Google App Engine rollback

Unable to update app: Error posting to URL: https://appengine.google.com/api/appversion/create?app_id=xxxxx&version=1&
409 Conflict
Another transaction by user xxxxxx is already in progress for app: 
xxxxx, version: 1. That user can undo the transaction with "appcfg rollback".

If you get this error which is usually due to a previously interrupted deployment process

Navigate to your app engine sdk folder and then the bin folder.
Execute the command appcfg.sh rollback "Your application Path/war/WEB-INF"
You will need to supply your google email and password and this is the tricky part. If your login information is rejected, you need to go to your google account security settings and "enable for less secure apps", and try again.

Error occurred during initialization of VM Could not reserve enough space

I got this error when I was trying to build a Gradle project

!ENTRY org.springsource.ide.eclipse.gradle.core 4 0 2014-09-16 18:26:42.625
!MESSAGE Unable to start the daemon process.
This problem might be caused by incorrect configuration of the daemon.
For example, an unrecognized jvm option is used.
Please refer to the user guide chapter on the daemon at http://gradle.org/docs/1.11/userguide/gradle_daemon.html
Please read below process output to find out more:
-----------------------
Error occurred during initialization of VM
Could not reserve enough space for 1048576KB object heap
Java HotSpot(TM) Client VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0


Solution:

In Eclipse Change the Gradle's JVM setting in Window/Preferences/Gradle/Arguments... on JVM Arguments section select "Use:" and write something like: -Xms128m -Xmx256m.

.gitignore not working

I had run into a problem where Git seems to not ignore files specified in .gitignore file.

It seems that files that git knows about, it can't ignore, e.g. files that are created at the project creation.

To solve this problems, run the following commands in order

git rm -r --cached .

git add .

git commit -m ".gitignore is now working"

Install a high speed USB host controller

When connecting a USB 2.0 device, Windows displays the following message:

The thing is
I DO HAVE A USB 2.0 HOST CONTROLLER
and I used to enjoy high speed using my USB ports, until I did some hard disk resizing, which I believe have nothing to do with USB ports.

Anyway, to solve this:

• Open the device manager. In Windows 7, right click on My computer -> Manage.
• In the Device Manager, double-click on the "USB Root Hub", then uncheck "Allow the computer to turn off this device to save power" 

It gave me a better speed, but not quite as the one I used to have.

If I find a better solution, I will to update this.

error "No module named jinja2"

Building a google app on eclipse in python, I got this error.

First jinga2 comes bundled with Google App Engine for Python, so there's no need to go through the painful process of installing it on your machine.

To reference it from your project, add the following under the libraries section in your .yaml file

- name: jinja2
  version: latest

and import jinja2 in your code

IOError: [Errno 13] file not accessible:

Trying to build a google app on eclipse using python, I got this error while trying to render an html file.

To solve it, put the folder that contains the html in the same folder that contains the yaml file.