[FIXED] How to communicate UI and backend application using ngnix reverse proxy in docker env

Issue

I have one UI application (Angular application) and backend application (Java Spring boot application). I want to deploy them in docker containers, and want to communicate backend and front-end application. without hard-coding URLs and other stuff, everything which is required for communication should be resolved dynamically.

So basically what I want to create is the local development environment which is kind of similar to the production one, not the exact replica but function like production env.

Solution

So the way I chose to resolved this problem is as described following. First of all, need to understand the dir structure.

E:.
│   .gitattributes
│   docker-compose.yml
│   README.md
│
├───beservice
│       Dockerfile
│
├───nginx
│   └───conf
│           ngnix.conf
│
└───ui-app
        Dockerfile

Backend application has its own docker file and frontend application have its own. One important file is Nginx file nginx.conf.

Let us have a look at what is inside the files.

└───beservice
        Dockerfile

---

FROM openjdk:11.0.4-jre
LABEL APP_ID="beservice"
VOLUME /app
EXPOSE 8080
ENTRYPOINT java -Xdebug -Xrunjdwp:transport=dt_socket,address=*:8000,server=y,suspend=n -jar /app/$JAR

---

└───ui-app
          Dockerfile

---

FROM nginx
LABEL APP_ID="ui-app"
RUN rm /etc/nginx/conf.d/default.conf
CMD ["nginx", "-g", "daemon off;"]

---

E:.
└───docker-compose.yml

---

version: "3"

services:
  beservice:
    build:
      context: ./beservice # beservice1 -> backend Service 1
    image: beservice:latest 
    container_name: beservice
    volumes:
      - [ REPLACE this with Backend Service path ]:/app # Like E:\repos\backend-service\build\libs
    ports:
      - 9002:8080 # App access Port, inside container it is 8080 and mappped with 9002
      - 1111:8000 # to remote debug springboot application
    environment:                                                                      
      JAR : [ jar file name - locate form build path ] # Just Jar Name like module-backend-0.0.1-SNAPSHOT.jar
  uiapp:
    build:
      context: ./ui-app
    image: ui-app:latest
    container_name: ui-app
    volumes:
      - [ path of ui app build ]:/usr/share/nginx/html # We need to Map UI app build path here, Like my angular UI App, E:\repos\ui-app\dist\ui-app 
      - nginx\conf\ngnix.conf:/etc/nginx/conf.d/
    depends_on:
      - beservice
    ports:
      - 80:80

The most important file, ngnix.conf

├───nginx
│   └───conf
│           ngnix.conf



server {    
    listen 80;  
    server_name host.docker.internal;   

    # By default land on localhost:80 to root so in root we copied UI build to the ngnix html dir.
    # have a look to docker-compose uiapp service.
    location / {    
            root   /usr/share/nginx/html;   
            index  index.html index.htm;    
    }   

   # after location add filter, from which every endpoint starts with or comes in endpoint 
   # so that ngnix can capture the URL and reroute it.
   # like /backend/getUserInfo/<UserId> 
   # In above example /backend is that filter which will be captured by Ngnix and reroute the flow.
    location /backend { 
        proxy_set_header X-Forwarded-Host $host;    
        proxy_set_header X-Forwarded-Server $host;  
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        #proxy_pass http://<ContainerName>:<PortNumber>; 
        # In our case Container name is as we setup in docker-compose `beservice` and port 8080
        proxy_pass http://beservice:8080;   
    }   
}

Development environment with containers

This repository contains all the required files and configuration which help you to setup a containerized enviournment, which have a UI application in different container and a backend application in different container. Both the applications are communication using Ngnix server.

Ngnix reverse-proxy configuration is described in detail.

Setup Instructions:

• Update repositories backend and repos with the latest code.
• Clean build your backend and UI app.
• Replace placeholder [ ... ] in docker-compose.yml file, as described in comments.
• Open docker-compose.yml, in each and every step I added comments. and suggests changes.
• Like I go through docker-compose in backend service, You just need to map app build path to the
• volume and pass build Jar Name
• In UI App, Just pass the UI build path. Exhibit in case of Angular App "E:\repos\ui-app\dist\ui-app" How to Run:

Open powershell in the root dir of current Repo/localDevEnv and run following command

docker-compose -f "docker-compose.yml" up -d --build

command complete with output:

Creating beservice ... done
Creating uiapp     ... done 

For more details visit this: https://github.com/dupinder/NgnixDockerizedDevEnv

Answered By - Dupinder Singh

Answer Checked By - Gilberto Lyons (PHPFixing Admin)