Docker-compose: node_modules mouting as volume - docker

I have an app with the following services:
cockpit/ - use as a headless CMS service.
frontend/ - bootstrapped by Create React App.
I have a question about frontend
frontend/Dockerfile
FROM node:12.16.3-alpine
RUN mkdir -p /app
WORKDIR /app
COPY package.json yarn.lock /app/
RUN yarn install --pure-lockfile
COPY . /app
CMD ["yarn", "run", "start"]
docker-compose.yml
frontend:
...
volumes:
- ./frontend:/app
- /app/node_modules
The question is /app/node_modules is same meaning with ./frontend/node_modules:/app/node_modules ?
If not, what is the difference?

/app/node_modules creates a directory inside the container and the Docker Engine automatically creates an anonymous volume for this (i.e. it should will probably be empty). This is from the docs about the compose file spec in the "Short Syntax" section.
./frontend/node_modules:/app/node_modules creates a bind mount. The ./frontend/node_modules directory from your host machine will be shared with the container.
In response to followups regarding why using /app/node_modules works but the other syntax does not:
Your yarn install command creates a node_modules folder inside the Docker image. This created folder conflicts with the existing frontend/node_modules folder you have locally when trying to run with ./frontend/node_modules:/app/node_modules. When you specify /app/node_modules, the container uses the directory created during the build step.

Related

Dockerfile for angular development not updating node_modules

I'm using the following Dockerfile for development of an Angular project:
FROM node:18-alpine
WORKDIR /code
COPY package*.json /code/
RUN npm ci --quiet
It gets started with docker compose. My code folder is mounted as a volume so the development server inside the container detects changes when editing and keeps live updates going:
version: "3"
services:
ui:
build: ./PathOnHostWithProjectRepo
command: sh -c "npm start"
ports:
- 4200:4200
volumes:
- ./PathOnHostWithProjectRepo:/code
- node_modules:/code/node_modules
volumes:
node_modules:
node_modules gets created when the image is created and, to my understanding, would only update if my package.json is changed. However, today I updated package.json with a new dependency and it is not being installed inside of the volume. I have tried everything I can think of. docker compose down, docker system prune -a -f, and rebuilding. Every time the container starts there is an error that it cannot find the new dependency added. If I step into the container and inspect the node_modules folder the library isn't there. It is present on my host machine if I run npm install locally without Docker, so I know the package and imports must be correct.
With this setup your node_modules will never be updated. Docker will completely ignore any changes in your package.json file. You've told it that directory contains user data that must not be modified.
For the setup you show you don't need Docker at all. It's straightforward to install Node and OS package managers like Debian/Ubuntu APT or MacOS Homebrew generally have a prepackaged version. If you use Node directly then you won't have problems like this; everything will work normally.
If you must use Docker here, the most straightforward thing to do is to make sure all of your application code is in a subdirectory; then you can mount only the subdirectory containing the code and leave the image's node_volumes directory intact.
$ ls -F
Dockerfile
docker-compose.yml
node_modules/
package.json
package-lock.json
src/
# Dockerfile
FROM node:lts
WORKDIR /code
COPY package*.json ./
RUN npm ci
COPY src/ ./src/
# RUN npm build
CMD ["npm", "start"]
# docker-compose.yml
version: '3.8'
services:
ui:
build: .
ports:
- '4200:4200'
volumes:
- ./src:/code/src
Mounting only the src subdirectory avoids the trouble of storing node_modules in a named volume (or an anonymous one). If you change your package.json file you will need to re-run docker-compose build, but since you're directly using the library tree in your image then this will in fact get updated.
If you're going to deploy this image somewhere, remember to delete the volumes: block during your local integration testing so that you're actually running the image you're going to deploy, and not a hybrid of an image and your potentially-modified local code.

NextJS Docker error: Couldn't find a `pages` directory. Please create one under the project root

Goal
Dockerize NextJS application
Problem
Docker compose up yields in the following error: Couldn't find a pages directory. Please create one under the project root.
Application
Files & folders
docker-compose.yml
web
.next
pages
public
.dockerignore
dockerfile
[more nextjs files & folders here]
docker-compose
version: '3'
services:
web:
build:
context: web
dockerfile: dockerfile
ports:
- "3000:3000"
container_name: rughood_web
dockerfile
FROM node:16
WORKDIR /web
COPY package*.json .
RUN npm install
COPY . .
EXPOSE 3000
CMD ["npm", "run", "dev"]
.dockerignore
Dockerfile
.dockerignore
node_modules
npm-debug.log
README.md
.git
Note!
The NextJS application itself is working fine when I run npm run dev within the web directory (which invokes the script "dev": "next dev" in package.json). I only have the error when trying to dockerize it. Moreover, in the docker-compose I also initiate a Redis cache, which is working fine too. Therefore I conclude the error must be how I try to combine Docker and NextJS. Thank you very much in advance :)
Update 1
How I got there
Using the tips from #HansKilian and Exploring Docker container's file system I did the following:
Cd to the web directory
Built an image from the dockerfile docker build .
Explored the image with the following command docker run --rm -it --entrypoint=/bin/bash name-of-image
Once inside, execute ls or ls -lsa
This gave me the following results:
What's in the derived image
dockerfile
next-env.d.ts
next.config.js
node_modules
package-lock.json
package.json
pages
public
tsconfig.json
[Among other files/folders]
So the pages folder actually seems to be in the root of the container, yet still I get the error (pages is a directory in the container in which I can cd and -ls)
P.s. don't forget to delete your image if you're not going to using it anymore
Update 2
Building the image and running it from within the web directory actually works, so it might actually have something to do with the docker-compose?
Here is my working Dockerfile with nextjs:
FROM node:16.14.0
RUN npm install -g npm#8.5.5
RUN mkdir -p /app
WORKDIR /app
COPY package*.json /app
RUN npm i
COPY . /app
EXPOSE 3000
RUN npm run build
CMD ["npm", "run", "dev"]
And docker-compose.yml :
version: "3.7"
services:
project-name:
image: project-name
build:
context: .
dockerfile: Dockerfile
container_name: project-name
restart: always
volumes:
- ./:/app
- /app/node_modules
- /app/.next
ports:
- "3000:3000"
While I was trying every single line of code ever uploaded to the internet, I came back to my initial set-up (from the question) and suddenly it now does work. Source control confirming I didn't change a thing.
To be sure, I deleted all containers, images and volumes from Docker and ran docker compose up. Yet still it worked. Tried many things to recreated the error, but I couldn't. Thank you all for helping and hopefully this may be come to use for someone else!

Why do some docker files copy files instead of mount them as a volume

Can somebody explain to me why some Dockerfiles have steps to copy files rather than just mount a volume with the files on.
I have been looking at the setup for a Django project with Docker and the dockerfile has steps with copy commands in:
FROM python:3
ENV PYTHONUNBUFFERED 1
RUN mkdir /
WORKDIR /code
COPY requirements.txt /code/
RUN pip install -r requirements.txt
COPY . /code/
In other Dockerfiles I have used (homeassistant) I have just mounted a directory as a volume and it's worked. What's going on here?
Can't I just keep the code and requirements in the same folder and mount them?
Just can't get my head around it
Edit:
For reference I'm looking at the Docker site tutorial for Django and it mounts the root dir as /code
version: '3'
services:
db:
image: postgres
web:
build: .
command: python manage.py runserver 0.0.0.0:8000
volumes:
- .:/code
ports:
- "8000:8000"
depends_on:
- db
Why is that volume mounted to /code if we copy the files there anyway. Maybe that is what is throwing me off?
Volumes are used to manage files stored by the Docker container. It allows the Docker container to write to that specific location on the file system. If the only thing you want is to execute a piece of code, it is better to just copy it over to the Docker container so that it does not have write access to the file-system of the host.
Edit:
I do not actually know why they specify the volume in the docker compose setup. The build: . specifies it should use the Dockerfile in the current directory, which already includes the copy statement. It seems a bit pointless. Might be a mistake in the tutorial.

Install node_modules inside Docker container and synchronize them with host

I have the problem with installing node_modules inside the Docker container and synchronize them with the host. My Docker's version is 18.03.1-ce, build 9ee9f40 and Docker Compose's version is 1.21.2, build a133471.
My docker-compose.yml looks like:
# Frontend Container.
frontend:
build: ./app/frontend
volumes:
- ./app/frontend:/usr/src/app
- frontend-node-modules:/usr/src/app/node_modules
ports:
- 3000:3000
environment:
NODE_ENV: ${ENV}
command: npm start
# Define all the external volumes.
volumes:
frontend-node-modules: ~
My Dockerfile:
# Set the base image.
FROM node:10
# Create and define the working directory.
RUN mkdir /usr/src/app
WORKDIR /usr/src/app
# Install the application's dependencies.
COPY package.json ./
COPY package-lock.json ./
RUN npm install
The trick with the external volume is described in a lot of blog posts and Stack Overflow answers. For example, this one.
The application works great. The source code is synchronized. The hot reloading works great too.
The only problem that I have is that node_modules folder is empty on the host. Is it possible to synchronize the node_modules folder that is inside Docker container with the host?
I've already read these answers:
docker-compose volume on node_modules but is empty
Accessing node_modules after npm install inside Docker
Unfortunately, they didn't help me a lot. I don't like the first one, because I don't want to run npm install on my host because of the possible cross-platform issues (e.g. the host is Windows or Mac and the Docker container is Debian 8 or Ubuntu 16.04). The second one is not good for me too, because I'd like to run npm install in my Dockerfile instead of running it after the Docker container is started.
Also, I've found this blog post. The author tries to solve the same problem I am faced with. The problem is that node_modules won't be synchronized because we're just copying them from the Docker container to the host.
I'd like my node_modules inside the Docker container to be synchronized with the host. Please, take into account that I want:
to install node_modules automatically instead of manually
to install node_modules inside the Docker container instead of the host
to have node_modules synchronized with the host (if I install some new package inside the Docker container, it should be synchronized with the host automatically without any manual actions)
I need to have node_modules on the host, because:
possibility to read the source code when I need
the IDE needs node_modules to be installed locally so that it could have access to the devDependencies such as eslint or prettier. I don't want to install these devDependencies globally.
At first, I would like to thank David Maze and trust512 for posting their answers. Unfortunately, they didn't help me to solve my problem.
I would like to post my answer to this question.
My docker-compose.yml:
---
# Define Docker Compose version.
version: "3"
# Define all the containers.
services:
# Frontend Container.
frontend:
build: ./app/frontend
volumes:
- ./app/frontend:/usr/src/app
ports:
- 3000:3000
environment:
NODE_ENV: development
command: /usr/src/app/entrypoint.sh
My Dockerfile:
# Set the base image.
FROM node:10
# Create and define the node_modules's cache directory.
RUN mkdir /usr/src/cache
WORKDIR /usr/src/cache
# Install the application's dependencies into the node_modules's cache directory.
COPY package.json ./
COPY package-lock.json ./
RUN npm install
# Create and define the application's working directory.
RUN mkdir /usr/src/app
WORKDIR /usr/src/app
And last but not least entrypoint.sh:
#!/bin/bash
cp -r /usr/src/cache/node_modules/. /usr/src/app/node_modules/
exec npm start
The trickiest part here is to install the node_modules into the node_module's cache directory (/usr/src/cache) which is defined in our Dockerfile. After that, entrypoint.sh will move the node_modules from the cache directory (/usr/src/cache) to our application directory (/usr/src/app). Thanks to this the entire node_modules directory will appear on our host machine.
Looking at my question above I wanted:
to install node_modules automatically instead of manually
to install node_modules inside the Docker container instead of the host
to have node_modules synchronized with the host (if I install some new package inside the Docker container, it should be
synchronized with the host automatically without any manual actions
The first thing is done: node_modules are installed automatically. The second thing is done too: node_modules are installed inside the Docker container (so, there will be no cross-platform issues). And the third thing is done too: node_modules that were installed inside the Docker container will be visible on our host machine and they will be synchronized! If we install some new package inside the Docker container, it will be synchronized with our host machine at once.
The important thing to note: truly speaking, the new package installed inside the Docker container, will appear in /usr/src/app/node_modules. As this directory is synchronized with our host machine, this new package will appear on our host machine's node_modules directory too. But the /usr/src/cache/node_modules will have the old build at this point (without this new package). Anyway, it is not a problem for us. During next docker-compose up --build (--build is required) the Docker will re-install the node_modules (because package.json was changed) and the entrypoint.sh file will move them to our /usr/src/app/node_modules.
You should take into account one more important thing. If you git pull the code from the remote repository or git checkout your-teammate-branch when Docker is running, there may be some new packages added to the package.json file. In this case, you should stop the Docker with CTRL + C and up it again with docker-compose up --build (--build is required). If your containers are running as a daemon, you should just execute docker-compose stop to stop the containers and up it again with docker-compose up --build (--build is required).
If you have any questions, please let me know in the comments.
Having run into this issue and finding the accepted answer pretty slow to copy all node_modules to the host in every container run, I managed to solve it by installing the dependencies in the container, mirror the host volume, and skip installing again if a node_modules folder is present:
Dockerfile:
FROM node:12-alpine
WORKDIR /usr/src/app
CMD [ -d "node_modules" ] && npm run start || npm ci && npm run start
docker-compose.yml:
version: '3.8'
services:
service-1:
build: ./
volumes:
- ./:/usr/src/app
When you need to reinstall the dependencies just delete node_modules.
A Simple, Complete Solution
You can install node_modules in the container using the external named volume trick and synchronize it with the host by configuring the volume's storage location to point to your host's node_modules directory. This can be done with a named volume using the local driver and a bind mount, as seen in the example below.
The volume's data is stored on your host anyway, in something like /var/lib/docker/volumes/, so we're just storing it inside your project instead.
To do this in Docker Compose, just add your node_modules volume to your front-end service, and then configure the volume in the named volumes section, where "device" is the relative path (from the location of docker-compose.yml) to your local (host) node_modules directory.
docker-compose.yml
version: '3.9'
services:
ui:
# Your service options...
volumes:
- node_modules:/path/to/node_modules
volumes:
node_modules:
driver: local
driver_opts:
type: none
o: bind
device: ./local/path/to/node_modules
The key with this solution is to never make changes directly in your host node_modules, but always install, update, or remove Node packages in the container.
Version Control Tip:
When your Node package.json/package-lock.json files change, either when pulling, or switching branches, in addition to rebuilding the Image, you have to remove the Volume, and delete its contents:
docker volume rm example_node_modules
rm -rf local/path/to/node_modules
mkdir local/path/to/node_modules
Documentation:
https://docs.docker.com/storage/volumes/
https://docs.docker.com/storage/bind-mounts/
https://docs.docker.com/compose/compose-file/compose-file-v3/#driver_opts
There's three things going on here:
When you run docker build or docker-compose build, your Dockerfile builds a new image containing a /usr/src/app/node_modules directory and a Node installation, but nothing else. In particular, your application isn't in the built image.
When you docker-compose up, the volumes: ['./app/frontend:/usr/src/app'] directive hides whatever was in /usr/src/app and mounts host system content on top of it.
Then the volumes: ['frontend-node-modules:/usr/src/app/node_modules'] directive mounts the named volume on top of the node_modules tree, hiding the corresponding host system directory.
If you were to launch another container and attach the named volume to it, I expect you'd see the node_modules tree there. For what you're describing you just don't want the named volume: delete the second line from the volumes: block and the volumes: section at the end of the docker-compose.yml file.
No one has mentioned solution with actually using docker's entrypoint feature.
Here is my working solution:
Dockerfile (multistage build, so it is both production and local dev ready):
FROM node:10.15.3 as production
WORKDIR /app
COPY package*.json ./
RUN npm install && npm install --only=dev
COPY . .
RUN npm run build
EXPOSE 3000
CMD ["npm", "start"]
FROM production as dev
COPY docker/dev-entrypoint.sh /usr/local/bin/
ENTRYPOINT ["dev-entrypoint.sh"]
CMD ["npm", "run", "watch"]
docker/dev-entrypoint.sh:
#!/bin/sh
set -e
npm install && npm install --only=dev ## Note this line, rest is copy+paste from original entrypoint
if [ "${1#-}" != "${1}" ] || [ -z "$(command -v "${1}")" ]; then
set -- node "$#"
fi
exec "$#"
docker-compose.yml:
version: "3.7"
services:
web:
build:
target: dev
context: .
volumes:
- .:/app:delegated
ports:
- "3000:3000"
restart: always
environment:
NODE_ENV: dev
With this approach you achieve all 3 points you required and imho it is much cleaner way - not need to move files around.
Binding your host node_modules folder with your container node_modules is not a good practice as you mention. I have seen the solution of creating an internal volume for this folder quite often. Not doing so will cause problems during the building stage.
I ran into this problem when I was trying to build a docker development environment for an angular app, that shows tslib errors when I was editing the files within my host folder cause my host's node_modules folder was empty (as expected).
The cheap solution that helps me, in this case, was to use the Visual Studio Code Extension called "Remote-Containers".
This extension will allow you to attach your Visual Studio Code to your container and edit transparently your files within your container folders. To do so, it will install an internal vscode server within your development container. For more information check this link.
Ensure, however, that your volumes are still created in your docker-compose.yml file.
I hope it helps :D!
I wouldn't suggest overlapping volumes, although I haven't seen any official docs ban it, I've had some issues with it in the past. How I do it is:
Get rid of the external volume as you are not planning on actually using it how it's meant to be used - respawning the container with its data created specifically in the container after stopping+removing it.
The above might be achieved by shortening your compose file a bit:
frontend:
build: ./app/frontend
volumes:
- ./app/frontend:/usr/src/app
ports:
- 3000:3000
environment:
NODE_ENV: ${ENV}
command: npm start
Avoid overlapping volume data with Dockerfile instructions when not necessary.
That means you might need two Dockerfiles - one for local development and one for deploying a fat image with all the application dist files layered inside.
That said, consider a development Dockerfile:
FROM node:10
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
RUN npm install
The above makes the application create a full node_modules installation and map it to your host location, while the docker-compose specified command would start your application off.
I'm not sure to understand why you want your source code to live inside the container and host and bind mount each others during development. Usually, you want your source code to live inside the container for deployments, not development since the code is available on your host and bind mounted.
Your docker-compose.yml
frontend:
volumes:
- ./app/frontend:/usr/src/app
Your Dockerfile
FROM node:10
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
Of course you must run npm install first time and everytime package.json changes, but you run it inside the container so there is no cross-platform issue: docker-compose exec frontend npm install
Finally start your server docker-compose exec frontend npm start
And then later, usually in a CI pipeline targetting a deployment, you build your final image with the whole source code copied and node_modules reinstalled, but of course at this point you don't need anymore the bind mount and "synchronization", so your setup could look like :
docker-compose.yml
frontend:
build:
context: ./app/frontend
target: dev
volumes:
- ./app/frontend:/usr/src/app
Dockerfile
FROM node:10 as dev
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
FROM dev as build
COPY package.json package-lock.json ./
RUN npm install
COPY . ./
CMD ["npm", "start"]
And you target the build stage of your Dockerfile later, either manually or during a pipeline, to build your deployment-ready image.
I know it's not the exact answer to your questions since you have to run npm install and nothing lives inside the container during development, but it solves your node_modules issue, and I feel like your questions are mixing development and deployment considerations, so maybe you thought about this problem in the wrong way.
The best for development
docker-compose.yml
...
frontend:
build: ./app/frontend
ports:
- 3000:3000
volumes:
- ./app/frontend:/usr/src/app
...
./app/frontend/Dockerfile
FROM node:lts
WORKDIR /usr/src/app
RUN npm install -g react-scripts
RUN chown -Rh node:node /usr/src/app
USER node
EXPOSE 3000
CMD [ "sh", "-c", "npm install && npm run start" ]
#FOR PROD
# CMD [ "sh", "-c", "npm install && npm run build" ]
The user node will help you with the rights of host<->guest
The folder node_modules will be accessible from the host and synchronize host<->guest
Thanks Vladyslav Turak for answer with entrypoint.sh where we copy node_modules from container to host.
I implemented the similar thing but I run into the issue with husky, #commitlint, tslint npm packages.
I can't push anything into repository.
Reason: I copied node_modules from Linux to Windows. In my case <5% of files are different (.bin and most of package.json) and 95% are the same. example: image with diff
So I returned to solution with npm install of node_modules for Windows first (for IDE and debugging). And Docker image will contain Linux version of node_modules.
I know that this was resolved, but what about:
Dockerfile:
FROM node
# Create app directory
WORKDIR /usr/src/app
# Your other staffs
EXPOSE 3000
docker-composer.yml:
version: '3.2'
services:
api:
build: ./path/to/folder/with/a/dockerfile
volumes:
- "./volumes/app:/usr/src/app"
command: "npm start"
volumes/app/package.json
{
... ,
"scripts": {
"start": "npm install && node server.js"
},
"dependencies": {
....
}
}
After run, node_modules will be present in your volumes, but its contents are generated within the container so no cross platform problems.
My workaround is to install dependencies when the container is starting instead of during build-time.
Dockerfile:
# We're using a multi-stage build so that we can install dependencies during build-time only for production.
# dev-stage
FROM node:14-alpine AS dev-stage
WORKDIR /usr/src/app
COPY package.json ./
COPY . .
# `yarn install` will run every time we start the container. We're using yarn because it's much faster than npm when there's nothing new to install
CMD ["sh", "-c", "yarn install && yarn run start"]
# production-stage
FROM node:14-alpine AS production-stage
WORKDIR /usr/src/app
COPY package.json ./
RUN yarn install
COPY . .
.dockerignore
Add node_modules to .dockerignore to prevent it from being copied when the Dockerfile runs COPY . .. We use volumes to bring in node_modules.
**/node_modules
docker-compose.yml
node_app:
container_name: node_app
build:
context: ./node_app
target: dev-stage # `production-stage` for production
volumes:
# For development:
# If node_modules already exists on the host, they will be copied
# into the container here. Since `yarn install` runs after the
# container starts, this volume won't override the node_modules.
- ./node_app:/usr/src/app
# For production:
#
- ./node_app:/usr/src/app
- /usr/src/app/node_modules
You could also use dockerized npm install. This is the same as npm install but it runs on a docker container.
https://github.com/datastack-net/dockerized
The node_modules will be written to the host. It should work out of the box and you can specify which npm version to use. If needed, the container can be extended or customized.
Be aware that some npm packages may require compilation, and the generated binaries may not be compatible with your host machine. If you just need the source code or dist files, this is not an issue.
Disclaimer: I'm the author of Dockerized.

Docker + node_modules: receiving error for local dependency while trying to run Dockerfile

I am working on creating a docker container for a node.js microservice and am running into an issue with a local dependency from another folder.
I added the dependency to the node_modules folder using:
npm install -S ../dependency1(module name).
This also added an entry in the package.json as follows:
"dependency1": "file:../dependency1".
When I run the docker-compose up -d command, I receive an error indicating the folowing:
npm ERR! Could not install from "../dependency1" as it does not contain a package.json file.
Dockerfile:
FROM node:latest
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
COPY . /usr/src/app
RUN npm install
CMD [ "npm", "start" ]
EXPOSE 3000
docker-compose.yml:
customer:
container_name: "app_customer"
build:
context: .
dockerfile: Dockerfile
volumes:
- .:/usr/src/app/
- /usr/src/app/node_modules
ports:
- "3000:3000"
depends_on:
- mongo
- rabbitmq
I found articles outlining an issue with symlinks in a node_modules folder and docker and a few outlining this issue but none seem to provide a solution to this problem. I am looking for a solution to this problem or a really good workaround.
A Docker build can't reference files outside of the build context, which is the . defined in the docker-compose.yml file.
docker build creates a tar bundle of all the files in a build context and sends that to the Docker daemon for the build. Anything outside the context directory doesn't exist to the build.
You could move your build context with context: ../ to the parent directory and shuffle all the paths you reference in the Dockerfile to match. Just be careful not to make the build context to large as it can slow down the build process.
The other option is to publish the private npm modules to a scope, possible on a private npm registry that you and the build server have access to and install the dependencies normally.

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