feature: Support remote docker host

Implemented get_docker_host() to enable sagemaker.local to work with remote docker host

Author: samadwar

src/sagemaker/local/entities.py

@@ -22,7 +22,7 @@
 
 import sagemaker.local.data
 from sagemaker.local.image import _SageMakerContainer
-from sagemaker.local.utils import copy_directory_structure, move_to_destination
+from sagemaker.local.utils import copy_directory_structure, move_to_destination, get_docker_host
 from sagemaker.utils import DeferredError, get_config_value
 
 logger = logging.getLogger(__name__)
@@ -295,7 +295,7 @@ def start(self, input_data, output_data, transform_resources, **kwargs):
         _wait_for_serving_container(serving_port)
 
         # Get capabilities from Container if needed
-        endpoint_url = "http://localhost:%s/execution-parameters" % serving_port
+        endpoint_url = "http://%s:%d/execution-parameters" % (get_docker_host(), serving_port)
         response, code = _perform_request(endpoint_url)
         if code == 200:
             execution_parameters = json.loads(response.read())
@@ -607,7 +607,7 @@ def _wait_for_serving_container(serving_port):
     i = 0
     http = urllib3.PoolManager()
 
-    endpoint_url = "http://localhost:%s/ping" % serving_port
+    endpoint_url = "http://%s:%d/ping" % (get_docker_host(), serving_port)
     while True:
         i += 5
         if i >= HEALTH_CHECK_TIMEOUT_LIMIT:

src/sagemaker/local/local_session.py

@@ -21,6 +21,7 @@
 from botocore.exceptions import ClientError
 
 from sagemaker.local.image import _SageMakerContainer
+from sagemaker.local.utils import get_docker_host
 from sagemaker.local.entities import (
     _LocalEndpointConfig,
     _LocalEndpoint,
@@ -448,7 +449,7 @@ def invoke_endpoint(
         Returns:
             object: Inference for the given input.
         """
-        url = "http://localhost:%s/invocations" % self.serving_port
+        url = "http://%s:%d/invocations" % (get_docker_host(), self.serving_port)
         headers = {}
 
         if ContentType is not None:

src/sagemaker/local/utils.py

@@ -16,6 +16,7 @@
 import os
 import shutil
 import subprocess
+import json
 
 from distutils.dir_util import copy_tree
 from six.moves.urllib.parse import urlparse
@@ -127,3 +128,21 @@ def get_child_process_ids(pid):
             return pids + get_child_process_ids(child_pid)
     else:
         return []
+    
+def get_docker_host():
+    """Discover remote docker host address (if applicable) or use "localhost"
+    
+    Use "docker context inspect" to read current docker host endpoint url
+    
+    Args:
+
+    Returns:
+        docker_host (str): Docker host DNS or IP
+    """
+    try:
+        docker_context_string = os.popen("docker context inspect").read()
+        docker_context_host_url = json.loads(docker_context_string)[0]['Endpoints']['docker']['Host']
+        docker_host = docker_context_host_url.split("//")[1].rsplit(":")[0] if not docker_context_host_url.startswith("unix") else "localhost"
+    except:
+        docker_host = "localhost"
+    return docker_host