英文:
Docker compose for java backend and python frontend application
问题
以下是翻译好的内容：
我有一个简单的Spring Boot Java后端应用程序，可以从列表中获取元素（端点/get/{id}）并将元素添加到列表中（端点/add/{product}）：
@RestController
public class DemoController {
List<String> products = Arrays.asList("test");
@PostMapping(path="/add/{product}")
public int addProduct(@PathVariable final String product){
products.add(product);
return products.size()-1;
}
@GetMapping(path="/get/{id}")
public String getValue(@PathVariable final int id){
return products.get(id);
}
}
我为此创建了Dockerfile，如下所示：
FROM openjdk:11
# 将打包的jar文件复制到我们的Docker镜像中
COPY target/demo-0.0.1-SNAPSHOT.jar /demo.jar
EXPOSE 8080/tcp
# 设置启动命令以执行jar文件
CMD ["java", "-jar", "/demo.jar"]
现在我可以构建镜像（docker build -t java_backend .）并运行应用程序（docker run --rm -p 8080:8080 java_backend）。
因此，在localhost:8080/get/0下，我得到了"test"，在localhost:8080/add/something下，我可以添加元素。一切正常。
作为前端，我有一个简单的Python应用程序，如下所示：
from flask import Flask, request
import requests as r
import os
app = Flask(__name__)
@app.route("/")
def renderProduct():
return """
<html>
<head>
<title>""" + os.environ["title"] + """</title>
</head>
<form id="1" method="POST">
<input name="getID"/>
<br>
<input name="addID">
<input type="submit">
</form>
</html>
"""
@app.route("/", methods=["POST"])
def queryAndRender():
builded = "<html>"
if request.form["getID"] is not None:
resp = r.get("http://localhost:8080/get/" + request.form["getID"])
builded = builded + "PRODUCT:" + resp.text + "<br>"
if request.form["addID"] is not None:
resp = r.get("http://localhost:8080/add/" + request.form["addID"])
builded = builded + "ADDED ID:" + resp.text + "<br>"
builded = builded + """<html>
<head>
<title>""" + os.environ["title"] + """</title>
</head>
<form id="1" method="POST">
<input name="getID"/>
<br>
<input name="addID">
<input type="submit">
</form>
</html>
"""
return builded;
if __name__ == "__main__":
app.run()
Dockerfile如下：
ARG version=3.8.5-alpine3.11
FROM python:${version}
ENV title="Hello world"
ENV test testspacja
ENV FLASK_APP=/main.py
RUN pip install Flask==1.1.2
RUN pip install requests==2.22.0
COPY main.py /
RUN sed -i 's/localhost:8080/backend/g' /main.py
EXPOSE 80/tcp
ENTRYPOINT ["flask", "run"]
CMD ["-h", "0.0.0.0", "-p", "80"]
最后，我创建了docker-compose.yml文件来运行它们两个：
version: '3.3'
services:
backend:
image: java_backend
ports:
- "8080:8080"
frontend:
image: frontend
ports:
- "8081:80"
现在我尝试启动docker-compose up --build backend frontend。
前端和后端是独立工作的，因此如果我尝试在localhost:8080/get/0中放置localhost:8080/get/0，我会得到"test"，如果我转到localhost:8081，我会看到我的前端。但是，如果我在文本框中输入一些值并单击提交，我会收到500 Internal Server Error。因此，服务之间没有连接。您能告诉我为什么吗？
英文:
I have simple spring boot java backend application which get element from the list (endpoint /get/{id}) and add element to the list (endpoint /add/{product}):
@RestController
public class DemoController {
List<String> products = Arrays.asList("test");
@PostMapping(path="/add/{product}")
public int addProduct(@PathVariable final String product){
products.add(product);
return products.size()-1;
}
@GetMapping(path="/get/{id}")
public String getValue(@PathVariable final int id){
return products.get(id);
}
}
I created Dockerfile for this like:
FROM openjdk:11
# copy the packaged jar file into our docker image
COPY target/demo-0.0.1-SNAPSHOT.jar /demo.jar
EXPOSE 8080/tcp
# set the startup command to execute the jar
CMD ["java", "-jar", "/demo.jar"]
Now I can build image (docker build -t java_backend .) and run application (docker run --rm -p 8080:8080 java_backend).
Thus, under localhost:8080/get/0 I got "test", under localhost:8080/add/something I can add element. Everything is fine.
As frontend I have simple python application like:
from flask import Flask, request
import requests as r
import os
app = Flask(__name__)
@app.route("/")
def renderProduct():
return """
<html>
<head>
<title>""" + os.environ["title"] + """</title>
</head>
<form id="1" method="POST">
<input name="getID"/>
<br>
<input name="addID">
<input type="submit">
</form>
</html>
"""
@app.route("/", methods=["POST"])
def queryAndRender():
builded = "<html>"
if request.form["getID"] is not None:
resp = r.get("http://localhost:8080/get/" + request.form["getID"])
builded = builded + "PRODUCT:" + resp.text + "<br>"
if request.form["addID"] is not None:
resp = r.get("http://localhost:8080/add/" + request.form["addID"])
builded = builded + "ADDED ID:" + resp.text + "<br>"
builded = builded + """<html>
<head>
<title>""" + os.environ["title"] + """</title>
</head>
<form id="1" method="POST">
<input name="getID"/>
<br>
<input name="addID">
<input type="submit">
</form>
</html>
"""
return builded;
if __name__ == "__main__":
app.run()
And Dockerfile:
ARG version=3.8.5-alpine3.11
FROM python:${version}
ENV title="Hello world"
ENV test testspacja
ENV FLASK_APP=/main.py
RUN pip install Flask==1.1.2
RUN pip install requests==2.22.0
COPY main.py /
RUN sed -i 's/localhost:8080/backend/g' /main.py
EXPOSE 80/tcp
ENTRYPOINT ["flask", "run"]
CMD ["-h", "0.0.0.0", "-p", "80"]
At the end I created docker-compose.yml file to run both of them:
version: '3.3'
services:
backend:
image: java_backend
ports:
- "8080:8080"
frontend:
image: frontend
ports:
- "8081:80"
Now I try to start docker-compose up --build backend frontend.
Frontend and backend are working independent, hence if I try put localhost:8080/get/0 I am getting "test", If I go to localhost:8081 I see my frontend. But if I put some values in textboxes and click submit then I got 500 Internal Server Error. So services are not connected. Could you please tell me why?
答案1
得分: 0
我认为你在意外地擦除了后端端口。尝试将以下内容替换为：
RUN sed -i 's/localhost:8080/backend:8080/g' /main.py
英文:
I think you are accidentally erasing the backend port. Try replacing
RUN sed -i 's/localhost:8080/backend/g' /main.py
with
RUN sed -i 's/localhost:8080/backend:8080/g' /main.py
答案2
得分: 0
我有一个额外的问题。假设我想从容器中启动前端，但只从我的本地IDE（IntelliJ）启动后端。
当然，RUN sed -i 's/localhost:8080/backend/g' /main.py 这一行被注释了，所以前端调用的是 http://localhost:8080 下的端点。
在这种情况下，前端位于 http://localhost:8081，后端位于 http://localhost:8080（两个端点 - /get/{id} 和 /add/{product}）。但为什么在容器中运行的前端无法“看到”我的后端呢？
英文:
I have one additional question for this. Let's suppose that I would like start frontend from container but backend only from the my local IDE (IntelliJ).
Of course line RUN sed -i 's/localhost:8080/backend/g' /main.py is commented so frontent is calling endpoints under http://localhost:8080.
In this case frontend is under http://localhost:8081 and backend under http://localhost:8080 (two endpoints - /get/{id} and /add/{product}). But why frontend which is running in container doesn't "see" my backend?
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