docs: updated README.md and a couple of examples

Signed-off-by: Mårten Svantesson <[email protected]>

README.md

@@ -79,6 +79,7 @@ aws_tag_select | Optional. A tag configuration to filter on, based on mapping fr
 tag_selections | Optional, under `aws_tag_select`. Specify a map from a tag key to a list of tag values to apply [tag filtering](https://docs.aws.amazon.com/resourcegroupstagging/latest/APIReference/API_GetResources.html#resourcegrouptagging-GetResources-request-TagFilters) on resources from which metrics will be gathered.
 resource_type_selection | Required, under `aws_tag_select`. Specify the [resource type](https://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html#genref-aws-service-namesspaces) to filter on. `resource_type_selection` should be comprised as `service:resource_type`, as per the [resource group tagging API](https://docs.aws.amazon.com/resourcegroupstagging/latest/APIReference/API_GetResources.html#resourcegrouptagging-GetResources-request-TagFilters). Where `resource_type` could be an empty string, like in S3 case: `resource_type_selection: "s3:"`.
 resource_id_dimension | Required, under `aws_tag_select`. For the current metric, specify which CloudWatch dimension maps to the ARN [resource ID](https://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html#arns-syntax).
+ arn_resource_id_regexp | If the Cloudwatch dimension specified in `resource_id_dimension` doesn't conform to the convention for resource ID an alternative regular expression to extract the resource ID from the ARN can be given here. The default is `(?:([^:/]+)|[^:/]+/([^:]+))$`. The first non empty match group will be used. 
 aws_statistics | Optional. A list of statistics to retrieve, values can include Sum, SampleCount, Minimum, Maximum, Average. Defaults to all statistics unless extended statistics are requested.
 aws_extended_statistics | Optional. A list of extended statistics to retrieve. Extended statistics currently include percentiles in the form `pN` or `pN.N`.
 delay_seconds | Optional. The newest data to request. Used to avoid collecting data that has not fully converged. Defaults to 600s. Can be set globally and per metric.

examples/ApplicationELB.yml

@@ -4,8 +4,20 @@ metrics:
   aws_metric_name: HealthyHostCount
   aws_dimensions:
   - LoadBalancer
-  aws_statistics:
-  - Sum
+  - TargetGroup
+  aws_statistics:
+  - Minimum
+  # In case you want to use some tag to select target group to monitor, or to have additional `info` metric
+  # with all target group tags as labels, use `aws_tag_select`.
+  # Since the TargetGroup dimension doesn't follow the convention for how to extract resource ids from ARN
+  # `arn_resource_id_regexp` is specified with an alternative regular expression.
+  aws_tag_select:
+    resource_type_selection: elasticloadbalancing:targetgroup
+    resource_id_dimension: TargetGroup
+    arn_resource_id_regexp: "(targetgroup/.*)$"
+    tag_selections:
+      Environment:
+      - production
 - aws_namespace: AWS/ApplicationELB
   aws_metric_name: UnHealthyHostCount
   aws_dimensions:

examples/WAFV2.yml

@@ -9,6 +9,17 @@ metrics:
   aws_namespace: AWS/WAFV2
   aws_statistics:
   - Sum
+  # In case you want to use some tag to select web acls to monitor, or to have additional `info` metric
+  # with all web acl tags as labels, use `aws_tag_select`.
+  # Since the WebACL dimension doesn't follow the convention for how to extract resource ids from ARN
+  # `arn_resource_id_regexp` is specified with an alternative regular expression.
+  aws_tag_select:
+    resource_type_selection: wafv2:regional/webacl
+    resource_id_dimension: WebACL
+    arn_resource_id_regexp: "([^/]+)/[^/]+$"
+    tag_selections:
+      Environment:
+      - production
 - aws_dimensions:
   - Region
   - Rule