There are a lot of people online asking this same question in different ways but there is no clear answer. Can anybody understand enough to explain why a docker build
fails when package-lock.json
file exists in the application, but runs successfully when it is not? Seemingly it is related to npm but it is not clear.
Everybody says delete the package-lock.json
, but it is there for a reason.
Note: npm install
works fine on my local machine, just fails in docker container.
If I have this Dockerfile:
# First Stage: Builder
FROM node:13.12.0-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
RUN npm run build
And run this:
docker build -t container-tag ./
I get this:
npm WARN tar ENOENT: no such file or directory, open '/app/node_modules/.staging/eventsource-c2615740/example/index.html'
npm WARN tar ENOENT: no such file or directory, open '/app/node_modules/.staging/eventsource-c2615740/example/sse-client.js'
npm WARN tar ENOENT: no such file or directory, open '/app/node_modules/.staging/react-router-a14663ae/README.md'
But this Dockerfile will run successfully:
# First Stage: Builder
FROM node:13.12.0-alpine AS build
WORKDIR /app
COPY package.json ./ #<-------- note that there is no start here
RUN npm install
COPY . .
RUN npm run build
Using a locked package is no different than using any package without a package lock: any commands that update node_modules and/or package. json 's dependencies will automatically sync the existing lockfile. This includes npm install , npm rm , npm update , etc.
The package-lock. json file stores the version information of each installed package unchanged, and npm will use those package versions when running the npm install command.
What is the purpose of package-lock. json. The purpose of package-lock. json is to describe the exact dependency tree that was used by npm to install needed packages and to guarantee a single representation of a dependency tree across deployments and continuous integration.
From your question:
Note: npm install works fine on my local machine, just fails in docker container
If you are using npm install
, you are not sure to have the same version of dependencies.
For having a reproducible environment, without unexpected issues because of different version of dependencies, you'd rather use npm ci
:
This command is similar to npm-install, except it’s meant to be used in automated environments such as test platforms, continuous integration, and deployment – or any situation where you want to make sure you’re doing a clean install of your dependencies. It can be significantly faster than a regular npm install by skipping certain user-oriented features. It is also more strict than a regular install, which can help catch errors or inconsistencies caused by the incrementally-installed local environments of most npm users.
In short, the main differences between using npm install and npm ci are:
- The project must have an existing package-lock.json or npm-shrinkwrap.json.
- If dependencies in the package lock do not match those in package.json, npm ci will exit with an error, instead of updating the package lock.
- npm ci can only install entire projects at a time: individual dependencies cannot be added with this command.
- If a node_modules is already present, it will be automatically removed before npm ci begins its install.
- It will never write to package.json or any of the package-locks: installs are essentially frozen.
A Fabian Gander's article gives further clarification about the npm install
and npm ci
tools and provides advice on when to use each one. The below table is from that source:
cases | npm install | npm ci
--------------------------------------|-------------|-------------
needs package.json | no | yes
needs package-lock.json | no | yes
installs from package.json | yes | no
installs from package-lock.json | no | yes
compares both | no | yes
updates loose package versions | yes | no
updates loose dependencies | yes | no
writes to package.json | yes | no
writes to package-lock.json | yes | no
deletes node_modules before install | no | yes
used for installing separate package | yes | no
should be used on build systems / CI | no | yes
can be used for development | yes | yes
reproducible installs | no | yes
This is why package-lock.json is there, to be available for tools like npm ci
.
After having a reproducible environment, if this doesn't fix your issue, you need to keep investigating, but IMO it should be the first step.
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