Support bash kernel in notebook-http mode (#382)

* Support bash kernel in notebook-http mode
* Add tests for bash kernel and startup banner

Author: kevin-bates

kernel_gateway/gatewayapp.py

@@ -562,12 +562,18 @@ def init_http_server(self):
                               'no available port could be found.')
             self.exit(1)
 
-    def start(self):
-        """Starts an IO loop for the application."""
+    def start_app(self):
+        """Starts the application (with ioloop to follow). """
         super(KernelGatewayApp, self).start()
         self.log.info('Jupyter Kernel Gateway {} is available at http{}://{}:{}'.format(
             KernelGatewayApp.version, 's' if self.keyfile else '', self.ip, self.port
         ))
+
+    def start(self):
+        """Starts an IO loop for the application."""
+
+        self.start_app()
+
         self.io_loop = ioloop.IOLoop.current()
 
         if sys.platform != 'win32':

kernel_gateway/notebook_http/request_utils.py

@@ -25,6 +25,8 @@ def format_request(bundle, kernel_language=''):
     bundle = json.dumps(bundle)
     if kernel_language.lower() == 'perl':
         statement = "my $REQUEST = {}".format(bundle)
+    elif kernel_language.lower() == 'bash':
+        statement = "REQUEST={}".format(bundle)
     else:
         statement = "REQUEST = {}".format(bundle)
     return statement

kernel_gateway/tests/notebook_http/test_request_utils.py

@@ -162,3 +162,8 @@ def test_format_request_with_a_kernel_language_perl(self):
         test_request = ('''{"body": "", "headers": {}, "args": {}, "path": {}}''')
         request_code = format_request(test_request, 'perl')
         self.assertTrue(request_code.startswith("my $REQUEST"), 'Call format_request with a kernel language "perl" was not formatted correctly')
+
+    def test_format_request_with_a_kernel_language_bash(self):
+        test_request = ('''{"body": "", "headers": {}, "args": {}, "path": {}}''')
+        request_code = format_request(test_request, 'bash')
+        self.assertTrue(request_code.startswith("REQUEST=\"{"), 'Call format_request with a kernel language "bash" was not formatted correctly')

kernel_gateway/tests/test_gatewayapp.py

@@ -6,8 +6,11 @@
 import logging
 import nbformat
 import os
+from io import StringIO
 import unittest
+from unittest.mock import patch
 from kernel_gateway.gatewayapp import KernelGatewayApp, ioloop
+from kernel_gateway import __version__
 from ..notebook_http.swagger.handlers import SwaggerSpecHandler
 from tornado.testing import AsyncHTTPTestCase, ExpectLog
 
@@ -101,6 +104,15 @@ def test_load_notebook_local(self):
         app.init_configurables()
         self.assertEqual(app.seed_notebook, nb_contents)
 
+    @patch('sys.stderr', new_callable=StringIO)
+    def test_start_banner(self, stderr):
+
+        app = KernelGatewayApp()
+        app.init_configurables()
+        app.start_app()
+        banner = stderr.getvalue()
+        self.assertIn(f"Jupyter Kernel Gateway {__version__}", banner)
+
 
 class TestGatewayAppBase(AsyncHTTPTestCase, ExpectLog):
     """Base class for integration style tests using HTTP/Websockets against an