adds server and client context

src/dls_utilpack/client_context_base.py

@@ -0,0 +1,47 @@
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class ClientContextBase:
+ """
+ Base class for client contexts.
+ Provides some basic commmon housekeeping.
+ """
+
+ # ----------------------------------------------------------------------------------------
+ def __init__(self, specification):
+ self.__specification = specification
+ self.__interface = None
+
+ # ----------------------------------------------------------------------------------------
+ def get_specification(self):
+ return self.__specification
+
+ def set_specification(self, specification):
+ self.__specification = specification
+
+ specification = property(get_specification, set_specification)
+
+ # ----------------------------------------------------------------------------------------
+ def get_interface(self):
+ return self.__interface
+
+ def set_interface(self, interface):
+ self.__interface = interface
+
+ interface = property(get_interface, set_interface)
+
+ # ----------------------------------------------------------------------------------------
+ async def __aenter__(self):
+ """ """
+
+ await self.aenter()
+
+ return self.interface
+
+ # ----------------------------------------------------------------------------------------
+ async def __aexit__(self, type, value, traceback):
+ """ """
+
+ await self.aexit()

src/dls_utilpack/server_context_base.py

@@ -0,0 +1,84 @@
+import logging
+
+# Utilities.
+from dls_utilpack.callsign import callsign
+
+# Base class for a Thing which has a name and traits.
+from dls_utilpack.thing import Thing
+
+logger = logging.getLogger(__name__)
+
+
+class ServerContextBase(Thing):
+ """
+ Base class for an "async with" context which can be wrapped around a server object.
+
+ Contains convenience methods common to all server contexts.
+
+ The server object reference is supplied to this object externally.
+
+ The server object must provide the follwing methods:
+ - is_process_started()
+ - is_process_alive()
+
+ """
+
+ # ----------------------------------------------------------------------------------------
+ def __init__(
+ self,
+ thing_type,
+ specification=None,
+ predefined_uuid=None,
+ ):
+ Thing.__init__(
+ self,
+ thing_type,
+ specification,
+ predefined_uuid=predefined_uuid,
+ )
+
+ # Reference to object which is a server, such as BaseAiohttp.
+ self.server = None
+
+ # The context specification of the server's specification.
+ self.context_specification = self.specification().get("context", {})
+
+ # ----------------------------------------------------------------------------------------
+ async def is_process_started(self):
+ """"""
+
+ if self.server is None:
+ raise RuntimeError(f"{callsign(self)} a process has not been defined")
+
+ try:
+ return await self.server.is_process_started()
+ except Exception:
+ raise RuntimeError(
+ f"unable to determing process started for server {callsign(self.server)}"
+ )
+
+ # ----------------------------------------------------------------------------------------
+ async def is_process_alive(self):
+ """"""
+
+ if self.server is None:
+ raise RuntimeError(f"{callsign(self)} a process has not been defined")
+
+ try:
+ return await self.server.is_process_alive()
+ except Exception:
+ raise RuntimeError(
+ f"unable to determing dead or alive for server {callsign(self.server)}"
+ )
+
+ # ----------------------------------------------------------------------------------------
+ async def __aenter__(self):
+ """ """
+
+ await self.aenter()
+
+ # ----------------------------------------------------------------------------------------
+ async def __aexit__(self, type, value, traceback):
+ """ """
+
+ await self.aexit(type, value, traceback)

src/dls_utilpack/thing.py

@@ -17,7 +17,12 @@ class Thing:
 
  def __init__(self, thing_type: str, specification, predefined_uuid=None):
  self.__thing_type = thing_type
- self.__specification = specification
+
+ if specification is None:
+ self.__specification = {}
+ else:
+ self.__specification = specification
+
  self.__uuid = predefined_uuid
  if self.__uuid is None:
  self.__uuid = str(uuid.uuid4())

tests/test_server_context.py

@@ -0,0 +1,70 @@
+import logging
+
+from dls_utilpack.server_context_base import ServerContextBase
+
+# Base class for the tester.
+from tests.base_tester import BaseTester
+
+logger = logging.getLogger(__name__)
+
+
+class Server:
+ # Minimal methods required for a "server" to provide.
+ async def is_process_alive(self):
+ return True
+
+ async def is_process_started(self):
+ return True
+
+
+class Context(ServerContextBase):
+ # For testing.
+ def __init__(self, thing_type, specification=None, predefined_uuid=None):
+ ServerContextBase.__init__(
+ self,
+ thing_type,
+ specification=specification,
+ predefined_uuid=predefined_uuid,
+ )
+
+ self.was_entered = 0
+ self.was_exited = 0
+
+ # Minimal methods required for a "context" to provide.
+ async def aenter(self):
+ """ """
+ self.was_entered += 1
+
+ async def aexit(self, type, value, traceback):
+ """ """
+ self.was_exited += 1
+
+
+# ----------------------------------------------------------------------------------------
+class TestServerContext(BaseTester):
+ def test(self, constants, logging_setup, output_directory):
+ """ """
+
+ self.main(constants, output_directory)
+
+ # ----------------------------------------------------------------------------------------
+ async def _main_coroutine(
+ self,
+ constants,
+ output_directory,
+ ):
+ """ """
+
+ # Make the context.
+ context = Context("some::thing")
+
+ # Assign the server.
+ context.server = Server()
+
+ # Run the context.
+ async with context:
+ assert await context.is_process_started()
+ assert await context.is_process_alive()
+
+ assert context.was_entered == 1
+ assert context.was_exited == 1