#!/bin/bash
# Co-op Cloud wrapper around pgautoupgrade's entrypoint.
#
# pgautoupgrade runs pg_upgrade assuming the old cluster's bootstrap superuser
# (the "install user", oid 10) equals $POSTGRES_USER. That is not always true
# (e.g. a cluster bootstrapped with the default "postgres" superuser and a
# separate "discourse" app role), and a mismatch makes pg_upgrade's consistency
# check fail (pgautoupgrade issue #115). When a major-version upgrade is pending,
# detect the old cluster's real install user and run the upgrade as that user;
# pgautoupgrade handles everything else (old binaries, initdb, pg_upgrade).
set -e

if [ -s "$PGDATA/PG_VERSION" ]; then
  OLD_VERSION="$(cat "$PGDATA/PG_VERSION")"
  TARGET_VERSION="${PGTARGET%%.*}"

  if [ -n "$OLD_VERSION" ] && [ -n "$TARGET_VERSION" ] && [ "$OLD_VERSION" != "$TARGET_VERSION" ]; then
    # query the old cluster in single-user mode (no socket/auth needed) with
    # pgautoupgrade's bundled old-version binaries
    OLD_POSTGRES="/usr/local-pg${OLD_VERSION}/bin/postgres"
    if [ -x "$OLD_POSTGRES" ]; then
      INSTALL_USER="$(echo 'select rolname from pg_authid where oid = 10;' \
        | gosu postgres "$OLD_POSTGRES" --single -D "$PGDATA" template1 2>/dev/null \
        | sed -n 's/.*rolname = "\([^"]*\)".*/\1/p' | head -n1)"
      if [ -n "$INSTALL_USER" ]; then
        echo "cc-db-entrypoint: old cluster (pg$OLD_VERSION) install user is '$INSTALL_USER'; running the pg$TARGET_VERSION upgrade as that user"
        export POSTGRES_USER="$INSTALL_USER"
      else
        echo "cc-db-entrypoint: WARNING could not detect old install user; letting pgautoupgrade use POSTGRES_USER=$POSTGRES_USER"
      fi
    fi
  fi
fi

exec /usr/local/bin/docker-entrypoint.sh "$@"