Sensors_temperatures no such file error

[nicolargo]

On my Dell XPS 13 on Ubuntu 16.04, with the latest 5.1.0 release and Puthon 2.7, i have the following error:

In [3]: psutil.sensors_battery()
---------------------------------------------------------------------------
IOError                                   Traceback (most recent call last)
<ipython-input-3-2cfac8b92a01> in <module>()
----> 1 psutil.sensors_battery()

/usr/local/lib/python2.7/dist-packages/psutil/__init__.pyc in sensors_battery()
   2244         - power_plugged: True if the AC power cable is connected.
   2245         """
-> 2246         return _psplatform.sensors_battery()
   2247 
   2248     __all__.append("sensors_battery")

/usr/local/lib/python2.7/dist-packages/psutil/_pslinux.pyc in sensors_battery()
   1110     power_plugged = cat(os.path.join(POWER_SUPPLY_PATH, "AC0/online"),
   1111                         fallback=b"0") == b"1"
-> 1112     energy_now = int(cat(root + "/energy_now"))
   1113     power_now = int(cat(root + "/power_now"))
   1114     percent = int(cat(root + "/capacity"))

/usr/local/lib/python2.7/dist-packages/psutil/_pslinux.pyc in cat(fname, fallback, binary)
    286     """Return file content."""
    287     try:
--> 288         f = open_binary(fname) if binary else open_text(fname)
    289     except IOError:
    290         if fallback != _DEFAULT:

/usr/local/lib/python2.7/dist-packages/psutil/_pslinux.pyc in open_binary(fname, **kwargs)
    185 
    186 def open_binary(fname, **kwargs):
--> 187     return open(fname, "rb", **kwargs)
    188 
    189 

IOError: [Errno 2] No such file or directory: '/sys/class/power_supply/BAT0/energy_now'

When i have a look on the /sys/class/power_supply/BAT0/ folder, no energy_now file but another ones:

# ll /sys/class/power_supply/BAT0/
total 0
-rw-r--r-- 1 root root 4096 janv. 29 17:03 alarm
-r--r--r-- 1 root root 4096 janv. 29 15:45 capacity
-r--r--r-- 1 root root 4096 janv. 29 17:03 capacity_level
-r--r--r-- 1 root root 4096 janv. 29 15:45 charge_full
-r--r--r-- 1 root root 4096 janv. 29 15:45 charge_full_design
-r--r--r-- 1 root root 4096 janv. 29 15:45 charge_now
-r--r--r-- 1 root root 4096 janv. 29 15:45 current_now
-r--r--r-- 1 root root 4096 janv. 29 17:03 cycle_count
lrwxrwxrwx 1 root root    0 janv. 29 17:03 device -> ../../../PNP0C0A:00/
-r--r--r-- 1 root root 4096 janv. 29 15:45 manufacturer
-r--r--r-- 1 root root 4096 janv. 29 15:45 model_name
drwxr-xr-x 2 root root    0 janv. 29 17:03 power/
-r--r--r-- 1 root root 4096 janv. 29 15:45 present
-r--r--r-- 1 root root 4096 janv. 29 15:45 serial_number
-r--r--r-- 1 root root 4096 janv. 29 15:45 status
lrwxrwxrwx 1 root root    0 janv. 29 15:45 subsystem -> ../../../../../../class/power_supply/
-r--r--r-- 1 root root 4096 janv. 29 15:45 technology
-r--r--r-- 1 root root 4096 janv. 29 15:45 type
-rw-r--r-- 1 root root 4096 janv. 29 15:45 uevent
-r--r--r-- 1 root root 4096 janv. 29 15:45 voltage_min_design
-r--r--r-- 1 root root 4096 janv. 29 15:45 voltage_now

[giampaolo]

Shit! I am also on Ubuntu 16.04 and I have that file (but I don't have charge_now as you do). It appears /sys/class/power_supply directory structure is not reliable. :-\

[giampaolo]

@nicolargo can you try this, then take a look at the output of acpi -b to see if the values match?

def sensors_battery():
    root = os.path.join(POWER_SUPPLY_PATH, "BAT0")
    if not os.path.exists(root):
        return None

    power_plugged = cat(os.path.join(POWER_SUPPLY_PATH, "AC0/online"),
                        fallback=b"0") == b"1"

    if os.path.exists(root + "/energy_now"):
        remaining_capacity = int(cat(root + "/energy_now"))
    elif os.path.exists(root + "/charge_now"):
        remaining_capacity = int(cat(root + "/charge_now"))
    else:
        return None

    if os.path.exists(root + "/power_now"):
        present_rate = int(cat(root + "/power_now"))
    elif os.path.exists(root + "/current_now"):
        present_rate = int(cat(root + "/current_now"))
    else:
        return None

    if os.path.exists(root + "/capacity"):
        percent = int(cat(root + "/capacity"))
    else:
        if os.path.exists(root + "/charge_full"):
            max_capacity = int(cat(root + "/charge_full"))
        elif os.path.exists(root + "/energy_full"):
            max_capacity = int(cat(root + "/energy_full"))
        else:
            return None
        percent = 100.0 * remaining_capacity / max_capacity

    if power_plugged:
        secsleft = _common.POWER_TIME_UNLIMITED
    else:
        try:
            secsleft = int(remaining_capacity / present_rate * 3600)
        except ZeroDivisionError:
            secsleft = _common.POWER_TIME_UNKNOWN

    return _common.sbattery(percent, secsleft, power_plugged)

[nicolargo]

@giampaolo The https://gist.github.com/nicolargo/292c0c6c9ea935c08b5163549e473c20 return None on my system...

Here is the return of acpi -b:

Battery 0: Full, 100%

[giampaolo]

@nicolargo I think this one should work:

def sensors_battery():
    """Return battery information."""
    null = object()

    def multi_cat(*paths):
        """Read content of multiple files which may not exist.
        # If none of them exist returns None.
        """
        for path in paths:
            ret = cat(path, fallback=null)
            if ret != null:
                return int(ret)
        return None

    root = os.path.join(POWER_SUPPLY_PATH, "BAT0")
    if not os.path.exists(root):
        return None

    # Base metrics.
    energy_now = multi_cat(
        root + "/energy_now",
        root + "/charge_now")
    power_now = multi_cat(
        root + "/power_now",
        root + "/current_now")
    energy_full = multi_cat(
        root + "/energy_full",
        root + "/charge_full")
    if energy_now is None or power_now is None:
        return None

    # Percent.  If we have energy_full the percentage will be more
    # prece compare to reading /capacity file (float vs. int).
    if energy_full is not None:
        try:
            percent = 100.0 * energy_now / energy_full
        except ZeroDivisionError:
            percent = 0.0
    else:
        percent = int(cat(root + "/capacity"), fallback=-1)
        if percent == -1:
            return None

    # Secs left.
    power_plugged = cat(os.path.join(POWER_SUPPLY_PATH, "AC0/online"),
                        fallback=b"0") == b"1"
    if power_plugged:
        secsleft = _common.POWER_TIME_UNLIMITED
    else:
        try:
            secsleft = int(energy_now / power_now * 3600)
        except ZeroDivisionError:
            secsleft = _common.POWER_TIME_UNKNOWN

    return _common.sbattery(percent, secsleft, power_plugged)

[nicolargo]

Yes it is !

$ python ./sb.py 
sbattery(percent=100.0, secsleft=21391200, power_plugged=False)

[giampaolo]

OK, good. Is power_plugged=False correct? Was your power cable not plugged?

[nicolargo]

Always display power_plugged=False either the cable is connected or not...

Another issue if i unplug and plug it and quickly run the script i have the following error:

 ~ ▶ tmp ▶ $ ▶ python ./sb.py 
sbattery(percent=100.0, secsleft=21391200, power_plugged=False)
 ~ ▶ tmp ▶ $ ▶ python ./sb.py 
sbattery(percent=100.0, secsleft=21391200, power_plugged=False)
 ~ ▶ tmp ▶ $ ▶ python ./sb.py 
sbattery(percent=99.326825984517, secsleft=14400, power_plugged=False)
 ~ ▶ tmp ▶ $ ▶ python ./sb.py 
sbattery(percent=99.326825984517, secsleft=14400, power_plugged=False)
 ~ ▶ tmp ▶ $ ▶ python ./sb.py 
Traceback (most recent call last):
  File "./sb.py", line 75, in <module>
    print sensors_battery()
  File "./sb.py", line 50, in sensors_battery
    root + "/current_now")
  File "./sb.py", line 30, in multi_cat
    ret = cat(path, fallback=null)
  File "./sb.py", line 24, in cat
    return f.read().strip()
IOError: [Errno 19] No such device
 ~ ▶ tmp ▶ $ ▶ python ./sb.py 
Traceback (most recent call last):
  File "./sb.py", line 75, in <module>
    print sensors_battery()
  File "./sb.py", line 50, in sensors_battery
    root + "/current_now")
  File "./sb.py", line 30, in multi_cat
    ret = cat(path, fallback=null)
  File "./sb.py", line 24, in cat
    return f.read().strip()
IOError: [Errno 19] No such device
 ~ ▶ tmp ▶ $ ▶ python ./sb.py 
sbattery(percent=100.0, secsleft=21391200, power_plugged=False)
 ~ ▶ tmp ▶ $ ▶ 

[giampaolo]

OK, I committed that change so now this should be fixed. As for the power cable, that is determined by:

~/svn/psutil {master}$ cat /sys/class/power_supply/AC0/online 
0

E.g., now it's 0 in my case because it's unplugged, otherwise it'd have been 1.
I suppose you don't have that file?

[giampaolo]

1f30d13 should fix the IOError you bumped into by disconnecting the power cable. If that happens it should now return None.

[nicolargo]

Ok it works ! None is returned instead of exception.

I also confirm that i do not have any /sys/class/power_supply/AC0/online file...

[giampaolo]

@nicolargo what about cat /sys/class/power_supply/BAT0/status when you're fully charged?
Does it return "Charging"?

[nicolargo]

It return "Full"....