135 lines
4.0 KiB
Plaintext
135 lines
4.0 KiB
Plaintext
This is a collection of snippets that I tend to use frequently, or would need
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in the future.
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###############################################################################
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To programmatically import a list of modules by name:
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_____
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import importlib
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mods = ['os', 'sys', 'shutil', 'platform']
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for m in mods:
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globals()[m] = importlib.import_module(m)
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_____
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you can then use them as if you did:
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import os
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import sys
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import shutil
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import platform
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etc.
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this breaks pep-8, but sometimes you need to programmatically import modules.
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ref: https://www.python.org/dev/peps/pep-0008/#imports
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###############################################################################
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To programmatically install modules via pip if they aren't installed (BROKEN IN RECENT PIP VERSIONS; pip._internal.main() i think):
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____
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import importlib
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import pip
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# I don't *think* pip/pypi is case-sensitive, but frequently module names are
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# not the same as their package names. ugh.
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# The key is the package name, the value is the module name. We use the above
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# trick here to try to import and install if it fails.
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mods = {'PyMySQL': 'pymysql',
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'Jinja2': 'jinja2',
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'psutil': None, # We show off a little bit here with this, see below.
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'paramiko': None} # ""
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for m in mods.keys():
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modname = mods[m]
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if not modname:
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modname = m
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try:
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globals()[modname] = importlib.import_module(modname)
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except ImportError:
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# We use --user to avoid conflicts with the host's python system.
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# pip.main() accepts all of pip (commandline)'s args!
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pip.main(['install', '--user', m])
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try:
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globals()[modname] = importlib.import_module(modname)
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except ImportError:
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raise RuntimeError('Unable to install {0}!'.format(m))
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____
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###############################################################################
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To convert an argparse set of parsed arguments into a dict from a class, you
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simply do:
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____
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def GenArgs():
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args = argparse.ArgumentParser()
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# args here
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return(args)
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def somefunc():
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args = vars(GenArgs().parse_args())
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____
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"args" in somefunc is a dict now.
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###############################################################################
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To dynamically allocate class parameters into constants from a dict (such as
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from argparse - see above), do something like this:
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____
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class ClassName(object):
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def __init__(self, **kwargs):
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for i in kwargs.keys():
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setattr(self, i, kwargs[i])
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----
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###############################################################################
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To store stdout and stderr to different files in a subprocess call:
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----
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with open('/tmp/test.o', 'w') as out, open('/tmp/test.e', 'w') as err:
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subprocess.run(['command'], stdout = out, stderr = err)
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----
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###############################################################################
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To use optools logging lib (or other "shared" modules):
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----
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import os
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import re
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import importlib
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spec = importlib.util.spec_from_file_location(
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'logger',
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'/opt/dev/optools/lib/python/logger.py')
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logger = importlib.util.module_from_spec(spec)
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spec.loader.exec_module(logger)
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log = logger.log(name = 'project.name')
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----
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###############################################################################
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# TODO #
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https://stackoverflow.com/questions/10265193/python-can-a-class-act-like-a-module
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###############################################################################
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To issue an equivalent of "reset" command in linux, assuming console is ANSI-compat,
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print('\x1bc', end = '')
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###############################################################################
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To get the default route via pyroute2,
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----
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import socket
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from pyroute2 import IPDB
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ip = IPDB()
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def_rt = ip.routes['default'] # a route object
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iface = ip.interfaces[def_rt.oif] # an interface object. name is e.g. iface.ifname, IPs are in tuple-of-tuples iface.ipaddr, etc.
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gw = def_rt.gateway # etc.
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ip.release()
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----
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###############################################################################
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