Django views.py code running automatically whenever I reload the server

Question

I have logs which are uploaded and inserted into MySQL table from CSV files using upload_log endpoint in views.py of a Django app. I also have another views.py in a different sub-app (Django as well) that parses the existing data from the logs table and splits it in different rows according to conditions.

The problem is the parsing happens whenever I reload the server which creates duplicates besides the fact that it is not my intention to have it like this. I need to have it so that whenever data is uploaded (post is triggered), it runs the function on that uploaded data to parse the logs.

Edit (clarification): It doesn't execute when I do py manage.py runserver - But it executes after I run the runserver command and CTRL + S inside the file to reload the server.

I would appreciate it if someone guides me through this.

Here's the views.py of that task (Logs app):

from rest_framework import viewsets
from rest_framework.decorators import action
from api.packets.models import Fields
from .models import LogsParsed
from api.logs.models import Logs
from .serializers import LogsParsedSerializer

class getLogs(viewsets.ModelViewSet):    
    
    serializer_class = LogsParsedSerializer
    queryset = LogsParsed.objects.all()            

    parsedLogs=[]
    for log in Logs.objects.all():        
        fields = Fields.objects.filter(pac_id=log.message_id_decimal)
        binaryTest=log.data_binary
        
        for field in fields:
            items=LogsParsed(
                pac_id=log.message_id_decimal,
                log_id=log.log_id,
                log_date=log.log_date,
                fld_name=field.fld_name,
                value=binaryTest[field.fld_offset:field.fld_offset+field.fld_len]
                )
            parsedLogs.append(items)
            
    LogsParsed.objects.bulk_create(parsedLogs)

And here's the views.py of the upload from CSV (ParsedLogs app):

from django.contrib import messages
from rest_framework import viewsets
from rest_framework.decorators import action
from datetime import datetime
from rest_framework.response import Response

from .models import Logs
from .serializers import LogsSerializer

import pandas as pd


class LogsViewSet(viewsets.ModelViewSet):

    serializer_class = LogsSerializer
    queryset = Logs.objects.all()

    @action(detail=False, methods=['POST'])
    def upload_log(self, request):
        """Upload data from CSV, with validation."""
        if request.method == 'POST':
            file = request.FILES['file']
            data_file = pd.read_csv(file, sep=';', encoding="utf8")
            file_name = request.FILES['file'].name
            _datetime = datetime.now()
            file_upload_date = _datetime.strftime("%Y_%m_%d %H:%M:%S")
      
            
            
            # Swap every 2-character blocks with the next 2-character blocks
            def swap_bits(data):

                blocks = [data[i:i+4] for i in range(0, len(data), 4)]
                for i in range(len(blocks)):
                    blocks[i] = blocks[i][2:] + blocks[i][:2]
                return "".join(blocks)
            

            # Iterating through rows
            row_iter = data_file.iterrows()
            logs = [
                        Logs(
                            file_upload_date=file_upload_date,
                            file_name=file_name,
                            log_date=row["Date and time[ms]"],
                            stamp=row[" Stamp"],
                            message_id=row[" Message Id"],
                            message_id_decimal=int(row[" Message Id"], 16),
                            length=row[" Length"],
                            data=row[" Data"],
                            # data_binary=swap_bits(row[" Data"])
                            data_binary=bin(int(swap_bits(row[" Data"]), 16))[2:]
                        )
                        for index, row in row_iter
                    ]
                            
            Logs.objects.bulk_create(logs)
            
            
            return Response({"success": "Successfully uploaded logs!"})

@JohnGordon It doesn't execute when I do py manage.py runserver - But it executes after I run the runserver command and CTRL + S inside the file to reload the server. Yes, it is as weird as that. Excuse my ignorance for I am still learning how Django works. — aleyazor, Jul 27 '22 at 00:41
@JohnGordon getLogs is a class not a function. You are writing loop inside a class rather than a method. So when the reload of the server happens, python loads the class into memory. Since loop is not inside the method, it gets executed. write parsedLogs inside the method and call whenever you need it. — Durai, Jul 27 '22 at 02:55
Does this answer your question? [Order of execution with python class](https://stackoverflow.com/questions/55793567/order-of-execution-with-python-class), also see [Why does a class' body get executed at definition time?](https://stackoverflow.com/questions/26193653/why-does-a-class-body-get-executed-at-definition-time) and [Print statement in class getting executed even though there is no class instance/object](https://stackoverflow.com/questions/47344625/print-statement-in-class-getting-executed-even-though-there-is-no-class-instance) — Abdul Aziz Barkat, Jul 27 '22 at 04:20

John Gordon · Accepted Answer · 2022-07-27T04:09:54.307

1

As @Durai pointed out, the getLogs class has code at the top level that is not inside of a method.

This code will be executed whenever the module is imported, as it is part of the class definition.

If you want the code to not execute automatically, put it inside of a method inside the class, and then call the method as needed.

edited Jul 27 '22 at 04:09

answered Jul 27 '22 at 03:41

John Gordon

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I moved the code inside the upload_log endpoint so that it runs whenever the api is triggered. Thank you. – aleyazor Jul 27 '22 at 14:51

Django views.py code running automatically whenever I reload the server

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