Define the default server context with ANSYS_DPF_SERVER_CONTEXT (#633)

* Implement default ServerContext type linked to  ANSYS_DPF_SERVER_CONTEXT environment variable.

* Add testing for the ANSYS_DPF_SERVER_CONTEXT environment variable.

Signed-off-by: paul.profizi <[email protected]>

* Resolve Code quality issues

Signed-off-by: paul.profizi <[email protected]>

* Fix flake8

Signed-off-by: paul.profizi <[email protected]>

* Fix test since AvailableServerContexts has no "user_defined" attribute.

Signed-off-by: paul.profizi <[email protected]>

* fix flake8

Signed-off-by: paul.profizi <[email protected]>

Signed-off-by: paul.profizi <[email protected]>

Author: PProfizi

ansys/dpf/core/server_context.py

@@ -4,7 +4,13 @@
 
 Gives the ability to choose the context with which the server should be started.
 The context allows to choose which capabilities are available.
+By default, an **Entry** type of :class:`ServerContext` is used.
+The default context can be overwritten using the ANSYS_DPF_SERVER_CONTEXT environment
+variable.
+ANSYS_DPF_SERVER_CONTEXT=ENTRY and ANSYS_DPF_SERVER_CONTEXT=PREMIUM can be used.
 """
+import os
+import warnings
 from enum import Enum
 
 
@@ -63,7 +69,20 @@ class AvailableServerContexts:
     """Loads the minimum number of plugins for a basic usage. Is the default."""
 
 
+DPF_SERVER_CONTEXT_ENV = "ANSYS_DPF_SERVER_CONTEXT"
+
 SERVER_CONTEXT = AvailableServerContexts.entry
+if DPF_SERVER_CONTEXT_ENV in os.environ.keys():
+    default_context = os.getenv(DPF_SERVER_CONTEXT_ENV)
+    try:
+        SERVER_CONTEXT = getattr(AvailableServerContexts, default_context.lower())
+    except AttributeError:
+        warnings.warn(UserWarning(
+                      f"{DPF_SERVER_CONTEXT_ENV} is set to {default_context}, which is not "
+                      f"recognized as an available DPF ServerContext type. \n"
+                      f"Accepted values are: {[t.name.upper() for t in EContextType]}.\n"
+                      f"Using {EContextType.entry.name.upper()} "
+                      f"as the default ServerContext type."))
 
 
 def apply_server_context(context=AvailableServerContexts.entry, server=None) -> None:

tests/test_service.py

@@ -461,6 +461,51 @@ def revert():
     request.addfinalizer(revert)
 
 
+@pytest.fixture(autouse=False, scope="function")
+def reset_context_environment_variable(request):
+    """Reset ANSYS_DPF_SERVER_CONTEXT."""
+    from ansys.dpf.core import server_context as s_c
+
+    environment = os.environ
+    key = s_c.DPF_SERVER_CONTEXT_ENV
+    if key in environment.keys():
+        init_context = environment[key]
+    else:
+        init_context = None
+
+    def revert():
+        if init_context:
+            os.environ[key] = init_context
+
+    request.addfinalizer(revert)
+
+
+@pytest.mark.skipif(running_docker or not conftest.SERVERS_VERSION_GREATER_THAN_OR_EQUAL_TO_5_0,
+                    reason="AWP ROOT is not set with Docker")
+@conftest.raises_for_servers_version_under("6.0")
+def test_context_environment_variable(reset_context_environment_variable):
+    from importlib import reload
+    from ansys.dpf.core import server_context as s_c
+
+    key = s_c.DPF_SERVER_CONTEXT_ENV
+
+    # Test raise on wrong value
+    os.environ[key] = "PREM"
+    with pytest.warns(UserWarning, match="which is not recognized as an available "
+                                         "DPF ServerContext type."):
+        reload(s_c)
+    assert s_c.SERVER_CONTEXT == s_c.AvailableServerContexts.entry
+
+    # Test each possible value is correctly understood and sets SERVER_CONTEXT
+    for context in s_c.EContextType:
+        os.environ[key] = context.name.upper()
+        reload(s_c)
+        try:
+            assert s_c.SERVER_CONTEXT == getattr(s_c.AvailableServerContexts, context.name)
+        except AttributeError:
+            continue
+
+
 @pytest.mark.order(1)
 @pytest.mark.skipif(running_docker or not conftest.SERVERS_VERSION_GREATER_THAN_OR_EQUAL_TO_5_0,
                     reason="AWP ROOT is not set with Docker")