#!/bin/sh
# This script wants to synchronize multiple public Git repositories with each
# other
#
# Use it (e.g. in a Jenkins job) like this:
#
# $0 ...
#
# where Git-URL is either a push URL, or a pair of a fetch and a push URL
# separated by an equal sign.
#
# Example:
#
# git-synchronizer.sh \
# git://fiji.sc/imglib.git=fiji.sc:/srv/git/imglib.git \
# git://github.com/imglib/imglib=github.com:imglib/imglib
errors=
add_error () {
errors="$(printf "%s\n\n%s\n\n" "$errors" "$*")"
}
url2remotename () {
echo "${1%=*}" |
sed 's/[^-A-Za-z0-9._]/_/g'
}
nullsha1=0000000000000000000000000000000000000000
find_deleted () {
test -n "$2" || return
printf '%s\n%s\n%s\n' "$1" "$2" "$2" |
sort -k 3 |
uniq -u -f 2 |
sed "s/^.\{40\}/$nullsha1/"
}
find_modified () {
printf '%s\n%s\n' "$2" "$1" |
sort -s -k 3 |
uniq -u |
uniq -d -f 2 |
uniq -f 2
}
find_new () {
printf '%s\n%s\n%s\n' "$1" "$1" "$2" |
sort -k 3 |
uniq -u -f 2
}
get_remote_branches () {
name="$1"
git for-each-ref refs/remotes/$name/\* |
sed "s| refs/remotes/$name/| |"
}
fetch_from () {
url="${1%=*}"
pushurl="${1#*=}"
name="$(url2remotename "$url")"
if test "$url" != "$(git config remote.$name.url 2> /dev/null)"
then
git remote add $name $url >&2 || {
add_error "Could not add remote $name ($url)"
return 1
}
fi
test -n "$pushurl" &&
test "$pushurl" != "$url" &&
git config remote.$name.pushURL "$pushurl"
previous="$(get_remote_branches $name)"
git fetch --prune $name >&2 || {
add_error "Could not fetch $name"
return 1
}
current="$(get_remote_branches $name)"
find_deleted "$previous" "$current"
# force modified branches
find_modified "$previous" "$current" |
sed 's/^/+/'
find_new "$previous" "$current"
}
has_spaces () {
test $# -gt 1
}
get_common_fast_forward () {
test $# -le 1 && {
echo "$*"
return
}
head=
while test $# -gt 0
do
commit=$1
shift
test -z "$(eval git rev-list --no-walk ^$commit $head $*)" && {
echo $commit
return
}
head="$head $commit"
done
echo $head
}
# Parameter check
test $# -lt 2 && {
echo "Usage: $0 [=] [=]..." >&2
exit 1
}
test -d .git ||
git init ||
exit
# Fetch
todo=
for urlpair
do
url="${urlpair%=*}"
has_spaces $url && {
add_error "Error: Ignoring URL with spaces: $url"
continue
}
echo "Getting updates from $url..."
thistodo="$(fetch_from $urlpair)" || {
add_error "$thistodo"
continue
}
test -z "$thistodo" && continue
printf "Updates from $url:\n%s\n" "$thistodo"
todo="$(printf "%s\n%s\n" "$todo" "$thistodo")"
done
remote_branches="$(for url
do
url="${url%=*}"
has_spaces $url && continue
name=$(url2remotename $url)
git for-each-ref refs/remotes/$name/\* |
sed "s|^\(.*\) refs/remotes/\($name\)/|\2 \1 |"
done)"
for ref in $(echo "$remote_branches" |
sed 's/.* //' |
sort |
uniq)
do
echo "$todo" | grep " $ref$" > /dev/null 2>&1 && continue
quoted_ref="$(echo "$ref" | sed 's/\./\\&/g')"
sha1="$(echo "$remote_branches" |
sed -n "s|^[^ ]* \([^ ]*\) [^ ]* $quoted_ref$|\1|p" |
sort |
uniq)"
sha1=$(eval get_common_fast_forward $sha1)
case "$sha1" in
*\ *)
add_error "$(printf "Ref $ref is diverging:\n%s\n\n" "$(echo "$remote_branches" |
grep " $ref$")")"
continue
;;
*)
if test $# = $(echo "$remote_branches" |
grep "$sha1 [^ ]* $ref$" |
wc -l)
then
# all refs agree on one sha1
continue
fi
;;
esac
echo "Need to fast-forward $ref to $sha1"
todo="$(printf "%s\n%s\n" "$todo" "$sha1 commit $ref")"
done
# Verify
# normalize todo
todo="$(echo "$todo" |
sort -k 3 |
uniq |
grep -v '^$')"
# test for disagreeing updates
refs=$(echo "$todo" |
sed 's/^[^ ]* [^ ]* //' |
sort |
uniq -d)
for ref in $refs
do
sha1=$(echo "$todo" |
sed -n "s|^\([^ ]*\) [^ ]* $ref$|\1|p")
sha1=$(get_common_fast_forward $sha1)
has_spaces $sha1 ||
todo="$(echo "$todo" |
sed "s|^[^ ]* \([^ ]* $ref\)$|$sha1 \1|" |
uniq)"
done
disagreeing=$(echo "$todo" |
cut -f 2 |
sort |
uniq -d)
if test -n "$disagreeing"
then
message="$(for name in $disagreeing
do
echo "$todo" | grep " $name$"
done)"
add_error "$(printf "Incompatible updates:\n%s\n\n" "$message")"
fi
test -z "$todo" || git gc --auto
# make it easier to test whether a name is in $disagreeing via:
# test "$disagreeing" != "${disagreeing#* $name }"
disagreeing=" $disagreeing "
# Push
test -z "$todo" ||
for url
do
url="${url%=*}"
has_spaces $url && continue
name="$(url2remotename $url)"
pushopts=$(echo "$todo" |
while read sha1 type ref
do
test -z "$sha1" && continue
test "$disagreeing" = "${disagreeing#* $name }" || continue
remoteref=refs/remotes/$name/$ref
if test $sha1 = $nullsha1
then
# to delete
if git rev-parse $remoteref > /dev/null 2>&1
then
echo ":refs/heads/$ref"
fi
else
sha1=${sha1#+}
if test $sha1 != "$(git rev-parse $remoteref 2> /dev/null)"
then
if test -n "$(git rev-list "$sha1..$remoteref")"
then
# really need to force
echo "+$sha1:refs/heads/$ref"
else
echo "$sha1:refs/heads/$ref"
fi
fi
fi
done)
test -z "$pushopts" && continue
deletefirst=
case "$(git config "remote.$name.pushurl"; git config "remote.$name.url")" in
git://*)
case "$pushopts" in
*+*)
add_error "Diverging $url: ${pushopts#*+}"
;;
esac
continue
;;
*.sf.net*|*.sourceforge.net*)
for opt in $pushopts
do
test "$opt" = "${opt#+*:}" ||
deletefirst="$deletefirst :${opt#+*:}"
done
esac
test -z "$deletefirst" ||
git push $name $deletefirst ||
add_error "Could not push $deletefirst to $url"
git push $name $pushopts ||
add_error "Could not push to $url"
done
# Maybe error out
test -z "$errors" || {
printf "\n\nErrors:\n%s\n" "$errors" >&2
exit 1
}