使用Windows 10和Nodemon进行Docker热加载节点应用

Question

I have an express app and I'm trying to setup hot reloading with nodemon using docker for windows 10 as a dev environment. However when I npm install on the volume it doesn't seem to work.

With powershell I use a volume like so:

docker build -t node-api .

docker run --rm -it -p 8080:8080 -v "${PWD}:/usr/src/app" node-api

Which outputs this error:

[nodemon] 1.18.6
[nodemon] to restart at any time, enter `rs`
[nodemon] watching: *.*
[nodemon] starting `node server/server.js`
internal/modules/cjs/loader.js:605
    throw err;
    ^

Error: Cannot find module 'express'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:603:15)
    at Function.Module._load (internal/modules/cjs/loader.js:529:25)
    at Module.require (internal/modules/cjs/loader.js:658:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.<anonymous> (/usr/src/app/server/server.js:1:79)
    at Module._compile (internal/modules/cjs/loader.js:722:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:733:10)
    at Module.load (internal/modules/cjs/loader.js:620:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:560:12)
    at Function.Module._load (internal/modules/cjs/loader.js:552:3)
[nodemon] app crashed - waiting for file changes before starting...

If I exclude the -v flag and docker run then it starts with no errors, but doesn't detect changes or restart on file saves.

Dockerfile

FROM node:alpine

#Create app directory
WORKDIR /usr/src/app

#Install nodemon for hot reloading
RUN npm install nodemon -g

#Install app dependencies
#A wildcard is used to ensure both package.json AND package-lock.json are copied
COPY package*.json ./

RUN npm install

#Bundle app source
COPY . .

EXPOSE 8080
CMD [ "nodemon", "-L", "server/server.js" ]

Folder Structure

server/

    >server.js

Dockerfile

package.json

Github repo for code

Answer 1

The problem is that by mounting the whole host app/ directory as volume, the app/node_modules/ inside the container would be overwritten by the host's app/ , thus all dependencies are missing.

The solution is to only mount the source code folder you need, ie

docker run --rm -it -p 8080:8080 -v "${PWD}/server:/usr/src/app/server" node-api