Avoid cred helpers errors in release script

Signed-off-by: Joffrey F <joffrey@docker.com>

script/release/README.md

@@ -20,6 +20,12 @@ following repositories:
 - docker/compose
 - docker/compose-tests
 
+### A local Python environment
+
+While most of the release script is running inside a Docker container,
+fetching local Docker credentials depends on the `docker` Python package
+being available locally.
+
 ### A Github account and Github API token
 
 Your Github account needs to have write access on the `docker/compose` repo.

script/release/release.sh

@@ -15,9 +15,19 @@ if test -z $BINTRAY_TOKEN; then
     exit 1
 fi
 
-docker run -e GITHUB_TOKEN=$GITHUB_TOKEN -e BINTRAY_TOKEN=$BINTRAY_TOKEN -e SSH_AUTH_SOCK=$SSH_AUTH_SOCK -it \
+if test -z $(python -c "import docker; print(docker.version)" 2>/dev/null); then
+    echo "This script requires the 'docker' Python package to be installed locally"
+    exit 1
+fi
+
+hub_credentials=$(python -c "from docker import auth; cfg = auth.load_config(); print(auth.encode_header(auth.resolve_authconfig(cfg, 'docker.io')).decode('ascii'))")
+
+docker run -it \
+    -e GITHUB_TOKEN=$GITHUB_TOKEN \
+    -e BINTRAY_TOKEN=$BINTRAY_TOKEN \
+    -e SSH_AUTH_SOCK=$SSH_AUTH_SOCK \
+    -e HUB_CREDENTIALS=$hub_credentials \
     --mount type=bind,source=$(pwd),target=/src \
-    --mount type=bind,source=$HOME/.docker,target=/root/.docker \
     --mount type=bind,source=$HOME/.gitconfig,target=/root/.gitconfig \
     --mount type=bind,source=/var/run/docker.sock,target=/var/run/docker.sock \
     --mount type=bind,source=$HOME/.ssh,target=/root/.ssh \

script/release/release/images.py

@@ -2,6 +2,8 @@ from __future__ import absolute_import
 from __future__ import print_function
 from __future__ import unicode_literals
 
+import base64
+import json
 import os
 import shutil
 
@@ -15,6 +17,12 @@ class ImageManager(object):
     def __init__(self, version):
         self.docker_client = docker.APIClient(**docker.utils.kwargs_from_env())
         self.version = version
+        if 'HUB_CREDENTIALS' in os.environ:
+            print('HUB_CREDENTIALS found in environment, issuing login')
+            credentials = json.loads(base64.urlsafe_b64decode(os.environ['HUB_CREDENTIALS']))
+            self.docker_client.login(
+                username=credentials['Username'], password=credentials['Password']
+            )
 
     def build_images(self, repository, files):
         print("Building release images...")