Fix user permissions and add support for Docker buildkit and credentials

skipper/data/skipper-entrypoint.sh

@@ -3,7 +3,6 @@
 if ! [ -z "${SKIPPER_DOCKER_GID}" ];then
 
   HOME_DIR=${HOME}
-
   SKIP_HOME_DIR_PARAM=""
 
   # if home directory already exists, useradd should not try to create it
@@ -29,8 +28,13 @@ if ! [ -z "${SKIPPER_DOCKER_GID}" ];then
      usermod -G root ${SKIPPER_USERNAME}
   fi
 
-
-  su -m ${SKIPPER_USERNAME} -c "$@"
+  if ! which sudo > /dev/null; then
+    su -m ${SKIPPER_USERNAME} -c "$@"
+  else
+    # for debian dsitros (maybe for others too) -m flag resets the PATH variable
+    # so we need to use sudo -E to preserve the PATH
+    sudo -sE -u ${SKIPPER_USERNAME} "$@"
+  fi
 else
   bash -c "$@"
 fi

skipper/runner.py

@@ -138,8 +138,11 @@ def handle_networking(cmd, publish, net):
 def handle_volumes_bind_mount(docker_cmd, homedir, volumes, workspace):
     volumes = volumes or []
     volumes.extend([f'{homedir}/.netrc:{homedir}/.netrc:ro',
-                    f'{homedir}/.gitconfig:{homedir}/.gitconfig:ro',
-                    f'{homedir}/.docker/config.json:{homedir}/.docker/config.json:ro'])
+                    f'{homedir}/.gitconfig:{homedir}/.gitconfig:ro'])
+
+    # required for docker buildkit and credentials
+    if os.path.exists(f'{homedir}/.docker'):
+        volumes.append(f'{homedir}/.docker:{homedir}/.docker:rw')
 
     # required for docker login (certificates)
     if os.path.exists('/etc/docker'):