Refactor application configuration; implement dynamic database URI setup based on environment variables for improved flexibility and maintainability

.gitignore

@@ -1,2 +1,3 @@
 __pycache__/
-.venv/
+.venv/
+.env

__init__.py

@@ -1,37 +1,28 @@
 from flask import Flask
 from flask_sqlalchemy import SQLAlchemy
-from urllib.parse import quote_plus
 import logging
 
 db = SQLAlchemy()
 
 logger = logging.getLogger('sqlalchemy.engine')
 logger.setLevel(logging.INFO)
-handler = logging.StreamHandler()
-handler.setFormatter(logging.Formatter('%(asctime)s [%(levelname)s] %(message)s'))
-logger.addHandler(handler)
+if not logger.handlers:
+    handler = logging.StreamHandler()
+    handler.setFormatter(logging.Formatter('%(asctime)s [%(levelname)s] %(message)s'))
+    logger.addHandler(handler)
 
 def create_app():
+    from config import Config
     app = Flask(__name__)
-
-    params = quote_plus(
-        "DRIVER=ODBC Driver 17 for SQL Server;"
-        "SERVER=NDVASQLCR01;"
-        "DATABASE=conradTest;"
-        "Trusted_Connection=yes;"
-    )
-
-    app.config['SQLALCHEMY_DATABASE_URI'] = f"mssql+pyodbc:///?odbc_connect={params}"
-    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+    app.config.from_object(Config)
 
     db.init_app(app)
 
+    with app.app_context():
+        from . import models
+        db.create_all()
+
     from .routes import main
     app.register_blueprint(main)
 
-    @app.route("/")
-    def index():
-        return "Hello, you've reached the terrible but functional root of the site."
-
-
     return app

config.py

@@ -0,0 +1,60 @@
+import os
+import urllib.parse
+from dotenv import load_dotenv
+
+load_dotenv()
+
+def quote(value):
+    return urllib.parse.quote_plus(value)
+
+class Config:
+    SQLALCHEMY_TRACK_MODIFICATIONS = False
+    DEBUG = False
+    TESTING = False
+
+    DB_BACKEND = os.getenv('DB_BACKEND', 'sqlite').lower()
+    DB_WINDOWS_AUTH = os.getenv('DB_WINDOWS_AUTH', 'false').strip().lower() in ['true', '1', 'yes']
+
+    DB_USER = os.getenv('DB_USER', '')
+    DB_PASSWORD = os.getenv('DB_PASSWORD', '')
+    DB_HOST = os.getenv('DB_HOST', 'localhost')
+    DB_PORT = os.getenv('DB_PORT', '')
+    DB_NAME = os.getenv('DB_NAME', 'app.db')  # default file for sqlite
+
+    SQLALCHEMY_DATABASE_URI = None  # <-- initialize properly
+
+    if DB_BACKEND == 'mssql':
+        driver = os.getenv('DB_DRIVER', 'ODBC Driver 17 for SQL Server')
+        quoted_driver = quote(driver)
+
+        if DB_WINDOWS_AUTH:
+            SQLALCHEMY_DATABASE_URI = (
+                f"mssql+pyodbc://@{DB_HOST}/{DB_NAME}?driver={quoted_driver}&Trusted_Connection=yes"
+            )
+        else:
+            SQLALCHEMY_DATABASE_URI = (
+                f"mssql+pyodbc://{quote(DB_USER)}:{quote(DB_PASSWORD)}@{DB_HOST}:{DB_PORT}/{DB_NAME}"
+                f"?driver={quoted_driver}"
+            )
+
+    elif DB_BACKEND == 'postgres':
+        SQLALCHEMY_DATABASE_URI = (
+            f"postgresql://{quote(DB_USER)}:{quote(DB_PASSWORD)}@{DB_HOST}:{DB_PORT or '5432'}/{DB_NAME}"
+        )
+
+    elif DB_BACKEND in ['mariadb', 'mysql']:
+        SQLALCHEMY_DATABASE_URI = (
+            f"mysql+pymysql://{quote(DB_USER)}:{quote(DB_PASSWORD)}@{DB_HOST}:{DB_PORT or '3306'}/{DB_NAME}"
+        )
+
+    elif DB_BACKEND == 'sqlite':
+        if DB_NAME == ':memory:':
+            SQLALCHEMY_DATABASE_URI = 'sqlite:///:memory:'
+        else:
+            SQLALCHEMY_DATABASE_URI = f"sqlite:///{DB_NAME}"
+
+    else:
+        raise ValueError(
+            f"Unsupported DB_BACKEND: {DB_BACKEND}. "
+            "Supported backends: mssql, postgres, mariadb, mysql, sqlite."
+        )

models/work_log.py

@@ -3,8 +3,7 @@ if TYPE_CHECKING:
     from .inventory import Inventory  
     from .inventory import User
 
-from sqlalchemy import Boolean, ForeignKeyConstraint, Identity, Integer, ForeignKey, Unicode, text
-from sqlalchemy.dialects.mssql import DATETIME2
+from sqlalchemy import Boolean, ForeignKeyConstraint, Identity, Integer, ForeignKey, Unicode, DateTime, text
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 import datetime
 
@@ -17,8 +16,8 @@ class WorkLog(db.Model):
     )
 
     id: Mapped[int] = mapped_column("ID", Integer, Identity(start=1, increment=1), primary_key=True)
-    start_time: Mapped[Optional[datetime.datetime]] = mapped_column('Start Timestamp', DATETIME2)
-    end_time: Mapped[Optional[datetime.datetime]] = mapped_column('End Timestamp', DATETIME2)
+    start_time: Mapped[Optional[datetime.datetime]] = mapped_column('Start Timestamp', DateTime)
+    end_time: Mapped[Optional[datetime.datetime]] = mapped_column('End Timestamp', DateTime)
     notes: Mapped[Optional[str]] = mapped_column('Description & Notes', Unicode())
     complete: Mapped[Optional[bool]] = mapped_column("Complete", Boolean, server_default=text('((0))'))
     followup: Mapped[Optional[bool]] = mapped_column('Needs Follow-Up', Boolean, server_default=text('((0))'))

requirements.txt

@@ -1,4 +1,5 @@
+dotenv
 flask
 flask_sqlalchemy
-pyodbc
 pandas
+pyodbc

routes.py

@@ -165,7 +165,12 @@ def index():
         'Deployed','Inoperable', 'Partially Inoperable',
         'Unverified', 'Working'
     ]
-    pivot = df['condition'].value_counts().reindex(expected_conditions, fill_value=0)
+    print(df)
+    if 'condition' in df.columns:
+        pivot = df['condition'].value_counts().reindex(expected_conditions, fill_value=0)
+    else:
+        pivot = pd.Series([0] * len(expected_conditions), index=expected_conditions)
+
 
     # Convert pandas/numpy int64s to plain old Python ints
     pivot = pivot.astype(int)
@@ -376,7 +381,7 @@ def search():
     query = request.args.get('q', '').strip()
 
     if not query:
-        return redirect(url_for('index'))
+        return redirect(url_for('main.index'))
     
     InventoryAlias = aliased(Inventory)
     UserAlias = aliased(User)

templates/fragments/_breadcrumb_fragment.html

@@ -5,7 +5,7 @@
         <div class="col">
             <ol class="breadcrumb">
                 <li class="breadcrumb-item">
-                    <a href="{{ url_for('index') }}" class="link-success link-underline-opacity-0">
+                    <a href="{{ url_for('main.index') }}" class="link-success link-underline-opacity-0">
                         {{ icons.render_icon('house', 16) }}
                     </a>
                 </li>

templates/index.html

@@ -25,6 +25,7 @@
             </div>
         </div>
         {% endif %}
+        {% if (datasets[0]['values'] | sum) > 0 %}
         <div class="col">
             <div class="card">
                 <div class="card-body">
@@ -33,6 +34,7 @@
                 </div>
             </div>
         </div>
+        {% endif %}
     </div>
 </div>
 {% endblock %}

templates/layout.html

@@ -30,7 +30,7 @@
 <body class="bg-tertiary text-primary-emphasis">
     <nav class="navbar navbar-expand bg-body-tertiary border-bottom">
         <div class="container-fluid">
-            <a class="navbar-brand" href="{{ url_for('index') }}">
+            <a class="navbar-brand" href="{{ url_for('main.index') }}">
                 Inventory Manager
             </a>
             <button class="navbar-toggler">