laptop_battery.py

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#!/usr/bin/env python

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##\author Kevin Watts
##\brief Monitors laptop battery status

from __future__ import division

from   collections import deque
import threading
import copy
import yaml
import math
import rospy
import os  # to check path existence

from linux_hardware.msg import LaptopChargeStatus
from diagnostic_msgs.msg import DiagnosticStatus, DiagnosticArray, KeyValue

def _strip_Ah(raw_val):
    if 'mAh' in raw_val:
        rv = float(raw_val.rstrip('mAh').strip()) / 1000.0
    elif 'Ah' in raw_val:
        rv = float(raw_val.rstrip('Ah').strip())
    elif 'mWh' in raw_val:
        rv = float(raw_val.rstrip('mWh').strip()) / 1000.0
    elif 'Wh' in raw_val:
        rv = float(raw_val.rstrip('Wh').strip())
    else:
        raise Exception('Value %s did not have supported units. (mAh,Ah,mWh,Wh)' % raw_val)
    return rv

def _strip_V(raw_val):
    if 'mV' in raw_val:
        rv = float(raw_val.rstrip('mV').strip()) / 1000.0
    elif 'V' in raw_val:
        rv = float(raw_val.rstrip('V').strip())
    else:
        raise Exception('Value %s did not have "V" or "mV"' % raw_val)
    return rv

def _strip_A(raw_val):
    if 'mA' in raw_val:
        rv = float(raw_val.rstrip('mA').strip()) / 1000.0
    elif 'A' in raw_val:
        rv = float(raw_val.rstrip('A').strip())
    elif 'mW' in raw_val:
        rv = float(raw_val.rstrip('mW').strip()) / 1000.0
    elif 'W' in raw_val:
        rv = float(raw_val.rstrip('W').strip())
    else:
        raise Exception('Value %s did not have supported units. (mAh,Ah,mWh,Wh)' % raw_val)
    return rv

def slerp(filename):
    f = open(filename, 'r')
    data = f.read()
    f.close()
    data = data.replace('\t', '  ')
    return data

def _read_string(filename, default=""):
    if not os.access(filename, os.F_OK):
        return default
    f = open(filename, 'r')
    data = f.read()
    f.close()
    return data

def _read_number(filename, default=0):
    try: 
        data = int(_read_string(filename))
        return data
    except exceptions.ValueError:
        return default

def _check_battery_info(_battery_acpi_path):
    if _battery_acpi_path.startswith('/proc'):

        if os.access(_battery_acpi_path, os.F_OK):
            o = slerp(_battery_acpi_path+'/info')
        else:
            raise Exception(_battery_acpi_path+' does not exist')
        
        batt_info = yaml.load(o)
        design_capacity    = _strip_Ah(batt_info.get('design capacity',    '0 mAh'))
        last_full_capacity = _strip_Ah(batt_info.get('last full capacity', '0 mAh'))
    else:
          # Provided as Wh * 10e5
        if os.path.exists(_battery_acpi_path + '/energy_full'):
            design_capacity    = _read_number(_battery_acpi_path + '/energy_full_design')/10e5
        else:
            design_capacity    = _read_number(_battery_acpi_path + '/charge_full_design')/10e5
            
        if os.path.exists(_battery_acpi_path + '/energy_full_design'):
            last_full_capacity = _read_number(_battery_acpi_path + '/energy_full')/10e5
        else:
            last_full_capacity = _read_number(_battery_acpi_path + '/charge_full')/10e5
            
    return (design_capacity, last_full_capacity)

state_to_val = {'charged':     LaptopChargeStatus.CHARGED,
                'full':        LaptopChargeStatus.CHARGED, 
                'charging':    LaptopChargeStatus.CHARGING, 
                'discharging': LaptopChargeStatus.DISCHARGING,
                'unknown':     LaptopChargeStatus.CHARGING, }

diag_level_to_msg = { DiagnosticStatus.OK:    'OK', 
                      DiagnosticStatus.WARN:  'Warning',
                      DiagnosticStatus.ERROR: 'Error'    }

def _check_battery_state(_battery_acpi_path):
    """
    @return LaptopChargeStatus
    """
    rv = LaptopChargeStatus()

    if _battery_acpi_path.startswith('/proc'):

        if os.access(_battery_acpi_path, os.F_OK):
            o = slerp(_battery_acpi_path+'/state')
        else:
            raise Exception(_battery_acpi_path+' does not exist')
        
        batt_info = yaml.load(o)

        state = batt_info.get('charging state', 'discharging')
        rv.charge_state = state_to_val.get(state, 0)
        rv.rate     = _strip_A(batt_info.get('present rate',        '-1 mA'))
        if rv.charge_state == LaptopChargeStatus.DISCHARGING:
            rv.rate = math.copysign(rv.rate, -1) # Need to set discharging rate to negative
        
        rv.charge   = _strip_Ah(batt_info.get('remaining capacity', '-1 mAh')) # /energy_now
        rv.voltage  = _strip_V(batt_info.get('present voltage',     '-1 mV')) # /voltage_now
        rv.present  = batt_info.get('present', False) # /present

        rv.header.stamp = rospy.get_rostime()
    else:

        # Charging state; make lowercase and remove trailing eol
        state = _read_string(_battery_acpi_path+'/status', 'discharging').lower().rstrip()
        rv.charge_state = state_to_val.get(state, 0)
        
        if os.path.exists(_battery_acpi_path + '/power_now'):
            rv.rate     = _read_number(_battery_acpi_path + '/power_now')/10e5
        else:
            rv.rate     = _read_number(_battery_acpi_path + '/current_now')/10e5
            
        if rv.charge_state == LaptopChargeStatus.DISCHARGING:
            rv.rate = math.copysign(rv.rate, -1) # Need to set discharging rate to negative
        
        if os.path.exists(_battery_acpi_path + '/energy_now'):
            rv.charge   = _read_number(_battery_acpi_path + '/energy_now')/10e5
        else:
            rv.charge   = _read_number(_battery_acpi_path + '/charge_now')/10e5
        
        rv.voltage  = _read_number(_battery_acpi_path + '/voltage_now')/10e5
        rv.present  = _read_number(_battery_acpi_path + '/present') == 1

        rv.header.stamp = rospy.get_rostime()



    return rv

def _laptop_charge_to_diag(laptop_msg):
    rv = DiagnosticStatus()
    rv.level   = DiagnosticStatus.OK
    rv.message = 'OK'
    rv.name    = 'Laptop Battery'

    if not laptop_msg.present:
        rv.level = DiagnosticStatus.ERROR
        rv.message = 'Laptop battery missing'

    rv.values.append(KeyValue('Voltage (V)',          str(laptop_msg.voltage)))
    rv.values.append(KeyValue('Current (A)',          str(laptop_msg.rate)))
    rv.values.append(KeyValue('Charge (Ah)',          str(laptop_msg.charge)))
    rv.values.append(KeyValue('Capacity (Ah)',        str(laptop_msg.capacity)))
    rv.values.append(KeyValue('Design Capacity (Ah)', str(laptop_msg.design_capacity)))

    return rv

class LaptopBatteryMonitor(object):
    def __init__(self):
        self._mutex = threading.Lock()

        self._last_info_update  = 0
        self._last_state_update = 0
        self._msg = LaptopChargeStatus()
        
        self._power_pub = rospy.Publisher('laptop_charge', LaptopChargeStatus, latch=True)
        self._diag_pub  = rospy.Publisher('/diagnostics', DiagnosticArray)
        
        # Battery info
        self._batt_acpi_path = rospy.get_param('~acpi_path', "/sys/class/power_supply/BAT0")
        self._batt_design_capacity = 0
        self._batt_last_full_capacity = 0
        self._last_info_update = 0

        self._batt_info_rate = 1 / 60.0
        self._batt_info_thread = threading.Thread(target=self._check_batt_info)
        self._batt_info_thread.daemon = True
        self._batt_info_thread.start()

        # Battery state
        self._batt_state_rate = 1 / 5.0
        self._batt_state_thread = threading.Thread(target=self._check_batt_state)
        self._batt_state_thread.daemon = True
        self._batt_state_thread.start()

    def _check_batt_info(self):
        rate = rospy.Rate(self._batt_info_rate)
        while not rospy.is_shutdown():
            try:
                design_cap, last_full_cap = _check_battery_info(self._batt_acpi_path)
                with self._mutex:
                    self._batt_last_full_capacity = last_full_cap
                    self._batt_design_capacity    = design_cap
                    self._last_info_update        = rospy.get_time()
            except Exception, e:
                rospy.logwarn('Battery : unable to check laptop battery info [%s]' % e)
                rospy.signal_shutdown('Battery : unable to check laptop battery info [%s]' % e)
                
            rate.sleep()

    def _check_batt_state(self):
        rate = rospy.Rate(self._batt_state_rate)
        while not rospy.is_shutdown():
            try:
                msg = _check_battery_state(self._batt_acpi_path)
                with self._mutex:
                    self._msg = msg
                    self._last_state_update = rospy.get_time()
            except Exception, e:
                rospy.logwarn('Battery : unable to check laptop battery state [%s]' % e)
                rospy.signal_shutdown('Battery : unable to check laptop battery state [%s]' % e)
                
            rate.sleep()

    def update(self):
        with self._mutex:
            diag = DiagnosticArray()
            diag.header.stamp = rospy.get_rostime()
            
            info_update_ok  = rospy.get_time() - self._last_info_update  < 5.0 / self._batt_info_rate
            state_update_ok = rospy.get_time() - self._last_state_update < 5.0 / self._batt_state_rate

            if info_update_ok:
                self._msg.design_capacity = self._batt_design_capacity
                self._msg.capacity        = self._batt_last_full_capacity
            else:
                self._msg.design_capacity = 0.0
                self._msg.capacity        = 0.0
                
            if info_update_ok and state_update_ok and self._msg.capacity != 0:
                self._msg.percentage = int(self._msg.charge / self._msg.capacity * 100.0)

            diag_stat = _laptop_charge_to_diag(self._msg)
            if not info_update_ok or not state_update_ok:
                diag_stat.level   = DiagnosticStatus.ERROR
                diag_stat.message = 'Laptop battery data stale'

            diag.status.append(diag_stat)

            self._diag_pub.publish(diag)
            self._power_pub.publish(self._msg)

if __name__ == '__main__':
    rospy.init_node('laptop_battery')

    bm = LaptopBatteryMonitor()
    try:
        r = rospy.Rate(1.0)
        while not rospy.is_shutdown():
            bm.update()
            r.sleep()
    except KeyboardInterrupt:
        pass
    except Exception:
        import traceback
        traceback.print_exc()