Docker volume with typescript - docker

Question

I have a dockerfile for my TS app
FROM node:alpine
WORKDIR /usr
COPY package.json ./
COPY tsconfig.json ./
COPY src ./src
RUN ls -a
RUN npm install
EXPOSE 4005
CMD ["npm","run","dev"]
and I'm able to build it with this command
docker build -t ts-prisma .
and run it like this
docker run -it -p 3000:4005 -v src-prisma:/usr/src ts-prisma
What I want to achieve is to attach a volume to it and everytime I change something in my code change it in the docker.
I mean,
first time I build my app I have and endpoint like this
app.get(
"/",
async (req: Request, res: Response): Promise<Response> => {
return res.status(200).send({
message: "Hello world!!!",
});
}
);
and if I do a curl to ´http://localhost:3000´ it sends me the correct response of
{
message: "Hello world!!!",
}
But if I change that for this
app.get(
"/",
async (req: Request, res: Response): Promise<Response> => {
return res.status(200).send({
message: "This is a new message",
});
}
);
I'm still getting the older message.
I access to the docker with
docker exec -it <id> /bin/sh
and do a cat of the index.ts file
and is still the first version of it, nothing changed.
What am I missing?
I know there is a way to do it with volumes but I couldn't figured out.

Answer 1

Assuming that you want to run node in a container strictly for development, then you want to keep the source on your host drive and not have it in the container at all. So your COPY statements in the Dockerfile aren't necessary. You might actually be able to get away with running a completely standard node image.
Please note that I assume your host is a Linux or MacOS machine. If you're on Windows with WSL2, then doing this is hard(er) since file changes on the Windows file system aren't sent to Linux containers, so the container won't get notified when you make changes to your files.
To make sure that you have the necessary packages installed, we can run
docker run --rm -v $(pwd):/src -w /src node:alpine npm install
That will install the packages you need on your host file system.
Now you can start your development environment with
docker run --rm -v $(pwd):/src -p 3000:4005 -w /src node:alpine npm run dev
Now you should be able to change your files on your host file system and your container should pick up the changes.
When your app is done and you want to create a final image, you can do it with a Dockerfile like this
FROM node:alpine
WORKDIR /src
COPY . ./
RUN npm install
EXPOSE 4005
CMD ["npm", "run", "production"]
That image will have all your source code inside it, so once it's built, no changes to the code will have an effect on it unless you build it again.
To build it and run it, you'd do
docker build -t myimage .
docker run -p 3000:4005 myimage