MacOS: Pulling Battery Data from IOReg to CSV File using Python and LaunchAgents

 I wanted to track battery data over time and have not found a reasonable approach using the current apps to store the information in a database. I decided the first step was to figure out how to pull the information and store in a CSV file. Next steps include either pushing to PostgresSQL and to Google Sheets.

First I found the ioreg command which enabled me to pull the data. I could have used a shell script but preferred to use Python 3 since it would give me more options in the future.

I used the command 

                            ioreg -rd1 -c AppleSmartBattery

Which enabled me to pull just the battery information I was interested in. I was able to use python to pull specific items and push to a csv file. I'm not sure I got everything I wanted but it is a start. Once the program worked I created a plist file to run it every 60 minutes via LaunchAgent. The cool part of LaunchAgents is the ability to run after coming out of sleep mode.

I did install pyinstaller to create an "executable" which I placed in the bin directory and it writes to a data directory. Below find the program and plist I used. 

local.batteryinfo.plist

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">

<plist version="1.0">

<dict>

<key>Label</key>

<string>com.username.personal.batteryinfo</string>

<key>Program</key>

<string>/Users/username/bin/battery-info</string>

<key>RunAtLoad</key>

<true/>

<key>StandardErrorPath</key>

<string>/dev/null</string>

<key>StandardOutPath</key>

<string>/Users/username/data/batteryinfo.out</string>

<key>StartInterval</key>

<integer>3600</integer>

<key>WorkingDirectory</key>

<string>/Users/username/data</string>

</dict>

</plist>

battery-info.py

!/opt/homebrew/bin/python3

import subprocess

from csv import DictWriter

from datetime import datetime

# datetime object containing current date and time

now = datetime.now()

nowDate = now.strftime("%Y%m%d")

nowTime = now.strftime("%H%M%S")

fileName = "/Users/username/data/batteryinfo.csv"

batteryRawInfo = {}

batteryInfo = {}

excludeList = ['+-o', '{', '}', "\r"]

headersCSV = [

'Date',

'Time',

'DeviceName',

'AtCriticalLevel',

'ExternalConnected',

'AppleRawCurrentCapacity',

'Serial',

'NominalChargeCapacity',

'FullyCharged',

'DesignCycleCount9C',

'MaxCapacity',

'DesignCapacity',

'IsCharging',

'CycleCount',

'AppleRawMaxCapacity',

'TimeRemaining',

'Temperature',

'VirtualTemperature',

'AtCriticalLevel',

]

def exist_and_not_empty(filepath):

try:

import pathlib as p

path = p.Path(filepath)

if '~' in filepath:

path = path.expanduser()

if not path.exists() and path.stat().st_size > 0:

return False

return True

except FileNotFoundError:

return False

def writeCSVFile(fileName, headers, batDict):

with open(fileName, 'a', newline='') as f_object:

# Pass the CSV file object to the Dictwriter() function

# Result - a DictWriter object

dictwriter_object = DictWriter(f_object, fieldnames=headers)

# Pass the data in the dictionary as an argument into the writerow() function

dictwriter_object.writerow(batDict)

# Close the file object

f_object.close()

def main():

with subprocess.Popen(['ioreg', '-rd1', '-c', 'AppleSmartBattery'], stdout=subprocess.PIPE, text=True) as proc:

# print(proc.__dict__)

# with proc.stdout.read() as stdoutString:,

# print(stdoutString)

batteryLines = proc.stdout.readlines()

for line in batteryLines:

if [ele for ele in excludeList if (ele in line)]:

continue

# print("Line: [{}]".format(line.strip().replace(' ','').replace('"','')))

if "=" in line:

(k, v) = line.strip().replace(' ', '').replace('"', '').split("=")

batteryRawInfo[k] = v

# print("Dictionary ........................... ")

# print(batteryRawInfo)

for key, value in batteryRawInfo.items():

# print(f'Key: {key}, Value: {value}')

if key in headersCSV:

batteryInfo[key] = value

batteryInfo["Date"] = nowDate

batteryInfo["Time"] = nowTime

# print(batteryInfo)

writeCSVFile(fileName, headersCSV, batteryInfo)

if __name__ == '__main__':

main()

I did have some issues loading the launch agent and finally download an application called LaunchControl. Helped with a permissions issue and fixed my issue.

Enjoy.