Make Quarkus initialization thread-safe in BaseFunction

extensions/azure-functions-http/runtime/src/main/java/io/quarkus/azure/functions/resteasy/runtime/BaseFunction.java

@@ -40,7 +40,13 @@ public class BaseFunction {
 
     private static final int BUFFER_SIZE = 8096;
 
-    protected static void initQuarkus() {
+    protected static void ensureQuarkusInitialized() {
+        // The following will atomically call initQuarkus if this hasn't been done before,
+        // and therefore make sure that deploymentStatus, started and bootstrapError are all set as necessary
+        QuarkusInitializer.ensureQuarkusInitialized();
+    }
+
+    private static void initQuarkus() {
         StringWriter error = new StringWriter();
         PrintWriter errorWriter = new PrintWriter(error, true);
         if (Application.currentApplication() == null) { // were we already bootstrapped?  Needed for mock azure unit testing.
@@ -55,6 +61,7 @@ protected static void initQuarkus() {
                 bootstrapError = true;
                 errorWriter.println("Quarkus bootstrap failed.");
                 ex.printStackTrace(errorWriter);
+                log.error("Quarkus bootstrap failed.", ex);
             }
         } else {
             errorWriter.println("Quarkus bootstrapped successfully.");
@@ -174,4 +181,19 @@ public void close() {
                 future.completeExceptionally(new RuntimeException("Connection closed"));
         }
     }
+
+    private static final class QuarkusInitializer {
+
+        static {
+            // Using an initializer block ensures that initQuarkus is called exactly once,
+            // and is called atomically, thereby making it thread-safe.
+
+            initQuarkus();
+        }
+
+        private static void ensureQuarkusInitialized() {
+            // No code needed; the static initializer block will take care of the initialization.
+            // This method exists to ensure that this class is loaded, and therefore Quarkus is initialized.
+        }
+    }
 }

extensions/azure-functions-http/runtime/src/main/java/io/quarkus/azure/functions/resteasy/runtime/Function.java

@@ -14,9 +14,9 @@ public class Function extends BaseFunction {
     public HttpResponseMessage run(
             @HttpTrigger(name = "req") HttpRequestMessage<Optional<String>> request,
             final ExecutionContext context) {
-        if (!started && !bootstrapError) {
-            initQuarkus();
-        }
+
+        ensureQuarkusInitialized();
+
         if (bootstrapError) {
             HttpResponseMessage.Builder responseBuilder = request
                     .createResponseBuilder(HttpStatus.valueOf(500)).body(