conf.sh

#!/bin/bash
set -Eeuo pipefail

# The inner sed finds the line number of the last match for the the regex ^\s*shared_preload_libraries\s*=
# The outer sed, operating on that line alone, extracts the text between single quotes after the equals sign
PREVIOUS_PRELOAD_LIBRARIES=$(sed -nE "$(sed -n '/^\s*shared_preload_libraries\s*=/ =' ${PGDATA}/postgresql.conf | tail -n 1) s/^\s*shared_preload_libraries\s*=\s*'(.*?)'/\1/p" ${PGDATA}/postgresql.conf)

# https://github.com/soycacan/pldebugger says '$libdir/plugin_debugger' should be added to shared_preload_libraries.
# TO-DO: Test it this way to see if $libdir/ is actually necessary.
NEW_PRELOAD_LIBRARIES="pg_cron,pgaudit,pglogical,pglogical_ticker,pgmemcache,plugin_debugger,pg_similarity"  # ,pg_partman_bgw

cat >> ${PGDATA}/postgresql.conf << EOT
listen_addresses = '*'

shared_preload_libraries = '$(echo "$PREVIOUS_PRELOAD_LIBRARIES,$NEW_PRELOAD_LIBRARIES" | sed 's/^,//')'

# pg_cron
cron.database_name = '${PG_CRON_DB:-${POSTGRES_DB:-${POSTGRES_USER:-postgres}}}'

## pg_partman
#pg_partman_bgw.dbname = '${PG_PARTMAN_DB:-{POSTGRES_DB:-${POSTGRES_USER:-postgres}}}'

# pglogical
wal_level = 'logical'
max_worker_processes = 10   # one per database needed on provider node
                            # one per node needed on subscriber node
max_replication_slots = 10  # one per node needed on provider node
max_wal_senders = 10        # one per node needed on provider node
track_commit_timestamp = on # needed for last/first update wins conflict resolution
EOT