start: support creation of user and database at launch

Refer #5

README.md

@@ -5,6 +5,7 @@
 - [Reporting Issues](#reporting-issues)
 - [Installation](#installation)
 - [Quick Start](#quick-start)
+- [Creating User and Database at Launch](creating-user-and-database-at-launch)
 - [Configuration](#configuration)
     - [Data Store](#data-store)
     - [Securing the server](#securing-the-server)
@@ -91,6 +92,41 @@ To test if the postgresql server is working properly, try connecting to the serv
 psql -U postgres -h $(docker inspect --format {{.NetworkSettings.IPAddress}} postgresql)
 ```
 
+# Creating User and Database at Launch
+
+The image allows you to create a user and database at launch time.
+
+To create a new user you should specify the `DB_USER` and `DB_PASS` variables. The following command will create a new user *dbuser* with the password *dbpass*.
+
+```bash
+docker run --name postgresql -d \
+  -e 'DB_USER=dbuser' -e 'DB_PASS=dbpass' \
+  sameersbn/postgresql:latest
+```
+
+**NOTE**
+- If the password is not specified the user will not be created
+- If the user user already exists no changes will be made
+
+Similarly, you can also create a new database by specifying the database name in the `DB_NAME` variable.
+
+```bash
+docker run --name postgresql -d \
+  -e 'DB_NAME=dbname' sameersbn/postgresql:latest
+```
+
+If the `DB_USER` and `DB_PASS` variables are also specified while creating the database, then the user is granted access to the database.
+
+For example,
+
+```bash
+docker run --name postgresql -d \
+  -e 'DB_USER=dbuser' -e 'DB_PASS=dbpass' -e 'DB_NAME=dbname' \
+  sameersbn/postgresql:latest
+```
+
+, will create a user *dbuser* with the password *dbpass*. It will also create a database named *dbname* and the *dbuser* user will have full access to the *dbname* database.
+
 # Configuration
 
 ## Data Store

start

@@ -6,6 +6,10 @@ PG_CONFDIR="/etc/postgresql/${PG_VERSION}/main"
 PG_BINDIR="/usr/lib/postgresql/${PG_VERSION}/bin"
 PG_DATADIR="/var/lib/postgresql/${PG_VERSION}/main"
 
+DB_NAME=${DB_NAME:-}
+DB_USER=${DB_USER:-}
+DB_PASS=${DB_PASS:-}
+
 # fix permissions and ownership of /var/lib/postgresql
 mkdir -p -m 0700 /var/lib/postgresql
 chown -R postgres:postgres /var/lib/postgresql
@@ -49,6 +53,35 @@ if [ -f /var/lib/postgresql/pwfile ]; then
   echo "|------------------------------------------------------------------|"
 fi
 
+if [ -n "${DB_USER}" ]; then
+  if [ -z "${DB_PASS}" ]; then
+    echo ""
+    echo "WARNING: "
+    echo "  Please specify a password for \"${DB_USER}\". Skipping user creation..."
+    echo ""
+    DB_USER=
+  else
+    echo "Creating user \"${DB_USER}\"..."
+    echo "CREATE ROLE ${DB_USER} with LOGIN CREATEDB PASSWORD '${DB_PASS}';" |
+      sudo -u postgres -H ${PG_BINDIR}/postgres --single \
+        -D ${PG_DATADIR} -c config_file=${PG_CONFDIR}/postgresql.conf >/dev/null 2>&1
+  fi
+fi
+
+if [ -n "${DB_NAME}" ]; then
+  echo "Creating database \"${DB_NAME}\"..."
+  echo "CREATE DATABASE ${DB_NAME};" | \
+    sudo -u postgres -H ${PG_BINDIR}/postgres --single \
+      -D ${PG_DATADIR} -c config_file=${PG_CONFDIR}/postgresql.conf >/dev/null 2>&1
+
+  if [ -n "${DB_USER}" ]; then
+    echo "Granting access to database \"${DB_NAME}\" for user \"${DB_USER}\"..."
+    echo "GRANT ALL PRIVILEGES ON DATABASE ${DB_NAME} to ${DB_USER};" |
+      sudo -u postgres -H ${PG_BINDIR}/postgres --single \
+        -D ${PG_DATADIR} -c config_file=${PG_CONFDIR}/postgresql.conf >/dev/null 2>&1
+  fi
+fi
+
 echo "Starting PostgreSQL server..."
 exec sudo -u postgres -H ${PG_BINDIR}/postgres \
   -D ${PG_DATADIR} -c config_file=${PG_CONFDIR}/postgresql.conf