Getting started with microservices

Microservices

Today's application development and IT System management is cloud driven . New cloud applications need to be fast 、 agile 、 Scalable and reliable .
Microservice architecture is a way to decompose large applications into a set of smaller Services . Each service runs in its own process , And use HTTP/HTTPS、WebSocket or AMQP Wait for the protocol to communicate with other processes . Each microservice implements a specific end-to-end domain or business function within a specific context boundary , Every microservice must be developed independently , And it can be deployed independently . Last , Each microservice should have its relevant domain data model and domain logic , And it can be based on different data storage technologies （SQL、NoSQL） And different programming languages .
It can be said that , Microservice is an idea , Split the previous large-scale monolithic applications into one that can run independently , Deployed Services , There is no detailed division of the split here , Generally, a service is responsible for implementing a business function according to the business scenario , The services are connected through HTTPS/HTTP Wait for the protocol to communicate ( Most commonly used Restful API). This is the basic idea of microservice .
Of course, in the actual use of microservices , There will be quite a number of extension issues .
Containerization is a method of software development , Through this method, applications or services can be 、 Its dependencies and their configuration （ Abstracted as a deployment manifest file ） Packaged together as a container image . Container applications can be tested as a unit , And deploy them as container image instances to the host operating system (OS). So use containers , It is an effective method to realize the microservice architecture pattern .
The typical microservice architecture is shown in the figure below ：

Docker

Docker Is an open source application container engine , be based on Go Language And follow Apache2.0 Open source agreement .Docker Allows developers to package their applications and dependencies into a lightweight package 、 In a portable container , Then post to any popular Linux On the machine , You can also implement virtualization . Containers are completely sandboxed using the sandbox mechanism , There will be no interface between them （ similar iPhone Of app）, More importantly, the container performance overhead is minimal .Docker Is a for development , An open platform for delivering and running applications .Docker Enables you to separate your applications from your infrastructure , So you can quickly deliver software . With the help of Docker, You can manage your infrastructure the same way you manage your applications . By using Docker The way to quickly deliver , Test and deploy code , You can significantly reduce the delay between writing code and running it in a production environment .

docker Use

1. install docker
2. Dockerfile

fsutil file createnew Dockerfile 0

The command creation name is Dockerfile The file of
And add the following ：

FROM mcr.microsoft.com/dotnet/sdk:6.0 AS buildWORKDIR /srcCOPY backend.csproj .RUN dotnet restoreCOPY . .RUN dotnet publish -c release -o /app

This will perform the following steps in order when called ：

• Pull mcr.microsoft.com/dotnet/sdk:6.0 Image and name it build
• Set the working directory in the image to /src
• The name that will be found locally is backend.csproj Copy the file to the newly created /src Directory
• Invoke in the project dotnet restore
• Copy everything in the local working directory to the image
• Invoke in the project dotnet publish

FROM mcr.microsoft.com/dotnet/aspnet:6.0WORKDIR /appEXPOSE 80EXPOSE 443COPY --from=build /app .ENTRYPOINT ["dotnet", "backend.dll"]

This will perform the following steps in order when called ：

• Pull mcr.microsoft.com/dotnet/aspnet:6.0 image
• Set the working directory in the image to /app
• Open port 80 and 443
• Create the build Mirrored /app Copy all contents in the directory to the application directory of this image
• Set the entry point of this image to dotnet, And will backend.dll Pass as a parameter

3. Build the image

docker build -t mymicroservice .

docker build Command to use Dockerfile structure Docker image .

• -t mymicroservice Parameter indicates that it marks the image ( name ) by mymicroservice.
• The last parameter tells it which directory to use to find Dockerfile (. Specify current directory ).
• This command will download and generate all dependencies to create Docker image , This operation may take some time .

4. See the build results , And run

docker images

A list of all images available on the computer , Including the image just created

docker run -it --rm -p 3000:80 --name mymicroservicecontainer mymicroservice

Run the image just created

docker ps

View the running container