Metadata

ID: docker-best-practices/avoid-add-use-copy

Language: Docker

Severity: Info

Category: Best Practices

Description

This rule encourages the use of COPY instead of ADD in Dockerfiles when simply copying files or directories. While both instructions can copy files into the image, ADD has additional functionality such as extracting local tar archives and fetching remote URLs.

To make your Dockerfiles more uniform and predictable, you should use COPY unless you need ADD’s extra functionality.

See official Docker documentation

Non-Compliant Code Examples

FROM python:3.4
ADD requirements.txt /usr/src/app/

Compliant Code Examples

FROM python:3.4
COPY requirements.txt /usr/src/app/
ADD https://example.com/file.go /src
ADD archive.tar.gz /src/archive
ADD git@github.com:user/repo.git /src/foorepo

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