Building images in parallel and pushing them to Docker Hub results in premature logout

[huyz]

Overview of the Issue

When I'm building 3 different images in parallel and pushing them to Docker Hub, the first one to complete will do a docker logout causing errors in the other 2 pushes.

Reproduction Steps

1. Build 3 images in parallel
2. Push them to Docker Hub

Plugin and Packer version

Packer v1.8.5
Docker plugin v1.0.8

Simplified Packer Buildfile

# Common config to be shared among multiple sources
source "docker" "ubuntu" {
   …
}

build {
  …
  dynamic "source" {
    for_each = ["ubuntu:22.04", "ubuntu:20.04", "ubuntu:18.04"]
    labels   = ["docker.ubuntu"]
    content {
      name  = source.value
      image = source.value
    }
  }
  …

  post-processors {
    post-processor "docker-tag" {
      repository = format("%s-%s", var.docker_repo_base, split(":", source.name)[0])
      tags = [split(":", source.name)[1]]
    }
    post-processor "docker-push" {
      login          = true
      login_username = var.docker_username
      login_password = var.docker_password
    }
  }
}

Operating system and Environment details

Log Fragments and crash.log files

See the 2 denied: requested access to the resource is denied below:

==> ansible-molecule.docker.ubuntu:20.04: Running post-processor:  (type docker-tag)
    ansible-molecule.docker.ubuntu:20.04 (docker-tag): Tagging image: sha256:67aaf5e084e8be28acf2f7382d25cc3fb9a252cf8a4477fc84229e20805e7fd2
    ansible-molecule.docker.ubuntu:20.04 (docker-tag): Repository: huyz/ansible-molecule-ubuntu:20.04
==> ansible-molecule.docker.ubuntu:20.04: Running post-processor:  (type docker-push)
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Creating temporary Docker configuration directory
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Logging in...
    ansible-molecule.docker.ubuntu:18.04:     Running setup.py install for ansible: finished with status 'done'
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Login Succeeded
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Pushing: huyz/ansible-molecule-ubuntu:20.04
    ansible-molecule.docker.ubuntu:20.04 (docker-push): The push refers to repository [docker.io/huyz/ansible-molecule-ubuntu]
==> ansible-molecule.docker.ubuntu:18.04: Committing the container
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 56fc03fd05e4: Layer already exists
==> ansible-molecule.docker.ubuntu:18.04: Running post-processor:  (type docker-tag)
    ansible-molecule.docker.ubuntu:18.04 (docker-tag): Tagging image: sha256:2f18df89a8c6a144a353ef73149a422364abcf1b8c06cdaa494cc056f14dbf84
    ansible-molecule.docker.ubuntu:18.04 (docker-tag): Repository: huyz/ansible-molecule-ubuntu:18.04
==> ansible-molecule.docker.ubuntu:18.04: Running post-processor:  (type docker-push)
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Creating temporary Docker configuration directory
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Logging in...
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Login Succeeded
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Pushing: huyz/ansible-molecule-ubuntu:18.04
    ansible-molecule.docker.ubuntu:18.04 (docker-push): The push refers to repository [docker.io/huyz/ansible-molecule-ubuntu]
    ansible-molecule.docker.ubuntu:18.04 (docker-push): 6b47c5c1f372: Preparing
    ansible-molecule.docker.ubuntu:18.04 (docker-push): a56e9bd192dc: Preparing
    ansible-molecule.docker.ubuntu:18.04 (docker-push): a56e9bd192dc: Layer already exists
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 4ef07da5ca01: Pushed
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 20.04: digest: sha256:ed4ad017978da4af4d148a0652b2964b0dc0d8f80fb18781d1ad04b29cc5f7d3 size: 742
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Pushing: huyz/ansible-molecule-ubuntu:20.04
    ansible-molecule.docker.ubuntu:20.04 (docker-push): The push refers to repository [docker.io/huyz/ansible-molecule-ubuntu]
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 4ef07da5ca01: Preparing
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 56fc03fd05e4: Preparing
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 56fc03fd05e4: Layer already exists
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 4ef07da5ca01: Layer already exists
    ansible-molecule.docker.ubuntu:20.04 (docker-push): 20.04: digest: sha256:ed4ad017978da4af4d148a0652b2964b0dc0d8f80fb18781d1ad04b29cc5f7d3 size: 742
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Logging out...
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Removing login credentials for https://index.docker.io/v1/
    ansible-molecule.docker.ubuntu:20.04 (docker-push): Removing temporary Docker configuration directory
Build 'ansible-molecule.docker.ubuntu:20.04' finished after 5 minutes 50 seconds.
    ansible-molecule.docker.ubuntu:18.04 (docker-push): 6b47c5c1f372: Pushed
    ansible-molecule.docker.ubuntu:22.04 (docker-push): 1cdb0b846b12: Pushed
    ansible-molecule.docker.ubuntu:18.04 (docker-push): 18.04: digest: sha256:2c5886599443533a38665f1b60097a4aca09650d3a26228fd507227ad9d7e7f4 size: 742
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Pushing: huyz/ansible-molecule-ubuntu:18.04
    ansible-molecule.docker.ubuntu:18.04 (docker-push): The push refers to repository [docker.io/huyz/ansible-molecule-ubuntu]
    ansible-molecule.docker.ubuntu:18.04 (docker-push): 6b47c5c1f372: Preparing
    ansible-molecule.docker.ubuntu:18.04 (docker-push): a56e9bd192dc: Preparing
    ansible-molecule.docker.ubuntu:18.04 (docker-push): a56e9bd192dc: Layer already exists
    ansible-molecule.docker.ubuntu:18.04 (docker-push): 6b47c5c1f372: Layer already exists
    ansible-molecule.docker.ubuntu:22.04 (docker-push): 22.04: digest: sha256:a667935e0b50c68ee8f8ff652b30d2144ec6c0199a9294160f95557b98a67436 size: 742
    ansible-molecule.docker.ubuntu:22.04 (docker-push): Pushing: huyz/ansible-molecule-ubuntu:22.04
    ansible-molecule.docker.ubuntu:22.04 (docker-push): The push refers to repository [docker.io/huyz/ansible-molecule-ubuntu]
    ansible-molecule.docker.ubuntu:22.04 (docker-push): 1cdb0b846b12: Preparing
    ansible-molecule.docker.ubuntu:22.04 (docker-push): 6142b8f76de4: Preparing
    ansible-molecule.docker.ubuntu:18.04 (docker-push): errors:
    ansible-molecule.docker.ubuntu:18.04 (docker-push): denied: requested access to the resource is denied
    ansible-molecule.docker.ubuntu:18.04 (docker-push): unauthorized: authentication required
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Logging out...
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Removing login credentials for https://index.docker.io/v1/
    ansible-molecule.docker.ubuntu:18.04 (docker-push): WARNING: could not erase credentials:
    ansible-molecule.docker.ubuntu:18.04 (docker-push): https://index.docker.io/v1/: error erasing credentials - err: exit status 1, out: `The specified item could not be found in the keychain.`
    ansible-molecule.docker.ubuntu:18.04 (docker-push): Removing temporary Docker configuration directory
Build 'ansible-molecule.docker.ubuntu:18.04' errored after 6 minutes 4 seconds: 1 error(s) occurred:

* Post-processor failed: Bad exit status: 1
    ansible-molecule.docker.ubuntu:22.04 (docker-push): 6142b8f76de4: Layer already exists
    ansible-molecule.docker.ubuntu:22.04 (docker-push): 1cdb0b846b12: Layer already exists
    ansible-molecule.docker.ubuntu:22.04 (docker-push): errors:
    ansible-molecule.docker.ubuntu:22.04 (docker-push): denied: requested access to the resource is denied
    ansible-molecule.docker.ubuntu:22.04 (docker-push): unauthorized: authentication required
    ansible-molecule.docker.ubuntu:22.04 (docker-push): Logging out...
    ansible-molecule.docker.ubuntu:22.04 (docker-push): Removing login credentials for https://index.docker.io/v1/
    ansible-molecule.docker.ubuntu:22.04 (docker-push): WARNING: could not erase credentials:
    ansible-molecule.docker.ubuntu:22.04 (docker-push): https://index.docker.io/v1/: error erasing credentials - err: exit status 1, out: `The specified item could not be found in the keychain.`
    ansible-molecule.docker.ubuntu:22.04 (docker-push): Removing temporary Docker configuration directory
Build 'ansible-molecule.docker.ubuntu:22.04' errored after 6 minutes 7 seconds: 1 error(s) occurred:

* Post-processor failed: Bad exit status: 1

[huyz]

As I explained in #142 (comment) , the best solution is simply to not do login = true and just handle it on my own, out of band.

So perhaps this may not even be considered a bug as long as the documentation were updated to make it clear that docker login isn't supported for simultaneous docker-push post-processors.