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    import logging
    from wsgiref import headers
    import azure.functions as func
    import psycopg2
    # Database to connect to
    DATABASE = {
        'user':     'postgres',
        'password': '{password}',
        'host':     'localhost',
        'port':     '5432',
        'database': '{database}'
        }
    def main(req: func.HttpRequest) -> func.HttpResponse:
        logging.info('Python HTTP trigger function processed a request.')
        DATABASE_CONNECTION = None
        # get url parameters http://localhost:7071/api/tileserver?zoom={z}&x={x}&y={y}
        # http://localhost:7071/api/tileserver?zoom=16&x=10556&y=22870
        zoom = int(req.params.get('zoom'))
        x = int(req.params.get('x'))
        y = int(req.params.get('y'))
        table = req.params.get('table')
        # calculate the envelope of the tile
        # Width of world in EPSG:3857
        worldMercMax = 20037508.3427892
        worldMercMin = -1 * worldMercMax
        worldMercSize = worldMercMax - worldMercMin
        # Width in tiles
        worldTileSize = 2 ** zoom
        
        # Tile width in EPSG:3857
        tileMercSize = worldMercSize / worldTileSize
        
        # Calculate geographic bounds from tile coordinates
        # XYZ tile coordinates are in "image space" so origin is
        # top-left, not bottom right
        xmin = worldMercMin + tileMercSize * x
        xmax = worldMercMin + tileMercSize * (x + 1)
        ymin = worldMercMax - tileMercSize * (y + 1)
        ymax = worldMercMax - tileMercSize * y
        # Generate SQL to materialize a query envelope in EPSG:3857.
        # Densify the edges a little so the envelope can be
        # safely converted to other coordinate systems.
        DENSIFY_FACTOR = 4
        segSize = (xmax - xmin)/DENSIFY_FACTOR
        sql01 = 'ST_Segmentize(ST_MakeEnvelope(' + str(xmin) + ', ' + str(ymin) + ', ' + str(xmax) + ', ' + str(ymax) + ', 3857), ' + str(segSize) +')'
       
        # Generate a SQL query to pull a tile worth of MVT data
        # from the table of interest. 
        # Materialize the bounds
        # Select the relevant geometry and clip to MVT bounds
        # Convert to MVT format
        sql02 = 'WITH bounds AS (SELECT ' + sql01 + ' AS geom, ' + sql01 + '::box2d AS b2d), mvtgeom AS (SELECT ST_AsMVTGeom(ST_Transform(t.geom, 3857), bounds.b2d) AS geom, elev FROM contourlines_smooth t, bounds WHERE ST_Intersects(t.geom, ST_Transform(bounds.geom, 4326))) SELECT ST_AsMVT(mvtgeom.*) FROM mvtgeom' 
        
        # Run tile query SQL and return error on failure conditions
        # Make and hold connection to database
        if not DATABASE_CONNECTION:
            try:
                DATABASE_CONNECTION = psycopg2.connect(**DATABASE)
                logging.info('Connected to database.')
            except (Exception, psycopg2.Error) as error:
                logging.error('ERROR: Cannot connect to database.')
        # Query for MVT
        with DATABASE_CONNECTION.cursor() as cur:
            cur.execute(sql02)
            if not cur:
                logging.error('ERROR: SQL Query failed.')
            pbf = cur.fetchone()[0]
            logging.info('Queried database')
        
        if zoom and x and y:
            return func.HttpResponse(
                # f"This HTTP triggered function executed successfully.\n\nzoom={zoom}\nx={x}\ny={y}\n\nxmin={xmin}\nxmax={xmax}\nymin={ymin}\nymax={ymax}\n\nsql01={sql01}\n\nsql02={sql02}",
                bytes(pbf),
                status_code=200,
                headers={"Content-type": "application/vnd.mapbox-vector-tile","Access-Control-Allow-Origin": "*"}
            )
        else: 
            return func.HttpResponse(
                "ERROR: Missing parameter!",
                status_code=400
            )
    

    sudo apt get update
    sudo apt get upgrade
    sudo apt install python3-pip
    pip install rio-rgbify
    PATH="$PATH:/home/<user  /.local/bin"
    # The following two steps are only necessary when mounting an external hard drive or USB flash drive:
    sudo mkdir /mnt/f
    sudo mount -t drvfs D: /mnt/f

    rio rgbify -b -10000 -i 0.1 wa_1arc_v3_merged_3857.tif wa_1arc_v3_merged_3857_rgb.tif

    # The following steps are only necessary when unmounting an external hard drive or USB flash drive:
    cd \~
    sudo umount /mnt/f/