grid: `debug` argument to SlapPopen

Add a `debug` argument, False by default, which if true keeps
interactive stdin and stdout.

slapos/grid/utils.py

@@ -91,12 +91,23 @@ LOCALE_ENVIRONMENT_REMOVE_LIST = [
 class SlapPopen(subprocess.Popen):
   """
   Almost normal subprocess with greedish features and logging.
+
   Each line is logged "live", and self.output is a string containing the whole
-  log.
+  log, unless kwargs['debug'] is True, in which case the process outputs
+  normally on stdout and stderr.
   """
   def __init__(self, *args, **kwargs):
     logger = kwargs.pop('logger')
-    kwargs.update(stdin=subprocess.PIPE)
+
+    debug = kwargs.pop('debug', False)
+    if debug:
+      kwargs.pop('stdout', None)
+      kwargs.pop('stderr', None)
+    else:
+      kwargs.setdefault('stdout', subprocess.PIPE)
+      kwargs.setdefault('stderr', subprocess.STDOUT)
+      kwargs.update(stdin=subprocess.PIPE)
+
     if sys.platform == 'cygwin' and kwargs.get('env') == {}:
       kwargs['env'] = None
 
@@ -104,6 +115,10 @@ class SlapPopen(subprocess.Popen):
     kwargs.setdefault('close_fds', True)
 
     subprocess.Popen.__init__(self, *args, **kwargs)
+    if debug:
+      self.wait()
+      self.output = '(output not captured in debug mode)'
+      return
     self.stdin.flush()
     self.stdin.close()
     self.stdin = None
@@ -273,8 +288,6 @@ def bootstrapBuildout(path, logger, buildout=None,
     process_handler = SlapPopen(invocation_list,
                                 preexec_fn=lambda: dropPrivileges(uid, gid, logger=logger),
                                 cwd=path,
-                                stdout=subprocess.PIPE,
-                                stderr=subprocess.STDOUT,
                                 logger=logger)
     if process_handler.returncode is None or process_handler.returncode != 0:
       message = 'Failed to run buildout profile in directory %r' % path
@@ -317,8 +330,6 @@ def launchBuildout(path, buildout_binary, logger,
                                 cwd=path,
                                 env=getCleanEnvironment(logger=logger,
                                                         home_path=path),
-                                stdout=subprocess.PIPE,
-                                stderr=subprocess.STDOUT,
                                 logger=logger)
     if process_handler.returncode is None or process_handler.returncode != 0:
       message = 'Failed to run buildout profile in directory %r' % path

slapos/tests/grid_utils.py

+##############################################################################
+#
+# Copyright (c) 2018 Vifib SARL and Contributors. All Rights Reserved.
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsibility of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# guarantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# This program is Free Software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 3
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+##############################################################################
+import os
+import sys
+import tempfile
+import unittest
+import logging
+import mock
+
+
+import slapos.grid.utils
+
+
+class SlapPopenTestCase(unittest.TestCase):
+  def setUp(self):
+    self.script = tempfile.NamedTemporaryFile(delete=False)
+    # make executable
+    os.chmod(self.script.name, 0o777)
+
+  def tearDown(self):
+    os.unlink(self.script.name)
+
+  def test_exec(self):
+    """Test command execution with SlapPopen.
+    """
+    self.script.write('#!/bin/sh\necho "hello"\nexit 123')
+    self.script.close()
+
+    logger = mock.MagicMock()
+    program = slapos.grid.utils.SlapPopen(
+        self.script.name,
+        logger=logger)
+
+    # error code and output are returned
+    self.assertEqual(123, program.returncode)
+    self.assertEqual('hello\n', program.output)
+
+    # output is also logged "live"
+    logger.info.assert_called_with('hello')
+
+  def test_debug(self):
+    """Test debug=True, which keeps interactive.
+    """
+    self.script.write('#!/bin/sh\necho "exit code?"\nread rc\nexit $rc')
+    self.script.close()
+
+    # keep a reference to stdin and stdout to restore them later
+    stdin_backup = os.dup(sys.stdin.fileno())
+    stdout_backup = os.dup(sys.stdout.fileno())
+
+    # replace stdin with a pipe that will write 123
+    child_stdin_r, child_stdin_w = os.pipe()
+    os.write(child_stdin_w, "123")
+    os.close(child_stdin_w)
+    os.dup2(child_stdin_r, sys.stdin.fileno())
+
+    # and stdout with the pipe to capture output
+    child_stdout_r, child_stdout_w = os.pipe()
+    os.dup2(child_stdout_w, sys.stdout.fileno())
+
+    try:
+      program = slapos.grid.utils.SlapPopen(
+          self.script.name,
+          debug=True,
+          logger=logging.getLogger())
+      # program output
+      self.assertEqual('exit code?\n', os.read(child_stdout_r, 1024))
+
+      self.assertEqual(123, program.returncode)
+      self.assertEqual('(output not captured in debug mode)', program.output)
+    finally:
+      # restore stdin & stderr
+      os.dup2(stdin_backup, sys.stdin.fileno())
+      os.dup2(stdout_backup, sys.stdout.fileno())
+      # close all fds open for the test
+      for fd in (child_stdin_r, child_stdout_r, child_stdout_w, stdin_backup, stdout_backup):
+        os.close(fd)
+
+