Quickly see memory usage from within a python process (Linux only)

memory_usage.py

import os


class MemoryUsage:
    # thanks to http://code.activestate.com/recipes/286222/
    def __init__(self):
        self._proc_status = '/proc/%d/status' % os.getpid()
        self._scale = {
            'kB': 1024.0, 'mB': 1024.0 * 1024.0,
            'KB': 1024.0, 'MB': 1024.0 * 1024.0
        }

    def _VmB(self, VmKey):
        '''Private.
        '''

        # get pseudo file  /proc/<pid>/status
        try:
            t = open(self._proc_status)
            v = t.read()
            t.close()
        except:
            return 0.0  # non-Linux?
        # get VmKey line e.g. 'VmRSS:  9999  kB\n ...'
        i = v.index(VmKey)
        v = v[i:].split(None, 3)  # whitespace
        if len(v) < 3:
            return 0.0  # invalid format?
        # convert Vm value to bytes
        return float(v[1]) * self._scale[v[2]]

    def memory(self, since=0.0):
        '''Return memory usage in bytes.
        '''
        return self._VmB('VmSize:') - since

    def resident(self, since=0.0):
        '''Return resident memory usage in bytes.
        '''
        return self._VmB('VmRSS:') - since

    def stacksize(self, since=0.0):
        '''Return stack size in bytes.
        '''
        return self._VmB('VmStk:') - since

    def print(self):
        print("VM: {} RSS: {} Stack: {}".format(
            self.memory(), self.resident(), self.stacksize()
        )