How to make local changes reflect in docker container upon saving - docker

Question

I am trying to play with docker and I am still in the process of setting up my development environment. I am trying to set up my container in such a way that I can save changes on the host machine and have them propagated to the container.
I thought by using a volume I was mounting my local ./code directory into the container. I was hoping that by doing this I could run docker-compose up, develop, save and have those changes pushed into the container. Though after saving I am not seeing my changes reflected in the app until I kill it and run docker-compose up again. Am I using the correct concepts? or is this possible with docker?
Dockerfile
FROM node:10.13-alpine
ENV NODE_ENV production
# RUN mkdir /code
WORKDIR /code
docker-compose.yml
version: '2.1'
services:
express-docker-test:
build: code
# command: npm install --production --silent && mv node_modules ../
volumes:
- E:\git\express-docker-test\code\:/code/
environment:
NODE_ENV: production
expose:
- "3000"
ports:
- "3000:3000"
command: npm start
Here is a test repo I am experimenting with. I would like it if I could, with this repo, run docker-compose up. Then make an edit to the response say go from
- Hello world!!!
+ Hello World.
and then be able to refresh localhost:3000 and see the new response.
Results from docker inspect express-docker-test_express-docker-test
[
{
"Id": "sha256:791e8fbd5c871af53a37f5e9f5058e423f8ddf914b09f21ff1d80a40ea4f142f",
"RepoTags": [
"express-docker-test_express-docker-test:latest"
],
"RepoDigests": [],
"Parent": "sha256:e87553281ff90e49977fb6166c70c0e5ebf7bb98f0ae06468d7883dc0314c606",
"Comment": "",
"Created": "2019-07-14T19:15:47.1174538Z",
"Container": "8426c3db78c23c1cfc594c500ce77adf81ddd43ca52ca58456ba5b49ec60fee9",
"ContainerConfig": {
"Hostname": "8426c3db78c2",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"NODE_VERSION=10.13.0",
"YARN_VERSION=1.10.1",
"NODE_ENV=production"
],
"Cmd": [
"/bin/sh",
"-c",
"#(nop) WORKDIR /code"
],
"ArgsEscaped": true,
"Image": "sha256:e87553281ff90e49977fb6166c70c0e5ebf7bb98f0ae06468d7883dc0314c606",
"Volumes": null,
"WorkingDir": "/code",
"Entrypoint": null,
"OnBuild": [],
"Labels": {}
},
"DockerVersion": "18.09.2",
"Author": "",
"Config": {
"Hostname": "",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"NODE_VERSION=10.13.0",
"YARN_VERSION=1.10.1",
"NODE_ENV=production"
],
"Cmd": [
"node"
],
"ArgsEscaped": true,
"Image": "sha256:e87553281ff90e49977fb6166c70c0e5ebf7bb98f0ae06468d7883dc0314c606",
"Volumes": null,
"WorkingDir": "/code",
"Entrypoint": null,
"OnBuild": [],
"Labels": null
},
"Architecture": "amd64",
"Os": "linux",
"Size": 70255071,
"VirtualSize": 70255071,
"GraphDriver": {
"Data": {
"LowerDir": "/var/lib/docker/overlay2/8a0293f507ec80f68197b3bcb49b12e1a61c08f122a8a85060ab2d766d881a93/diff:/var/lib/docker/overlay2/a159e965ecf6e91533397def52fb1b3aef900c9793f933dc5120eed2381a37f4/diff:/var/lib/docker/overlay2/49f6493daf037bc88f9fb474ae71e36f13b58224082ff1f28ee367c795207c8d/diff",
"MergedDir": "/var/lib/docker/overlay2/9c4a3691e175f15585034acf7146ce5601f9e9d9c9cb60023bd348172116ae5c/merged",
"UpperDir": "/var/lib/docker/overlay2/9c4a3691e175f15585034acf7146ce5601f9e9d9c9cb60023bd348172116ae5c/diff",
"WorkDir": "/var/lib/docker/overlay2/9c4a3691e175f15585034acf7146ce5601f9e9d9c9cb60023bd348172116ae5c/work"
},
"Name": "overlay2"
},
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:df64d3292fd6194b7865d7326af5255db6d81e9df29f48adde61a918fbd8c332",
"sha256:387bc77dd3f21547b74752dd03f6018b5d750684c832c39cd239704052ce366e",
"sha256:2faeaaebb1134fe62e2cc1603a761301e281c04a8e2e36ff2ac1005f7c06780f",
"sha256:dfb2bf93a77a1907921d8f1622e831fa31c924c6c612e593b8937f95e42a0afa"
]
},
"Metadata": {
"LastTagTime": "2019-07-14T19:31:00.4646905Z"
}
}
]

Answer 1

Don't RUN mkdir /code in the Dockerfile.
If you're mounting a local directory into /code, then your Dockerfile should just expect it be exist (have been mounted by docker run ...--volume=` or by Docker Compose as you have.
Leave WORKDIR /code.
I thought mounts had to be absolute paths but if ./code then works, you're good.