Re: [PATCH] bpf: Add Python 3 support to selftests scripts for bpf

[Daniel Borkmann <daniel@iogearbox.net>]

On 07/18/2018 11:36 PM, Jeremy Cline wrote:
> Adjust tcp_client.py and tcp_server.py to work with Python 3 by using
> the print function, marking string literals as bytes, and using the
> newer exception syntax. This should be functionally equivalent and
> support Python 2.6 through Python 3.7.
> 
> Signed-off-by: Jeremy Cline <jcline@redhat.com>

Thanks for the patch, Jeremy! Given we also have test_offload.py in BPF
kselftests and it is written for python 3 only, it would probably make
sense to adapt the tcp_{client,server}.py towards python 3 as well, so
we wouldn't need to keep extra compat for 2 and have a consistent version
dependency. Lawrence / Jeremy, any objections?

>  tools/testing/selftests/bpf/tcp_client.py | 12 ++++++------
>  tools/testing/selftests/bpf/tcp_server.py | 17 +++++++++--------
>  2 files changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/tcp_client.py b/tools/testing/selftests/bpf/tcp_client.py
> index 481dccdf140c..9fe5f1b5c020 100755
> --- a/tools/testing/selftests/bpf/tcp_client.py
> +++ b/tools/testing/selftests/bpf/tcp_client.py
> @@ -1,4 +1,4 @@
> -#!/usr/bin/env python2
> +#!/usr/bin/env python
>  #
>  # SPDX-License-Identifier: GPL-2.0
>  #
> @@ -9,11 +9,11 @@ import subprocess
>  import select
>  
>  def read(sock, n):
> -    buf = ''
> +    buf = b''
>      while len(buf) < n:
>          rem = n - len(buf)
>          try: s = sock.recv(rem)
> -        except (socket.error), e: return ''
> +        except (socket.error) as e: return b''
>          buf += s
>      return buf
>  
> @@ -22,7 +22,7 @@ def send(sock, s):
>      count = 0
>      while count < total:
>          try: n = sock.send(s)
> -        except (socket.error), e: n = 0
> +        except (socket.error) as e: n = 0
>          if n == 0:
>              return count;
>          count += n
> @@ -39,10 +39,10 @@ try:
>  except socket.error as e:
>      sys.exit(1)
>  
> -buf = ''
> +buf = b''
>  n = 0
>  while n < 1000:
> -    buf += '+'
> +    buf += b'+'
>      n += 1
>  
>  sock.settimeout(1);
> diff --git a/tools/testing/selftests/bpf/tcp_server.py b/tools/testing/selftests/bpf/tcp_server.py
> index bc454d7d0be2..1d4a40a6584b 100755
> --- a/tools/testing/selftests/bpf/tcp_server.py
> +++ b/tools/testing/selftests/bpf/tcp_server.py
> @@ -1,7 +1,8 @@
> -#!/usr/bin/env python2
> +#!/usr/bin/env python
>  #
>  # SPDX-License-Identifier: GPL-2.0
>  #
> +from __future__ import print_function
>  
>  import sys, os, os.path, getopt
>  import socket, time
> @@ -9,11 +10,11 @@ import subprocess
>  import select
>  
>  def read(sock, n):
> -    buf = ''
> +    buf = b''
>      while len(buf) < n:
>          rem = n - len(buf)
>          try: s = sock.recv(rem)
> -        except (socket.error), e: return ''
> +        except (socket.error) as e: return b''
>          buf += s
>      return buf
>  
> @@ -22,7 +23,7 @@ def send(sock, s):
>      count = 0
>      while count < total:
>          try: n = sock.send(s)
> -        except (socket.error), e: n = 0
> +        except (socket.error) as e: n = 0
>          if n == 0:
>              return count;
>          count += n
> @@ -43,7 +44,7 @@ host = socket.gethostname()
>  
>  try: serverSocket.bind((host, 0))
>  except socket.error as msg:
> -    print 'bind fails: ', msg
> +    print('bind fails: ' + str(msg))
>  
>  sn = serverSocket.getsockname()
>  serverPort = sn[1]
> @@ -51,10 +52,10 @@ serverPort = sn[1]
>  cmdStr = ("./tcp_client.py %d &") % (serverPort)
>  os.system(cmdStr)
>  
> -buf = ''
> +buf = b''
>  n = 0
>  while n < 500:
> -    buf += '.'
> +    buf += b'.'
>      n += 1
>  
>  serverSocket.listen(MAX_PORTS)
> @@ -79,5 +80,5 @@ while True:
>                  serverSocket.close()
>                  sys.exit(0)
>      else:
> -        print 'Select timeout!'
> +        print('Select timeout!')
>          sys.exit(1)
>