sshdriver: Log keepalive output

While it is not normally expected for the keepalive process to produce
any output, it can be helpful for debugging purposes to log any output
it may have produced. As such, try harder to get output when terminating
the process, and also report any output after it exits

Signed-off-by: Joshua Watt <[email protected]>

labgrid/driver/sshdriver.py

@@ -507,16 +507,35 @@ def _check_keepalive(self):
         return self._keepalive.poll() is None
 
     def _stop_keepalive(self):
+        def log_output(name, output):
+            if not output:
+                return
+
+            s = output.decode("utf-8", errors="ignore")
+            for line in s.splitlines():
+                self.logger.warning("Keepalive %s %s: %s", self.networkservice.address, name, line)
+
         assert self._keepalive is not None
 
         self.logger.debug('Stopping keepalive for %s', self.networkservice.address)
 
+        stdout = None
+        stderr = None
+
         try:
-            self._keepalive.communicate(timeout=60)
+            stdout, stderr = self._keepalive.communicate(timeout=60)
         except subprocess.TimeoutExpired:
             self._keepalive.kill()
-
-        try:
-            self._keepalive.wait(timeout=60)
+            try:
+                # Try again to get output
+                stdout, stderr = self._keepalive.communicate(timeout=60)
+            except subprocess.TimeoutExpired:
+                try:
+                    self._keepalive.wait(timeout=60)
+                except subprocess.TimeoutExpired:
+                    self.logger.warning("ssh keepalive for %s timed out during termination", self.networkservice.address)
         finally:
             self._keepalive = None
+
+        log_output("stdout", stdout)
+        log_output("stderr", stderr)