proper setup for the fallback logger (#269)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: rvalieris

jupyterlab_server/process.py

@@ -32,9 +32,6 @@ def list2cmdline(cmd_list):
         return " ".join(map(pipes.quote, cmd_list))
 
 
-logging.basicConfig(format="%(message)s", level=logging.INFO)
-
-
 def which(command, env=None):
     """Get the full path to a command.
 
@@ -92,7 +89,7 @@ def __init__(self, cmd, logger=None, cwd=None, kill_event=None, env=None, quiet=
         if kill_event and kill_event.is_set():
             raise ValueError("Process aborted")
 
-        self.logger = logger = logger or logging.getLogger("jupyterlab")
+        self.logger = logger = logger or self.get_log()
         self._last_line = ""
         if not quiet:
             self.logger.info(f"> {list2cmdline(cmd)}")
@@ -180,6 +177,14 @@ def _cleanup(cls):
         for proc in list(cls._procs):
             proc.terminate()
 
+    def get_log(self):
+        if hasattr(self, "logger") and self.logger:
+            return self.logger
+        # fallback logger
+        self.logger = logging.getLogger("jupyterlab")
+        self.logger.setLevel(logging.INFO)
+        return self.logger
+
 
 class WatchHelper(Process):
     """A process helper for a watch process."""