Create sg_maintenance.sh (#53)

repo-converter/build/sg_maintenance.sh

@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+
+# Custom implementation of sg_maintenance.sh
+# Original: https://github.com/sourcegraph/sourcegraph/blob/3.40/cmd/gitserver/server/sg_maintenance.sh
+# Retrieved from customer Slack channel on 2024-12-13
+# 
+# The differences are:
+# 1. This script can be stored in /home/sourcegraph on gitserver's volume,
+# and executed from there
+# 2. The path to the needed git repo can be passed in as a script parameter,
+# ex. ~/sg_maintenance.sh /data/repos/perforce/repo
+# 3. Most importantly, this script creates the SG_PAUSE and gc.pid lock files in the repo's directory,
+# which should prevent Sourcegraph's background processes from running on the repo while this script is running,
+# and git gc
+
+set -euxo pipefail
+
+REPOSITORY_FOLDER="${1:-""}"
+if [ -z "${REPOSITORY_FOLDER}" ]; then
+  echo "USAGE: $(basename "${BASH_SOURCE[0]}") [REPOSITORY_ROOT_FOLDER]"
+  exit 1
+fi
+cd "$REPOSITORY_FOLDER"
+
+declare -a files_to_cleanup
+
+function cleanup() {
+  for file in "${files_to_cleanup[@]}"; do
+    rm "$file" || true
+  done
+}
+trap cleanup EXIT
+
+set -o noclobber
+
+# pause all cleanup jobs, including garbage collection
+echo "running sg maintenance manually" >SG_PAUSE
+
+# cleanup the pause file once the script is done
+files_to_cleanup+=("SG_PAUSE")
+
+# set the 'git gc' pause file to prevent concurrent gc jobs
+echo "1 $(hostname)" >.git/gc.pid
+
+set +o noclobber
+
+# try running 'git gc' (expecting to it fail) to confirm that our lock file works as expected
+if git gc &>/dev/null; then
+  echo "expected 'git gc' to fail, but it didn't. Please inspect the .git/gc.pid lockfile to confirm that it contains the correct contents."
+  exit 1
+fi
+
+# cleanup the 'git gc' lock file once the script is done
+files_to_cleanup+=(".git/gc.pid")
+
+# Run sg_maintenance.sh steps from https://github.com/sourcegraph/sourcegraph/blob/3.40/cmd/gitserver/server/sg_maintenance.sh
+
+# Usually run by git gc. Pack heads and tags for efficient repository access.
+# --all Pack branch tips as well. Useful for a repository with many branches of
+# historical interest.
+git pack-refs --all --prune
+
+# Usually run by git gc. The "expire" subcommand prunes older reflog entries.
+# Entries older than expire time, or entries older than expire-unreachable time
+# and not reachable from the current tip, are removed from the reflog.
+# --all Process the reflogs of all references
+git reflog expire --all
+
+# Usually run by git gc. Here with the additional option --window-memory
+# and --write-bitmap-index. We previously set the option --geometric=2, however
+# this turned out to be too memory intensive for monorepos on some customer
+# instances. Restricting the memory consumption by setting pack.windowMemory,
+# pack.deltaCacheSize and pack.threads in addition to --geometric=2 seemed to
+# have no effect.
+git repack -d -l -A --write-bitmap-index --window-memory 100m --unpack-unreachable=now
+
+# With the --changed-paths option, compute and write information about the
+# paths changed between a commit and its first parent. This operation can take
+# a while on large repositories. It provides significant performance gains for
+# getting history of a directory or a file with git log -- <path>. If this
+# option is given, future commit-graph writes will automatically assume that
+# this option was intended
+git commit-graph write --progress --reachable --changed-paths