Lay foundation to pass notebook names to kernel at startup.

jupyter_client/manager.py

@@ -34,6 +34,17 @@
 from jupyter_client import kernelspec
 
 
+# Name of the env variable that contains the name of the current session associated
+# with the kernel we are launching.
+# Frontends can decide to set this session name to the name of the file when
+# when the kernel is started.
+# This is useful in notebook context to find which notebook we are working with
+# though we might not be working with a notebook, we could be working with a
+# markdown file, or python file.
+# as with other Jupyter Related Env variable with use the JPY prefix.
+JPY_KERNEL_SESSION_NAME = 'JPY_SESSION_NAME'
+
+
 class _ShutdownStatus(Enum):
     """
 
@@ -332,6 +343,7 @@ async def _async_start_kernel(self, **kw):
 
         # launch the kernel subprocess
         self.log.debug("Starting kernel: %s", kernel_cmd)
+        kw.pop('session_name', None)
         await ensure_async(self._launch_kernel(kernel_cmd, **kw))
         await ensure_async(self.post_start_kernel(**kw))
 

jupyter_client/multikernelmanager.py

@@ -151,6 +151,9 @@ def pre_start_kernel(
         constructor_kwargs = {}
         if self.kernel_spec_manager:
             constructor_kwargs["kernel_spec_manager"] = self.kernel_spec_manager
+
+        if 'session_name' in kwargs:
+            constructor_kwargs['session_name'] = kwargs.copy().pop('session_name')
         km = self.kernel_manager_factory(
             connection_file=os.path.join(self.connection_dir, "kernel-%s.json" % kernel_id),
             parent=self,

jupyter_client/provisioning/local_provisioner.py

@@ -139,6 +139,7 @@ async def pre_launch(self, **kwargs: Any) -> Dict[str, Any]:
 
         # This should be considered temporary until a better division of labor can be defined.
         km = self.parent
+        extra_arguments = kwargs.pop('extra_arguments', [])
         if km:
             if km.transport == 'tcp' and not is_local_ip(km.ip):
                 raise RuntimeError(
@@ -149,7 +150,6 @@ async def pre_launch(self, **kwargs: Any) -> Dict[str, Any]:
                     "Currently valid addresses are: %s" % (km.ip, local_ips())
                 )
             # build the Popen cmd
-            extra_arguments = kwargs.pop('extra_arguments', [])
 
             # write connection file / get default ports
             # TODO - change when handshake pattern is adopted
@@ -169,7 +169,6 @@ async def pre_launch(self, **kwargs: Any) -> Dict[str, Any]:
                 extra_arguments=extra_arguments
             )  # This needs to remain here for b/c
         else:
-            extra_arguments = kwargs.pop('extra_arguments', [])
             kernel_cmd = self.kernel_spec.argv + extra_arguments
 
         return await super().pre_launch(cmd=kernel_cmd, **kwargs)

jupyter_client/provisioning/provisioner_base.py

@@ -16,6 +16,16 @@
 
 from ..connect import KernelConnectionInfo
 
+# Name of the env variable that contains the name of the current session associated
+# with the kernel we are launching.
+# Frontends can decide to set this session name to the name of the file when
+# when the kernel is started.
+# This is useful in notebook context to find which notebook we are working with
+# though we might not be working with a notebook, we could be working with a
+# markdown file, or python file.
+# as with other Jupyter Related Env variable with use the JPY prefix.
+JPY_SESSION_NAME = 'JPY_SESSION_NAME'
+
 
 class KernelProvisionerMeta(ABCMeta, type(LoggingConfigurable)):  # type: ignore
     pass
@@ -160,6 +170,8 @@ async def pre_launch(self, **kwargs: Any) -> Dict[str, Any]:
         :meth:`launch_kernel()`.
         """
         env = kwargs.pop('env', os.environ).copy()
+        if 'session_name' in kwargs:
+            env.update({JPY_SESSION_NAME: kwargs['session_name']})
         env.update(self.__apply_env_substitutions(env))
         self._finalize_env(env)
         kwargs['env'] = env