mount usbdrive also in telegraf container as readonly

Author: janvda

telegraf/Dockerfile

@@ -1,2 +1,8 @@
 FROM arm32v7/telegraf:latest
 COPY telegraf.conf /etc/telegraf/telegraf.conf
+
+RUN echo "LABEL=influxdb /mnt/usbdrive ext4 ro,relatime,discard,data=ordered 0 2" >> /etc/fstab
+
+# The script "my_entrypoint.sh" is an extension of the existing script with extra instructions to mount the usb memory stick.
+COPY my_entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh

telegraf/my_entrypoint.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+# JVA 2018-11-15 I have added following instructions to mount usbdrive and create subfolder influxdb
+# this is added to that we can also monitor the usbdrive.
+mkdir -p /mnt/usbdrive
+mount /mnt/usbdrive
+
+# here below copy paste of original entrypoint.sh. see : 
+# https://github.com/influxdata/influxdata-docker/blob/e90ed7bbdcd69305c615fe9be7903ef2e93ad978/telegraf/1.8/entrypoint.sh
+set -e
+
+if [ "${1:0:1}" = '-' ]; then
+    set -- telegraf "$@"
+fi
+
+exec "$@"