Added gsutil to depot tools

third_party/gsutil/boto/docs/source/cloudwatch_tut.rst

+.. cloudwatch_tut:
+
+==========
+CloudWatch
+==========
+
+First, make sure you have something to monitor.  You can either create a
+LoadBalancer or enable monitoring on an existing EC2 instance.  To enable
+monitoring, you can either call the monitor_instance method on the
+EC2Connection object or call the monitor method on the Instance object.
+
+It takes a while for the monitoring data to start accumulating but once
+it does, you can do this::
+
+    >>> import boto
+    >>> c = boto.connect_cloudwatch()
+    >>> metrics = c.list_metrics()
+    >>> metrics
+    [Metric:NetworkIn,
+     Metric:NetworkOut,
+     Metric:NetworkOut(InstanceType,m1.small),
+     Metric:NetworkIn(InstanceId,i-e573e68c),
+     Metric:CPUUtilization(InstanceId,i-e573e68c),
+     Metric:DiskWriteBytes(InstanceType,m1.small),
+     Metric:DiskWriteBytes(ImageId,ami-a1ffb63),
+     Metric:NetworkOut(ImageId,ami-a1ffb63),
+     Metric:DiskWriteOps(InstanceType,m1.small),
+     Metric:DiskReadBytes(InstanceType,m1.small),
+     Metric:DiskReadOps(ImageId,ami-a1ffb63),
+     Metric:CPUUtilization(InstanceType,m1.small),
+     Metric:NetworkIn(ImageId,ami-a1ffb63),
+     Metric:DiskReadOps(InstanceType,m1.small),
+     Metric:DiskReadBytes,
+     Metric:CPUUtilization,
+     Metric:DiskWriteBytes(InstanceId,i-e573e68c),
+     Metric:DiskWriteOps(InstanceId,i-e573e68c),
+     Metric:DiskWriteOps,
+     Metric:DiskReadOps,
+     Metric:CPUUtilization(ImageId,ami-a1ffb63),
+     Metric:DiskReadOps(InstanceId,i-e573e68c),
+     Metric:NetworkOut(InstanceId,i-e573e68c),
+     Metric:DiskReadBytes(ImageId,ami-a1ffb63),
+     Metric:DiskReadBytes(InstanceId,i-e573e68c),
+     Metric:DiskWriteBytes,
+     Metric:NetworkIn(InstanceType,m1.small),
+     Metric:DiskWriteOps(ImageId,ami-a1ffb63)]
+
+The list_metrics call will return a list of all of the available metrics
+that you can query against.  Each entry in the list is a Metric object.
+As you can see from the list above, some of the metrics are generic metrics
+and some have Dimensions associated with them (e.g. InstanceType=m1.small).
+The Dimension can be used to refine your query.  So, for example, I could
+query the metric Metric:CPUUtilization which would create the desired statistic
+by aggregating cpu utilization data across all sources of information available
+or I could refine that by querying the metric
+Metric:CPUUtilization(InstanceId,i-e573e68c) which would use only the data
+associated with the instance identified by the instance ID i-e573e68c.
+
+Because for this example, I'm only monitoring a single instance, the set
+of metrics available to me are fairly limited.  If I was monitoring many
+instances, using many different instance types and AMI's and also several
+load balancers, the list of available metrics would grow considerably.
+
+Once you have the list of available metrics, you can actually
+query the CloudWatch system for that metric.  Let's choose the CPU utilization
+metric for our instance.::
+
+    >>> m = metrics[5]
+    >>> m
+    Metric:CPUUtilization(InstanceId,i-e573e68c)
+
+The Metric object has a query method that lets us actually perform
+the query against the collected data in CloudWatch.  To call that,
+we need a start time and end time to control the time span of data
+that we are interested in.  For this example, let's say we want the
+data for the previous hour::
+
+    >>> import datetime
+    >>> end = datetime.datetime.now()
+    >>> start = end - datetime.timedelta(hours=1)
+
+We also need to supply the Statistic that we want reported and
+the Units to use for the results.  The Statistic can be one of these
+values::
+
+    ['Minimum', 'Maximum', 'Sum', 'Average', 'SampleCount']
+
+And Units must be one of the following::
+
+    ['Seconds', 'Percent', 'Bytes', 'Bits', 'Count',
+    'Bytes/Second', 'Bits/Second', 'Count/Second']
+
+The query method also takes an optional parameter, period.  This
+parameter controls the granularity (in seconds) of the data returned.
+The smallest period is 60 seconds and the value must be a multiple
+of 60 seconds.  So, let's ask for the average as a percent::
+
+    >>> datapoints = m.query(start, end, 'Average', 'Percent')
+    >>> len(datapoints)
+    60
+
+Our period was 60 seconds and our duration was one hour so
+we should get 60 data points back and we can see that we did.
+Each element in the datapoints list is a DataPoint object
+which is a simple subclass of a Python dict object.  Each
+Datapoint object contains all of the information available
+about that particular data point.::
+
+    >>> d = datapoints[0]
+    >>> d
+    {u'Average': 0.0,
+     u'SampleCount': 1.0,
+     u'Timestamp': u'2009-05-21T19:55:00Z',
+     u'Unit': u'Percent'}
+
+My server obviously isn't very busy right now!