IOError: [Errno 0] Error when calling proc.as_dict(attrs=['pid', 'environ'])

[pwilczynskiclearcode]

IOError: [Errno 0] Error was raised when calling proc.as_dict(attrs=['pid', 'environ'])

env/lib/python2.7/site-packages/mirakuru/base.py:224: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

env_name = 'mirakuru_uuid'
env_value = '19074:99420fe3-bbf0-4479-91d0-648ba4b35572'

    def processes_with_env_psutil(env_name, env_value):
        """
        Find PIDs of processes having environment variable matching given one.

        Internally it uses `psutil` library.

        :param str env_name: name of environment variable to be found
        :param str env_value: environment variable value prefix
        :return: process identifiers (PIDs) of processes that have certain
                 environment variable equal certain value
        :rtype: set
        """
        pids = set()

        for proc in psutil.process_iter():
            try:
>               pinfo = proc.as_dict(attrs=['pid', 'environ'])

env_name   = 'mirakuru_uuid'
env_value  = '19074:99420fe3-bbf0-4479-91d0-648ba4b35572'
penv       = {}
pids       = set([])
pinfo      = {'environ': {}, 'pid': 28289}
proc       = <psutil.Process(pid=28368, name='gunicorn') at 140211648444560>

env/lib/python2.7/site-packages/mirakuru/base_env.py:54: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <psutil.Process(pid=28368, name='gunicorn') at 140211648444560>
attrs = ['pid', 'environ'], ad_value = None

    def as_dict(self, attrs=None, ad_value=None):
        """Utility method returning process information as a
            hashable dictionary.

            If 'attrs' is specified it must be a list of strings
            reflecting available Process class' attribute names
            (e.g. ['cpu_times', 'name']) else all public (read
            only) attributes are assumed.

            'ad_value' is the value which gets assigned in case
            AccessDenied or ZombieProcess exception is raised when
            retrieving that particular process information.
            """
        excluded_names = set(
            ['send_signal', 'suspend', 'resume', 'terminate', 'kill', 'wait',
             'is_running', 'as_dict', 'parent', 'children', 'rlimit'])
        valid_names = _process_attrnames - excluded_names
        retdict = dict()
        ls = set(attrs) if attrs else _process_attrnames
        for name in ls:
            if name not in valid_names:
                continue
            try:
                attr = getattr(self, name)
                if callable(attr):
>                   ret = attr()

ad_value   = None
attr       = <bound method Process.environ of <psutil.Process(pid=28368, name='gunicorn') at 140211648444560>>
attrs      = ['pid', 'environ']
excluded_names = set(['as_dict', 'children', 'is_running', 'kill', 'parent', 'resume', ...])
ls         = set(['environ', 'pid'])
name       = 'environ'
retdict    = {}
self       = <psutil.Process(pid=28368, name='gunicorn') at 140211648444560>
valid_names = set(['cmdline', 'connections', 'cpu_affinity', 'cpu_percent', 'cpu_times', 'create_time', ...])

env/lib/python2.7/site-packages/psutil/__init__.py:473: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <psutil.Process(pid=28368, name='gunicorn') at 140211648444560>

    def environ(self):
        """The environment variables of the process as a dict.  Note: this
                might not reflect changes made after the process started.  """
>       return self._proc.environ()

self       = <psutil.Process(pid=28368, name='gunicorn') at 140211648444560>

env/lib/python2.7/site-packages/psutil/__init__.py:767: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <psutil._pslinux.Process object at 0x7f859189cc30>, args = ()
kwargs = {}, err = IOError(0, 'Error')

    @functools.wraps(fun)
    def wrapper(self, *args, **kwargs):
        try:
>           return fun(self, *args, **kwargs)

args       = ()
err        = IOError(0, 'Error')
fun        = <function environ at 0x7f85a42b1a28>
kwargs     = {}
self       = <psutil._pslinux.Process object at 0x7f859189cc30>

env/lib/python2.7/site-packages/psutil/_pslinux.py:962: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <psutil._pslinux.Process object at 0x7f859189cc30>

    @wrap_exceptions
    def environ(self):
        with open_text("%s/%s/environ" % (self._procfs_path, self.pid)) as f:
>           data = f.read()
E           IOError: [Errno 0] Error

f          = <closed file '/proc/28368/environ', mode 'rt' at 0x7f85914b94b0>
self       = <psutil._pslinux.Process object at 0x7f859189cc30>

env/lib/python2.7/site-packages/psutil/_pslinux.py:1053: IOError

environment:
python 2.7.11, psutil 4.3.0, happened during running a test suite in py.test 2.9.2

[giampaolo]

Hhmm... that looks like a Python bug. open(...).read() sets IOError with errno to 0. Weird.
For completeness open_text() here is just a 1:1 wrapper around open(), so nothing "special":

psutil/psutil/_pslinux.py

Line 183 in e4e0500

def open_text(fname, **kwargs):

Are you able to reproduce this issue when you want? If so, can you replicate it on Python 3?

[pwilczynskiclearcode]

Unfortunately it's a random failure.
Maybe it's not Python's fault by the old Debian Wheezy that I use

[giampaolo]

Yeah, unfortunately in case of errno = 0 there really isn't a sane decision that psutil can take regarding how to handle it: letting it propagate is the best compromise IMO.
And yeah, I agree this looks like a bug with the old Linux distro you're using.
Closing this out.