debian: add postinst script to create user

closes #25

debian/control

@@ -42,6 +42,7 @@ Depends:
  ${shlibs:Depends},
  ${misc:Depends},
  ${python3:Depends},
+ adduser,
  python3-gwdatafind-server (= ${binary:Version}),
  python3-gunicorn,
 Description: Server app for the GWDataFind service

debian/gwdatafind-server.postinst

+#!/bin/bash
+# postinst script for gwdatafind-server
+
+set -e
+
+. /usr/share/debconf/confmodule
+
+db_version 2.0
+
+gwdatafind_server_user="gwdatafind"
+gwdatafind_server_gecos="Dedicated gwdatafind service account"
+gwdatafind_server_home="/var/lib/${gwdatafind_server_user}"
+
+case "$1" in
+  configure)
+    # -- add the gwdatafind_server user (and group)
+
+    if [ ! "$(getent passwd '${gwdatafind_server_user}')" ]; then
+      adduser \
+        --system \
+        --group \
+        --gecos "${gwdatafind_server_gecos}" \
+        --home "${gwdatafind_server_home}" \
+        --disabled-password \
+        --disabled-login \
+        --quiet \
+        ${gwdatafind_server_user} 2>/dev/null;
+    else
+      echo "I: Assuming that user "${gwdatafind_server_user}" already exists..."
+    fi
+
+    # -- configure systemd
+
+    # tell systemd to create tmpfiles, but do no harm if not available
+    systemd-tmpfiles --create --exclude-prefix=/dev || true
+
+    # reload system-daemon as service unit may have changed
+    systemctl daemon-reload >/dev/null || true
+  ;;
+
+  abort-upgrade|abort-remove|abort-deconfigure)
+  ;;
+
+  *)
+    echo "postinst called with unknown argument \`$1'" >&2
+    exit 1
+  ;;
+esac
+
+db_stop
+
+# dh_installdeb will replace this with shell code automatically
+# generated by other debhelper scripts.
+
+#DEBHELPER#
+
+exit 0