Rework SSH debugging output to tmp file (#31)

Rework SSH login and debug output to tmp file.

Author: romecode

src/pytest_netdut/factories.py

@@ -19,7 +19,7 @@
 import pytest
 from packaging import version
 from .wrappers import CLI, xapi
-from functools import wraps
+import tempfile
 
 logger = logging.getLogger(__name__)
 
@@ -200,32 +200,6 @@ def _softened(dut_ssh):
     return _softened
 
 
-def retry(limit):
-    def decorator(fn):
-        @wraps(fn)
-        def wrapper(*args, **kwargs):
-            attempt, limit_ = 0, limit
-            result = None
-            while attempt < limit_:
-                try:
-                    result = fn(*args, **kwargs)
-                    break
-                except Exception as e:
-                    attempt += 1
-                    logging.error(
-                        "An error occurred in %s, attempt %d of %d: %s",
-                        fn.__name__,
-                        attempt,
-                        limit_,
-                        e,
-                    )
-            return result
-
-        return wrapper
-
-    return decorator
-
-
 class _CLI_wrapper:
     _cli = None
 
@@ -243,7 +217,6 @@ def close_and_re_init(self):
     def close(self, *args, **kwargs):
         return self._cli.close(*args, **kwargs)
 
-    @retry(3)
     def login(self, *args, **kwargs):
         return self._cli.login(*args, **kwargs)
 
@@ -322,20 +295,41 @@ def args(self):
         return self._cli.args
 
 
+class _SSH_CLI_wrapper(_CLI_wrapper):
+    def login(self, *args, **kwargs):
+        attempt = 0
+        while attempt < 3:
+            try:
+                self._cli.login(*args, **kwargs)
+                break
+            except Exception as e:
+                attempt += 1
+                with open(self._cli.ssh_debug_filename, "r", encoding="utf-8") as f:
+                    ssh_debug = f.read()
+                logging.error(
+                    "An error occurred during login, attempt %d\n%s%s",
+                    attempt,
+                    ssh_debug,
+                    e,
+                )
+
+
 def create_ssh_fixture(name):
     @pytest.fixture(scope="session", name=f"{name}_ssh")
     def _ssh(request):
-        ssh = _CLI_wrapper(f"ssh://{request.getfixturevalue(f'{name}_hostname')}")
-        # do not break the fixture if SSH failed
-        # pass the failure into the test
-        try:
+        with tempfile.NamedTemporaryFile(delete=True) as ssh_debug_file:
+            ssh = _SSH_CLI_wrapper(
+                f"ssh://{request.getfixturevalue(f'{name}_hostname')}",
+                ssh_debug_filename=ssh_debug_file.name,
+            )
             if ssh.cli_flavor == "mos":
-                ssh.sendcmd("enable")
-            # Disable pagination
-            ssh.sendcmd("terminal length 0")
-        except AttributeError:
-            pass
-        yield ssh
+                # do not break the fixture if SSH failed
+                # pass the failure into the test
+                try:
+                    ssh.sendcmd("enable")
+                except AttributeError:
+                    pass
+            yield ssh
 
     return _ssh
 

src/pytest_netdut/px.py

@@ -1,5 +1,5 @@
 # -------------------------------------------------------------------------------
-# - Copyright (c) 2021 Arista Networks, Inc. All rights reserved.
+# - Copyright (c) 2021-2024 Arista Networks, Inc. All rights reserved.
 # -------------------------------------------------------------------------------
 # - Author:
 # -   [email protected]
@@ -144,13 +144,16 @@ def __init__(  # pylint: disable=dangerous-default-value,too-many-arguments
         enable_cli_timeout=False,
         cli_flavor="mos",
         ignore_encoding_errors=False,
+        ssh_debug_filename="/dev/null",
         extra_args=[],
     ):
         o = six.moves.urllib.parse.urlparse(url)  # pylint: disable=invalid-name
         self.cmd = o.scheme
+        self.ssh_debug_filename = ssh_debug_filename
         if self.cmd == "ssh":
             self.args = ["%s@%s" % (username, o.hostname)]
-            self.args += ["-o LogLevel DEBUG3"]
+            self.args += ["-vvv"]
+            self.args += [f"-E{ssh_debug_filename}"]
             self.args += ["-o ConnectionAttempts 10"]
             self.args += ["-o StrictHostKeyChecking no"]
             self.args += ["-o UserKnownHostsFile /dev/null"]