[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

[Pulp-list] Pulp CLI + Reposync Patch



Greetings pulp-list,

Attached is a patch (in mbox format for git-am) introducing the
beginnigs of a pulp CLI and a couple initial commands. It's still rough
around the edges, not using persistent data and not ready for system
installation. 

Command line script is in scripts/ and I've been running it like so:

    (root elaine)[scripts] # PYTHONPATH=../ ./pulp repo --sync-all

Commands supported:

    pulp repo --list
    pulp repo --sync-all

There's only one repository hard coded currently (packagekit) for
testing purposes.

After running --sync-all you'll have a "utopia" repo in /tmp/repos/.

The generated config.repo file doesn't look right yet and I really don't
know what it should look like yet.

Some questions:

1. How do we want to support persistent storage of these repositories?
(i.e. pulp repo add stores data where?)

2. Does it make sense to have pulp CLI in the same project (or
ultimately RPM) as the pulp TG UI? Wanted to see what people thought of
this before attempting any kind of installation code.

3. Should pulp CLI configuration options (i.e. the REPO_STORAGE_PATH) be
configured in the TG configuration file or a new one that will most
likely end up in /etc?

4. Is the patch in this state suitable for pushing to master so others
can build on it or does some or all of the above need to be addressed
and first and then the whole shebang resubmitted?

Other work assignments now appearing so will have limited time to
address issues in the next little while but will attempt to do so as
much as possible.


Cheers,

Devan

-- 
Devan Goodwin <dgoodwin redhat com>
Software Engineer      Red Hat Network
Halifax, Canada     650.567.9039x79267
From 015751ca248f543de525b8034fa7b572196007b9 Mon Sep 17 00:00:00 2001
From: Devan Goodwin <dgoodwin dangerouslyinc com>
Date: Mon, 3 Mar 2008 17:52:23 -0400
Subject: [PATCH] Added beginnings of the pulp command line interface.

Semi-implemented with hard coded data:

    pulp repo --list
    pulp repo --sync-all

Hard coded repository will be synced to /tmp/repo. Still needs work around persistent storage and adding/removing repositories, configuration, system installation, etc.
---
 .gitignore                   |    2 +
 pulp/actions/reposync.py     |  221 ++++++++
 pulp/cli/cli.py              |   54 ++
 pulp/cli/modules.py          |   89 ++++
 pulp/model/contentmanager.py |   33 ++
 pulp/model/mockmodel.py      |   13 +-
 pulp/sub_process.py          | 1149 ++++++++++++++++++++++++++++++++++++++++++
 scripts/pulp                 |    7 +
 8 files changed, 1565 insertions(+), 3 deletions(-)
 create mode 100644 pulp/actions/__init__.py
 create mode 100644 pulp/actions/reposync.py
 create mode 100644 pulp/cli/__init__.py
 create mode 100644 pulp/cli/cli.py
 create mode 100644 pulp/cli/modules.py
 create mode 100644 pulp/sub_process.py
 create mode 100755 scripts/pulp

diff --git a/.gitignore b/.gitignore
index 3b36484..13174c3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@
 *.pyc
 .project
 .pydevproject
+*.swp
+*.swo
diff --git a/pulp/actions/__init__.py b/pulp/actions/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pulp/actions/reposync.py b/pulp/actions/reposync.py
new file mode 100644
index 0000000..37b654f
--- /dev/null
+++ b/pulp/actions/reposync.py
@@ -0,0 +1,221 @@
+"""
+Sync Yum repository content.
+
+Based heavily on action_reposync.py from Cobbler.
+See: http://cobbler.et.redhat.com/
+
+Copyright 2006-2008, Red Hat, Inc
+Michael DeHaan <mdehaan redhat com>
+Devan Goodwin <dgoodwin redhat com>
+
+This software may be freely redistributed under the terms of the GNU
+general public license.
+
+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., 675 Mass Ave, Cambridge, MA 02139, USA.
+"""
+
+import os
+import os.path
+import time
+import pulp.sub_process
+import sys
+
+#from cexceptions import *
+
+#from rhpl.translate import _, N_, textdomain, utf8
+
+REPOSYNC_PATH = "/usr/bin/reposync"
+REPO_STORAGE_DIR = "/tmp/repos/"
+HTTP_SERVER = "localhost"
+HTTP_PORT = "80"
+
+def remove_yum_olddata(path):
+    """
+    Delete .olddata files that might be present from a failed run
+    of createrepo.
+    """
+    trythese = [
+        ".olddata",
+        ".repodata/.olddata",
+        "repodata/.oldata",
+        "repodata/repodata"
+    ]
+    for pathseg in trythese:
+        olddata = os.path.join(path, pathseg)
+        if os.path.exists(olddata):
+            print "- removing: %s" % olddata
+            shutil.rmtree(olddata, ignore_errors=False, onerror=None)
+
+class RepoSync:
+    """
+    Handles conversion of internal state to the tftpboot tree layout
+    """
+
+    def __init__(self, repos):
+        """
+        Create a RepoSync action with a list of repositories to be synced.
+        """
+        self.repos = repos
+
+    def run(self):
+        """
+        Syncs the current repo configuration file with the filesystem.
+        """
+
+        for repo in self.repos:
+
+            repo_path = os.path.join(REPO_STORAGE_DIR, 
+                repo.name)
+            print "repo_path = %s" % repo_path
+
+            if not os.path.isdir(repo_path):
+                os.makedirs(repo_path)                                        
+            
+            # TODO: Add support for rsync/rhn URLs?
+            self.do_reposync(repo)
+
+            self.update_permissions(repo_path)
+
+        return True
+    
+    # TODO: Resurrect this when the time comes to support rsync URLs.
+    #def __is_rsync_url(self, url):
+    #    lower = url.lower()
+    #    if lower.startswith("http://";) or lower.startswith("ftp://";) or \
+    #        lower.startswith("rhn://"):
+    #        return False
+    #    else:
+    #        return True
+
+    def do_reposync(self, repo):
+        """
+        Handle copying of http:// and ftp:// repos.
+        """
+
+        # warn about not having yum-utils.  We don't want to require it in the 
+        # package because RHEL4 and RHEL5U0 don't have it.
+        if not os.path.exists(REPOSYNC_PATH):
+            raise Exception(
+                "no /usr/bin/reposync found, please install yum-utils")
+
+        cmds = []                 # queues up commands to run
+        has_rpm_list = False      # flag indicating not to pull the whole repo
+
+        store_path = REPO_STORAGE_DIR
+        dest_path = os.path.join(REPO_STORAGE_DIR, repo.name)
+        # Origin dir stores the source yum repo config files:
+        temp_path = os.path.join(REPO_STORAGE_DIR, ".origin") 
+        if not os.path.isdir(temp_path):
+            # FIXME: there's a chance this might break the RHN D/L case
+            os.makedirs(temp_path)
+         
+        # this is the simple non-RHN case.
+        # create the config file that yum will use for the copying
+
+        temp_file = self.create_local_file(repo, temp_path, output=False)
+
+        if not has_rpm_list:
+            # If we have not requested only certain RPMs, use reposync:
+            cmd = "/usr/bin/reposync " + \
+                "--config=%s --repoid=%s --download_path=%s" % \
+                    (temp_file, repo.name, store_path)
+            if repo.arch != "":
+                cmd = "%s -a %s" % (cmd, "x86_64")
+                
+            print _("- %s") % cmd
+            cmds.append(cmd)
+        
+        # NOTE: "else" clause handling syncing of only certain RPMs in the
+        # cobbler source was removed here. May need to re-add if this
+        # functionality is needed later on.
+
+        for cmd in cmds:
+            rc = pulp.sub_process.call(cmd, shell=True)
+            if rc !=0:
+                raise Exception("reposync failed")
+
+        # now run createrepo to rebuild the index
+        os.path.walk(dest_path, self.createrepo_walker, repo)
+
+        # create the config file the hosts will use to access the repository.
+        self.create_local_file(repo, dest_path)
+ 
+    def create_local_file(self, repo, dest_path, output=True):
+        """
+        Two uses:
+        (A) output=True, Create local files that can be used with yum on 
+        provisioned clients to make use of this mirror.
+
+        (B) output=False, Create a temporary file for yum to feed into yum 
+        for mirroring
+        """
+    
+        # the output case will generate repo configuration files which are 
+        # usable for the installed systems.  They need to be made compatible 
+        # with --server-override which means they are actually templates, 
+        # which need to be rendered by a cobbler-sync on per profile/system 
+        #basis.
+
+        if output:
+            fname = os.path.join(dest_path,"config.repo")
+        else:
+            fname = os.path.join(dest_path, "%s.repo" % repo.name)
+        print _("- creating: %s") % fname
+        config_file = open(fname, "w+")
+        config_file.write("[%s]\n" % repo.name)
+        config_file.write("name=%s\n" % repo.name)
+        if output:
+            line = "baseurl=http://${server}/cobbler/repo_mirror/%s\n"; % \
+                (repo.name)
+            config_file.write(line)
+            # user may have options specific to certain yum plugins
+            # add them to the file
+            #for x in repo.yumopts:
+            #    config_file.write("%s=%s\n" % (x, repo.yumopts[x]))
+        else:
+            line = "baseurl=%s\n" % repo.url
+            http_server = "%s:%s" % (HTTP_SERVER, HTTP_PORT)
+            line = line.replace("@@server@@", http_server)
+            config_file.write(line)
+        config_file.write("enabled=1\n")
+        config_file.write("priority=%s\n" % repo.priority)
+        config_file.write("gpgcheck=0\n")
+        config_file.close()
+        return fname 
+
+    def createrepo_walker(self, repo, dirname, fnames):
+        """
+        Used to run createrepo on a copied mirror.
+        """
+        remove_yum_olddata(dirname)
+        try:
+            cmd = "createrepo -c cache %s" % (dirname)
+            print "- %s" % cmd
+            pulp.sub_process.call(cmd, shell=True)
+        except:
+            print "- createrepo failed.  Is it installed?"
+        del fnames[:] # we're in the right place
+
+    def update_permissions(self, repo_path):
+        """
+        Verifies that permissions and contexts after an rsync are as expected.
+        Sending proper rsync flags should prevent the need for this, though 
+        this is largely a safeguard.
+        """
+        # all_path = os.path.join(repo_path, "*")
+        cmd1 = "chown -R root:apache %s" % repo_path
+        pulp.sub_process.call(cmd1, shell=True)
+
+        cmd2 = "chmod -R 755 %s" % repo_path
+        pulp.sub_process.call(cmd2, shell=True)
+
+        getenforce = "/usr/sbin/getenforce"
+        if os.path.exists(getenforce):
+            data = pulp.sub_process.Popen(getenforce, shell=True, 
+                stdout=pulp.sub_process.PIPE).communicate()[0]
+            if data.lower().find("disabled") == -1:
+                cmd3 = "chcon --reference /var/www %s" % repo_path
+                sub_process.call(cmd3, shell=True)
+            
diff --git a/pulp/cli/__init__.py b/pulp/cli/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pulp/cli/cli.py b/pulp/cli/cli.py
new file mode 100644
index 0000000..ad37376
--- /dev/null
+++ b/pulp/cli/cli.py
@@ -0,0 +1,54 @@
+"""
+Pulp Command Line Interface
+
+Copyright 2008, Red Hat, Inc
+Devan Goodwin <dgoodwin redhat com>
+
+This software may be freely redistributed under the terms of the GNU
+general public license.
+
+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., 675 Mass Ave, Cambridge, MA 02139, USA.
+"""
+
+import sys
+from pulp.cli.modules import *
+
+from optparse import OptionParser
+
+MODULES = {
+    "repo": RepoModule()
+}
+
+class PulpCommandLine:
+    """
+    Main entry point for the Pulp command line interface.
+    """
+
+    def main(self, argv):
+        """ Main CLI entry point """
+
+        # We expect at least one argument representing the module name.
+        # Otherwise display help info.
+        if len(argv) < 2:
+            self.help()
+
+        module_name = argv[1]
+        print "Module: %s" % module_name
+        if not MODULES.has_key(module_name):
+            print "ERROR: Unknown module: %s" % module_name
+            self.help()
+
+        parser = OptionParser()
+        module = MODULES[module_name]
+        module.add_options(parser)
+
+        (options, args) = parser.parse_args(argv[2:])
+        module.run(options)
+
+    def help(self):
+        """ Display help info to the user. """
+        # TODO
+        print "Help!"
+        sys.exit(1)
diff --git a/pulp/cli/modules.py b/pulp/cli/modules.py
new file mode 100644
index 0000000..31d463a
--- /dev/null
+++ b/pulp/cli/modules.py
@@ -0,0 +1,89 @@
+"""
+Pulp Command Line Modules
+
+Optparse code used for parsing calls to the pulp command line interface.
+Module here refers to the first argument in a call to pulp, i.e.
+
+    pulp modulename --do-something
+
+Copyright 2008, Red Hat, Inc
+Devan Goodwin <dgoodwin redhat com>
+
+This software may be freely redistributed under the terms of the GNU
+general public license.
+
+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., 675 Mass Ave, Cambridge, MA 02139, USA.
+"""
+
+from pulp.model.contentmanager import DummyContentSourceContentManager 
+from pulp.actions.reposync import RepoSync
+
+class CliModule:
+    """
+    Parent command line module class.
+    """
+
+    def add_options(self, parser):
+        """
+        Modules add their own parser options. Must be implemented in child
+        classes.
+        """
+        raise NotImplementedError
+
+    def run(self, options):
+        """
+        Process a command send to this module.
+        """
+        raise NotImplementedError
+
+
+
+class RepoModule(CliModule):
+
+    def add_options(self, parser):
+
+        parser.add_option("--sync-all", action="store_true", dest="sync_all",
+            help="Sync all repositories.")
+        parser.add_option("--list", action="store_true", dest="list",
+            help="List all repositories.")
+
+
+    def run(self, options):
+        print "Hello world!"
+        print options
+
+        # TODO: Better way to do this with optparse?
+        # Restrict to only one "sub-command":
+        sub_commands = {
+            options.list: self.__list,
+            options.sync_all: self.__sync_all,
+        }
+        command_to_run = None
+        for sub_command in sub_commands:
+            if sub_command:
+                if command_to_run is not None:
+                    print "ERROR: Must specify only one sub-command"
+                else:
+                    command_to_run = sub_command
+
+        # Run the command we identified:
+        sub_commands[command_to_run](options)
+
+    def __list(self, options):
+        content_mgr = DummyContentSourceContentManager()
+        repos = content_mgr.list_all_content_sources(None) # Subject?
+        for repo in repos:
+            print repo.name
+            print "   %s" % repo.url
+
+    def __sync_all(self, options):
+        content_mgr = DummyContentSourceContentManager()
+        repos = content_mgr.list_all_content_sources(None) # Subject?
+        print "Syncing all repos:"
+        reposync = RepoSync(repos)
+        reposync.run()
+    
+
+
diff --git a/pulp/model/contentmanager.py b/pulp/model/contentmanager.py
index 8f25e0c..feaa726 100644
--- a/pulp/model/contentmanager.py
+++ b/pulp/model/contentmanager.py
@@ -1,4 +1,5 @@
 from pulp.model.pulpserviceproxy import PulpServiceProxy 
+from pulp.model.mockmodel import MockContentSource
 import logging
 
 log = logging.getLogger("pulp.model")
@@ -71,3 +72,35 @@ class ContentManager(object):
         if pcount is None:
             pcount = 0
         return pcount                      
+
+
+
+class DummyContentSourceContentManager(ContentManager):
+    """
+    Dummy class used currently to return some valid countent sources.
+    Used in testing the repo sync command.
+
+    TODO: Destroy this once the model and methods for testing against it are
+    a little more clear.
+    """
+
+    def __init__(self):
+        """ Overload to not do any networking. """
+        pass
+
+    def list_all_content_sources(self, subject):
+        """
+        Overload method in ContentManager to return real Yum repositories.
+        """
+        repos = []
+
+        # TODO: Remove hard coded repository data here. Using packagekit
+        # repository for testing until we have repository storage
+        # straightened out.
+        repos.append(MockContentSource(id=1, name="utopia", 
+            url="http://people.freedesktop.org/~hughsient/fedora/8/i386/";))
+
+        return repos
+
+
+
diff --git a/pulp/model/mockmodel.py b/pulp/model/mockmodel.py
index 1878f55..cc5e082 100644
--- a/pulp/model/mockmodel.py
+++ b/pulp/model/mockmodel.py
@@ -12,17 +12,24 @@ class MockSubject(object):
     emailAddress = 'nobody localhost'
     id = 2
     
+
     
 class MockContentSource(Property):
     '''
     ContentSource is a class representing a location to fetch packages from.
     Examples of this would be a http served yum repository or a mounted DVD drive
     '''
-    def __init__(self, id):
+    def __init__(self, id, name=None, url=None):
         Property.__init__(self)
+
         self.id = str(id)
-        self.name = "fake-source[%s]" % id
-        self.url = "http://some.redhat.com/url/%s"; % id
+        self.name = name
+        if name is None:
+            self.name = "fake-source[%s]" % id
+        self.url = url
+        if url is None:
+            self.url = "http://some.redhat.com/url/%s"; % id
+
         self.contentSourceType = Property()
         self.contentSourceType.displayName  = "Fake Type"
         self.configuration = Property()
diff --git a/pulp/sub_process.py b/pulp/sub_process.py
new file mode 100644
index 0000000..bbd26c7
--- /dev/null
+++ b/pulp/sub_process.py
@@ -0,0 +1,1149 @@
+# subprocess - Subprocesses with accessible I/O streams
+#
+# For more information about this module, see PEP 324.
+#
+# This module should remain compatible with Python 2.2, see PEP 291.
+#
+# Copyright (c) 2003-2005 by Peter Astrand <astrand lysator liu se>
+#
+# Licensed to PSF under a Contributor Agreement.
+# See http://www.python.org/2.4/license for licensing details.
+
+r"""subprocess - Subprocesses with accessible I/O streams
+
+This module allows you to spawn processes, connect to their
+input/output/error pipes, and obtain their return codes.  This module
+intends to replace several other, older modules and functions, like:
+
+os.system
+os.spawn*
+os.popen*
+popen2.*
+commands.*
+
+Information about how the subprocess module can be used to replace these
+modules and functions can be found below.
+
+
+
+Using the subprocess module
+===========================
+This module defines one class called Popen:
+
+class Popen(args, bufsize=0, executable=None,
+            stdin=None, stdout=None, stderr=None,
+            preexec_fn=None, close_fds=False, shell=False,
+            cwd=None, env=None, universal_newlines=False,
+            startupinfo=None, creationflags=0):
+
+
+Arguments are:
+
+args should be a string, or a sequence of program arguments.  The
+program to execute is normally the first item in the args sequence or
+string, but can be explicitly set by using the executable argument.
+
+On UNIX, with shell=False (default): In this case, the Popen class
+uses os.execvp() to execute the child program.  args should normally
+be a sequence.  A string will be treated as a sequence with the string
+as the only item (the program to execute).
+
+On UNIX, with shell=True: If args is a string, it specifies the
+command string to execute through the shell.  If args is a sequence,
+the first item specifies the command string, and any additional items
+will be treated as additional shell arguments.
+
+On Windows: the Popen class uses CreateProcess() to execute the child
+program, which operates on strings.  If args is a sequence, it will be
+converted to a string using the list2cmdline method.  Please note that
+not all MS Windows applications interpret the command line the same
+way: The list2cmdline is designed for applications using the same
+rules as the MS C runtime.
+
+bufsize, if given, has the same meaning as the corresponding argument
+to the built-in open() function: 0 means unbuffered, 1 means line
+buffered, any other positive value means use a buffer of
+(approximately) that size.  A negative bufsize means to use the system
+default, which usually means fully buffered.  The default value for
+bufsize is 0 (unbuffered).
+
+stdin, stdout and stderr specify the executed programs' standard
+input, standard output and standard error file handles, respectively.
+Valid values are PIPE, an existing file descriptor (a positive
+integer), an existing file object, and None.  PIPE indicates that a
+new pipe to the child should be created.  With None, no redirection
+will occur; the child's file handles will be inherited from the
+parent.  Additionally, stderr can be STDOUT, which indicates that the
+stderr data from the applications should be captured into the same
+file handle as for stdout.
+
+If preexec_fn is set to a callable object, this object will be called
+in the child process just before the child is executed.
+
+If close_fds is true, all file descriptors except 0, 1 and 2 will be
+closed before the child process is executed.
+
+if shell is true, the specified command will be executed through the
+shell.
+
+If cwd is not None, the current directory will be changed to cwd
+before the child is executed.
+
+If env is not None, it defines the environment variables for the new
+process.
+
+If universal_newlines is true, the file objects stdout and stderr are
+opened as a text files, but lines may be terminated by any of '\n',
+the Unix end-of-line convention, '\r', the Macintosh convention or
+'\r\n', the Windows convention.  All of these external representations
+are seen as '\n' by the Python program.  Note: This feature is only
+available if Python is built with universal newline support (the
+default).  Also, the newlines attribute of the file objects stdout,
+stdin and stderr are not updated by the communicate() method.
+
+The startupinfo and creationflags, if given, will be passed to the
+underlying CreateProcess() function.  They can specify things such as
+appearance of the main window and priority for the new process.
+(Windows only)
+
+
+This module also defines two shortcut functions:
+
+call(*args, **kwargs):
+    Run command with arguments.  Wait for command to complete, then
+    return the returncode attribute.
+
+    The arguments are the same as for the Popen constructor.  Example:
+
+    retcode = call(["ls", "-l"])
+
+
+Exceptions
+----------
+Exceptions raised in the child process, before the new program has
+started to execute, will be re-raised in the parent.  Additionally,
+the exception object will have one extra attribute called
+'child_traceback', which is a string containing traceback information
+from the childs point of view.
+
+The most common exception raised is OSError.  This occurs, for
+example, when trying to execute a non-existent file.  Applications
+should prepare for OSErrors.
+
+A ValueError will be raised if Popen is called with invalid arguments.
+
+
+Security
+--------
+Unlike some other popen functions, this implementation will never call
+/bin/sh implicitly.  This means that all characters, including shell
+metacharacters, can safely be passed to child processes.
+
+
+Popen objects
+=============
+Instances of the Popen class have the following methods:
+
+poll()
+    Check if child process has terminated.  Returns returncode
+    attribute.
+
+wait()
+    Wait for child process to terminate.  Returns returncode attribute.
+
+communicate(input=None)
+    Interact with process: Send data to stdin.  Read data from stdout
+    and stderr, until end-of-file is reached.  Wait for process to
+    terminate.  The optional stdin argument should be a string to be
+    sent to the child process, or None, if no data should be sent to
+    the child.
+
+    communicate() returns a tuple (stdout, stderr).
+
+    Note: The data read is buffered in memory, so do not use this
+    method if the data size is large or unlimited.
+
+The following attributes are also available:
+
+stdin
+    If the stdin argument is PIPE, this attribute is a file object
+    that provides input to the child process.  Otherwise, it is None.
+
+stdout
+    If the stdout argument is PIPE, this attribute is a file object
+    that provides output from the child process.  Otherwise, it is
+    None.
+
+stderr
+    If the stderr argument is PIPE, this attribute is file object that
+    provides error output from the child process.  Otherwise, it is
+    None.
+
+pid
+    The process ID of the child process.
+
+returncode
+    The child return code.  A None value indicates that the process
+    hasn't terminated yet.  A negative value -N indicates that the
+    child was terminated by signal N (UNIX only).
+
+
+Replacing older functions with the subprocess module
+====================================================
+In this section, "a ==> b" means that b can be used as a replacement
+for a.
+
+Note: All functions in this section fail (more or less) silently if
+the executed program cannot be found; this module raises an OSError
+exception.
+
+In the following examples, we assume that the subprocess module is
+imported with "from subprocess import *".
+
+
+Replacing /bin/sh shell backquote
+---------------------------------
+output=`mycmd myarg`
+==>
+output = Popen(["mycmd", "myarg"], stdout=PIPE).communicate()[0]
+
+
+Replacing shell pipe line
+-------------------------
+output=`dmesg | grep hda`
+==>
+p1 = Popen(["dmesg"], stdout=PIPE)
+p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
+output = p2.communicate()[0]
+
+
+Replacing os.system()
+---------------------
+sts = os.system("mycmd" + " myarg")
+==>
+p = Popen("mycmd" + " myarg", shell=True)
+sts = os.waitpid(p.pid, 0)
+
+Note:
+
+* Calling the program through the shell is usually not required.
+
+* It's easier to look at the returncode attribute than the
+  exitstatus.
+
+A more real-world example would look like this:
+
+try:
+    retcode = call("mycmd" + " myarg", shell=True)
+    if retcode < 0:
+        print >>sys.stderr, "Child was terminated by signal", -retcode
+    else:
+        print >>sys.stderr, "Child returned", retcode
+except OSError, e:
+    print >>sys.stderr, "Execution failed:", e
+
+
+Replacing os.spawn*
+-------------------
+P_NOWAIT example:
+
+pid = os.spawnlp(os.P_NOWAIT, "/bin/mycmd", "mycmd", "myarg")
+==>
+pid = Popen(["/bin/mycmd", "myarg"]).pid
+
+
+P_WAIT example:
+
+retcode = os.spawnlp(os.P_WAIT, "/bin/mycmd", "mycmd", "myarg")
+==>
+retcode = call(["/bin/mycmd", "myarg"])
+
+
+Vector example:
+
+os.spawnvp(os.P_NOWAIT, path, args)
+==>
+Popen([path] + args[1:])
+
+
+Environment example:
+
+os.spawnlpe(os.P_NOWAIT, "/bin/mycmd", "mycmd", "myarg", env)
+==>
+Popen(["/bin/mycmd", "myarg"], env={"PATH": "/usr/bin"})
+
+
+Replacing os.popen*
+-------------------
+pipe = os.popen(cmd, mode='r', bufsize)
+==>
+pipe = Popen(cmd, shell=True, bufsize=bufsize, stdout=PIPE).stdout
+
+pipe = os.popen(cmd, mode='w', bufsize)
+==>
+pipe = Popen(cmd, shell=True, bufsize=bufsize, stdin=PIPE).stdin
+
+
+(child_stdin, child_stdout) = os.popen2(cmd, mode, bufsize)
+==>
+p = Popen(cmd, shell=True, bufsize=bufsize,
+          stdin=PIPE, stdout=PIPE, close_fds=True)
+(child_stdin, child_stdout) = (p.stdin, p.stdout)
+
+
+(child_stdin,
+ child_stdout,
+ child_stderr) = os.popen3(cmd, mode, bufsize)
+==>
+p = Popen(cmd, shell=True, bufsize=bufsize,
+          stdin=PIPE, stdout=PIPE, stderr=PIPE, close_fds=True)
+(child_stdin,
+ child_stdout,
+ child_stderr) = (p.stdin, p.stdout, p.stderr)
+
+
+(child_stdin, child_stdout_and_stderr) = os.popen4(cmd, mode, bufsize)
+==>
+p = Popen(cmd, shell=True, bufsize=bufsize,
+          stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True)
+(child_stdin, child_stdout_and_stderr) = (p.stdin, p.stdout)
+
+
+Replacing popen2.*
+------------------
+Note: If the cmd argument to popen2 functions is a string, the command
+is executed through /bin/sh.  If it is a list, the command is directly
+executed.
+
+(child_stdout, child_stdin) = popen2.popen2("somestring", bufsize, mode)
+==>
+p = Popen(["somestring"], shell=True, bufsize=bufsize
+          stdin=PIPE, stdout=PIPE, close_fds=True)
+(child_stdout, child_stdin) = (p.stdout, p.stdin)
+
+
+(child_stdout, child_stdin) = popen2.popen2(["mycmd", "myarg"], bufsize, mode)
+==>
+p = Popen(["mycmd", "myarg"], bufsize=bufsize,
+          stdin=PIPE, stdout=PIPE, close_fds=True)
+(child_stdout, child_stdin) = (p.stdout, p.stdin)
+
+The popen2.Popen3 and popen3.Popen4 basically works as subprocess.Popen,
+except that:
+
+* subprocess.Popen raises an exception if the execution fails
+* the capturestderr argument is replaced with the stderr argument.
+* stdin=PIPE and stdout=PIPE must be specified.
+* popen2 closes all filedescriptors by default, but you have to specify
+  close_fds=True with subprocess.Popen.
+
+
+"""
+
+import sys
+mswindows = (sys.platform == "win32")
+
+import os
+import types
+import traceback
+
+if mswindows:
+    import threading
+    import msvcrt
+    if 0: # <-- change this to use pywin32 instead of the _subprocess driver
+        import pywintypes
+        from win32api import GetStdHandle, STD_INPUT_HANDLE, \
+                             STD_OUTPUT_HANDLE, STD_ERROR_HANDLE
+        from win32api import GetCurrentProcess, DuplicateHandle, \
+                             GetModuleFileName, GetVersion
+        from win32con import DUPLICATE_SAME_ACCESS, SW_HIDE
+        from win32pipe import CreatePipe
+        from win32process import CreateProcess, STARTUPINFO, \
+                                 GetExitCodeProcess, STARTF_USESTDHANDLES, \
+                                 STARTF_USESHOWWINDOW, CREATE_NEW_CONSOLE
+        from win32event import WaitForSingleObject, INFINITE, WAIT_OBJECT_0
+    else:
+        from _subprocess import *
+        class STARTUPINFO:
+            dwFlags = 0
+            hStdInput = None
+            hStdOutput = None
+            hStdError = None
+        class pywintypes:
+            error = IOError
+else:
+    import select
+    import errno
+    import fcntl
+    import pickle
+
+__all__ = ["Popen", "PIPE", "STDOUT", "call"]
+
+try:
+    MAXFD = os.sysconf("SC_OPEN_MAX")
+except:
+    MAXFD = 256
+
+# True/False does not exist on 2.2.0
+try:
+    False
+except NameError:
+    False = 0
+    True = 1
+
+_active = []
+
+def _cleanup():
+    for inst in _active[:]:
+        inst.poll()
+
+PIPE = -1
+STDOUT = -2
+
+
+def call(*args, **kwargs):
+    """Run command with arguments.  Wait for command to complete, then
+    return the returncode attribute.
+
+    The arguments are the same as for the Popen constructor.  Example:
+
+    retcode = call(["ls", "-l"])
+    """
+    return Popen(*args, **kwargs).wait()
+
+
+def list2cmdline(seq):
+    """
+    Translate a sequence of arguments into a command line
+    string, using the same rules as the MS C runtime:
+
+    1) Arguments are delimited by white space, which is either a
+       space or a tab.
+
+    2) A string surrounded by double quotation marks is
+       interpreted as a single argument, regardless of white space
+       contained within.  A quoted string can be embedded in an
+       argument.
+
+    3) A double quotation mark preceded by a backslash is
+       interpreted as a literal double quotation mark.
+
+    4) Backslashes are interpreted literally, unless they
+       immediately precede a double quotation mark.
+
+    5) If backslashes immediately precede a double quotation mark,
+       every pair of backslashes is interpreted as a literal
+       backslash.  If the number of backslashes is odd, the last
+       backslash escapes the next double quotation mark as
+       described in rule 3.
+    """
+
+    # See
+    # http://msdn.microsoft.com/library/en-us/vccelng/htm/progs_12.asp
+    result = []
+    needquote = False
+    for arg in seq:
+        bs_buf = []
+
+        # Add a space to separate this argument from the others
+        if result:
+            result.append(' ')
+
+        needquote = (" " in arg) or ("\t" in arg)
+        if needquote:
+            result.append('"')
+
+        for c in arg:
+            if c == '\\':
+                # Don't know if we need to double yet.
+                bs_buf.append(c)
+            elif c == '"':
+                # Double backspaces.
+                result.append('\\' * len(bs_buf)*2)
+                bs_buf = []
+                result.append('\\"')
+            else:
+                # Normal char
+                if bs_buf:
+                    result.extend(bs_buf)
+                    bs_buf = []
+                result.append(c)
+
+        # Add remaining backspaces, if any.
+        if bs_buf:
+            result.extend(bs_buf)
+
+        if needquote:
+            result.extend(bs_buf)
+            result.append('"')
+
+    return ''.join(result)
+
+
+class Popen(object):
+    def __init__(self, args, bufsize=0, executable=None,
+                 stdin=None, stdout=None, stderr=None,
+                 preexec_fn=None, close_fds=False, shell=False,
+                 cwd=None, env=None, universal_newlines=False,
+                 startupinfo=None, creationflags=0):
+        """Create new Popen instance."""
+        _cleanup()
+
+        if not isinstance(bufsize, (int, long)):
+            raise TypeError("bufsize must be an integer")
+
+        if mswindows:
+            if preexec_fn is not None:
+                raise ValueError("preexec_fn is not supported on Windows "
+                                 "platforms")
+            if close_fds:
+                raise ValueError("close_fds is not supported on Windows "
+                                 "platforms")
+        else:
+            # POSIX
+            if startupinfo is not None:
+                raise ValueError("startupinfo is only supported on Windows "
+                                 "platforms")
+            if creationflags != 0:
+                raise ValueError("creationflags is only supported on Windows "
+                                 "platforms")
+
+        self.stdin = None
+        self.stdout = None
+        self.stderr = None
+        self.pid = None
+        self.returncode = None
+        self.universal_newlines = universal_newlines
+
+        # Input and output objects. The general principle is like
+        # this:
+        #
+        # Parent                   Child
+        # ------                   -----
+        # p2cwrite   ---stdin--->  p2cread
+        # c2pread    <--stdout---  c2pwrite
+        # errread    <--stderr---  errwrite
+        #
+        # On POSIX, the child objects are file descriptors.  On
+        # Windows, these are Windows file handles.  The parent objects
+        # are file descriptors on both platforms.  The parent objects
+        # are None when not using PIPEs. The child objects are None
+        # when not redirecting.
+
+        (p2cread, p2cwrite,
+         c2pread, c2pwrite,
+         errread, errwrite) = self._get_handles(stdin, stdout, stderr)
+
+        self._execute_child(args, executable, preexec_fn, close_fds,
+                            cwd, env, universal_newlines,
+                            startupinfo, creationflags, shell,
+                            p2cread, p2cwrite,
+                            c2pread, c2pwrite,
+                            errread, errwrite)
+
+        if p2cwrite:
+            self.stdin = os.fdopen(p2cwrite, 'wb', bufsize)
+        if c2pread:
+            if universal_newlines:
+                self.stdout = os.fdopen(c2pread, 'rU', bufsize)
+            else:
+                self.stdout = os.fdopen(c2pread, 'rb', bufsize)
+        if errread:
+            if universal_newlines:
+                self.stderr = os.fdopen(errread, 'rU', bufsize)
+            else:
+                self.stderr = os.fdopen(errread, 'rb', bufsize)
+
+        _active.append(self)
+
+
+    def _translate_newlines(self, data):
+        data = data.replace("\r\n", "\n")
+        data = data.replace("\r", "\n")
+        return data
+
+
+    if mswindows:
+        #
+        # Windows methods
+        #
+        def _get_handles(self, stdin, stdout, stderr):
+            """Construct and return tupel with IO objects:
+            p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite
+            """
+            if stdin == None and stdout == None and stderr == None:
+                return (None, None, None, None, None, None)
+
+            p2cread, p2cwrite = None, None
+            c2pread, c2pwrite = None, None
+            errread, errwrite = None, None
+
+            if stdin == None:
+                p2cread = GetStdHandle(STD_INPUT_HANDLE)
+            elif stdin == PIPE:
+                p2cread, p2cwrite = CreatePipe(None, 0)
+                # Detach and turn into fd
+                p2cwrite = p2cwrite.Detach()
+                p2cwrite = msvcrt.open_osfhandle(p2cwrite, 0)
+            elif type(stdin) == types.IntType:
+                p2cread = msvcrt.get_osfhandle(stdin)
+            else:
+                # Assuming file-like object
+                p2cread = msvcrt.get_osfhandle(stdin.fileno())
+            p2cread = self._make_inheritable(p2cread)
+
+            if stdout == None:
+                c2pwrite = GetStdHandle(STD_OUTPUT_HANDLE)
+            elif stdout == PIPE:
+                c2pread, c2pwrite = CreatePipe(None, 0)
+                # Detach and turn into fd
+                c2pread = c2pread.Detach()
+                c2pread = msvcrt.open_osfhandle(c2pread, 0)
+            elif type(stdout) == types.IntType:
+                c2pwrite = msvcrt.get_osfhandle(stdout)
+            else:
+                # Assuming file-like object
+                c2pwrite = msvcrt.get_osfhandle(stdout.fileno())
+            c2pwrite = self._make_inheritable(c2pwrite)
+
+            if stderr == None:
+                errwrite = GetStdHandle(STD_ERROR_HANDLE)
+            elif stderr == PIPE:
+                errread, errwrite = CreatePipe(None, 0)
+                # Detach and turn into fd
+                errread = errread.Detach()
+                errread = msvcrt.open_osfhandle(errread, 0)
+            elif stderr == STDOUT:
+                errwrite = c2pwrite
+            elif type(stderr) == types.IntType:
+                errwrite = msvcrt.get_osfhandle(stderr)
+            else:
+                # Assuming file-like object
+                errwrite = msvcrt.get_osfhandle(stderr.fileno())
+            errwrite = self._make_inheritable(errwrite)
+
+            return (p2cread, p2cwrite,
+                    c2pread, c2pwrite,
+                    errread, errwrite)
+
+
+        def _make_inheritable(self, handle):
+            """Return a duplicate of handle, which is inheritable"""
+            return DuplicateHandle(GetCurrentProcess(), handle,
+                                   GetCurrentProcess(), 0, 1,
+                                   DUPLICATE_SAME_ACCESS)
+
+
+        def _find_w9xpopen(self):
+            """Find and return absolut path to w9xpopen.exe"""
+            w9xpopen = os.path.join(os.path.dirname(GetModuleFileName(0)),
+                                    "w9xpopen.exe")
+            if not os.path.exists(w9xpopen):
+                # Eeek - file-not-found - possibly an embedding
+                # situation - see if we can locate it in sys.exec_prefix
+                w9xpopen = os.path.join(os.path.dirname(sys.exec_prefix),
+                                        "w9xpopen.exe")
+                if not os.path.exists(w9xpopen):
+                    raise RuntimeError("Cannot locate w9xpopen.exe, which is "
+                                       "needed for Popen to work with your "
+                                       "shell or platform.")
+            return w9xpopen
+
+
+        def _execute_child(self, args, executable, preexec_fn, close_fds,
+                           cwd, env, universal_newlines,
+                           startupinfo, creationflags, shell,
+                           p2cread, p2cwrite,
+                           c2pread, c2pwrite,
+                           errread, errwrite):
+            """Execute program (MS Windows version)"""
+
+            if not isinstance(args, types.StringTypes):
+                args = list2cmdline(args)
+
+            # Process startup details
+            default_startupinfo = STARTUPINFO()
+            if startupinfo == None:
+                startupinfo = default_startupinfo
+            if not None in (p2cread, c2pwrite, errwrite):
+                startupinfo.dwFlags |= STARTF_USESTDHANDLES
+                startupinfo.hStdInput = p2cread
+                startupinfo.hStdOutput = c2pwrite
+                startupinfo.hStdError = errwrite
+
+            if shell:
+                default_startupinfo.dwFlags |= STARTF_USESHOWWINDOW
+                default_startupinfo.wShowWindow = SW_HIDE
+                comspec = os.environ.get("COMSPEC", "cmd.exe")
+                args = comspec + " /c " + args
+                if (GetVersion() >= 0x80000000L or
+                        os.path.basename(comspec).lower() == "command.com"):
+                    # Win9x, or using command.com on NT. We need to
+                    # use the w9xpopen intermediate program. For more
+                    # information, see KB Q150956
+                    # (http://web.archive.org/web/20011105084002/http://support.microsoft.com/support/kb/articles/Q150/9/56.asp)
+                    w9xpopen = self._find_w9xpopen()
+                    args = '"%s" %s' % (w9xpopen, args)
+                    # Not passing CREATE_NEW_CONSOLE has been known to
+                    # cause random failures on win9x.  Specifically a
+                    # dialog: "Your program accessed mem currently in
+                    # use at xxx" and a hopeful warning about the
+                    # stability of your system.  Cost is Ctrl+C wont
+                    # kill children.
+                    creationflags |= CREATE_NEW_CONSOLE
+
+            # Start the process
+            try:
+                hp, ht, pid, tid = CreateProcess(executable, args,
+                                         # no special security
+                                         None, None,
+                                         # must inherit handles to pass std
+                                         # handles
+                                         1,
+                                         creationflags,
+                                         env,
+                                         cwd,
+                                         startupinfo)
+            except pywintypes.error, e:
+                # Translate pywintypes.error to WindowsError, which is
+                # a subclass of OSError.  FIXME: We should really
+                # translate errno using _sys_errlist (or simliar), but
+                # how can this be done from Python?
+                raise WindowsError(*e.args)
+
+            # Retain the process handle, but close the thread handle
+            self._handle = hp
+            self.pid = pid
+            ht.Close()
+
+            # Child is launched. Close the parent's copy of those pipe
+            # handles that only the child should have open.  You need
+            # to make sure that no handles to the write end of the
+            # output pipe are maintained in this process or else the
+            # pipe will not close when the child process exits and the
+            # ReadFile will hang.
+            if p2cread != None:
+                p2cread.Close()
+            if c2pwrite != None:
+                c2pwrite.Close()
+            if errwrite != None:
+                errwrite.Close()
+
+
+        def poll(self):
+            """Check if child process has terminated.  Returns returncode
+            attribute."""
+            if self.returncode == None:
+                if WaitForSingleObject(self._handle, 0) == WAIT_OBJECT_0:
+                    self.returncode = GetExitCodeProcess(self._handle)
+                    _active.remove(self)
+            return self.returncode
+
+
+        def wait(self):
+            """Wait for child process to terminate.  Returns returncode
+            attribute."""
+            if self.returncode == None:
+                obj = WaitForSingleObject(self._handle, INFINITE)
+                self.returncode = GetExitCodeProcess(self._handle)
+                _active.remove(self)
+            return self.returncode
+
+
+        def _readerthread(self, fh, buffer):
+            buffer.append(fh.read())
+
+
+        def communicate(self, input=None):
+            """Interact with process: Send data to stdin.  Read data from
+            stdout and stderr, until end-of-file is reached.  Wait for
+            process to terminate.  The optional input argument should be a
+            string to be sent to the child process, or None, if no data
+            should be sent to the child.
+
+            communicate() returns a tuple (stdout, stderr)."""
+            stdout = None # Return
+            stderr = None # Return
+
+            if self.stdout:
+                stdout = []
+                stdout_thread = threading.Thread(target=self._readerthread,
+                                                 args=(self.stdout, stdout))
+                stdout_thread.setDaemon(True)
+                stdout_thread.start()
+            if self.stderr:
+                stderr = []
+                stderr_thread = threading.Thread(target=self._readerthread,
+                                                 args=(self.stderr, stderr))
+                stderr_thread.setDaemon(True)
+                stderr_thread.start()
+
+            if self.stdin:
+                if input != None:
+                    self.stdin.write(input)
+                self.stdin.close()
+
+            if self.stdout:
+                stdout_thread.join()
+            if self.stderr:
+                stderr_thread.join()
+
+            # All data exchanged.  Translate lists into strings.
+            if stdout != None:
+                stdout = stdout[0]
+            if stderr != None:
+                stderr = stderr[0]
+
+            # Translate newlines, if requested.  We cannot let the file
+            # object do the translation: It is based on stdio, which is
+            # impossible to combine with select (unless forcing no
+            # buffering).
+            if self.universal_newlines and hasattr(open, 'newlines'):
+                if stdout:
+                    stdout = self._translate_newlines(stdout)
+                if stderr:
+                    stderr = self._translate_newlines(stderr)
+
+            self.wait()
+            return (stdout, stderr)
+
+    else:
+        #
+        # POSIX methods
+        #
+        def _get_handles(self, stdin, stdout, stderr):
+            """Construct and return tupel with IO objects:
+            p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite
+            """
+            p2cread, p2cwrite = None, None
+            c2pread, c2pwrite = None, None
+            errread, errwrite = None, None
+
+            if stdin == None:
+                pass
+            elif stdin == PIPE:
+                p2cread, p2cwrite = os.pipe()
+            elif type(stdin) == types.IntType:
+                p2cread = stdin
+            else:
+                # Assuming file-like object
+                p2cread = stdin.fileno()
+
+            if stdout == None:
+                pass
+            elif stdout == PIPE:
+                c2pread, c2pwrite = os.pipe()
+            elif type(stdout) == types.IntType:
+                c2pwrite = stdout
+            else:
+                # Assuming file-like object
+                c2pwrite = stdout.fileno()
+
+            if stderr == None:
+                pass
+            elif stderr == PIPE:
+                errread, errwrite = os.pipe()
+            elif stderr == STDOUT:
+                errwrite = c2pwrite
+            elif type(stderr) == types.IntType:
+                errwrite = stderr
+            else:
+                # Assuming file-like object
+                errwrite = stderr.fileno()
+
+            return (p2cread, p2cwrite,
+                    c2pread, c2pwrite,
+                    errread, errwrite)
+
+
+        def _set_cloexec_flag(self, fd):
+            try:
+                cloexec_flag = fcntl.FD_CLOEXEC
+            except AttributeError:
+                cloexec_flag = 1
+
+            old = fcntl.fcntl(fd, fcntl.F_GETFD)
+            fcntl.fcntl(fd, fcntl.F_SETFD, old | cloexec_flag)
+
+
+        def _close_fds(self, but):
+            for i in range(3, MAXFD):
+                if i == but:
+                    continue
+                try:
+                    os.close(i)
+                except:
+                    pass
+
+
+        def _execute_child(self, args, executable, preexec_fn, close_fds,
+                           cwd, env, universal_newlines,
+                           startupinfo, creationflags, shell,
+                           p2cread, p2cwrite,
+                           c2pread, c2pwrite,
+                           errread, errwrite):
+            """Execute program (POSIX version)"""
+
+            if isinstance(args, types.StringTypes):
+                args = [args]
+
+            if shell:
+                args = ["/bin/sh", "-c"] + args
+
+            if executable == None:
+                executable = args[0]
+
+            # For transferring possible exec failure from child to parent
+            # The first char specifies the exception type: 0 means
+            # OSError, 1 means some other error.
+            errpipe_read, errpipe_write = os.pipe()
+            self._set_cloexec_flag(errpipe_write)
+
+            self.pid = os.fork()
+            if self.pid == 0:
+                # Child
+                try:
+                    # Close parent's pipe ends
+                    if p2cwrite:
+                        os.close(p2cwrite)
+                    if c2pread:
+                        os.close(c2pread)
+                    if errread:
+                        os.close(errread)
+                    os.close(errpipe_read)
+
+                    # Dup fds for child
+                    if p2cread:
+                        os.dup2(p2cread, 0)
+                    if c2pwrite:
+                        os.dup2(c2pwrite, 1)
+                    if errwrite:
+                        os.dup2(errwrite, 2)
+
+                    # Close pipe fds.  Make sure we doesn't close the same
+                    # fd more than once.
+                    if p2cread:
+                        os.close(p2cread)
+                    if c2pwrite and c2pwrite not in (p2cread,):
+                        os.close(c2pwrite)
+                    if errwrite and errwrite not in (p2cread, c2pwrite):
+                        os.close(errwrite)
+
+                    # Close all other fds, if asked for
+                    if close_fds:
+                        self._close_fds(but=errpipe_write)
+
+                    if cwd != None:
+                        os.chdir(cwd)
+
+                    if preexec_fn:
+                        apply(preexec_fn)
+
+                    if env == None:
+                        os.execvp(executable, args)
+                    else:
+                        os.execvpe(executable, args, env)
+
+                except:
+                    exc_type, exc_value, tb = sys.exc_info()
+                    # Save the traceback and attach it to the exception object
+                    exc_lines = traceback.format_exception(exc_type,
+                                                           exc_value,
+                                                           tb)
+                    exc_value.child_traceback = ''.join(exc_lines)
+                    os.write(errpipe_write, pickle.dumps(exc_value))
+
+                # This exitcode won't be reported to applications, so it
+                # really doesn't matter what we return.
+                os._exit(255)
+
+            # Parent
+            os.close(errpipe_write)
+            if p2cread and p2cwrite:
+                os.close(p2cread)
+            if c2pwrite and c2pread:
+                os.close(c2pwrite)
+            if errwrite and errread:
+                os.close(errwrite)
+
+            # Wait for exec to fail or succeed; possibly raising exception
+            data = os.read(errpipe_read, 1048576) # Exceptions limited to 1 MB
+            os.close(errpipe_read)
+            if data != "":
+                os.waitpid(self.pid, 0)
+                child_exception = pickle.loads(data)
+                raise child_exception
+
+
+        def _handle_exitstatus(self, sts):
+            if os.WIFSIGNALED(sts):
+                self.returncode = -os.WTERMSIG(sts)
+            elif os.WIFEXITED(sts):
+                self.returncode = os.WEXITSTATUS(sts)
+            else:
+                # Should never happen
+                raise RuntimeError("Unknown child exit status!")
+
+            _active.remove(self)
+
+
+        def poll(self):
+            """Check if child process has terminated.  Returns returncode
+            attribute."""
+            if self.returncode == None:
+                try:
+                    pid, sts = os.waitpid(self.pid, os.WNOHANG)
+                    if pid == self.pid:
+                        self._handle_exitstatus(sts)
+                except os.error:
+                    pass
+            return self.returncode
+
+
+        def wait(self):
+            """Wait for child process to terminate.  Returns returncode
+            attribute."""
+            if self.returncode == None:
+                pid, sts = os.waitpid(self.pid, 0)
+                self._handle_exitstatus(sts)
+            return self.returncode
+
+
+        def communicate(self, input=None):
+            """Interact with process: Send data to stdin.  Read data from
+            stdout and stderr, until end-of-file is reached.  Wait for
+            process to terminate.  The optional input argument should be a
+            string to be sent to the child process, or None, if no data
+            should be sent to the child.
+
+            communicate() returns a tuple (stdout, stderr)."""
+            read_set = []
+            write_set = []
+            stdout = None # Return
+            stderr = None # Return
+
+            if self.stdin:
+                # Flush stdio buffer.  This might block, if the user has
+                # been writing to .stdin in an uncontrolled fashion.
+                self.stdin.flush()
+                if input:
+                    write_set.append(self.stdin)
+                else:
+                    self.stdin.close()
+            if self.stdout:
+                read_set.append(self.stdout)
+                stdout = []
+            if self.stderr:
+                read_set.append(self.stderr)
+                stderr = []
+
+            while read_set or write_set:
+                rlist, wlist, xlist = select.select(read_set, write_set, [])
+
+                if self.stdin in wlist:
+                    # When select has indicated that the file is writable,
+                    # we can write up to PIPE_BUF bytes without risk
+                    # blocking.  POSIX defines PIPE_BUF >= 512
+                    bytes_written = os.write(self.stdin.fileno(), input[:512])
+                    input = input[bytes_written:]
+                    if not input:
+                        self.stdin.close()
+                        write_set.remove(self.stdin)
+
+                if self.stdout in rlist:
+                    data = os.read(self.stdout.fileno(), 1024)
+                    if data == "":
+                        self.stdout.close()
+                        read_set.remove(self.stdout)
+                    stdout.append(data)
+
+                if self.stderr in rlist:
+                    data = os.read(self.stderr.fileno(), 1024)
+                    if data == "":
+                        self.stderr.close()
+                        read_set.remove(self.stderr)
+                    stderr.append(data)
+
+            # All data exchanged.  Translate lists into strings.
+            if stdout != None:
+                stdout = ''.join(stdout)
+            if stderr != None:
+                stderr = ''.join(stderr)
+
+            # Translate newlines, if requested.  We cannot let the file
+            # object do the translation: It is based on stdio, which is
+            # impossible to combine with select (unless forcing no
+            # buffering).
+            if self.universal_newlines and hasattr(open, 'newlines'):
+                if stdout:
+                    stdout = self._translate_newlines(stdout)
+                if stderr:
+                    stderr = self._translate_newlines(stderr)
+
+            self.wait()
+            return (stdout, stderr)
+
+
+def _demo_posix():
+    #
+    # Example 1: Simple redirection: Get process list
+    #
+    plist = Popen(["ps"], stdout=PIPE).communicate()[0]
+    print "Process list:"
+    print plist
+
+    #
+    # Example 2: Change uid before executing child
+    #
+    if os.getuid() == 0:
+        p = Popen(["id"], preexec_fn=lambda: os.setuid(100))
+        p.wait()
+
+    #
+    # Example 3: Connecting several subprocesses
+    #
+    print "Looking for 'hda'..."
+    p1 = Popen(["dmesg"], stdout=PIPE)
+    p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
+    print repr(p2.communicate()[0])
+
+    #
+    # Example 4: Catch execution error
+    #
+    print
+    print "Trying a weird file..."
+    try:
+        print Popen(["/this/path/does/not/exist"]).communicate()
+    except OSError, e:
+        if e.errno == errno.ENOENT:
+            print "The file didn't exist.  I thought so..."
+            print "Child traceback:"
+            print e.child_traceback
+        else:
+            print "Error", e.errno
+    else:
+        print >>sys.stderr, "Gosh.  No error."
+
+
+def _demo_windows():
+    #
+    # Example 1: Connecting several subprocesses
+    #
+    print "Looking for 'PROMPT' in set output..."
+    p1 = Popen("set", stdout=PIPE, shell=True)
+    p2 = Popen('find "PROMPT"', stdin=p1.stdout, stdout=PIPE)
+    print repr(p2.communicate()[0])
+
+    #
+    # Example 2: Simple execution of program
+    #
+    print "Executing calc..."
+    p = Popen("calc")
+    p.wait()
+
+
+if __name__ == "__main__":
+    if mswindows:
+        _demo_windows()
+    else:
+        _demo_posix()
diff --git a/scripts/pulp b/scripts/pulp
new file mode 100755
index 0000000..1017fb2
--- /dev/null
+++ b/scripts/pulp
@@ -0,0 +1,7 @@
+#!/usr/bin/python
+
+import sys
+
+from pulp.cli.cli import PulpCommandLine
+PulpCommandLine().main(sys.argv)
+
-- 
1.5.4.1

Attachment: pgpJIdVbhhdbL.pgp
Description: PGP signature


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]