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Suppose you have already created a Docker container previously and have worked with it. Now, you have stopped the container. So, the container is in exited state. What if you want to run a command inside the container?Typically, there can be two cases. Either the container is stopped using the Docker stop command or the container is currently running in the background. In such a case, either you can start the container back, access it’s bash, and execute whatever command that you want. This is perfect for containers that are not running. Another solution is that you use the Docker ... Read More
Suppose you are using a MySQL Docker container and you want to pass environment variables to your container while running the container. It’s always a good idea to isolate the services from the configuration and it’s always advised to use environment variables for this purpose.Predominantly, there are three different ways through which we can pass environment variables to our Docker containers. These are by using the -e, --env-file, and the ENV instruction inside the Dockerfile. Let’s check out all these methods one by one with examples.Passing environment variables using the --env or -e flagTo demonstrate this example, let’s use the ... Read More
Once you have your Docker container up and running, you can work with the environment of the Docker container in the same way you would do with an Ubuntu machine. You can access the bash or shell of the container and execute commands inside it and play around with the file system. You can build, test, and deploy your applications inside the container itself.Predominantly, there are 3 ways to access the shell of a running container. These are -Using the Docker run command to run a container and access its shell.Using the Docker exec command to run commands in an ... Read More
Suppose you have an Nginx web server running inside an Nginx container in your host machine. And you have a MySQL database running in your host machine. Now, you want to access the MySQL server in your host machine from the Nginx container. Also, the MySQL is running on your localhost and the host machine does not expose any port to the outside world. Hence, we can conclude that MySQL is bound to be run on localhost only and not accessible to the outside world because it is not bound on the IP address.In this article, we will explain the ... Read More
We can use the Docker build command to build Docker images using a build context. The build context contains all the files which are required to create your containerized application environment. This includes the Dockerfile to build the Docker images, source code of the application, Dockerignore files, all the files, and directories that you want to be there beforehand in the container when you run it.However, it often happens that you might want to copy some files from the container to the host machine. For example, if you are working on an application inside a Docker container and you have ... Read More
The label widget in Tkinter is used to display text and images in a Tkinter application. In order to change the properties of the label widget such as its font-property, color, background color, foreground color, etc., you can use the configure() method.If you want to change the size of the text in a Label widget, then you can configure the font=('font-family font-size style') property in the widget constructor.Example# Import the required libraries from tkinter import * import tkinter.font as tkFont # Create an instance of tkinter frame or window win=Tk() # Set the size of the tkinter window ... Read More
The Entry widget is a single-line text widget defined in Tcl/Tk toolkit. We can use the Entry widget to accept and display single-line user input.In order to use the Entry widget, you have to first create an Entry widget using the constructor Entry(parent, width, **options). Once we've defined our Entry widget, we can configure its properties such as font-properties, color, width, etc., using the configure() method.ExampleLet use create an Entry widget to accept the username and display it in the window.# Import the required libraries from tkinter import * # Create an instance of tkinter frame or window win ... Read More
The Tkinter library has many built-in functions and methods which can be used to implement the functional part of an application. We can use messagebox module in Tkinter to create various popup dialog boxes. The messagebox property has different types of built-in popup windows that the users can use in their applications.If you need to display the error messagebox in your application, you can use showerror("Title", "Error Message") method. This method can be invoked with the messagebox itself.Example# Import the required libraries from tkinter import * from tkinter import messagebox # Create an instance of tkinter frame or window ... Read More
Most often, Tkinter Label widgets are used in the application to display the text or images. We can configure the label widget such as its text property, color, background or foreground color using the config(**options) method.If you need to modify or change the label widget dynamically, then you can use a button and a function to change the text of the label widget.Example# Import the required libraries from tkinter import * # Create an instance of tkinter frame or window win = Tk() # Set the size of the tkinter window win.geometry("700x350") # Define a function update ... Read More
Using the Canvas widget, we can create text, images, graphics, and visual content to add to the Canvas widget. If you need to configure the Canvas item dynamically, then tkinter provides itemconfig(**options) method. You can use this method to configure the properties and attributes of the Canvas items. For example, if we create a line inside the Canvas widget, we can configure its color or width using itemconfig() method.Example# Import the required libraries from tkinter import * # Create an instance of tkinter frame or window win = Tk() # Set the size of the tkinter window win.geometry("700x350") ... Read More