moar

Author: nir0s

install.py

@@ -1,13 +1,20 @@
+# Note, this contains some advanced info.
+
 import os
 import sys
 import subprocess
 
+# Import Cloudify's context object.
+# This provides several useful functions as well as allowing to pass
+# contextual information of an application.
 from cloudify import ctx
 
 
 IS_WIN = os.name == 'nt'
-# is this needed?
 IS_DARWIN = (sys.platform == 'darwin')
+
+# Get the port from the blueprint. We're running in the context of the
+# `http_web_server` node so we can read its `port` property.
 PORT = ctx.node.properties['port']
 
 
@@ -16,11 +23,15 @@ def run_server():
     if not IS_WIN:
         webserver_cmd.insert(0, 'nohup')
 
+    # The ctx object provides a built in logger.
     ctx.logger.info('Running WebServer locally on port: {0}'.format(PORT))
+    # emulating /dev/null
     dn = open(os.devnull, 'wb')
     process = subprocess.Popen(webserver_cmd, stdout=dn, stderr=dn)
 
-    if not IS_WIN:
+    # we need this for linux because on linux process.pid is not accurate.
+    # it provides somewhat arbitrary values.
+    if not IS_WIN and not IS_DARWIN:
         del webserver_cmd[0]
         get_pid = ['pidof', '-s']
         get_pid.extend(webserver_cmd)
@@ -31,6 +42,10 @@ def run_server():
 
 def set_pid(pid):
     ctx.logger.info('Setting `pid` runtime property: {0}'.format(pid))
+    # We can set runtime information in our context object which
+    # can later be read somewhere in the context of the instance.
+    # For instance, we want to save the `pid` here so that when we
+    # run `uninstall.py`, we can destroy the process.
     ctx.instance.runtime_properties['pid'] = pid
 
 

uninstall.py

@@ -3,6 +3,8 @@
 
 from cloudify import ctx
 
+# Here, we read the `pid` runtime property which we previously
+# saved when running `install.py`
 pid = ctx.instance.runtime_properties['pid']
 ctx.logger.info('Running process PID: {0}'.format(pid))
 try: