Running an Application with Docker Using Dockerfile and Docker Compose

In this article, we will show you how to run your application with Docker using Dockerfile and Docker Compose. Docker is a powerful multi-platform containerization tool used to create, package, and deploy applications. The main reason for using Docker is to simplify development, testing, and deployment processes.

What is Dockerfile?

Dockerfile is a simple text file that contains a set of commands used to create an image that will be used to run containers. It's essentially a recipe that specifies how to build an application.

The following are some key features of Dockerfile:

• It's used to create a custom image for your application
• It enables you to package your application and its dependencies
• It's easy to use and makes deployment simpler

Dockerfile Boilerplate Code

The following is a step-by-step guide on how to create a Dockerfile for your application.

1. The first step is to install the Microsoft SDK, which is the .NET 4.2 SDK. To do this, you can run the following command:

dotnetSDKfromdockerregistry

2. The next step is to add some arguments. For example, we could specify the build configuration by adding the following line:

buildconfig=release

This tells the SDK to use the release version of our code.

3. We can also specify a version by adding the following line:

version=1.0.0

4. We then need to copy the CH proj file into the build folder by adding the following command:

copyCHprojintobuildfolder

5. Next, we need to run a dotnet restore command to restore all the dependencies for our application:

rundotnetrestoreinthebuildfolderagainstthereleaseversion

6. We then copy everything from the project directory into the build folder by adding the following command:

copyeverythingfromtheprojectdirectoryintobuildfolder

7. We set the working directory to the build folder by adding the following command:

settheworkingdirectoryasthebuildfolder

8. Finally, we run a dotnet publish command to publish our project:

rundotnetpublish

This is the boilerplate code for creating a Dockerfile for an application.

What is Docker Compose?

Docker Compose is a tool used to define and run multi-container Docker applications. It's essentially a YAML file that allows you to define the services needed for your application.

The following are some key features of Docker Compose:

• It simplifies the deployment process by defining all the services needed for your application
• It makes it easy to replicate your development environment
• It's straightforward to use and enables you to run your application in a containerized environment

Docker Compose Boilerplate Code

The following is a step-by-step guide on how to create a Docker Compose file for your application.

1. The first step is to specify the version of Docker Compose you want to use. In this example, we'll use version 3.5:

version:3.5

2. Next, we define the networks our application will use. In this example, we'll use a network named "local_dev":

networks:local_dev:

3. We then need to define the services our application needs. In this example, we need two services: the main API and the database. To define the services, we use the "services" keyword:

services:main_api:db_server:

4. We need to define the build context for the main API service. To do this, we use the "build" keyword:

main_api:build:"./tweetbook"

5. We need to specify that the API service should always start. We can do this by adding the "restart" parameter:

main_api:build:"./tweetbook"restart:always

6. We need to specify the ports the API service will use. We can do this by adding the "ports" parameter:

main_api:build:"./tweetbook"restart:alwaysports:-"7000:80"

7. We specify that the API service depends on the DB server by adding the "depends_on" parameter:

main_api:build:"./tweetbook"restart:alwaysports:-"7000:80"depends_on:-db_server

8. We need to define the DB server service. We can do this by specifying the image and adding environment variables:

db_server:image:microsoft/mssql-server-linux:2017container_name:"db_server"environment:SA_PASSWORD:"Nick1234"ACCEPT_EULA:"Y"MSSQL_TCP_PORT:"1433"ports:-"1433:1433"networks:-local_dev

9. Finally, we need to specify which networks our services should use. We can do this using the "networks" parameter:

services:main_api:build:"./tweetbook"restart:alwaysports:-"7000:80"depends_on:-db_servernetworks:-local_devdb_server:image:microsoft/mssql-server-linux:2017container_name:"db_server"environment:SA_PASSWORD:"Nick1234"ACCEPT_EULA:"Y"MSSQL_TCP_PORT:"1433"ports:-"1433:1433"networks:-local_devnetworks:local_dev:

This is the boilerplate code for creating a Docker Compose file.

Running an Application with Docker

Now that we have created our Dockerfile and Docker Compose files, we can run our application with Docker.

1. First, we need to build the Dockerfile by running the following command in the same directory as the Dockerfile:

dockerbuild-tmy-app.

2. Then, we can run our application with Docker Compose by running the following command in the same directory as the Docker Compose file:

docker-composeup

This will start the containers for our application and database.

Conclusion

Docker is a powerful tool that simplifies the development, testing, and deployment processes. In this article, we showed you how to create a Dockerfile and Docker Compose file for your application, and how to run your application with Docker. By using Docker, you can create an isolated and consistent development environment, which makes it easy to replicate your environment for development and testing purposes.