Make connecting to server more robust (#133)

pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "flit_core.buildapi"
 [project]
 # Check https://flit.readthedocs.io/en/latest/pyproject_toml.html for all available sections
 name = "ansys-additive-core"
-version = "0.16.dev1"
+version = "0.16.dev2"
 description = "A python client for the Ansys Additive service"
 readme = "README.rst"
 requires-python = ">=3.9,<4"

src/ansys/additive/core/additive.py

@@ -51,7 +51,7 @@
 import ansys.additive.core.misc as misc
 from ansys.additive.core.porosity import PorositySummary
 from ansys.additive.core.progress_logger import ProgressLogger
-from ansys.additive.core.server_utils import find_open_port, launch_server
+from ansys.additive.core.server_utils import find_open_port, launch_server, server_ready
 from ansys.additive.core.simulation import SimulationError
 from ansys.additive.core.single_bead import SingleBeadSummary
 from ansys.additive.core.thermal_history import ThermalHistoryInput, ThermalHistorySummary
@@ -120,6 +120,9 @@ def __init__(
         self._simulation_stub = SimulationServiceStub(self._channel)
         self._about_stub = AboutServiceStub(self._channel)
 
+        if not server_ready(self._about_stub):
+            raise RuntimeError("Unable to connect to server")
+
         # Setup data directory
         self._user_data_path = USER_DATA_PATH
         if not os.path.exists(self._user_data_path):  # pragma: no cover

src/ansys/additive/core/server_utils.py

@@ -25,6 +25,9 @@
 import subprocess
 import time
 
+from ansys.api.additive.v0.about_pb2_grpc import AboutServiceStub
+from google.protobuf.empty_pb2 import Empty
+
 from ansys.additive.core import USER_DATA_PATH
 
 DEFAULT_ANSYS_VERSION = "241"
@@ -111,3 +114,32 @@ def find_open_port() -> int:
     port = s.getsockname()[1]
     s.close()
     return port
+
+
+def server_ready(stub: AboutServiceStub, retries: int = 5) -> bool:
+    """Return whether the server is ready.
+
+    Parameters
+    ----------
+    stub: AboutServiceStub
+        Stub used to call the about service on the server.
+    retries: int
+        Number of times to retry before giving up. An exponential backoff delay
+        is used between each retry.
+
+    Returns
+    -------
+    bool:
+        True means server is ready. False means the number of retries was exceeded
+        without successfully connecting to the server.
+    """
+    ready = False
+    for i in range(retries):
+        try:
+            stub.About(Empty())
+            ready = True
+            break
+        except Exception:
+            time.sleep(i + 1)
+
+    return ready

tests/parametric_study/test_parametric_runner.py

@@ -23,6 +23,7 @@
 from unittest.mock import create_autospec
 
 import pandas as pd
+import pytest
 
 from ansys.additive.core import (
     AdditiveMachine,
@@ -279,9 +280,9 @@ def test_create_microstructure_input_assigns_defaults_for_nans():
     assert input.material == material
 
 
-def test_simulate_sorts_by_priority():
+def test_simulate_sorts_by_priority(tmp_path: pytest.TempPathFactory):
     # arrange
-    study = ps.ParametricStudy(study_name="test_study")
+    study = ps.ParametricStudy("test_study", tmp_path)
     material = AdditiveMaterial(name="test_material")
     sb = SingleBeadInput(id="test_1", material=material)
     p = PorosityInput(id="test_2", material=material)
@@ -300,9 +301,9 @@ def test_simulate_sorts_by_priority():
     mock_additive.simulate.assert_called_once_with(inputs)
 
 
-def test_simulate_filters_by_priority():
+def test_simulate_filters_by_priority(tmp_path: pytest.TempPathFactory):
     # arrange
-    study = ps.ParametricStudy(study_name="test_study")
+    study = ps.ParametricStudy("test_study", tmp_path)
     material = AdditiveMaterial(name="test_material")
     sb = SingleBeadInput(id="test_1", material=material)
     p = PorosityInput(id="test_2", material=material)
@@ -321,9 +322,9 @@ def test_simulate_filters_by_priority():
     mock_additive.simulate.assert_called_once_with(inputs)
 
 
-def test_simulate_filters_by_single_simulation_type():
+def test_simulate_filters_by_single_simulation_type(tmp_path: pytest.TempPathFactory):
     # arrange
-    study = ps.ParametricStudy(study_name="test_study")
+    study = ps.ParametricStudy("test_study", tmp_path)
     material = AdditiveMaterial(name="test_material")
     sb = SingleBeadInput(id="test_1", material=material)
     p = PorosityInput(id="test_2", material=material)
@@ -342,9 +343,9 @@ def test_simulate_filters_by_single_simulation_type():
     mock_additive.simulate.assert_called_once_with(inputs)
 
 
-def test_simulate_filters_by_simulation_type_list():
+def test_simulate_filters_by_simulation_type_list(tmp_path: pytest.TempPathFactory):
     # arrange
-    study = ps.ParametricStudy(study_name="test_study")
+    study = ps.ParametricStudy("test_study", tmp_path)
     material = AdditiveMaterial(name="test_material")
     sb = SingleBeadInput(id="test_1", material=material)
     p = PorosityInput(id="test_2", material=material)
@@ -367,9 +368,9 @@ def test_simulate_filters_by_simulation_type_list():
     mock_additive.simulate.assert_called_once_with(inputs)
 
 
-def test_simulate_skips_simulations_with_missing_materials():
+def test_simulate_skips_simulations_with_missing_materials(tmp_path: pytest.TempPathFactory):
     # arrange
-    study = ps.ParametricStudy(study_name="test_study")
+    study = ps.ParametricStudy("test_study", tmp_path)
     material = AdditiveMaterial(name="test_material")
     sb = SingleBeadInput(id="test_1", material=material)
     p = PorosityInput(id="test_2", material=material)

tests/parametric_study/test_parametric_study.py

@@ -20,7 +20,6 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-import os
 import platform
 from unittest.mock import PropertyMock, create_autospec, patch
 import uuid
@@ -113,7 +112,7 @@ def test_load_raises_exception_when_version_too_great(tmp_path: pytest.TempPathF
             ps.ParametricStudy.load(filename)
 
 
-@pytest.mark.skipif(platform.system != "Windows", reason="Only runs on Windows.")
+@pytest.mark.skipif(platform.system() != "Windows", reason="Test only valid on Windows.")
 def test_load_reads_linux_file_on_windows(tmp_path: pytest.TempPathFactory):
     # arrange
     filename = test_utils.get_test_file_path("linux.ps")
@@ -125,7 +124,7 @@ def test_load_reads_linux_file_on_windows(tmp_path: pytest.TempPathFactory):
     assert study != None
 
 
-@pytest.mark.skipif(platform.system == "Windows", reason="Only runs on linux.")
+@pytest.mark.skipif(platform.system() == "Windows", reason="Test only valid on Linux.")
 def test_load_reads_windows_file_on_linux(tmp_path: pytest.TempPathFactory):
     # arrange
     filename = test_utils.get_test_file_path("windows.ps")
@@ -151,9 +150,6 @@ def test_save_and_load_returns_original_object(tmp_path: pytest.TempPathFactory)
     assert study.data_frame().equals(study2.data_frame())
     assert study2.file_name == test_path
 
-    # cleanup
-    os.remove(f"{study_name}.ps")
-
 
 def test_add_summaries_with_porosity_summary_adds_row(tmp_path: pytest.TempPathFactory):
     # arrange

tests/test_additive.py

@@ -27,6 +27,7 @@
 
 from ansys.api.additive import __version__ as api_version
 from ansys.api.additive.v0.about_pb2 import AboutResponse
+import ansys.api.additive.v0.about_pb2_grpc
 from ansys.api.additive.v0.about_pb2_grpc import AboutServiceStub
 import ansys.platform.instancemanagement as pypim
 from callee import Contains
@@ -59,6 +60,10 @@ def test_Additive_init_connects_with_defaults(monkeypatch):
     monkeypatch.setattr(ansys.additive.core.additive, "launch_server", mock_launcher)
     mock_insecure_channel = create_autospec(grpc.insecure_channel, return_value=channel)
     monkeypatch.setattr(grpc, "insecure_channel", mock_insecure_channel)
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
 
     # act
     additive = Additive()
@@ -100,6 +105,10 @@ def test_Additive_init_can_connect_with_pypim(monkeypatch):
     monkeypatch.setattr(pypim, "connect", mock_connect)
     monkeypatch.setattr(pypim, "is_configured", mock_is_configured)
     monkeypatch.setattr(grpc, "insecure_channel", mock_insecure_channel)
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
 
     # act
     additive = Additive()
@@ -132,6 +141,10 @@ def test_Additive_init_connects_using_ANSYS_ADDITIVE_ADDRESS_if_available(monkey
     )
     mock_insecure_channel = create_autospec(grpc.insecure_channel, return_value=channel)
     monkeypatch.setattr(grpc, "insecure_channel", mock_insecure_channel)
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
 
     # act
     additive = Additive()
@@ -157,6 +170,10 @@ def test_Additive_init_connects_with_ip_and_port_parameters(monkeypatch):
     )
     mock_insecure_channel = create_autospec(grpc.insecure_channel, return_value=channel)
     monkeypatch.setattr(grpc, "insecure_channel", mock_insecure_channel)
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
 
     # act
     additive = Additive(host=ip, port=port)
@@ -185,6 +202,10 @@ def test_Additive_init_converts_hostname_to_ip(monkeypatch):
     monkeypatch.setattr(grpc, "insecure_channel", mock_insecure_channel)
     mock_gethostbyname = create_autospec(socket.gethostbyname, return_value=ip)
     monkeypatch.setattr(socket, "gethostbyname", mock_gethostbyname)
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
 
     # act
     additive = Additive(host=host, port=port)
@@ -196,6 +217,29 @@ def test_Additive_init_converts_hostname_to_ip(monkeypatch):
     )
 
 
+def test_Additive_init_raises_exception_if_server_ready_false(monkeypatch):
+    # arrange
+    ip = "1.2.3.4"
+    port = 12345
+    target = f"{ip}:{port}"
+    channel = grpc.insecure_channel(
+        "channel_str",
+        options=[
+            ("grpc.max_receive_message_length", MAX_MESSAGE_LENGTH),
+        ],
+    )
+    mock_insecure_channel = create_autospec(grpc.insecure_channel, return_value=channel)
+    monkeypatch.setattr(grpc, "insecure_channel", mock_insecure_channel)
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=False
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
+
+    # act, assert
+    with pytest.raises(RuntimeError, match="Unable to connect to server"):
+        Additive(host=ip, port=port)
+
+
 @pytest.mark.parametrize(
     "input",
     [
@@ -205,17 +249,27 @@ def test_Additive_init_converts_hostname_to_ip(monkeypatch):
         ThermalHistoryInput(),
     ],
 )
-def test_simulate_without_material_assigned_raises_exception(input):
+def test_simulate_without_material_assigned_raises_exception(monkeypatch, input):
     # arrange
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
+
     additive = Additive(host="localhost", port=12345)
 
     # act, assert
     with pytest.raises(ValueError, match="Material must be specified"):
         additive.simulate(input)
 
 
-def test_simulate_list_of_inputs_with_duplicate_ids_raises_exception():
+def test_simulate_list_of_inputs_with_duplicate_ids_raises_exception(monkeypatch):
     # arrange
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
+
     additive = Additive(host="localhost", port=12345)
     inputs = [
         SingleBeadInput(id="id"),
@@ -227,8 +281,13 @@ def test_simulate_list_of_inputs_with_duplicate_ids_raises_exception():
         additive.simulate(inputs)
 
 
-def test_about_returns_about_response():
+def test_about_returns_about_response(monkeypatch):
     # arrange
+    mock_server_ready = create_autospec(
+        ansys.additive.core.additive.server_ready, return_value=True
+    )
+    monkeypatch.setattr(ansys.additive.core.additive, "server_ready", mock_server_ready)
+
     def mock_about_endpoint(request: Empty):
         response = AboutResponse()
         response.metadata["key1"] = "value1"

tests/test_server_utils.py

@@ -27,9 +27,16 @@
 import tempfile
 from unittest.mock import ANY, Mock, patch
 
+from ansys.api.additive.v0.about_pb2_grpc import AboutServiceStub
+import grpc
 import pytest
 
-from ansys.additive.core.server_utils import DEFAULT_ANSYS_VERSION, find_open_port, launch_server
+from ansys.additive.core.server_utils import (
+    DEFAULT_ANSYS_VERSION,
+    find_open_port,
+    launch_server,
+    server_ready,
+)
 
 
 @patch("os.name", "unknown_os")
@@ -185,3 +192,27 @@ def test_find_open_port_returns_valid_port():
 
     # assert
     assert port > 1024 and port < 65535
+
+
+def test_server_ready_returns_false_when_server_cannot_be_reached():
+    # arrange
+    channel = grpc.insecure_channel("channel")
+    stub = AboutServiceStub(channel)
+
+    # act
+    ready = server_ready(stub, 1)
+
+    # assert
+    assert ready == False
+
+
+@patch("ansys.api.additive.v0.about_pb2_grpc.AboutServiceStub")
+def test_server_ready_returns_true_when_server_can_be_reached(mock_stub):
+    # arrange
+    mock_stub.About.return_value = "all about it"
+
+    # act
+    ready = server_ready(mock_stub)
+
+    # assert
+    assert ready == True