Implement download step

boxes/common/download.sh

@@ -1,5 +1,32 @@
 #!/bin/bash
 set -e
 
-echo "    Will check if the '${CONTAINER}' exists and error if doesnt"
+source common/ui.sh
-echo "    Will create '${CONTAINER}'"
+
+container_exists=$(lxc-ls | grep -q ${CONTAINER})
+# If container exists, check if want to continue
+if $container_exists; then
+  if ! $(confirm "The '${CONTAINER}' container already exists, do you want to continue building the box?" 'n'); then
+    log 'Aborting...'
+    exit 1
+  fi
+fi
+
+# If container exists and wants to continue building the box
+if $container_exists; then
+  if $(confirm "Do you want to rebuild the '${CONTAINER}' container?" 'n'); then
+    log "Destroying container ${CONTAINER}..."
+    lxc-stop -n ${CONTAINER} &>/dev/null || true
+    lxc-destroy -n ${CONTAINER}
+  else
+    log "Reusing existing container..."
+    exit 0
+  fi
+fi
+
+# If we got to this point, we need to create the container
+log "Creating container..."
+lxc-create -n ${CONTAINER} -t download -- \
+           --dist ${DISTRIBUTION} \
+           --release ${RELEASE} \
+           --arch ${ARCH}

boxes/common/ui.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+log() {
+  echo "    ${1}" >&2
+}
+
+debug() {
+  [ ! $DEBUG ] || echo "    [DEBUG] ${1}" >&2
+}
+
+confirm() {
+  question=${1}
+  default=${2}
+  default_prompt=
+
+  if [ $default = 'n' ]; then
+    default_prompt="y/N"
+    default='No'
+  else
+    default_prompt="Y/n"
+    default='Yes'
+  fi
+
+  echo -n "    ${question} [${default_prompt}] " >&2
+  read answer
+
+  if [ -z $answer ]; then
+    debug "Answer not provided, assuming '${default}'"
+    answer=${default}
+  fi
+
+  if $(echo ${answer} | grep -q -i '^y'); then
+    return 0
+  else
+    return 1
+  fi
+}