How do I reuse the code from this function cleanly? - python

The following function is used within a module to query network devices and is called from multiple scripts I use. The arguments it takes are a nested dictionary (the device IP and creds etc) and a string (the command to run on the device):
def query_devices(hosts, cmd):
results = {
'success' : [],
'failed' : [],
}
for host in hosts:
device = hosts[host]
try:
swp = ConnectHandler(device_type=device['dev_type'],
ip=device['ip'],
username=device['user'],
password=device['pwd'],
secret=device['secret'])
swp.enable()
results[host] = swp.send_command(cmd)
results['success'].append(host)
swp.disconnect()
except (NetMikoTimeoutException, NetMikoAuthenticationException) as e:
results['failed'].append(host)
results[host] = e
return results
I want to reuse all of the code to update a device and the only changes would be:
The function would take the same dictionary but the cmd argument would now be a list of commands.
The following line:
results[host] = swp.send_command(cmd)
would be replaced by:
results[host] = swp.send_config_set(cmd)
I could obviously just replicate the function making those two changes and as it is in a module I reuse, I am only having to do it once but I am still basically repeating a lot of the same code.
Is there a better way to do this as I seem to come across the same issue quite often in my code.

You could just add a check on the changed line:
...
if isinstance(cmd, str):
results[host] = swp.send_command(cmd)
else:
results[host] = swp.send_config_set(cmd)
...
The rest of the function can stay the same and now you can simply call it with either a string or a list of strings...

You could use the unpacking operator to always make cmds an iterable (a tuple, actually) even if it is a single value. That way you could always call send_config_set. Here is a super simplified example to illustrate the concept.
def query_devices(hosts, *cmds):
for one_cmd in cmds:
print(one_cmd)
print('query_devices("hosts", "cmd_1")')
query_devices("hosts", "cmd_1")
print('\nquery_devices("hosts", "cmd_1", "cmd_2", "cmd_3")')
query_devices("hosts", "cmd_1", "cmd_2", "cmd_3")
print('\nquery_devices("hosts", *["cmd_1", "cmd_2", "cmd_3"])')
query_devices("hosts", *["cmd_1", "cmd_2", "cmd_3"])
Output:
query_devices("hosts", "cmd_1")
cmd_1
query_devices("hosts", "cmd_1", "cmd_2", "cmd_3")
cmd_1
cmd_2
cmd_3
query_devices("hosts", *["cmd_1", "cmd_2", "cmd_3"])
cmd_1
cmd_2
cmd_3

Related

Checking len of azure blob storage folder causes function to not run

Weird problem I've run into. I'm currently using the following code:
generic.py
def function_in_different_pyfile(input_folder):
# do stuff here
folder_1 = f"/folder_1"
folder_1_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_1)
folder_2 = f"/folder_2"
folder_2_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_2)
if len([file for file in folder_1_virtualdir]) !=(len([file for file in folder_2_virtualdir]):
generic.function_in_different_pyfile(folder_1_virtualdir)
else:
print('Already done')
So what I'm trying to do is:
Check the number of files in folder_1_virtualdir and folder_2_virtualdir
If they aren't equal, run the function.
If they are, then print statement/pass.
The problem:
The generic.function() runs although doesn't do anything when you pass in the list comprehension.
The generic.function() works totally fine if you don't have a list comprehension in the code e.g:
folder_1 = f"/folder_1"
folder_1_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_1)
folder_2 = f"/folder_2"
folder_2_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_2)
generic.function_in_different_pyfile(folder_1_virtualdir)
Will work completely fine.
There are no error messages. It passes through the function as if the function doesn't do anything.
What I've tried:
I've tested this by modifying the function:
generic.py
def function_in_different_pyfile(input_folder):
print('Start of the function')
# do stuff here
print('End of the function')
You will see these print statements although the function doesn't process any of the files in the input_folder argument if you include the list comprehension.
This is extended to when the list comprehension is ANYWHERE in the code:
folder_1 = f"/folder_1"
folder_1_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_1)
folder_1_contents = [file for file in folder_1_virtualdir]
folder_2 = f"/folder_2"
folder_2_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_2)
generic.function_in_different_pyfile(folder_1_virtualdir)
# Function doesn't run.
I'm fairly new to Python although can't seem to understand why the list comprehension here completely prevents the function from running correctly.
You could try the code if the number of files in the folder is less than 5000:
folder_1 = f"/folder_1"
folder_1_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_1)
folder_2 = f"/folder_2"
folder_2_virtualdir = CONTAINER_CLIENT.list_blobs(name_starts_with=folder_2)
folder_1_count = len(folder_1_virtualdir)
folder_2_count = len(folder_2_virtualdir)
if folder_1_count != folder_2_count :
generic.function_in_different_pyfile(folder_1_virtualdir)
else:
print('Already done')
If greater than 5000, you need to get the number iterating through your blob.
count = 0
for count, item in enumerate(blobs):
print("number", count + 1, "in the list is", item)

Multiprocessing With r2pipe

I'm having issues with using r2pipe, Radare2's API, with the multiprocessing Pool.map function in python. The problem I am facing is the application hangs on pool.join().
My hope was to use multithreading via the multiprocessing.dummy class in order to evaluate functions quickly through r2pipe. I have tried passing my r2pipe object as a namespace using the Manager class. I have attempted using events as well, but none of these seem to work.
class Test:
def __init__(self, filename=None):
if filename:
self.r2 = r2pipe.open(filename)
else:
self.r2 = r2pipe.open()
self.r2.cmd('aaa')
def t_func(self, args):
f = args[0]
r2_ns = args[1]
print('afbj # {}'.format(f['name']))
try:
bb = r2_ns.cmdj('afbj # {}'.format(f['name']))
if bb:
return bb[0]['addr']
else:
return None
except Exception as e:
print(e)
return None
def thread(self):
funcs = self.r2.cmdj('aflj')
mgr = ThreadMgr()
ns = mgr.Namespace()
ns.r2 = self.r2
pool = ThreadPool(2)
results = pool.map(self.t_func, product(funcs, [ns.r2]))
pool.close()
pool.join()
print(list(results))
This is the class I am using. I make a call to the Test.thread function in my main function.
I expect the application to print out the command it is about to run in r2pipe afbj # entry0, etc. Then to print out the list of results containing the first basic block address [40000, 50000, ...].
The application does print out the command about to run, but then hangs before printing out the results.
ENVIRONMENT
radare2: radare2 4.2.0-git 23712 # linux-x86-64 git.4.1.1-97-g5a48a4017
commit: 5a48a401787c0eab31ecfb48bebf7cdfccb66e9b build: 2020-01-09__21:44:51
r2pipe: 1.4.2
python: Python 3.6.9 (default, Nov 7 2019, 10:44:02)
system: Ubuntu 18.04.3 LTS
SOLUTION
This may be due to passing the same instance of r2pipe.open() to every call of t_func in the pool. One solution is to move the following lines of code into t_func:
r2 = r2pipe.open('filename')
r2.cmd('aaa')
This works, however its terribly slow to reanalyze for each thread/process.
Also, it is often faster to allow radare2 to do as much of the work as possible and limit the number of commands we need to send using r2pipe.
This problem is solved by using the command: afbj ##f
afbj # List basic blocks of given function and show results in json
##f # Execute the command for each function
EXAMPLE
Longer Example
import r2pipe
R2: r2pipe.open_sync = r2pipe.open('/bin/ls')
R2.cmd("aaaa")
FUNCS: list = R2.cmd('afbj ##f').split("\n")[:-1]
RESULTS: list = []
for func in FUNCS:
basic_block_info: list = eval(func)
first_block: dict = basic_block_info[0]
address_first_block: int = first_block['addr']
RESULTS.append(hex(address_first_block))
print(RESULTS)
'''
['0x4a56', '0x1636c', '0x3758', '0x15690', '0x15420', '0x154f0', '0x15420',
'0x154f0', '0x3780', '0x3790', '0x37a0', '0x37b0', '0x37c0', '0x37d0', '0x0',
...,
'0x3e90', '0x6210', '0x62f0', '0x8f60', '0x99e0', '0xa860', '0xc640', '0x3e70',
'0xd200', '0xd220', '0x133a0', '0x14480', '0x144e0', '0x145e0', '0x14840', '0x15cf0']
'''
Shorter Example
import r2pipe
R2 = r2pipe.open('/bin/ls')
R2.cmd("aaaa")
print([hex(eval(func)[0]['addr']) for func in R2.cmd('afbj ##f').split("\n")[:-1]])

AWS Lambda, Python : Get Instances with launch tme for sorting syntax error, Error in Comparing tags

I am working on an AWS Lambda code where I want to get all instances with a specific Value, sort them in reverse order to remove the oldest instance, and pass commands to the remaining instances.
Here are the 2 issues I am facing :
1) As soon as I remove print "Tag value is %s"%(tag['Value']) from the code part, I am getting null response for perfectly working code otherwise.
2) As I am adding the instances to a list, I am not able to sort them with LaunchTime attribute, is there any alternate way?
Code :
def lambda_handler(event, context):
reservations = boto3.client('ec2').describe_instances()['Reservations']
instances_list = []
process_instance_list = []
command = 'crontab -r'
ssm = boto3.client('ssm')
for res in reservations:
instances = res['Instances']
for inst in res['Instances']:
for tag in inst['Tags']:
print("Tag value is {}".format(tag['Value']))
//Below if loop doesn't work if above printout is removed.
if tag['Value']=='Ubuntu_Magento':
print("{} {} {}".format(tag['Value'], inst['InstanceId'], inst['LaunchTime']))
instances_list.append(inst)
// Below line gives syntax error, even though I have used LaunchTime param above
instances_list.sort(key=lambda x: x['LaunchTime'] reverse=False)
non_processed_id=instances_list[0]['InstanceId']
for val in instances_list:
if val['InstanceId'] != non_processed_id['InstanceId']:
ssmresponse = ssm.send_command(InstanceIds=[val['InstanceId']], DocumentName='AWS-RunShellScript', Parameters= { 'commands': [command]})

How to append to python dictionary inside a function

I have the following code:
def main():
content = si.RetrieveContent()
esx_vm = {}
search_index = si.content.searchIndex
for child in content.rootFolder.childEntity:
if hasattr(child, 'vmFolder'):
datacenter = child
vmFolder = datacenter.vmFolder
vmList = vmFolder.childEntity
for vm in vmList:
vmname = PrintVmInfo(vm)
if vmname is not None:
hostname = vmname
vm = si.content.searchIndex.FindByDnsName(None, hostname, True)
try :
ESX = vm.runtime.host.name
except :
pass
esx_vm.update({ESX:hostname})
print(esx_vm)
if __name__ == "__main__":
main()
The code is supposed to create a dictionary mapping esx to vm in the below format:
{'esx1': 'vm1'}
But I am getting only one key-value {'esx1': 'vm1'} and not all the esx:vm mappings. I am excepting to get:
{'esx1': 'vm1','esx2': 'vm2','esx3': 'vm3','esx4': 'vm4'}
and so on.
Any advise how to get the the correct values of the dictionary?
You might want to update ESX values inside "for loop". But its happening to be outside, that's why there is one key in the dict. Please add ESX key as part of for loop. Something like this (inside for loop),
try :
ESX = vm.runtime.host.name
esx_vm.update({ESX:hostname}) # Or, just, esx_vm[ESX]=hostname
except :
pass

Creating loop for __main__

I am new to Python, and I want your advice on something.
I have a script that runs one input value at a time, and I want it to be able to run a whole list of such values without me typing the values one at a time. I have a hunch that a "for loop" is needed for the main method listed below. The value is "gene_name", so effectively, i want to feed in a list of "gene_names" that the script can run through nicely.
Hope I phrased the question correctly, thanks! The chunk in question seems to be
def get_probes_from_genes(gene_names)
import json
import urllib2
import os
import pandas as pd
api_url = "http://api.brain-map.org/api/v2/data/query.json"
def get_probes_from_genes(gene_names):
if not isinstance(gene_names,list):
gene_names = [gene_names]
#in case there are white spaces in gene names
gene_names = ["'%s'"%gene_name for gene_name in gene_names]**
api_query = "?criteria=model::Probe"
api_query= ",rma::criteria,[probe_type$eq'DNA']"
api_query= ",products[abbreviation$eq'HumanMA']"
api_query= ",gene[acronym$eq%s]"%(','.join(gene_names))
api_query= ",rma::options[only$eq'probes.id','name']"
data = json.load(urllib2.urlopen(api_url api_query))
d = {probe['id']: probe['name'] for probe in data['msg']}
if not d:
raise Exception("Could not find any probes for %s gene. Check " \
"http://help.brain- map.org/download/attachments/2818165/HBA_ISH_GeneList.pdf? version=1&modificationDate=1348783035873 " \
"for list of available genes."%gene_name)
return d
def get_expression_values_from_probe_ids(probe_ids):
if not isinstance(probe_ids,list):
probe_ids = [probe_ids]
#in case there are white spaces in gene names
probe_ids = ["'%s'"%probe_id for probe_id in probe_ids]
api_query = "? criteria=service::human_microarray_expression[probes$in%s]"% (','.join(probe_ids))
data = json.load(urllib2.urlopen(api_url api_query))
expression_values = [[float(expression_value) for expression_value in data["msg"]["probes"][i]["expression_level"]] for i in range(len(probe_ids))]
well_ids = [sample["sample"]["well"] for sample in data["msg"] ["samples"]]
donor_names = [sample["donor"]["name"] for sample in data["msg"] ["samples"]]
well_coordinates = [sample["sample"]["mri"] for sample in data["msg"] ["samples"]]
return expression_values, well_ids, well_coordinates, donor_names
def get_mni_coordinates_from_wells(well_ids):
package_directory = os.path.dirname(os.path.abspath(__file__))
frame = pd.read_csv(os.path.join(package_directory, "data", "corrected_mni_coordinates.csv"), header=0, index_col=0)
return list(frame.ix[well_ids].itertuples(index=False))
if __name__ == '__main__':
probes_dict = get_probes_from_genes("SLC6A2")
expression_values, well_ids, well_coordinates, donor_names = get_expression_values_from_probe_ids(probes_dict.keys())
print get_mni_coordinates_from_wells(well_ids)
whoa, first things first. Python ain't Java, so do yourself a favor and use a nice """xxx\nyyy""" string, with triple quotes to multiline.
api_query = """?criteria=model::Probe"
,rma::criteria,[probe_type$eq'DNA']
...
"""
or something like that. you will get white spaces as typed, so you may need to adjust.
If, like suggested, you opt to loop on the call to your function through a file, you will need to either try/except your data-not-found exception or you will need to handle missing data without throwing an exception. I would opt for returning an empty result myself and letting the caller worry about what to do with it.
If you do opt for raise-ing an Exception, create your own, rather than using a generic exception. That way your code can catch your expected Exception first.
class MyNoDataFoundException(Exception):
pass
#replace your current raise code with...
if not d:
raise MyNoDataFoundException(your message here)
clarification about catching exceptions, using the accepted answer as a starting point:
if __name__ == '__main__':
with open(r"/tmp/genes.txt","r") as f:
for line in f.readlines():
#keep track of your input data
search_data = line.strip()
try:
probes_dict = get_probes_from_genes(search_data)
except MyNoDataFoundException, e:
#and do whatever you feel you need to do here...
print "bummer about search_data:%s:\nexception:%s" % (search_data, e)
expression_values, well_ids, well_coordinates, donor_names = get_expression_values_from_probe_ids(probes_dict.keys())
print get_mni_coordinates_from_wells(well_ids)
You may want to create a file with Gene names, then read content of the file and call your function in the loop. Here is an example below
if __name__ == '__main__':
with open(r"/tmp/genes.txt","r") as f:
for line in f.readlines():
probes_dict = get_probes_from_genes(line.strip())
expression_values, well_ids, well_coordinates, donor_names = get_expression_values_from_probe_ids(probes_dict.keys())
print get_mni_coordinates_from_wells(well_ids)

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