1 files changed, 26 insertions, 1 deletions
diff --git a/packages/meshbay-node/src/meshbay_node/cli/dispatch.py b/packages/meshbay-node/src/meshbay_node/cli/dispatch.py
index 849d589..fc5712f 100644
--- a/packages/meshbay-node/src/meshbay_node/cli/dispatch.py
+++ b/packages/meshbay-node/src/meshbay_node/cli/dispatch.py
@@ -28,11 +28,36 @@ def start():
                              "reset")
     logging.basicConfig(
         level=logging.ERROR if quiet else getattr(logging, args.log_level),
-        format="%(asctime)s %(levelname)-8s %(name)s: %(message)s",
+        format=LOG_FORMAT,
     )
+    if args.command is None:
+        add_log_file()
     return args
 
 
+LOG_FORMAT = "%(asctime)s %(levelname)-8s %(name)s: %(message)s"
+
+
+def add_log_file() -> None:
+    """Also log the daemon to platform.log_file(), where there is one."""
+    from logging.handlers import RotatingFileHandler
+
+    from meshbay_node.platform import log_file
+    path = log_file()
+    if path is None:
+        return
+    try:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        # delay: nothing is created until there is something to write.
+        handler = RotatingFileHandler(path, maxBytes=5 * 1024 * 1024, backupCount=3,
+                                      encoding="utf-8", delay=True)
+    except OSError as e:
+        logging.getLogger(__name__).warning("cannot open the log file %s: %s", path, e)
+        return
+    handler.setFormatter(logging.Formatter(LOG_FORMAT))
+    logging.getLogger().addHandler(handler)
+
+
 # Each verb and what runs it. A command line naming none of them starts the
 # daemon, which is daemon.main's to do.
 VERBS = {