PostgreSQL settings.

9.2/Dockerfile

@@ -24,13 +24,13 @@ EXPOSE 5432
 # to make sure of that.
 RUN rpmkeys --import file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 && \
     yum -y --setopt=tsflags=nodocs install https://www.softwarecollections.org/en/scls/rhscl/postgresql92/epel-7-x86_64/download/rhscl-postgresql92-epel-7-x86_64.noarch.rpm && \
-    yum -y --setopt=tsflags=nodocs install postgresql92 && \
+    yum -y --setopt=tsflags=nodocs install gettext postgresql92 && \
     yum clean all && \
     mkdir -p /var/lib/pgsql/data && chown postgres.postgres /var/lib/pgsql/data && \
     test "$(id postgres)" = "uid=26(postgres) gid=26(postgres) groups=26(postgres)"
 
 COPY run-postgresql.sh /usr/local/bin/
-COPY contrib/.bashrc /var/lib/pgsql/
+COPY contrib /var/lib/pgsql/
 
 VOLUME ["/var/lib/pgsql/data"]
 

9.2/Dockerfile.rhel7

@@ -22,7 +22,7 @@ EXPOSE 5432
 # This image must forever use UID 26 for postgres user so our volumes are
 # safe in the future. This should *never* change, the last test is there
 # to make sure of that.
-RUN yum install -y yum-utils && \
+RUN yum install -y yum-utils gettext && \
     yum-config-manager --enable rhel-server-rhscl-7-rpms && \
     yum-config-manager --enable rhel-7-server-optional-rpms && \
     yum install -y --setopt=tsflags=nodocs postgresql92 && \
@@ -31,7 +31,7 @@ RUN yum install -y yum-utils && \
     test "$(id postgres)" = "uid=26(postgres) gid=26(postgres) groups=26(postgres)"
 
 COPY run-postgresql.sh /usr/local/bin/
-COPY contrib/.bashrc /var/lib/pgsql/
+COPY contrib /var/lib/pgsql/
 
 VOLUME ["/var/lib/pgsql/data"]
 

9.2/contrib/openshift-custom-postgresql.conf.template

@@ -0,0 +1,15 @@
+#
+# Custom OpenShift configuration.
+#
+# NOTE: This file is rewritten everytime the container is started!
+#       Changes to this file will be overrwritten.
+#
+
+# Listen on all interfaces.
+listen_addresses = '*'
+
+# Determines the maximum number of concurrent connections to the database server. Default: 100
+max_connections = ${POSTGRESQL_MAX_CONNECTIONS}
+
+# Sets the amount of memory the database server uses for shared memory buffers. Default: 32MB
+shared_buffers = ${POSTGRESQL_SHARED_BUFFERS}

9.2/run-postgresql.sh

@@ -6,7 +6,12 @@ source $HOME/.bashrc
 set -eu
 
 # Data dir
-export PGDATA=/var/lib/pgsql/data
+export PGDATA=$HOME/data
+POSTGRESQL_CONFIG_FILE=$HOME/openshift-custom-postgresql.conf
+
+# Configuration settings.
+export POSTGRESQL_MAX_CONNECTIONS=${POSTGRESQL_MAX_CONNECTIONS:-100}
+export POSTGRESQL_SHARED_BUFFERS=${POSTGRESQL_SHARED_BUFFERS:-32MB}
 
 # Be paranoid and stricter than we should be.
 psql_identifier_regex='^[a-zA-Z_][a-zA-Z0-9_]*$'
@@ -22,10 +27,17 @@ function usage() {
 	echo "  \$POSTGRESQL_DATABASE (regex: '$psql_identifier_regex')"
 	echo "Optional:"
 	echo "  \$POSTGRESQL_ADMIN_PASSWORD (regex: '$psql_password_regex')"
+	echo "Settings:"
+	echo "  \$POSTGRESQL_MAX_CONNECTIONS (default: 100)"
+	echo "  \$POSTGRESQL_SHARED_BUFFERS (default: 32MB)"
 	exit 1
 }
 
 function check_env_vars() {
+	if ! [[ -v POSTGRESQL_USER && -v POSTGRESQL_PASSWORD && -v POSTGRESQL_DATABASE ]]; then
+		usage
+	fi
+
 	[[ "$POSTGRESQL_USER"     =~ $psql_identifier_regex ]] || usage
 	[ ${#POSTGRESQL_USER} -le 63 ] || usage "PostgreSQL username too long (maximum 63 characters)"
 	[[ "$POSTGRESQL_PASSWORD" =~ $psql_password_regex   ]] || usage
@@ -44,8 +56,7 @@ function unset_env_vars() {
 	unset POSTGRESQL_ADMIN_PASSWORD
 }
 
-if [ "$1" = "postgres" -a ! -f "$PGDATA/postgresql.conf" ]; then
-
+function initialize_database() {
 	check_env_vars
 
 	# Initialize the database cluster with utf8 support enabled by default.
@@ -56,12 +67,8 @@ if [ "$1" = "postgres" -a ! -f "$PGDATA/postgresql.conf" ]; then
 	# PostgreSQL configuration.
 	cat >> "$PGDATA/postgresql.conf" <<-EOF
 
-		#
-		# Custom OpenShift configuration starting at this point.
-		#
-
-		# Listen on all interfaces.
-		listen_addresses = '*'
+		# Custom OpenShift configuration:
+		include '../openshift-custom-postgresql.conf'
 	EOF
 
 	# Access control configuration.
@@ -85,6 +92,14 @@ if [ "$1" = "postgres" -a ! -f "$PGDATA/postgresql.conf" ]; then
 	fi
 
 	pg_ctl stop
+}
+
+# New config is generated every time a container is created. It only contains
+# additional custom settings and is included from $PGDATA/postgresql.conf.
+envsubst < ${POSTGRESQL_CONFIG_FILE}.template > ${POSTGRESQL_CONFIG_FILE}
+
+if [ "$1" = "postgres" -a ! -f "$PGDATA/postgresql.conf" ]; then
+	initialize_database
 fi
 
 unset_env_vars

9.2/test/run

@@ -138,6 +138,23 @@ function run_container_creation_tests() {
 	echo "  Success!"
 }
 
+function test_config_option() {
+	local env_var=$1 ; shift
+	local setting=$1 ; shift
+	local value=$1 ; shift
+
+	# If $value is a string, it needs to be in simple quotes ''.
+	# If nothing is found, grep returns 1 and test fails.
+	docker run --rm -e $env_var=${value//\'/} $IMAGE_NAME cat /var/lib/pgsql/openshift-custom-postgresql.conf | grep -q "$setting = $value"
+}
+
+function run_configuration_tests() {
+	echo "  Testing image configuration settings"
+	test_config_option POSTGRESQL_MAX_CONNECTIONS max_connections 42
+	test_config_option POSTGRESQL_SHARED_BUFFERS shared_buffers 64MB
+	echo "  Success!"
+}
+
 function run_tests() {
 	local name=$1 ; shift
 	envs="-e POSTGRESQL_USER=$USER -e POSTGRESQL_PASSWORD=$PASS -e POSTGRESQL_DATABASE=db"
@@ -164,5 +181,6 @@ function run_tests() {
 # Tests.
 
 run_container_creation_tests
+run_configuration_tests
 USER=user PASS=pass run_tests no_admin
 USER=user1 PASS=pass1 ADMIN_PASS=r00t run_tests admin

README.md

@@ -34,6 +34,13 @@ The image recognizes following environment variables that you can set during ini
 |  `POSTGRESQL_DATABASE`       | Database name                                  |
 |  `POSTGRESQL_ADMIN_PASSWORD` | Password for the `postgres` admin account (optional)     |
 
+Following environment variables influence PostgreSQL configuration file. They are all optional.
+
+|    Variable name              |    Description                                                          |    Default
+| :---------------------------- | ----------------------------------------------------------------------- | -------------------------------
+|  `POSTGRESQL_MAX_CONNECTIONS` | The maximum number of client connections allowed                        |  100
+|  `POSTGRESQL_SHARED_BUFFERS`  | Sets how much memory is dedicated to PostgreSQL to use for caching data |  32M
+
 You can also set following mount points by passing `-v /host:/container` flag to docker.
 
 |  Volume mount point      | Description                           |