Raise exception when node is not on PATH

lib/galaxy/tools/__init__.py

@@ -753,8 +753,10 @@ class Tool(Dictifiable):
             mod = __import__(module, globals(), locals(), [cls])
             self.tool_action = getattr(mod, cls)()
             if getattr(self.tool_action, "requires_js_runtime", False):
-                if expressions.find_engine(self.app.config) is None:
-                    message = REQUIRES_JS_RUNTIME_MESSAGE % self.tool_id
+                try:
+                    expressions.find_engine(self.app.config)
+                except Exception:
+                    message = REQUIRES_JS_RUNTIME_MESSAGE % self.tool_id or self.tool_uuid
                     raise Exception(message)
         # Tests
         self.__parse_tests(tool_source)

lib/galaxy/tools/expressions/util.py

@@ -5,4 +5,6 @@ def find_engine(config):
     nodejs_path = getattr(config, "nodejs_path", None)
     if nodejs_path is None:
         nodejs_path = which("nodejs") or which("node") or None
+    if nodejs_path is None:
+        raise Exception("nodejs or node not found on PATH")
     return nodejs_path