Memfault Devices API python processing for last_seen field

last_seen.py

#!/usr/bin/env python3

"""
Small python program to load json data generated by the Memfault "list Devices"
API:

https://api-docs.memfault.com/#2634f3fb-d137-42a8-b093-e05d420b8932

And spit out a json object with the following format:
{
    "device_serial": "last_seen_timestamp",
    ...
}

For example, can be used in a one-liner with curl:

❯ curl -sSL --user ":${MEMFAULT_ORG_TOKEN}" --location --request GET --header \
    "Content-Type: application/json" \
        'https://api.memfault.com/api/v0/organizations/${MEMFAULT_ORG}/projects/${MEMFAULT_PROJ}/devices?per_page=1000' \
            | ./last_seen.py | jq
{
  "0025CA37A463": "2022-03-04T21:39:20.056866+00:00",
  ...
}

The resulting json object can be used for example to find devices that have not
been seen within a window.
"""

import json
import pprint
import sys


def process(infile):
    data = json.load(infile)

    d = {}
    for item in data["data"]:
        d[item["device_serial"]] = item["last_seen"]

    print(json.dumps(d))


def main():
    for infile in sys.argv[1:]:
        with open(infile) as infile:
            process(infile)
    if not sys.stdin.isatty():
        process(sys.stdin)


if __name__ == "__main__":
    main()