* Change check for root directory during rollback
`rollback_tool` tries to infer the root of the nomulus tree by checking for a
directory named "nomulus". This is potentially problematic (and, indeed, was
for me) since there is no guarantee what that directory will be named.
There are a number of features that characterize the root directory. Check
for the presence of the `rollback_tool` wrapper script, as this is both at
root level and tightly coupled to the python code, so hopefully we won't
move it without testing that the script still works.
* Script to rolling-start Nomulus
Add a script to restart Nomulus non-disruptively. This can be used after
a configuration change to external resources (e.g., Cloud SQL
credential) to make Nomulus pick up the latest config.
Also added proper support to paging based List api methods, replacing the
current hack that forces the server to return everything in one response.
The List method for instances has a lower limit on page size than others
which is not sufficient for our project.
* An automated rollback tool for Nomulus
A tool that directs traffic between deployed versions. It handles the
conversion between Nomulus tags and AppEngine versions, executes schema
compatibility tests, ensures that steps are executed in the correct order,
and updates deployment records appropriately.
