Docker: Don't increase number of inotfiy watches

scripts/create_plugin

@@ -23,62 +23,65 @@ OUTFILE_FINAL=/tmp/plugin_file_list_final
 DPKG_STATUS=/var/lib/dpkg/status
 INITIAL_DPKG_STATUS=/tmp/initial_status
 FINAL_DPKG_STATUS=/tmp/dpkg_status
+PID_FILE=/tmp/plugin_create_pid
 
 function start {
-echo "200000" | sudo tee /proc/sys/fs/inotify/max_user_watches
-
-sudo rm -fv $OUTFILE
-rm -fv $OUTFILE_FINAL
-
-# TODO Also track deleted files
-# According to strace is looks like --exclude is not preventing building the
-# "watches" for the excluded directories but filters all file system events on them.
-if [ $(which inotifywait) ]; then
-  sudo rm -f $OUTFILE
-  nohup sudo inotifywait -m -r --format '%w%f' -e create -e attrib -e moved_from -e moved_to -e modify --exclude $EXCLUDE -o $OUTFILE / > /tmp/plugin.log 2>&1 &
-else
-  echo 'inotifywait is missing.'
-  echo 'Please install the package inotify-tools'
-  exit
-fi
-
-PID=$!
-
-echo "PID of the process watch for file changes is: $PID"
-
-echo $PID > /tmp/plugin_create_pid
-
-# Inotifywait takes some time to build up the recursive file watching on
-# / - so we have to wait and verify that we only proceed after the prepations
-# are done.
-while ! grep -q 'Watches established.' /tmp/plugin.log; do
-  echo -ne 'Waiting for file watching to be established...\r'
-  sleep 0.2
-done
-
-cp $DPKG_STATUS $INITIAL_DPKG_STATUS
+  # Inside a Docker container '/proc' is read-only, so we are skipping this step.
+  if ! grep -q docker /proc/1/cgroup; then
+    echo "200000" | sudo tee /proc/sys/fs/inotify/max_user_watches
+  fi
+
+  sudo rm -fv $OUTFILE $OUTFILE_FINAL $INITIAL_DPKG_STATUS $FINAL_DPKG_STATUS $PID_FILE
+
+  # TODO Also track deleted files
+  # According to strace is looks like --exclude is not preventing building the
+  # "watches" for the excluded directories but filters all file system events on them.
+  if [ $(which inotifywait) ]; then
+    sudo rm -f $OUTFILE
+    nohup sudo inotifywait -m -r --format '%w%f' -e create -e attrib -e moved_from -e moved_to -e modify --exclude $EXCLUDE -o $OUTFILE / > /tmp/plugin.log 2>&1 &
+  else
+    echo 'inotifywait is missing.'
+    echo 'Please install the package inotify-tools'
+    exit
+  fi
+
+  PID=$!
+
+  echo "PID of the process watch for file changes is: $PID"
+
+  echo $PID > $PID_FILE
+
+  # Inotifywait takes some time to build up the recursive file watching on
+  # / - so we have to wait and verify that we only proceed after the prepations
+  # are done.
+  while ! grep -q 'Watches established.' /tmp/plugin.log; do
+    echo -ne 'Waiting for file watching to be established...\r'
+    sleep 0.2
+  done
+
+  cp $DPKG_STATUS $INITIAL_DPKG_STATUS
 }
 
 function finish {
-plugin_name=$1
+  plugin_name=$1
 
-sudo kill $(cat /tmp/plugin_create_pid)
+  sudo kill $(cat /tmp/plugin_create_pid)
 
-dpkg_status.py --old $INITIAL_DPKG_STATUS --new $DPKG_STATUS --diff > $FINAL_DPKG_STATUS
+  dpkg_status.py --old $INITIAL_DPKG_STATUS --new $DPKG_STATUS --diff > $FINAL_DPKG_STATUS
 
-# Test all collected files if they really exists and if so write them
-# to a final file list.
-# Finally add the dpkg_status file we create beforehand.
-while read path; do
-  if [ -f "$path" ]; then
-    echo $path
-    echo $path >> "$OUTFILE_FINAL"
-  fi
-done < <(sort -u $OUTFILE)
+  # Test all collected files if they really exists and if so write them
+  # to a final file list.
+  # Finally add the dpkg_status file we create beforehand.
+  while read path; do
+    if [ -f "$path" ]; then
+      echo $path
+      echo $path >> "$OUTFILE_FINAL"
+    fi
+  done < <(sort -u $OUTFILE)
 
-echo $FINAL_DPKG_STATUS >> $OUTFILE_FINAL
+  echo $FINAL_DPKG_STATUS >> $OUTFILE_FINAL
 
-tar -czvf $plugin_name.tar.gz -P -T $OUTFILE_FINAL
+  tar -czvf $plugin_name.tar.gz -P -T $OUTFILE_FINAL
 }
 
 function upload {