lnprototest: add the print_logs to print the node logs

During the failure of one test, we want to see what is happening and why the test is failing.

This is usualy not trivial to understand and required to consult the log. Now there is the possibility to add a flag to tell the runner to store the log and print in the lnprototest logging.

Changelog-Add: add the `print_logs` to the runner stop method to have the possibility to print the log when it is needed.

Signed-off-by: Vincenzo Palazzo <[email protected]>

lnprototest/clightning/clightning.py

@@ -15,6 +15,7 @@
 import shutil
 import logging
 
+from datetime import date
 from concurrent import futures
 from ephemeral_port_reserve import reserve
 from lnprototest.backend import Bitcoind
@@ -169,12 +170,19 @@ def shutdown(self) -> None:
         self.rpc.stop()
         self.bitcoind.stop()
 
-    def stop(self) -> None:
+    def stop(self, print_logs: bool = False) -> None:
         self.logger.debug("[STOP]")
         self.shutdown()
         self.running = False
         for c in self.conns.values():
             cast(CLightningConn, c).connection.connection.close()
+        if print_logs:
+            log_path = f"{self.lightning_dir}/log"
+            with open(log_path) as log:
+                self.logger.info("---------- c-lightning logging ----------------")
+                self.logger.info(log.readlines())
+                # now we make a backup of the log
+                shutil.copy(log_path, f'/tmp/log_{date.today().strftime("%b-%d-%Y")}')
         shutil.rmtree(os.path.join(self.lightning_dir, "regtest"))
 
     def restart(self) -> None:

lnprototest/runner.py

@@ -150,7 +150,14 @@ def start(self) -> None:
         pass
 
     @abstractmethod
-    def stop(self) -> None:
+    def stop(self, print_logs: bool = False) -> None:
+        """
+        Stop the runner, and print all the log that the ln
+        implementation produced.
+
+        Print the log is useful when we have a failure e we need
+        to debug what happens during the tests.
+        """
         pass
 
     @abstractmethod

tests/helpers.py

@@ -166,7 +166,7 @@ def run_runner(runner: Runner, test: Union[Sequence, List[Event], Event]) -> Non
     try:
         runner.run(test)
     except Exception as ex:
-        runner.stop()
+        runner.stop(print_logs=True)
         logging.error(get_traceback(ex))
         assert False, ex