build: remove explicit PY2/PY3 references. (#10664)

Now that we are Python 3 everywhere, remove explicit python_versions. I haven't made this change yet
to the Thrift extension, as it has explicit PY2/PY3 overrides that I'm guessing relate to external
libs.

Risk level: Low (tooling only)
Testing: bazel.api

Signed-off-by: Harvey Tuch <htuch@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 197f6b1cebbd49a591b916ece168d7e984c87a15

tools/BUILD

@@ -4,7 +4,6 @@ py_binary(
     name = "tap2pcap",
     srcs = ["tap2pcap.py"],
     licenses = ["notice"],  # Apache 2
-    python_version = "PY2",
     visibility = ["//visibility:public"],
     deps = ["//envoy/data/tap/v2alpha:pkg_py_proto"],
 )
@@ -16,7 +15,6 @@ py_test(
         "data/tap2pcap_h2_ipv4.pb_text",
         "data/tap2pcap_h2_ipv4.txt",
     ],
-    python_version = "PY2",
     # Don't run this by default, since we don't want to force local dependency on Wireshark/tshark,
     # will explicitly invoke in CI.
     tags = ["manual"],

tools/tap2pcap.py

@@ -20,8 +20,8 @@ TODO(htuch):
 from __future__ import print_function
 
 import datetime
+import io
 import socket
-import StringIO
 import subprocess as sp
 import sys
 import time
@@ -32,14 +32,14 @@ from envoy.data.tap.v2alpha import wrapper_pb2
 
 
 def DumpEvent(direction, timestamp, data):
-  dump = StringIO.StringIO()
+  dump = io.StringIO()
   dump.write('%s\n' % direction)
   # Adjust to local timezone
   adjusted_dt = timestamp.ToDatetime() - datetime.timedelta(seconds=time.altzone)
   dump.write('%s\n' % adjusted_dt)
   od = sp.Popen(['od', '-Ax', '-tx1', '-v'], stdout=sp.PIPE, stdin=sp.PIPE, stderr=sp.PIPE)
   packet_dump = od.communicate(data)[0]
-  dump.write(packet_dump)
+  dump.write(packet_dump.decode())
   return dump.getvalue()
 
 
@@ -78,7 +78,7 @@ def Tap2Pcap(tap_path, pcap_path):
       '%d,%d' % (remote_port, local_port), '-', pcap_path
   ]
   text2pcap = sp.Popen(text2pcap_args, stdout=sp.PIPE, stdin=sp.PIPE)
-  text2pcap.communicate('\n'.join(dumps))
+  text2pcap.communicate('\n'.join(dumps).encode())
 
 
 if __name__ == '__main__':

tools/tap2pcap_test.py

@@ -18,7 +18,7 @@ if __name__ == '__main__':
 
   tap2pcap.Tap2Pcap(tap_path, pcap_path)
   actual_output = sp.check_output(['tshark', '-r', pcap_path, '-d', 'tcp.port==10000,http2', '-P'])
-  with open(expected_path, 'r') as f:
+  with open(expected_path, 'rb') as f:
     expected_output = f.read()
   if actual_output != expected_output:
     print('Mismatch')