make the container easily configurable

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

@@ -61,6 +61,47 @@ or if it was already present, [`postgres`](http://www.postgresql.org/docs/9.2/st
 is executed and will run as PID 1. You can stop the detached container by running
 `docker stop postgresql_database`.
 
+Supplying custom configuration file
+--------------------
+
+You are able to supply your custom configuration file. PostgreSQL container
+image is using templating to fill in configuration file in container startup
+script. You are able to override the default template. With this approach you
+can even define your own variables which you can pass as envinronment variables
+to the container.
+
+The template is located within container image on path:
+
+    /usr/share/container-scripts/postgresql/openshift-custom-postgresql.conf.template
+
+You can copy it like this:
+
+    $ docker create --name=pg registry.access.redhat.com/rhscl/postgresql-95-rhel7:latest
+    $ docker cp pg:/usr/share/container-scripts/postgresql/openshift-custom-postgresql.conf.template .
+
+And then file `openshift-custom-postgresql.conf.template` will be present in
+your current working directory. At this point, you can start editing the
+template. For more information on the configuration file, please see [the
+upstream documentation for runtime
+configuration](https://www.postgresql.org/docs/9.5/static/runtime-config.html).
+
+Once you are done, you can run the PostgreSQL container with the custom configuration template:
+
+    $ docker run -v ${PWD}/openshift-custom-postgresql.conf.template:/usr/share/container-scripts/postgresql/openshift-custom-postgresql.conf.template:Z ...
+
+If you want to check the current runtime configuration and be sure that all the
+values were picked up, you can run this command which will output it:
+
+    $ docker exec postgresql-container bash -c 'psql --command "show all;"'
+
+There is a shorter version where you can just see a single value, in this case `work_mem`:
+
+    $ docker exec postgresql-container bash -c 'psql --command "show work_mem;"'
+     work_mem
+    ----------
+     128MB
+    (1 row)
+
 PostgreSQL auto-tuning
 --------------------
 

hack/run_test

@@ -15,7 +15,8 @@ run_general_tests
 run_change_password_test
 run_replication_test
 run_master_restart_test
-run_doc_test"
+run_doc_test
+run_config_change_test"
 
 test $# -eq 1 -a "${1-}" == --list && echo "$TEST_LIST" && exit 0
 test -n "${IMAGE_NAME-}" || false 'make sure $IMAGE_NAME is defined'
@@ -202,6 +203,14 @@ function test_config_option() {
   docker exec $(get_cid ${name}) grep -q "${setting} = ${value}" /var/lib/pgsql/openshift-custom-postgresql.conf
 }
 
+function test_runtime_config_value() {
+  local name=$1 ; shift
+  local setting=$1 ; shift
+  local value=$1 ; shift
+
+  docker exec $(get_cid ${name}) bash -c "psql --command \"show ${setting};\"" | grep "${value}"
+}
+
 function run_configuration_tests() {
   local name=$1 ; shift
   echo "  Testing image configuration settings"
@@ -523,6 +532,51 @@ run_doc_test() {
   echo
 }
 
+function run_config_change_test() {
+  local tmpdir=$(mktemp -d)
+  local template_basename=openshift-custom-postgresql.conf.template
+  local template_local_tmp_path=${tmpdir}/${template_basename}
+  local template_container_dir=/usr/share/container-scripts/postgresql/
+  local template_container_path=${template_container_dir}/${template_basename}
+  local work_mem="128MB"
+  echo "  Testing changing configuration file"
+
+  docker run --rm ${IMAGE_NAME} \
+    /bin/bash -c \
+    "cat ${template_container_path}" >${template_local_tmp_path}
+
+  printf "\nwork_mem = \${POSTGRESQL_WORK_MEM}\n" >>${template_local_tmp_path}
+  cat ${template_local_tmp_path}
+
+  local name="config_test"
+  local database='db'
+  local user='user'
+  local password='password'
+  local admin_password='adminPassword'
+  local volume_options="-v ${template_local_tmp_path}:${template_container_path}:Z"
+
+  DOCKER_ARGS="
+-e POSTGRESQL_DATABASE=${database}
+-e POSTGRESQL_USER=${user}
+-e POSTGRESQL_PASSWORD=${password}
+-e POSTGRESQL_WORK_MEM=${work_mem}
+$volume_options
+" create_container ${name}
+
+  # need to set these because `postgresql_cmd` relies on global variables
+  PGUSER=${user}
+  PASS=${password}
+
+  # need this to wait for the container to start up
+  CONTAINER_IP=$(get_container_ip ${name})
+  test_connection ${name}
+
+  test_runtime_config_value ${name} work_mem ${work_mem}
+
+  echo "  Success!"
+  echo
+}
+
 function run_general_tests() {
   PGUSER=user PASS=pass POSTGRESQL_MAX_CONNECTIONS=42 POSTGRESQL_MAX_PREPARED_TRANSACTIONS=42 POSTGRESQL_SHARED_BUFFERS=64MB run_tests no_admin
   PGUSER=user1 PASS=pass1 ADMIN_PASS=r00t run_tests admin