Fixes #112: Add dramble-node-monitor script and service for Blinkstic…

…k LED control.

roles/leds-blinkstick/files/dramble-node-monitor.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=Start the Pi Dramble Node monitor script.
+After=network.target
+
+[Service]
+Type=simple
+ExecStart=/usr/bin/dramble-node-monitor
+RemainAfterExit=true
+Restart=on-failure
+RestartSec=10s
+StandardOutput=journal
+StandardError=journal
+User=root
+Group=root
+
+[Install]
+WantedBy=multi-user.target

roles/leds-blinkstick/tasks/main.yml

@@ -21,12 +21,8 @@
 - name: Make Blinkstick control scripts available in the user's PATH.
   file:
     path: "/usr/bin/{{ item }}"
-    src: "/opt/gpio-leds/{{ item }}"
+    src: "/opt/blinkstick-leds/{{ item }}"
     state: link
   with_items: "{{ blinkstick_scripts }}"
 
-- name: Set up cron jobs for Blinkstick control.
-  cron: 'name="{{ item.name }}" special_time=reboot job="{{ item.job }}"'
-  with_items:
-    - name: "Set up blinkstick on startup"
-      job: "blinkstick --set-mode 3 && blinkstick --set-color {{ blinkstick_startup_color }}"
+- include_tasks: systemd-service.yml

roles/leds-blinkstick/tasks/systemd-service.yml

@@ -0,0 +1,21 @@
+---
+- name: Copy systemd unit file into place.
+  copy:
+    src: dramble-node-monitor.service
+    dest: /lib/systemd/system/dramble-node-monitor.service
+    mode: 0644
+  register: dramble_node_monitor_service
+
+- name: Reload systemd after adding service.
+  systemd:
+    state: stopped
+    daemon_reload: true
+    name: dramble-node-monitor
+  when: dramble_node_monitor_service.changed
+
+- name: Ensure dramble-node-monitor is running and enabled at boot.
+  service:
+    name: dramble-node-monitor
+    state: started
+    enabled: yes
+  when: deploy_target == 'pi'

roles/leds-blinkstick/templates/dramble-node-monitor.j2

@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+#
+# Kubernetes node monitoring script for the Raspberry Pi Dramble.
+
+from blinkstick import blinkstick
+import urllib2
+import time
+import sys, signal
+
+# Class to handle SIGINT/SIGTERM gracefully.
+class GracefulKiller:
+    kill_now = False
+    def __init__(self):
+        signal.signal(signal.SIGINT, self.exit_gracefully)
+        signal.signal(signal.SIGTERM, self.exit_gracefully)
+
+    def exit_gracefully(self,signum, frame):
+        self.kill_now = True
+
+# Define what to do when script is stopped externally.
+def signal_handler(signal, frame):
+    print "\nStopping node monitor."
+    nano.turn_off()
+    sys.exit(0)
+signal.signal(signal.SIGINT, signal_handler)
+
+# Function to check if Kubernetes node is ready or not.
+def check_node_status():
+    status = False;
+
+    try:
+        contents = urllib2.urlopen(url="http://localhost:10248/healthz", timeout=1).read()
+        if contents == 'ok':
+            status = True
+        else:
+            status = False
+
+    except urllib2.URLError:
+        status = False
+
+    return status
+
+# Function to update Blinkstick light to reflect current node status.
+def update_blinkenlights(nano):
+    current_color = nano.get_color()
+    if check_node_status():
+        if current_color != [0, 128, 0]:
+            nano.set_color(red=0, green=128, blue=0)
+            print 'Blinkstick changed to reflect Ready status.'
+    else:
+        if current_color != [128, 0, 0]:
+            nano.set_color(red=128, green=0, blue=0)
+            print 'Blinkstick changed to reflect NotReady status.'
+    time.sleep(5)
+
+# Main.
+nano = blinkstick.find_first()
+nano.set_mode(3)
+time.sleep(0.05)
+killer = GracefulKiller()
+while True:
+    try:
+        update_blinkenlights(nano)
+        if killer.kill_now:
+            break
+    except Exception, e:
+        nano.turn_off()
+
+        print >> sys.stderr, "Exiting for exception."
+        print >> sys.stderr, "Exception: %s" % str(e)
+        sys.exit(1)
+nano.turn_off()
+print "Exiting gracefully."

roles/leds-blinkstick/vars/main.yml

@@ -1,2 +1,3 @@
 ---
-blinkstick_scripts: []
+blinkstick_scripts:
+  - dramble-node-monitor