12 CloudWatch (Monitoring)
Among the Amazon Web Services, the
CloudWatch API is the most quirky, least documented, and provides the fewest
specific examples of making requests.
As a result, there are more likely to be mistakes or problems in this
module. Your feedback or contributions to improve it are welcome.
Meanwhle, I’ve tried to focus mostly on put-metric-data, less on the
other metrics procedures, and least of all on alarms and alarm history. (This is
in line with the overall priority of this library, which is to support
applications not “infrastucture.”)
Set the endpoint for the service. Defaults to
(endpoint "monitoring.us-east-1.amazonaws.com" #t).
12.1 Contracts
| unit/c | : | | (or/c 'None | | 'Percent | | 'Count | | 'Seconds 'Microseconds 'Milliseconds | | 'Bytes 'Kilobytes 'Megabytes 'Gigabytes 'Terabytes | | 'Bits 'Kilobits 'Megabits 'Gigabits 'Terabits | | 'Count/Second | | 'Bytes/Second 'Kilobytes/Second 'Megabytes/Second | | 'Gigabytes/Second 'Terabytes/Second | | 'Bits/Second 'Kilobits/Second 'Megabits/Second | | 'Gigabits/Second 'Terabits/Second) |
|
|
A contract for the Units that CloudWatch accepts.
A contract for the period argument to get-metric-statistcs
and describe-alarms-for-metric. CloudWatch requires the Period to
be a non-zero multiple of 60 seconds.
statistic/c : (or/c 'Sum 'Average 'Maximum 'Minimum 'SampleCount)
|
A contract for the Statistic values that CloudWatch knows about.
12.2 Putting metric data and getting statistics
This struct is accepted by put-metric-data and returned by
get-metric-statistics.
The timestamp member is an exact-integer?, like
current-seconds, but all CloudWatch timestamps are UTC not local
time.
Put metric data to CloudWatch.
The value member must not be #f.
The min, max, sum, and sample-count members
may be #f if you are putting individual values and will let CloudWatch
do the aggregation, or, they may be non-#f if you are providing
CloudWatch data you have already aggregated.
| (get-metric-statistics | | #:metric-name metric-name | | | | | #:namespace namespace | | | | | #:statistics statistics | | | | | #:unit unit | | | | | #:start-time start-time | | | | | #:end-time end-time | | | | [ | #:period period | | | | | #:dimensions dimensions]) | |
|
| → (listof datum?) |
| metric-name : string? |
| namespace : string? |
| statistics : (listof statistic/c) |
| unit : unit/c |
| start-time : exact-integer? |
| end-time : exact-integer? |
| period : period/c = 60 |
| dimensions : dimensions/c = '() |
Return statistics for a given metric
metric-name in
namespace. The statistics are returned as a list of
datum structs.
The value member of datum will always be #f
because CloudWatch only returns aggregated data. Even if you put individual
values using put-metric-data, it will return only the aggregated
statistics.
Whether the min, max, sum, and sample-count
members of datum are #f, depends on whether you asked
those statistics to be returned by specifying them in statistics. For
example if statistics includes the symbol 'Sum, then the
sum member will be non-#f, otherwise it will be #f.
12.3 Listing metrics
| (struct | | metric (name namespace dimensions) | | | | #:extra-constructor-name make-metric) |
|
| name : string? |
| namespace : string? |
| dimensions : dimensions/c |
Return a list of
metric? meeting the criteria.
12.4 Alarms
| (struct | | alarm | ( | name | | | | | | description | | | | | | arn | | | | | | configuration-updated-timestamp | | | | | | metric-name | | | | | | namespace | | | | | | threshold | | | | | | comparison-operator | | | | | | alarm-actions | | | | | | ok-actions | | | | | | insufficient-data-actions | | | | | | state-value | | | | | | state-reason | | | | | | state-reason-data | | | | | | state-updated-timestamp | | | | | | period | | | | | | actions-enabled | | | | | | evaluation-periods | | | | | | statistic | | | | | | dimensions) | | | | #:extra-constructor-name make-alarm) |
|
| name : string? |
| description : string? |
| arn : string? |
| configuration-updated-timestamp : exact-integer? |
| metric-name : string? |
| namespace : string? |
| threshold : number? |
| comparison-operator : string? |
| alarm-actions : xexpr? |
| ok-actions : xexpr? |
| insufficient-data-actions : xexpr? |
| state-value : string? |
| state-reason : string? |
| state-reason-data : string? |
| state-updated-timestamp : exact-integer? |
| period : period/c |
| actions-enabled : boolean? |
| evaluation-periods : exact-nonnegative-integer |
| statistic : string? |
| dimensions : dimensions/c |
The configuration-updated-timestamp and
state-updated-timestamp members are exact-integer? as with
current-seconds, but remember the CloudWatch times are UTC not local
time.
| (describe-alarms | [ | #:alarm-name-prefix alarm-name-prefix | | | | | #:alarm-names alarm-names | | | | | #:state-value state-value]) | |
|
| → (listof metric-alarm?) |
| alarm-name-prefix : (or/c #f string?) = #f |
| alarm-names : (listof string?) = '() |
| state-value : (or/c #f 'OK 'ALARM 'INSUFFICIENT_DATA) = #f |
Return the alarms meeting the criteria.
| (describe-alarms-for-metric | | #:metric-name metric-name | | | | | #:namespace namespace | | | | [ | #:statistic statistic | | | | | #:unit unit | | | | | #:period period | | | | | #:dimensions dimensions]) | |
|
| → (listof metric-alarm?) |
| metric-name : string? |
| namespace : string? |
| statistic : (or/c #f statistic/c) = #f |
| unit : (or/c #f unit/c) = #f |
| period : (or/c #f period/c) = #f |
| dimensions : dimensions/c = '() |
Return the alarms meeting the criteria.
The data is JSON, which you will get as an xexpr? and need to
parse yourself.
The timestamp member is an exact-integer?, like
current-seconds, but all CloudWatch timestamps are UTC not local
time.
Return the history for alarms meeting the criteria.