiceConstraints(service RawService, serviceName string) error {
 }
 
 func validateServiceConstraintsv2(service RawService, serviceName string) error {
-	if err := setupSchemaLoaders(servicesSchemaDataV2, &schemaV2, &schemaLoaderV2, &constraintSchemaLoaderV2); err != nil {
-		return err
-	}
-
 	service = convertServiceKeysToStrings(service)
 
 	var validationErrors []string