Cluster updates + add new start/stop options

-More graceful shutdown of node cluster on 'npm stop' with better cleanup of resources on exit
-Added new stop_explorer.sh script which looks up the explorer port # via settings file and closes the application running on that port # instead of saving and killing the process by pid as it did before
-Added support for pm2 and forever using 'npm run start-pm2' and 'npm run start-forever' respectively
-pm2 is automatically installed when starting with 'npm run start-pm2' if it is not already installed
-forever is automatically installed when starting with 'npm run start-forever' if it is not already installed
-Updated existing npm commands in package.json by replacing hardcoded 'node' with '$(which node)'
-/path/to/nodejs changed to /path/to/node in the /settings.json.template, /lib/settings.js and /scripts/sync.js files
-README updates:
 -Added a new 'Start/Stop the Explorer' section
 -Added PM2 instructions to the 'Start/Stop the Explorer' section
 -Moved Start/Stop Explorer instructions to the 'Start/Stop the Explorer' section
 -Moved Forever instructions to the 'Start/Stop the Explorer' section
 -/path/to/nodejs changed to /path/to/node
 -Some additional small misc fixes

scripts/prestart.sh

@@ -6,6 +6,27 @@
 #  npm update
 #fi
 
+# Check if an argument was passed into this script
+if [ -n "${1}" ]; then
+  # Determine which argument was passed
+  case "${1}" in
+    "pm2")
+      # Check if pm2 is installed
+      if [ -z "$(which pm2)" ]; then
+        # Install pm2
+        npm install pm2@latest -g
+      fi
+    ;;
+    "forever")
+      # Check if forever is installed
+      if [ -z "$(which forever)" ]; then
+        # Install forever
+        npm install forever -g
+      fi
+    ;;
+  esac
+fi
+
 # Ensure that selected theme is properly installed
 sh ./scripts/sass_theme_reader.sh
 

scripts/stop_explorer.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+validate_port() {
+  if [ -z "$1" ] || ([ -n "$1" ] && ((echo $1 | egrep -q '^[0-9]+$' && ([ $1 -lt 1 ] || [ $1 -gt 65535 ])) || ! test "$1" -gt 0 2> /dev/null)); then
+    echo "err"
+  fi
+}
+
+# Check if the settings.json file exists
+if [ -f ./settings.json ]; then
+  # Read the webserver.port value from settings.json file
+  readonly SERVER_PORT="$(./node_modules/.bin/strip-json-comments settings.json | ./node_modules/.bin/json -q webserver.port)"
+  # Check if the webserver.port value is a valid port #
+  if [ -z "$(validate_port $SERVER_PORT)" ]; then
+    # Check if the server is currently running
+    if  [ -n "$(lsof -t -i:${SERVER_PORT} 2> /dev/null)" ]; then
+      # Send a SIGINT kill signal to the process that is currently using the explorer's server port
+      kill -2 $(lsof -t -i:${SERVER_PORT})
+      # Show shutdown msg
+      echo "Explorer shutting down... Please wait..."
+    else
+      # Webserver is not running
+      echo "Error: Cannot stop explorer because it is not currently running"
+    fi
+  else
+    # Invalid port number
+    echo "Error: webserver.port value not found in settings.json. webserver.port value is missing or file is not valid json."
+  fi
+else
+  # Missing settings file
+  echo "Error: Cannot find settings.json"
+fi

scripts/sync.js

@@ -12,7 +12,7 @@ var database = 'index';
 
 // displays usage and exits
 function usage() {
-  console.log('Usage: scripts/sync.sh /path/to/nodejs [mode]');
+  console.log('Usage: scripts/sync.sh /path/to/node [mode]');
   console.log('');
   console.log('Mode: (required)');
   console.log('update           Updates index from last sync to current block');