Micro Pie Maker

This microservice takes a JSON file containing a dictionary of key: value pairs and generates a pie chart based on the given data. The program uses a ZeroMQ communication pipe to request data from the client and receive data back from the server.

Languages Used

• Python

Technologies, Libraries, and IDEs Used

• ZeroMQ
• JSON
• PyCharm
• Matplotlib

Setup

1. Clone the Git repo and navigate to the directory

   git clone https://github.com/nohabean/Micro-Pie-Maker.git
   cd ./path/to/Micro-Pie-Maker
   

2. Install Dependancies

   • Python 3.11+

     pip install -r requirements.txt
     

3. Update data.json config file with the desired data.

4. Run the client and the microservice in separete terminals, starting with the client

   • Terminal 1: Run TestClient.py

     python TestClient.py
     

   • Terminal 2: Run CreatePieMicroservice.py

     python CreatePieMicroservice.py
     

Requesting and Receiving Data

Requesting Data

The CreatePieMicroservice.py opens a server socket that waits for a message from the client using a ZeroMQ communication pipe. The message should contain the file name of the JSON config file containing the data to be displayed in the pie chart. Using the ZeroMQ communication pipe, this is achieved programatically using the following code:

Initialize Server socket and bind to the desired port (set to default) to connect with the client on.

    context = zmq.Context()
    socket = context.socket(zmq.REP)
    socket.bind("tcp://*:5555")
    print("Pie Chart Microservice started, server is listening for requests...")

Receive messages from the client.

        while True:
            # Receive JSON message from the client (the filename to read)
            message = socket.recv_json()
            print(f"Received request: {message}")

            # When the client is closed, send a stop message to the server to close the server
            if message.get('command') == 'stop':
                print("Stopping Pie Chart Microservice, closing sockets...")
                break

Take the message, parse the JSON file, and create a pie chart by generating the image data to send back to the client to display.

            try:
                # Read title and data from the JSON file
                filename = message.get('filename', 'data.json')
                with open(filename, 'r') as file:
                    json_data = json.load(file)
                    metadata = json_data.get('metadata', {})
                    title = metadata.get('title', 'Pie Chart')  # Default title is 'Pie Chart' if not found
                    data = json_data.get('data', {})

                chart_data = create_pie_chart(title, data)  # Creates the pie chart image data
                socket.send(chart_data)  # Send the image buffer data back to the client to display the pie chart

Receiving Data

Once CreatePieMicroservice.py receives the message and creates the pie chart, it sends the image data back to the client. The client can then take the image data and display the pie chart. This is accomplished using the ZeroMQ communication pipe:

Initialize client socket and connect to the server port

    context = zmq.Context()
    socket = context.socket(zmq.REQ)
    socket.connect("tcp://localhost:5555")

Send the request to the server containing the filename.

     try:
        # Specify the name of the JSON file to send in the message to the server
        filename = 'data.json'

        # Send request to the server containing the filename
        message = {'filename': filename}
        socket.send_json(message)

Receive the image data from the server to display the pie chart.

        # Receive the image buffer from the server
        chart_data = socket.recv()

        # Display the pie chart
        display_pie_chart(chart_data)

Additional code to open and display the pie charted based on the image data.

    def display_pie_chart(data):
        # Display the pie chart image data as a plot
        image_data = BytesIO(data)
        plt.figure(figsize=(8, 6))  # Adjust figure size as needed
        plt.imshow(plt.imread(image_data))
        plt.axis('off')
        plt.show()

Example JSON File and Pie Chart Output

The data to display is in data.json. This contains a dictionary of key:value pairs and includes metadata containing the title of the pie chart.

{
  "metadata": {
    "title": "Fruits I've Eaten Today"
  },
  "data": {
    "apples": "2",
    "oranges": "3",
    "bananas": "5"
  }
}

Below is the pie chart generated from the data in the JSON file.

Stopping the Microservice

To stop the program from running (and closing the socket connection), close the open pie chart window. This will close the client and send a "stop" message to the server. This message will tell the server to close and end its process. To re-open the server socket for new messages, the progrm will need to be ran again.

UML Sequence Diagram