title: map AWS instances/volumes to snapshots with boto
body: <p>I'm writing a <strong>python</strong> script to check all my running instances for <strong>ebs</strong> snapshots...</p>
  
  <pre><code>rsv = self.botoEC2.get_all_instances()
  for r in rsv:
    ins = r.instances[0]
    blockDevice = self.getInstanceAttribute(ins,"blockDeviceMapping")
    print blockDevice
  
  def getInstanceAttribute(self,instance,attribute):
      return instance.get_attribute(attribute)
  </code></pre>
  
  <p>output:</p>
  
  <pre><code>{u'blockDeviceMapping': {u'/dev/sda1': &lt;boto.ec2.blockdevicemapping.BlockDeviceType object at 0x10d5faed0&gt;}}
  </code></pre>
  
  <p>I am new to boto.  Am I on the right path?  </p>
  
  <p>Do I need to get the <code>blockDeviceMapping</code> first, then call the volume functions?</p>
  
  <p>How do I get the actual volume id, so i can check it for existing snapshots?</p>