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weave-scope/tools/rebuild-image

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#!/bin/bash
# Rebuild a cached docker image if the input files have changed.
# Usage: ./rebuild-image <image name> <image dir> <image files...>
set -eux
IMAGENAME=$1
SAVEDNAME=$(echo $IMAGENAME | sed "s/[\/\-]/\./g")
IMAGEDIR=$2
shift 2
INPUTFILES=$@
CACHEDIR=$HOME/docker/
# Rebuild the image
rebuild() {
mkdir -p $CACHEDIR
rm $CACHEDIR/$SAVEDNAME* || true
docker build -t $IMAGENAME $IMAGEDIR
docker save $IMAGENAME:latest | gzip - > $CACHEDIR/$SAVEDNAME-$CIRCLE_SHA1.gz
}
# Get the revision the cached image was build at
cached_image_rev() {
find $CACHEDIR -name "$SAVEDNAME-*" -type f | sed -n 's/^[^\-]*\-\([a-z0-9]*\).gz$/\1/p'
}
# Have there been any revision beween $1 and $2
has_changes() {
local rev1=$1
local rev2=$2
local changes=$(git diff --oneline $rev1..$rev2 -- $INPUTFILES | wc -l)
[ "$changes" -gt 0 ]
}
commit_timestamp() {
local rev=$1
git show -s --format=%ct $rev
}
cached_revision=$(cached_image_rev)
if [ -z "$cached_revision" ]; then
echo ">>> No cached image found; rebuilding"
rebuild
exit 0
fi
echo ">>> Found cached image rev $cached_revision"
if has_changes $cached_revision $CIRCLE_SHA1 ; then
echo ">>> Found changes, rebuilding"
rebuild
exit 0
fi
if [ "$(commit_timestamp $cached_revision)" -lt "$(( $(date +%s) - 86400 ))" ]; then
echo ">>> Image is more the 24hrs old; rebuilding"
rebuild
exit 0
fi
# we didn't rebuild; import cached version
echo ">>> No changes found, importing cached image"
zcat $CACHEDIR/$SAVEDNAME-$cached_revision.gz | docker load