COPY with docker but with exclusion - docker

Question

In a Dockerfile, I have
COPY . .
I want to exclude an entire directory, in my case, node_modules directory.
Something like this:
COPY [all but **/node_modules/**] .
Is this possible with Docker?

Answer 1

Create file .dockerignore in your docker build context directory (so in this case, most likely a directory that is a parent to node_modules) with one line in it:
**/node_modules
although you probably just want:
node_modules
Info about dockerignore: https://docs.docker.com/engine/reference/builder/#dockerignore-file

Answer 2

For those who can't use a .dockerignore file (e.g. if you need the file in one COPY but not another):
Yes, but you need multiple COPY instructions. Specifically, you need a COPY for each letter in the filename you wish to exclude.
COPY [^n]* # All files that don't start with 'n'
COPY n[^o]* # All files that start with 'n', but not 'no'
COPY no[^d]* # All files that start with 'no', but not 'nod'
Continuing until you have the full file name, or just the prefix you're reasonably sure won't have any other files.

Answer 3

FOR A ONE LINER SOLUTION, type the following in Command prompt or Terminal at project root.
echo node_modules >> .dockerignore
This command appends "node_modules" in the .dockerignore file. If the .dockerignore does not exist already, it will create a new one. Replace node_modules with the folder you want to exclude.
Warning:
If you are new to Docker ecosystem and/or you already have the .dockerignore file in your project, please take a backup before proceeding.
BONUS: (as pointed out by Joey Baruch)
(To CREATE/OVERWRITE the .dockerignore file via PowerShell, which can be handled by Docker):
>> echo node_modules | Out-File -Encoding UTF8 .dockerignore

Answer 4

Excluding node_modules from current directory
node_modules
Excluding node_modules in any immediate subdirectories
*/node_modules
Here is the official docs

Answer 5

For those using gcloud build:
gcloud build ignores .dockerignore and looks instead for .gcloudignore
Use:
cp .dockerignore .gcloudignore
Source

Answer 6

Adding .dockerignore works for me.
One additional point Those who are trying this solution on Windows , windows will not let you create .dockerignore file (as it doesn't by default allows creating file starting with .)
To create such file starting with . on Windows, include an ending dot also, like : .dockerignore. and hit enter ( provided you have enabled view extension options from folder options )

Answer 7

I used a multi stage build approach since I needed one stage to have access to the file but not another stage so .dockerignore wouldn't work:
FROM ruby AS builder
COPY app/ app/
# Do stuff with app
# remove the stuff you don't want
RUN rm -Rf app/assets
FROM ruby AS publish
# In my real version I needed the absolute path to builder WORKDIR.
# Since I'm copying from the builder stage, app/assets won't exist
# and neither will it be part of the publish image.
COPY --from=builder app app