From 316ee5df41ca92dee9242e521af2b8d116996d7c Mon Sep 17 00:00:00 2001
From: Ameya Shenoy <shenoy.ameya@gmail.com>
Date: Sat, 13 Feb 2021 04:59:48 +0530
Subject: [PATCH] fix: optimize postgres endpoint to offload task

offload db population task to rq

Signed-off-by: Ameya Shenoy <shenoy.ameya@gmail.com>
---
 backend/app/utils.py            | 35 +++++++++++++++++++++++++++------
 backend/app/views.py            | 31 +++++++++++++++++++++++------
 frontend/src/views/BhavCopy.vue |  2 +-
 3 files changed, 55 insertions(+), 13 deletions(-)

diff --git a/backend/app/utils.py b/backend/app/utils.py
index 0b87ce3..e417832 100644
--- a/backend/app/utils.py
+++ b/backend/app/utils.py
@@ -35,8 +35,9 @@ def fetch_bhav_copy_equity_data(date=None):
     }
     if date is None:
         date = datetime.datetime.now()
-    zipurl = f'https://www.bseindia.com/download/BhavCopy/Equity/EQ{date.strftime("%d%m%y")}_CSV.ZIP'
-    logger.info(f'Fetching data from {zipurl}')
+    datestr = date.strftime("%d%m%y")
+    zipurl = f'https://www.bseindia.com/download/BhavCopy/Equity/EQ{datestr}_CSV.ZIP'
+    logger.info('Fetching data from %s', zipurl)
     resp = requests.get(zipurl, headers=headers)
 
     if resp.ok:
@@ -52,7 +53,7 @@ def populate_bhav_copy_data(date=None):
     """Populate DB with Bhav Copy data."""
     try:
         data = fetch_bhav_copy_equity_data(date=date)
-    except:
+    except Exception as err:
         # Potentially add code for alerting if needed
         # Repeat job after 10 mins if job fails
         scheduler = django_rq.get_scheduler('default')
@@ -60,7 +61,7 @@ def populate_bhav_copy_data(date=None):
             scheduled_time=datetime.datetime.now()+datetime.timedelta(minutes=10),
             func=populate_bhav_copy_data,
         )
-        raise ValueError(f"Error fetching data from BSE for {date}")
+        raise ValueError(f"Error fetching data from BSE for {date}\nDetails: {err}")
     else:
         del data[0]  # delete title row
         populate_bhav_copy_data_into_redis(data)
@@ -68,7 +69,7 @@ def populate_bhav_copy_data(date=None):
 
 
 def populate_bhav_copy_data_into_redis(data):
-    logger.info(f'Populating data into redis')
+    logger.info('Populating data into redis')
     pipe = cache.pipeline()
     cache.delete("stocks")
     for stock in data:
@@ -98,7 +99,7 @@ def populate_bhav_copy_data_into_redis(data):
 
 @transaction.atomic
 def populate_bhav_copy_data_into_postgres(data, date=None):
-    logger.info(f'Populating data into postgres for {date}')
+    logger.info('Populating data into postgres for %s', date)
     if date is None:
         date = datetime.datetime.now().date()
     for stock in data:
@@ -120,3 +121,25 @@ def populate_bhav_copy_data_into_postgres(data, date=None):
             tdcloindi=stock[13],
         )
 
+
+def stocks_csv_to_json(data):
+    stocks = []
+    for stock in data:
+        stocks.append({
+            "sc_code": stock[0],
+            "sc_name": stock[1],
+            "sc_group": stock[2],
+            "sc_type": stock[3],
+            "open_price": float(stock[4]),
+            "high_price": float(stock[5]),
+            "low_price": float(stock[6]),
+            "close_price": float(stock[7]),
+            "last_price": float(stock[8]),
+            "prevclose_price": float(stock[9]),
+            "no_trades": int(stock[10]),
+            "no_of_shrs": int(stock[11]),
+            "net_turnov": float(stock[12]),
+            "tdcloindi": stock[13],
+        })
+    return stocks
+
diff --git a/backend/app/views.py b/backend/app/views.py
index 041ed6f..7ddc444 100644
--- a/backend/app/views.py
+++ b/backend/app/views.py
@@ -8,6 +8,8 @@ import datetime
 import logging
 
 # third-party imports
+import django_rq
+
 from rest_framework import generics
 from rest_framework.response import Response
 from rest_framework.decorators import api_view
@@ -16,7 +18,12 @@ from django_redis import get_redis_connection
 # app imports
 from app.models import BhavCopyEquity
 from app.serializers import BhavCopyEquitySerializer
-from app.utils import populate_bhav_copy_data
+from app.utils import (
+    populate_bhav_copy_data,
+    fetch_bhav_copy_equity_data,
+    stocks_csv_to_json,
+    populate_bhav_copy_data_into_postgres
+)
 
 
 cache = get_redis_connection("default")
@@ -42,11 +49,23 @@ def bhavCopyEquityList(request):
 
     # Fetch data if not present
     if len(serializer.data) == 0:
-        logger.info(f'Data not available in DB')
-        populate_bhav_copy_data(date=req_date)
-        queryset = BhavCopyEquity.objects.all().filter(date=req_date)
-        serializer = BhavCopyEquitySerializer(queryset, many=True)
-
+        logger.info('Data not available in DB, trying to fetch from BSE')
+        try:
+            data = fetch_bhav_copy_equity_data(date=req_date)
+        except:
+            return Response({
+                'data': [],
+                'message': "Unable to fetch data from BSE"
+            })
+        del data[0]  # delete title row
+        logger.info('Enqueue background task to populate Postgres DB')
+        django_rq.enqueue(populate_bhav_copy_data_into_postgres, args=(data, req_date))
+        logger.info('Return quick response')
+        stocks = stocks_csv_to_json(data)
+        return Response({
+            "data": stocks,
+            "message": 'Data was directly sourced from BSE!'
+        })
     return Response({
         "data": serializer.data,
         "message": ret_message
diff --git a/frontend/src/views/BhavCopy.vue b/frontend/src/views/BhavCopy.vue
index e9ee5f2..aebfaea 100644
--- a/frontend/src/views/BhavCopy.vue
+++ b/frontend/src/views/BhavCopy.vue
@@ -214,7 +214,7 @@
           {text: 'High', value: 'high_price'},
           {text: 'Low', value: 'low_price'},
           {text: 'Close', value: 'close_price'},
-          { text: 'Diff (%)', value: 'diff_percent' },
+          {text: 'Diff (%)', value: 'diff_percent' },
           {text: 'Last', value: 'last_price'},
           {text: 'Previous Close', value: 'prevclose_price'},
           {text: 'No. of Trades', value: 'no_trades'},