microservice-workshop

Goal: To run a .NET api in a docker container, and use docker compose to make it easier.

Prerequisites

Install dotnet

• Chocolatey - choco install dotnetcore-sdk

• Download installer

Install docker

• Download installer

Hello world

Run the API

dotnet run --project MicroserviceWorkshop

The API should start and show you the uris to access it from. Verify the API is running by navigating there in your browser.

Run with Docker

Create Dockerfile

To build a docker container to host our app we must create a Dockerfile.

We are going to create a Dockerfile that builds and publishes the artifacts of our app from the dotnet sdk container. We will then use those artifacts in our dotnet core runtime container as our entrypoint.

Build steps

1. Create a file named Dockerfile in the root of the project. Add the following line to load the dotnet sdk container.

FROM microsoft/dotnet:2.1-sdk AS build-env

2. Copy the source code from our project to the container.

COPY ./MicroserviceWorkshop /app/src/

If you build and run the container now, you can see our source files in the /app/src/ directory.

docker build .
docker run -p 5000:80 -it --name=microservice-workshop <container-id>
cd /app/src
ls
exit

docker rm microservice-workshop

3. Build and publish the artefacts.

WORKDIR /app/src
RUN dotnet publish -c Release -o ../out

Run steps

1. In the same Dockerfile, load the dotnet runtime container.

FROM microsoft/dotnet:2.1-aspnetcore-runtime

2. Copy the artefacts from the dotnet sdk container into the app directory of the dotnet runtime container.

WORKDIR /app
EXPOSE 80

COPY --from=build-env /app/out .

3. Run

ENTRYPOINT ["dotnet", "MicroserviceWorkshop.dll"]

Build and run the container

Now that we have a Dockerfile we can build and run it.

docker build .
docker run -p 5000:80 --name=microservice-workshop <container-id>

Test it by navigating to [http://localhost:5000]

Stop the running container

docker stop microservice-workshop

Remove the container

docker rm microservice-workshop

Docker compose

Docker commands can quickly become unweildy and very often we want to launch a bunch of containers that interact with each other together. This is where the docker-compose command comes in.

Notice the docker-compose.yml file; this file is picked up by the docker-compose command. The file contains information about the port number mappings in this case but there are lots more things you can do with it. As ours is a simple case, this is all we need.

Run docker-compose up to launch the container.