Configure multi-database PostgreSQL routing with custom DatabaseRouter

config/db_router.py

@@ -0,0 +1,33 @@
+class DatabaseRouter:
+    """
+    A database router to route model operations to different PostgreSQL databases.
+    """
+    def db_for_read(self, model, **hints):
+        if model is not None:
+            model_name = model._meta.model_name
+        else:
+            model_name = hints.get('model_name')
+
+        if model_name in ['user', 'supplierprofile', 'otprecord']:
+            return 'sellerprofile'
+        elif model_name in ['product', 'bulkuploadlog']:
+            return 'productprofile'
+        elif model_name in ['order', 'returnrequest', 'wallet', 'wallettransaction']:
+            return 'customerprofile'
+        return 'default'
+
+
+    def db_for_write(self, model, **hints):
+        return self.db_for_read(model, **hints)
+
+    def allow_relation(self, obj1, obj2, **hints):
+        # We removed cross-database foreign key constraints, so we can allow logical relations.
+        return True
+
+    def allow_migrate(self, db, app_label, model_name=None, **hints):
+        if model_name:
+            target_db = self.db_for_read(None, **{'model_name': model_name})
+            if db == target_db:
+                return True
+            return False
+        return None

config/settings.py

@@ -115,49 +115,45 @@ def _fetch_db_secret(secret_arn: str) -> dict:
 if _DB_SECRET_ARN:
     # --- Mode 1: Production — credentials from AWS Secrets Manager ---
     _secret = _fetch_db_secret(_DB_SECRET_ARN)
-    DATABASES = {
-        'default': {
-            'ENGINE':   'django.db.backends.mysql',
-            'NAME':     _secret['dbname'],
-            'USER':     _secret['username'],
-            'PASSWORD': _secret['password'],
-            'HOST':     _secret['host'],
-            'PORT':     str(_secret.get('port', 3306)),
-            'OPTIONS': {
-                'charset': 'utf8mb4',
-                'init_command': "SET sql_mode='STRICT_TRANS_TABLES'",
-                'connect_timeout': 10,
-            },
-        }
+    db_credentials = {
+        'ENGINE':   'django.db.backends.postgresql',
+        'USER':     _secret['username'],
+        'PASSWORD': _secret['password'],
+        'HOST':     _secret['host'],
+        'PORT':     str(_secret.get('port', 5432)),
     }
-
-elif _DB_ENGINE == 'django.db.backends.mysql':
-    # --- Mode 2: Local MySQL via explicit env vars (docker-compose) ---
-    DATABASES = {
-        'default': {
-            'ENGINE':   'django.db.backends.mysql',
-            'NAME':     os.environ.get('DB_NAME', 'seller_central'),
-            'USER':     os.environ.get('DB_USER', 'root'),
-            'PASSWORD': os.environ.get('DB_PASSWORD', ''),
-            'HOST':     os.environ.get('DB_HOST', '127.0.0.1'),
-            'PORT':     os.environ.get('DB_PORT', '3306'),
-            'OPTIONS': {
-                'charset': 'utf8mb4',
-                'init_command': "SET sql_mode='STRICT_TRANS_TABLES'",
-                'connect_timeout': 10,
-            },
-        }
-    }
-
 else:
-    # --- Mode 3: Local dev — SQLite (no config needed) ---
-    DATABASES = {
-        'default': {
-            'ENGINE': 'django.db.backends.sqlite3',
-            'NAME': BASE_DIR / 'db.sqlite3',
-        }
+    # --- Mode 2: Local dev / fallback with default credentials ---
+    db_credentials = {
+        'ENGINE':   'django.db.backends.postgresql',
+        'USER':     os.environ.get('DB_USER', 'vignesh'),
+        'PASSWORD': os.environ.get('DB_PASSWORD', 'vtechnosoft@123A'),
+        'HOST':     os.environ.get('DB_HOST', '127.0.0.1'),
+        'PORT':     os.environ.get('DB_PORT', '5432'),
     }
 
+DATABASES = {
+    'default': {
+        'NAME': 'sellerprofile',
+        **db_credentials
+    },
+    'sellerprofile': {
+        'NAME': 'sellerprofile',
+        **db_credentials
+    },
+    'customerprofile': {
+        'NAME': 'customerprofile',
+        **db_credentials
+    },
+    'productprofile': {
+        'NAME': 'productprofile',
+        **db_credentials
+    }
+}
+
+DATABASE_ROUTERS = ['config.db_router.DatabaseRouter']
+
+
 
 # Password validation
 # https://docs.djangoproject.com/en/6.1/ref/settings/#auth-password-validators

requirements.txt

@@ -8,6 +8,7 @@ django-cors-headers
 pytest
 pytest-django
 pillow
-mysqlclient
+psycopg2-binary
 boto3
 djangorestframework-simplejwt
+