如何使用apt.progress类检查python_apt中commit()的进度？

Question

我在查看一个叫 python_apt 的代码，但感觉这个代码有点过时了：

https://github.com/jolicloud/python-apt/blob/master/doc/examples/inst.py

我现在想做的就是跟踪一下 commit() 这个方法的进展；目前当我们调用 commit() 并传入 fprogress 和 iprogress 时，我在控制台上可以看到 pkg_list 中的所有包都下载得很顺利，但问题似乎出现在这之后。

程序继续执行，但我觉得它应该触发 dpkg_status_change()，可它并没有？

我不知道安装多个包是否成功？

import apt 
from apt.progress.base import InstallProgress

    class InstallStatusUpdate(InstallProgress):

            def conffile(self, current, new):
                print "conffile prompt: %s %s" % (current, new)

            def processing(self, pkg, stage):
                print "Processing ", pkg, " stage: ", stage

            def error(self, pkg, errormsg):
                print "Package ", pkg, " error: ", errormsg

            def finish_update(self):
                print "Installation is complete"

            def status_change(self, pkg, percent, status):
                print "Package: ", pkg, " at ", percent, " -> ", status

            def dpkg_status_change(self, pkg, status):
                print "Package ", pkg, ", Status: ", status



    def install_updates(self, pkg_list):
            fprogress = apt.progress.TextFetchProgress()
            iprogress = InstallStatusUpdate()

            cache_tmp = apt.Cache()
            cache_tmp.update()
            cache_tmp.open(None)

            for pkg in pkg_list:
                try:
                    self.pkgname = cache_tmp[pkg.name]
                    if self.pkgname.is_installed and self.pkgname.is_upgradable:
                        self.pkgname.mark_upgrade()
                    else:
                        self.pkgname.mark_install()
                except Exception as e:
                    print e.message

            result = self.pkgname.commit(fprogress, iprogress)
            #Maybe i'm doing something wrong here but result always = None...

Answer 1

看起来使用 python_apt 的 commit() 方法挺麻烦的，我最后选择用 subprocess 来等待所有操作完成（就应该这样），然后在最后解析输出，以确认软件包确实已经升级。

在 _apt_update() 里，我会先检查系统是否在线，然后再尝试执行 apt-get update，接着继续安装传递给 _apt_install() 的软件包。

 def _apt_update(self):
        import urllib2

        try:
            response = urllib2.urlopen('http://74.125.113.99', timeout=1)
            #We have internet access
            subprocess.Popen(['apt-get', 'update'])
            return True
        except urllib2.URLError as err: pass
        return False

 def _apt_install(self, pkg, update=True):
        upgraded = 0

        if update == True:
            self._apt_update()

        proc = subprocess.Popen(['apt-get', 'install', pkg, "-y"], stdout=subprocess.PIPE)
        for line in proc.stdout:
            if "upgraded" in line and "newly installed" in line and "to remove" in line:
                values = line.split(",")
                for pos in values:
                    key, value = pos.split(" ")
                    if value == "upgraded":
                        upgraded = int(key)
                    break

        print "Upgraded OK (", upgraded, ")"
        if upgraded > 0:
            return True
        else:
            return False