Generic Filters

These filters can be applied to all policies for all resources. See the Resource-Specific Filters and Actions reference for resource-specific filters.

Value Filters

Cloud Custodian provides for a flexible query language on any resource by allowing for rich queries on JSON objects via JMESPath, and allows for mixing and combining those with a boolean conditional operators that are nest-able. Comparison between values is configurable supporting scalar operators:

  • Comparison operators:
    • equal or eq
    • not-equal or ne
    • greater-than or gt
    • gte or ge
    • less-than or lt
    • lte or le
  • Other operators
    • absent
    • present
    • not-null
    • empty
  • Collection operators against user supplied lists:
    • in
    • not-in or ni
    • or or Or
    • and or And
    • not
    • intersect - Provides comparison between 2 lists
  • Special operators:
    • glob - Provides Glob matching support
    • regex - Provides Regex matching support but ignores case
AgeFilter
Automatically filter resources older than a given date in Days (see Dateutil Parser)

JMESPath Filter

ValueFilter

Generic value filter using jmespath based on the data returned from a describe call

- name: ebs-unmark-attached-deletion
  resource: ebs
  comments: |
    Unmark any attached EBS volumes that were scheduled for deletion
    if they are now attached
  filters:
    - type: value                     ─┐ The value of the key from the describe
      key: "Attachments[0].Device"     ├▶EBS call
      value: not-null                 ─┘
    - "tag:maid_status": not-null     ─▶ This filter
  actions:
    - unmark

Transformations on the value can be done using the value_type keyword. The following value types are supported:

  • age - convert to a datetime (for past date comparisons)
  • cidr - parse an ipaddress
  • cidr_size - the length of the network prefix
  • expiration - convert to a datetime (for future date comparisons)
  • integer - convert the value to an integer
  • normalize - convert the value to lowercase
  • resource_count - compare against the number of matched resources
  • size - the length of an element
  • swap - swap the value and the evaluated key

Examples:

# Get the size of a group
- type: value
  key: SecurityGroups[].GroupId
  value_type: size
  value: 2

# Membership example using swap
- type: value
  key: SecurityGroups[].GroupId
  value_type: swap
  op: in
  value: sg-49b87f44

# Convert to integer before comparison
- type: value
  key: tag:Count
  op: greater-than
  value_type: integer
  value: 0

# Find instances launched within the last 31 days
- type: value
  key: LaunchTime
  op: less-than
  value_type: age
  value: 32

# Use `resource_count` to filter resources based on the number that matched
# Note that no `key` is used for this value_type since it is matching on
# the size of the list of resources and not a specific field.
- type: value
  value_type: resource_count
  op: lt
  value: 2

 # This policy will use `intersect` op to compare rds instances subnet group list
 # against a user provided list of public subnets from a s3 txt file.
 - name: find-rds-on-public-subnets-using-s3-list
   comment:  |
      The txt file needs to be in utf-8 no BOM format and contain one
      subnet per line in the file no quotes around the subnets either.
   resource: rds
   filters:
       - type: value
         key: "DBSubnetGroup.Subnets[].SubnetIdentifier"
         op: intersect
         value_from:
             url: s3://cloud-custodian-bucket/PublicSubnets.txt
             format: txt

# This policy will compare rds instances subnet group list against a
# inline user provided list of public subnets.
- name: find-rds-on-public-subnets-using-inline-list
  resource: rds
  filters:
      - type: value
        key: "DBSubnetGroup.Subnets[].SubnetIdentifier"
        op: intersect
        value:
            - subnet-2a8374658
            - subnet-1b8474522
            - subnet-2d2736444
EventFilter

Filter against a CloudWatch event JSON associated to a resource type

- name: no-ec2-public-ips
  resource: ec2
  mode:
    type: cloudtrail
    events:
        - RunInstances
  filters:
    - type: event                                                                           ─┐ The key is a JMESPath Query of
      key: "detail.requestParameters.networkInterfaceSet.items[].associatePublicIpAddress"   ├▶the event JSON from CloudWatch
      value: true                                                                           ─┘
  actions:
    - type: terminate
      force: true