Docker Volumes - Changes not reflected - docker

Question

Using node.js
I am having an issue with docker volumes. I set up a volume in my docker-compose.yml file, but for some reason, changes I am making locally are not being reflected. Any idea why?
I have the current docker-compose.yml file
version: "3"
services:
posts:
build:
dockerfile: Dockerfile.dev
context: ./posts
ports:
- "4000:4000"
volumes:
- /app/node_modules
- ./posts:/app
...// more services here
Excerpt from index.js in posts
app.get("/posts", (req, res) => {
console.log("Quackss!");
res.send(posts);
});
Now lets say I run
docker-compose up --build posts
When I make my first request via postman to /posts
I see "Quackss!" in my console.
Now when I change the code to
app.get("/posts", (req, res) => {
console.log("Double Quack");
res.send(posts);
});
and save, then make a request via postman
I still see "Quacks!!" instead of "Double Quack".
I do have nodemon setup, so I didn't think that was the issue.
I ran docker ps to see the name of the container
Then ran docker exec -it <container name> sh
then cat index.js
If volumes were setup correctly, I'd expect to see
app.get("/posts", (req, res) => {
console.log("Double Quack");
res.send(posts);
});
Instead, I saw the original
app.get("/posts", (req, res) => {
console.log("Quackss!");
res.send(posts);
});
Here is my posts package.json
{
"name": "posts",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "nodemon"
},
"keywords": [],
"author": "",
"license": "ISC",
"dependencies": {
"axios": "^0.19.2",
"cors": "^2.8.5",
"express": "^4.17.1",
"nodemon": "^2.0.4"
}
}
And dockerfile.dev
FROM node:alpine
WORKDIR /usr/app/
COPY ./package.json ./
RUN npm install
COPY ./ ./
CMD ["npm", "start"]
Any idea why this is happening?

Answer 1

Your dockerfile.dev has a WORKDIR of /usr/app/ and you're copying the source code into that directory.
Your docker-compose.yml file is mapping the volumes to /app instead.
One solution is to change the WORKDIR to /app/ and rebuild your image.