Added Docker setup for initial database import

This MR adds the import of an osm.pbf file into an empty database.

Related to https://git.gfz-potsdam.de/dynamicexposure/server-components/compositions/docker-openbuildingmap-import/-/merge_requests/2

\rfc @marius \approve @ds

files/start.sh

+#!/bin/bash
+
+# Copyright (C) 2021:
+#   Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+
+printf "\nWelcome to the OpenBuildingMap importer\n\n"
+
+main () {
+  printf "Connecting to PostgreSQL on '%s':\n" "${OBM_DATABASE_HOST}"
+
+  # Wait until database comes up and is available
+  until execute_database_command "SELECT datname FROM pg_database;"; do
+    printf "Database is unavailable - trying again in 10s\n"
+    sleep 10
+  done
+
+  # Initiate new or reuse existing database
+  if execute_database_command "\connect ${OBM_DATABASE_NAME}"; then
+    printf "Reuse existing database: %s\n" "${OBM_DATABASE_NAME}"
+  else
+    execute_database_command "CREATE DATABASE ${OBM_DATABASE_NAME};"
+    add_database_extensions
+    printf "Initiated new database: %s\n" "${OBM_DATABASE_NAME}"
+  fi
+
+  # Obtain mapping information for database schema
+  get_opentstreetmap_database_style
+
+  # Import OpenStreetMap data if database is empty
+  database_exists=$(psql --host="${OBM_DATABASE_HOST}" --username="${OBM_DATABASE_USER}" "${OBM_DATABASE_NAME}" --tuples-only --command="SELECT CASE WHEN EXISTS (SELECT FROM pg_tables WHERE schemaname = 'public' AND tablename = 'planet_osm_line' LIMIT 1) THEN 'true' ELSE 'false' end;")
+  if ${database_exists}; then
+    printf "Assuming already imported database: %s\n" "${OBM_DATABASE_NAME}"
+  else
+    import_openstreetmap_data
+    printf "OpenStreetMap data has been imported.\n"  
+  fi
+}
+
+execute_database_command () {
+  psql --host="${OBM_DATABASE_HOST}" --username="${OBM_DATABASE_USER}" --command="${1}"
+}
+
+execute_database_query () {
+  psql --host="${OBM_DATABASE_HOST}" --username="${OBM_DATABASE_USER}" "${OBM_DATABASE_NAME}" --command="${1}"
+}
+
+add_database_extensions () {
+  if psql -h "${OBM_DATABASE_HOST}" -U "${OBM_DATABASE_USER}" -c "\connect ${OBM_DATABASE_NAME}"; then
+    execute_database_query "CREATE EXTENSION postgis;"
+    printf " postgis extension added to %s database.\n" "${OBM_DATABASE_NAME}"
+    execute_database_query "CREATE EXTENSION hstore;"
+    printf " hstore extension added to %s database.\n" "${OBM_DATABASE_NAME}"
+    execute_database_query "CREATE EXTENSION btree_gin;"
+    printf " btree_gin extension added to %s database.\n" "${OBM_DATABASE_NAME}"
+    execute_database_query "CREATE EXTENSION btree_gist;"
+    printf " btree_gist extension added to %s database.\n" "${OBM_DATABASE_NAME}"
+  else 
+    printf "Error: Unable to connect to database: %s\n" "${OBM_DATABASE_NAME}"
+    exit 1
+  fi
+}
+
+# Prepare style file for osm2pgsql
+get_opentstreetmap_database_style () {
+  base_style="/usr/share/osm2pgsql/empty.style"
+  if [ ! -r "${base_style}" ]
+  then
+    printf "Cannot find the 'empty.style' file of osm2pgsql\n"
+    exit 1
+  fi
+  cat /usr/share/osm2pgsql/empty.style > /usr/share/osm2pgsql/the.style
+  cat "${OBM_IMPORT_STYLE}" >> /usr/share/osm2pgsql/the.style
+}
+
+import_openstreetmap_data () {
+  if [ -f "${OBM_IMPORT_FILE}" ]; then
+      printf " \nImporting OpenStreetMap data with "
+      osm2pgsql \
+        --host "${OBM_DATABASE_HOST}" --username "${OBM_DATABASE_USER}" --database "${OBM_DATABASE_NAME}" \
+        --verbose \
+        --create \
+        --slim \
+        --style "/usr/share/osm2pgsql/the.style" \
+        --multi-geometry \
+        --hstore \
+        --latlong \
+        --extra-attributes \
+        --hstore-add-index \
+        --cache-strategy dense \
+        "${OBM_IMPORT_FILE}"
+  else
+      printf "Error: No import file '%s' has been found.\Aborting.\n" "${OBM_IMPORT_FILE}"
+      exit 1
+  fi
+}
+
+main