Reproducing a bug in the Terraform Docker provider

The Terraform Docker provider added the ability to interpret a .dockerignore file recently, however, there appears to be a bug in it which "ignores" the ignored files in it and adds them to an image anyway /o.

This repository should aid in reproducing said bug.

Versions

• Terraform 1.0.5
• Provider version 2.15.0
• Docker 20.10.8, build 3967b7d
• Ubuntu Linux 21.04

Setup

You need:

• a Github Access Token which allows for accessing the GitHub Container Registry (ghcr.io)
• a valid GitHub username
• a valid GitHub repository to push to. This module assumes it carries the same name as this very repository.

Reproducing the bug

Fork this repository and copy the file terraform/terraform.tfvars.example to terraform/terraform.tfvars and fill it with content. Alternatively, you can also specify the required variables (see below) manually during the run.

To build the image, run:

$ terraform -chdir=terraform init
$ terraform -chdir=terraform apply

You should then have a copy of the pushed image stored locally on your machine.

The .dockerignore file contains a ton of files (e.g. the Dockerfile itself, the terraform directory, to name a few) that shouldn't be present inside the image:

$ cat .dockerignore
some_ignored_file.txt
terraform*
Dockerfile
docs
README.md

However, if you peak inside, they are all there:

$ docker run -ti --rm $(terraform -chdir=terraform output -raw image_reference) ls -la
total 72
----------    1 root     root          4128 Jan  1  1970 README.md
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 bin
drwxr-xr-x    5 root     root           360 Sep  2 07:47 dev
d---------    2 root     root          4096 Jan  1  1970 docs
drwxr-xr-x    1 root     root          4096 Sep  2 07:47 etc
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 home
drwxr-xr-x    7 root     root          4096 Aug  5 12:25 lib
drwxr-xr-x    5 root     root          4096 Aug  5 12:25 media
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 mnt
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 opt
dr-xr-xr-x  428 root     root             0 Sep  2 07:47 proc
drwx------    2 root     root          4096 Aug  5 12:25 root
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 run
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 sbin
----------    1 root     root             0 Jan  1  1970 some_file.txt
----------    1 root     root             0 Jan  1  1970 some_ignored_file.txt
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 srv
dr-xr-xr-x   13 root     root             0 Sep  2 07:47 sys
d---------    3 root     root          4096 Jan  1  1970 terraform
drwxrwxrwt    2 root     root          4096 Aug  5 12:25 tmp
drwxr-xr-x    7 root     root          4096 Aug  5 12:25 usr
drwxr-xr-x   12 root     root          4096 Aug  5 12:25 var

Note: the permissions are also horrible wrong, but that's for another bug to consider

You can verify that the .dockerignore file is being properly observed when build the container manually and inspecting its content:

$ docker build -t test-container .
[...]
$ docker run --rm -ti test-container ls -l
total 56
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 bin
drwxr-xr-x    5 root     root           360 Sep  2 07:49 dev
drwxr-xr-x    1 root     root          4096 Sep  2 07:49 etc
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 home
drwxr-xr-x    7 root     root          4096 Aug  5 12:25 lib
drwxr-xr-x    5 root     root          4096 Aug  5 12:25 media
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 mnt
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 opt
dr-xr-xr-x  425 root     root             0 Sep  2 07:49 proc
drwx------    2 root     root          4096 Aug  5 12:25 root
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 run
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 sbin
-rw-rw-r--    1 root     root             0 Sep  2 06:43 some_file.txt
drwxr-xr-x    2 root     root          4096 Aug  5 12:25 srv
dr-xr-xr-x   13 root     root             0 Sep  2 07:49 sys
drwxrwxrwt    2 root     root          4096 Aug  5 12:25 tmp
drwxr-xr-x    7 root     root          4096 Aug  5 12:25 usr
drwxr-xr-x   12 root     root          4096 Aug  5 12:25 var

---

Requirements

Name	Version
docker	2.15.0

Providers

Name	Version
docker	2.15.0

Modules

No modules.

Resources

Name	Type
docker_registry_image.image	resource

Inputs

Name	Description	Type	Default	Required
github_access_token	n/a	string	n/a	yes
registry_url	n/a	string	n/a	yes
username	n/a	string	n/a	yes

Outputs

Name	Description
image_reference	n/a