list top 20 proceses by memory usage

processes.py

import psutil
import json
import datetime

procs = []

timestamp = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
for proc in psutil.process_iter():
    try:
        pinfo = proc.as_dict(attrs=['pid', 'name', 'cmdline'])
    except psutil.NoSuchProcess:
        pass
    else:
        try:
            mem = proc.memory_info_ex().rss
        except AttributeError:
            mem = 0
            pass
        if mem > 0:
            procs.append((pinfo['name'], pinfo['pid'], mem))



procs=sorted(procs, key=lambda process: process[2], reverse=True)
output = json.dumps({'date': timestamp, 'list': procs[0:20]})
print output