Running nTop Command Line in Python scripts

Daeho Hong

August 12, 2020 18:01

This article explains how to run your nTop notebook using nTop Command Line (nTopCL) in Python scripts.

Prepare the nTop notebook and JSON input for running nTopCL
Python dictionary data can be saved as a JSON file using Python’s json module
Execute nTopCL process using Python’s subprocess module
Python Script_JSON.py will run a windows process command like "C:/Program Files/nTopology/nTop Platform/nTopCL.exe" -j input.json -o out.json SampleFile.ntop
Check if the return messages are printed as below.

[info] Logging Engine started
[info] Login successful[info] Parasolid started
[info] Parasolid started
[info] nTop successfully built.
[info] Logout successful

Feel free to change this script to batch process your workflow by passing input lists in a for loop!

#Imports
import os
import subprocess 
import json 

#Assuming this script, ntop file, and json files will be in the same folder
Current_Directory = os.path.dirname(os.path.realpath('__file__')) 
exePath = r"C:/Program Files/nTopology/nTop Platform/nTopCL.exe"  #nTopCL path
nTopFilePath = r"SampleFile.ntop"   #nTop notebook file name
Input_File_Name = "input.json"      #JSON input file name to be saved as
Output_File_Name = "out.json"       #JSON output file name to be saved as

#Input variables in JSON structure
Inputs_JSON = {
    "inputs": [
        {
        	"name": "Output directory",
        	"type": "text",
        	"value": "C:\\Users\\Your Account\\Your Path\\"
       	},
       	{
            "name": "Length",
            "type": "scalar",
            "values": 7,
            "units": "mm"
        },
       	{
            "name": "Width",
            "type": "scalar",
            "values": 2,
            "units": "mm"
        },
       	{
            "name": "Height",
            "type": "scalar",
            "values": 2,
            "units": "mm"
        }
    ]
}

#nTopCL arguments in a list
Arguments = [exePath]               #nTopCL path
Arguments.append("-j")              #json input argument
Arguments.append(Input_File_Name)   #json path
Arguments.append("-o")              #output argument
Arguments.append(Output_File_Name)  #output json path
Arguments.append(nTopFilePath)      #.ntop notebook file path

#Creating in.json file
with open(Input_File_Name, 'w') as outfile:
    json.dump(Inputs_JSON, outfile, indent=4)

#nTopCL call with arguments
print(" ".join(Arguments))
output,error = subprocess.Popen(Arguments,stdout = subprocess.PIPE, 
               stderr= subprocess.PIPE).communicate()

#Print the return messages
print(output.decode("utf-8"))

Download the Example Files

Sample File
Script_JSON.py

Labels: ntopcl command line python api script

Download the Example Files

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