From 2213e9beea7e6c642a7643620573d7d5db59dfc5 Mon Sep 17 00:00:00 2001
From: Jeremi Piotrowski <jpiotrowski@microsoft.com>
Date: Mon, 25 Oct 2021 14:02:15 +0200
Subject: [PATCH] update_chroot: introduce '--setuponly' flag

Currently the os/sdk and os/toolchains job perform a chroot update whose
results are immediately discarded because the rest of the build uses a fresh
chroot and catalyst. Towards the end of a release period this can extend the
build time by about an hour (longer if rust is involved).

Introduce a `--setuponly` flag that bails after the chroot configuration, and
the skips chroot update.

Signed-off-by: Jeremi Piotrowski <jpiotrowski@microsoft.com>
---
 jenkins/sdk.sh        | 2 +-
 jenkins/toolchains.sh | 2 +-
 update_chroot         | 7 +++++++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/jenkins/sdk.sh b/jenkins/sdk.sh
index 4f0a4880bf..1c52fa3581 100755
--- a/jenkins/sdk.sh
+++ b/jenkins/sdk.sh
@@ -48,7 +48,7 @@ bin/cork update \
     --sdk-url storage.googleapis.com \
     --sdk-url-path "/flatcar-jenkins/sdk" \
     --manifest-name "${MANIFEST_NAME}" \
-    --manifest-url "${MANIFEST_URL}"  -- --dev_builds_sdk="${DOWNLOAD_ROOT_SDK}"
+    --manifest-url "${MANIFEST_URL}"  -- --dev_builds_sdk="${DOWNLOAD_ROOT_SDK}" --setuponly
 
 if [[ ${FULL_BUILD} == "false" ]]; then
     export FORCE_STAGES="stage4"
diff --git a/jenkins/toolchains.sh b/jenkins/toolchains.sh
index b638349e91..59723f874c 100755
--- a/jenkins/toolchains.sh
+++ b/jenkins/toolchains.sh
@@ -69,7 +69,7 @@ export FLATCAR_BUILD_ID
 enter gangue get --verify-key /opt/verify.asc --json-key /etc/portage/gangue.json "${DOWNLOAD_ROOT_SDK}/amd64/${FLATCAR_SDK_VERSION}/flatcar-sdk-amd64-${FLATCAR_SDK_VERSION}.tar.bz2.DIGESTS" /mnt/host/source/.cache/sdks/
 
 script update_chroot \
-    --toolchain_boards="${BOARD}" --dev_builds_sdk="${DOWNLOAD_ROOT_SDK}"
+    --toolchain_boards="${BOARD}" --dev_builds_sdk="${DOWNLOAD_ROOT_SDK}" --setuponly
 
 # Set up GPG for signing uploads.
 gpg --import "${GPG_SECRET_KEY_FILE}"
diff --git a/update_chroot b/update_chroot
index 0045f7be0b..5b560df274 100755
--- a/update_chroot
+++ b/update_chroot
@@ -24,6 +24,8 @@ DEFINE_boolean workon "${FLAGS_TRUE}" \
   "Automatically rebuild updated cros-workon packages."
 DEFINE_boolean skip_toolchain_update "${FLAGS_FALSE}" \
   "Don't update the toolchains."
+DEFINE_boolean setuponly "${FLAGS_FALSE}" \
+  "Only configure portage, without updating packages. Useful when only boostrap_sdk/build_toolchains will be called"
 DEFINE_string toolchain_boards "" \
   "Extra toolchains to setup for the specified boards."
 DEFINE_string dev_builds_sdk "" \
@@ -216,6 +218,11 @@ sudo -E ${EMERGE_CMD} --quiet "${EMERGE_FLAGS[@]}" \
 
 gcc_set_latest_profile "$(portageq envvar CHOST)"
 
+if [[ "${FLAGS_setuponly}" -eq "${FLAGS_TRUE}" ]]; then
+  command_completed
+  exit 0
+fi
+
 if [[ "${FLAGS_skip_toolchain_update}" -eq "${FLAGS_FALSE}" && \
       -n "${FLAGS_toolchain_boards}" ]]; then
   CROSS_CHOSTS=( $(get_board_chost ${FLAGS_toolchain_boards} | sort -u) )