etime

The time command, with energy awareness.

Outline:

• Getting started
• Measurement information
• Program information
• Repository information

Getting started

1. Purchase an Emporia Smart Plug and set your device up.
2. Download the latest released version or build from source.
3. Optionally, create a symbolic link to or move the compiled binary into your /bin to run the command globally:

$ ln -s ~/path/to/emporia-time/etime /usr/local/bin

$ mv etime /usr/local/bin

4. Use the binary with your favorite command or script:

$ etime sleep 12
       12.00 real         0.00 user         0.00 sys
      922.63 joules      76.87 watts      100.0% sure

The first time you run etime, you will be prompted to login with your Emporia credentials and select a device. Credentials are only used to gather API tokens, and tokens are stored in ~/.config/etime/settings.json.

Measurement information

Time

The duration of the input command is measured with the built-in time command.

Meanings of these measurements are as follows:

• real: the actual execution time from start to finish
• user: CPU time spent executing user-mode code for the process
• sys: CPU time spent making system calls in kernel mode

A more detailed explanation can be found in this StackOverflow answer.

Energy

Measurments of electricity used while executing the input command are collected from the Smart Plug.

This usage is shown in the following units:

• joules: the total energy used during the command duration
• watts: the average power output over the command duration
• sure: a confidence score for the above values

Results from the Emporia API may not always be complete, so missing usage is estimated by scaling the average measured energy over the total elapsed time.

The ratio of observed-to-expected measurements is shown in the sure score. Lookups are repeated until a sureness greater than 80.0% is achieved.

Program information

Usage guide

This program can be configured using positional flags and arguments to produce certain behaviors:

$ etime [flags] <command> [args]

• flags: optional flags to provide this program
• command: the program to execute and measure
• args: optional arguments for the command

Flags

Configurations to this program can be made using flags before the command:

• -h, --help: display a hopefully helpful message
• -p, --portable: output measurements on separate lines
• --device <string>: name or ID of the smart plug to measure
• --username <string>: account username for Emporia
• --password <string>: account password for Emporia
• --version: print the current version of the build

Command

The provided command can be either a program or a path to an executable. Pretty much anything that can be invoked from the command line.

Args

Any additional arguments for the command should follow the command. These might include subcommands, positional values, or other flags.

Program environment variables

Environment variables can be used as another way to configure the program:

• EMPORIA_DEVICE: name or ID of the smart plug to measure
• EMPORIA_USERNAME: account username for Emporia
• EMPORIA_PASSWORD: account password for Emporia
• XDG_CONFIG_HOME: the directory to store configurations

Manual pages

Program documentation can be downloaded from root or the releases and added to reference:

$ cp etime.1 /usr/local/share/man/man1/
$ mandb
$ man etime

Additional permissions or created paths might be needed to complete the process.

Repository information

This project is licensed under the MIT license and is not affiliated with or endorsed by Emporia Energy.

Documentation for the Emporia API was graciously gathered from the magico13/PyEmVue project.

Notes on submitting contributions of any type are taken in .github/CONTRIBUTING.md.

Details on the processes around code for this repository are shared in the .github/MAINTAINERS_GUIDE.md.