From 68e6fa0f8d2564f22f5c6d87a7fb4d4574db9fb8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafael=20Fern=C3=A1ndez=20L=C3=B3pez?=
 <ereslibre@ereslibre.es>
Date: Sat, 1 Dec 2018 19:13:34 +0100
Subject: [PATCH] Allow to build docker images offline (do not always use
 `docker build --pull`)

Passing `KUBE_BUILD_PULL_LATEST_IMAGES=n` will disable building the artifacts
with `--pull`, so they can be built in an offline environment.

By default, `KUBE_BUILD_PULL_LATEST_IMAGES` is `y`, so the default behavior
is kept unchanged.
---
 build/lib/release.sh | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/build/lib/release.sh b/build/lib/release.sh
index 98f6767d958..18e2ca65440 100644
--- a/build/lib/release.sh
+++ b/build/lib/release.sh
@@ -30,6 +30,7 @@ readonly RELEASE_IMAGES="${LOCAL_OUTPUT_ROOT}/release-images"
 
 KUBE_BUILD_HYPERKUBE=${KUBE_BUILD_HYPERKUBE:-y}
 KUBE_BUILD_CONFORMANCE=${KUBE_BUILD_CONFORMANCE:-y}
+KUBE_BUILD_PULL_LATEST_IMAGES=${KUBE_BUILD_PULL_LATEST_IMAGES:-y}
 
 # Validate a ci version
 #
@@ -372,7 +373,15 @@ EOF
         if [[ "${base_image}" =~ busybox ]]; then
           echo "COPY nsswitch.conf /etc/" >> "${docker_file_path}"
         fi
-        "${DOCKER[@]}" build --pull -q -t "${docker_image_tag}" "${docker_build_path}" >/dev/null
+
+        # provide `--pull` argument to `docker build` if `KUBE_BUILD_PULL_LATEST_IMAGES`
+        # is set to y or Y; otherwise try to build the image without forcefully
+        # pulling the latest base image.
+        local -a docker_build_opts=()
+        if [[ "${KUBE_BUILD_PULL_LATEST_IMAGES}" =~ [yY] ]]; then
+            docker_build_opts+=("--pull")
+        fi
+        "${DOCKER[@]}" build "${docker_build_opts[@]}" -q -t "${docker_image_tag}" "${docker_build_path}" >/dev/null
         "${DOCKER[@]}" save "${docker_image_tag}" > "${binary_dir}/${binary_name}.tar"
         echo "${docker_tag}" > "${binary_dir}/${binary_name}.docker_tag"
         rm -rf "${docker_build_path}"