fix: perform deeper healthcheck

setup.py

@@ -45,7 +45,7 @@ def read(fname):
     # freeze numpy version because of the python2 bug
     # in 16.0: https://github.com/numpy/numpy/pull/12754
     install_requires=['sagemaker-containers==2.5.0', 'chainer==5.0.0', 'retrying==1.3.3',
-                      'numpy==1.16.2'],
+                      'numpy==1.16.2', 'requests==2.22.0'],
 
     extras_require={
         'test': [

src/sagemaker_chainer_container/serving.py

@@ -13,6 +13,7 @@
 from __future__ import absolute_import
 
 import logging
+import requests
 
 import chainer
 import numpy as np
@@ -29,6 +30,17 @@
 logger.setLevel(logging.DEBUG)
 
 
+def default_healthcheck_fn():
+    """A default healthcheck_fn for Chainer. Sends GET request to model server.
+
+    Returns:
+        (flask.Response): status code returned by server.
+    """
+    ping_url = "http://0.0.0.0:{}/ping".format(env.http_port)
+    res = requests.get(ping_url)
+    return requests.Response(res.status_code)
+
+
 def default_input_fn(input_data, content_type):
     """Takes request data and de-serializes the data into an object for prediction.
 
@@ -117,6 +129,7 @@ def main(environ, start_response):
         user_module_transformer = _user_module_transformer(user_module)
         user_module_transformer.initialize()
         app = worker.Worker(transform_fn=user_module_transformer.transform,
-                            module_name=serving_env.module_name)
+                            module_name=serving_env.module_name,
+                            healthcheck_fn=default_healthcheck_fn)
 
     return app(environ, start_response)