third_party_mesa3d/.gitlab-ci/download-git-cache.sh
Benjamin Tissoires 0b6e03b848 CI: reduce bandwidth for git pull
Over the last 7 days, git pulls represented a total of 1.7 TB.

On those 1.7 TB, we can see:
- ~300 GB for the CI farm on hetzner
- ~730 GB for the CI farm on packet.net
- ~680 GB for the rest of the world

We can not really change the rest of the world*, but we can
certainly reduce the egress costs towards our CI farms.

Right now, the gitlab runners are not doing a good job at
caching the git trees for the various jobs we make, and
we end up with a lot of cache-misses. A typical pipeline
ends up with a good 2.8GB of git pull data. (a compressed
archive of the mesa folder accounts for 280MB)

In this patch, we implemented what was suggested in
https://gitlab.com/gitlab-org/gitlab/-/issues/215591#note_334642576

- we host a brand new MinIO server on packet
- jobs can upload files on 2 locations:
  * git-cache/<namespace>/<project>/<branch-name>.tar.gz
  * artifacts/<namespace>/<project>/<pipeline-id>/
- the authorization is handled by gitlab with short tokens
  valid only for the time of the job is running
- whenever a job runs, the runner are configured to execute
  (eval) $CI_PRE_CLONE_SCRIPT
- this variable is set globally to download the current cache
  from the MinIO packet server, unpack it and replace the
  possibly out of date cache found on the runner
- then git fetch is run by the runner, and only the delta
  between the upstream tree and the local tree gets pulled.

We can rebuild the git cache in a schedule job (once a day
seems sufficient), and then we can stop the cache miss
entirely.

First results showed that instead of pulling 280MB of data
in my fork, I got a pull of only 250KB. That should help us.

* arguably, there are other farms in the rest of the world, so
hopefully we can change those too.

Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5428>
2020-07-03 09:44:36 +02:00

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Bash

#!/bin/bash
set +e
set -o xtrace
# if we run this script outside of gitlab-ci for testing, ensure
# we got meaningful variables
CI_PROJECT_DIR=${CI_PROJECT_DIR:-$(mktemp -d)/mesa}
if [[ -e $CI_PROJECT_DIR/.git ]]
then
echo "Repository already present, skip cache download"
exit
fi
TMP_DIR=$(mktemp -d)
echo "Downloading archived master..."
/usr/bin/wget -O $TMP_DIR/mesa.tar.gz \
https://minio-packet.freedesktop.org/git-cache/mesa/mesa/mesa.tar.gz
# check wget error code
if [[ $? -ne 0 ]]
then
echo "Repository cache not available"
exit
fi
set -e
rm -rf "$CI_PROJECT_DIR"
echo "Extracting tarball into '$CI_PROJECT_DIR'..."
mkdir -p "$CI_PROJECT_DIR"
tar xzf "$TMP_DIR/mesa.tar.gz" -C "$CI_PROJECT_DIR"
rm -rf "$TMP_DIR"
chmod a+w "$CI_PROJECT_DIR"