Add support for extensions loading and creation.

Using POSTGRESQL_LIBRARIES and POSTGRESQL_EXTENSIONS allow
users to enable extensions (some bundled in the container) without
having to do anything but adding 2 variables.

src/root/usr/bin/run-postgresql

@@ -47,6 +47,7 @@ if $PG_INITIALIZED ; then
     create_users
 fi
 
+create_extensions
 process_extending_files \
     "${APP_DATA}/src/postgresql-start" \
     "${CONTAINER_SCRIPTS_PATH}/start"

src/root/usr/share/container-scripts/postgresql/README.md

@@ -102,6 +102,15 @@ The following environment variables influence the PostgreSQL configuration file.
        Set to an estimate of how much memory is available for disk caching by the operating system and within the database itself
 
 
+The following environment variables deal with extensions. They are all optional, and if not set, no extensions will be enabled.
+
+**`POSTGRESQL_LIBRARIES`**
+       A comma-separated list of libraries that Postgres will preload using shared_preload_libraries.
+
+**`POSTGRESQL_EXTENSIONS`**
+       A space-separated list of extensions to create when the server start. Once created, the extensions will stay even if the variable is cleared.
+
+
 You can also set the following mount points by passing the `-v /host/dir:/container/dir:Z` flag to Docker.
 
 **`/var/lib/pgsql/data`**  

src/root/usr/share/container-scripts/postgresql/common.sh

@@ -143,6 +143,13 @@ function should_hack_data_sync_retry() {
   return 1
 }
 
+function generate_postgresql_libraries_config() {
+  if [ -v POSTGRESQL_LIBRARIES ]; then
+    echo "shared_preload_libraries='${POSTGRESQL_LIBRARIES}'" >> "${POSTGRESQL_CONFIG_FILE}"
+  fi
+}
+
+
 # New config is generated every time a container is created. It only contains
 # additional custom settings and is included from $PGDATA/postgresql.conf.
 function generate_postgresql_config() {
@@ -160,6 +167,7 @@ function generate_postgresql_config() {
     echo "data_sync_retry = on" >>"${POSTGRESQL_CONFIG_FILE}"
   fi
 
+  generate_postgresql_libraries_config
   (
   shopt -s nullglob
   for conf in "${APP_DATA}"/src/postgresql-cfg/*.conf; do
@@ -478,3 +486,12 @@ process_extending_files()
     done
   done <<<"$(get_matched_files '*.sh' "$@" | sort -u)"
 }
+
+create_extensions()
+{
+  if [ -v POSTGRESQL_EXTENSIONS ]; then
+    for EXT in $POSTGRESQL_EXTENSIONS; do
+      psql -c "CREATE EXTENSION IF NOT EXISTS ${EXT};"
+    done;
+  fi
+}

test/run_test

@@ -867,6 +867,8 @@ run_pgaudit_test()
 
   DOCKER_ARGS="
 -e POSTGRESQL_ADMIN_PASSWORD=password
+-e POSTGRESQL_EXTENSIONS=pgaudit
+-e POSTGRESQL_LIBRARIES=pgaudit
 -v ${config_dir}:/opt/app-root/src:Z
 -v ${data_dir}:/var/lib/pgsql/data:Z
   " create_container "$name"
@@ -878,7 +880,6 @@ run_pgaudit_test()
   # Deliberately moving heredoc into the container, otherwise it does not work
   # in podman 1.6.x due to https://bugzilla.redhat.com/show_bug.cgi?id=1827324
   docker exec -i $(get_cid "$name") bash -c "psql <<EOSQL
-CREATE EXTENSION pgaudit;
 SET pgaudit.log = 'read, ddl';
 CREATE DATABASE pgaudittest;
 EOSQL"