Disable stdout decoding to stream when reading Tcpdump file

Change-Id: Ib9ed0bb6f4c8a2b50daa2a7c05652f55f1f3517e

tobiko/shell/sh/_execute.py

@@ -42,7 +42,7 @@ class ShellExecuteStatus(enum.Enum):
 
 def execute_result(command, exit_status=None, timeout=None,
                    status=None, login=None, stdin=None, stdout=None,
-                   stderr=None):
+                   stderr=None, decode_streams=True):
     command = str(command)
     if exit_status is not None:
         exit_status = int(exit_status)
@@ -50,9 +50,14 @@ def execute_result(command, exit_status=None, timeout=None,
         timeout = float(timeout)
     if status is not None:
         status = ShellExecuteStatus(status)
+    if decode_streams:
         stdin = _process.str_from_stream(stdin)
         stdout = _process.str_from_stream(stdout)
         stderr = _process.str_from_stream(stderr)
+    else:
+        stdin = _process.bytes_from_stream(stdin)
+        stdout = _process.bytes_from_stream(stdout)
+        stderr = _process.bytes_from_stream(stderr)
     return ShellExecuteResult(command=command,
                               exit_status=exit_status,
                               timeout=timeout,
@@ -120,7 +125,7 @@ def _indent(text, space='    ', newline='\n'):
 
 def execute(command, environment=None, timeout=None, shell=None,
             stdin=None, stdout=None, stderr=None, ssh_client=None,
-            expect_exit_status=0, **kwargs):
+            expect_exit_status=0, decode_streams=True, **kwargs):
     """Execute command inside a remote or local shell
 
     :param command: command argument list
@@ -153,10 +158,12 @@ def execute(command, environment=None, timeout=None, shell=None,
     return execute_process(process=process,
                            stdin=stdin,
                            login=login,
-                           expect_exit_status=expect_exit_status)
+                           expect_exit_status=expect_exit_status,
+                           decode_streams=decode_streams)
 
 
-def execute_process(process, stdin, expect_exit_status, login=None):
+def execute_process(process, stdin, expect_exit_status, login=None,
+                    decode_streams=True):
     error = None
     status = None
     try:
@@ -186,7 +193,8 @@ def execute_process(process, stdin, expect_exit_status, login=None):
                             login=login,
                             stdin=process.stdin,
                             stdout=process.stdout,
-                            stderr=process.stderr)
+                            stderr=process.stderr,
+                            decode_streams=decode_streams)
     if error:
         LOG.info("Command error:\n%s\n", result.details)
         error.result = result

tobiko/shell/sh/_process.py

@@ -435,6 +435,13 @@ def str_from_stream(stream):
         return None
 
 
+def bytes_from_stream(stream):
+    if stream is not None:
+        return stream.data
+    else:
+        return None
+
+
 def default_shell_command():
     from tobiko import config
     CONF = config.CONF

tobiko/shell/tcpdump/_execute.py

@@ -65,7 +65,9 @@ def get_pcap(process,
              ssh_client: ssh.SSHClientType = None) -> dpkt.pcap.Reader:
     stop_capture(process)
 
-    stdout = sh.execute(
-        f'cat {capture_file}', ssh_client=ssh_client, sudo=True).stdout
+    stdout = sh.execute(f"cat '{capture_file}'",
+                        ssh_client=ssh_client,
+                        sudo=True,
+                        decode_streams=False).stdout
     pcap = dpkt.pcap.Reader(io.BytesIO(stdout))
     return pcap