341: Fix Validation Rule Engine concurrency issues

etor/src/main/java/gov/hhs/cdc/trustedintermediary/etor/ruleengine/RuleEngine.java

@@ -28,7 +28,7 @@ public void unloadRules() {
         rules.clear();
     }
 
-    public void ensureRulesLoaded() {
+    public synchronized void ensureRulesLoaded() {
         if (rules.isEmpty()) {
             loadRules();
         }

etor/src/main/resources/rule_definitions.json

@@ -5,7 +5,7 @@
       "violationMessage": "Message doesn't have required receiver id",
       "conditions": [ ],
       "validations": [
-        "Bundle.entry.resource.ofType(MessageHeader).destination.receiver.resolve().identifier.value.exists()"
+        "Bundle.entry.resource.ofType(MessageHeader).destination.receiver.resolve().identifier.where(system = 'urn:ietf:rfc:3986').value.exists()"
       ]
     },
     {

etor/src/test/groovy/gov/hhs/cdc/trustedintermediary/etor/ruleengine/RuleEngineTest.groovy

@@ -39,6 +39,27 @@ class RuleEngineTest extends Specification {
         1 * mockRuleLoader.loadRules(_ as String) >> [Mock(Rule)]
     }
 
+    def "ensureRulesLoaded loads rules only once on multiple threads"() {
+        given:
+        def threadsNum = 2
+        def iterations = 4
+
+        when:
+        List<Thread> threads = []
+        (1..threadsNum).each { threadId ->
+            threads.add(new Thread({
+                for (int i = 0; i < iterations; i++) {
+                    ruleEngine.ensureRulesLoaded()
+                }
+            }))
+        }
+        threads*.start()
+        threads*.join()
+
+        then:
+        1 * mockRuleLoader.loadRules(_ as String) >> [Mock(Rule)]
+    }
+
     def "ensureRulesLoaded logs an error if there is an exception loading the rules"() {
         given:
         def exception = new RuleLoaderException("Error loading rules", new Exception())