x-sqs¶

Define your AWS SQS Queues and service scaling based on messages queue depth¶

Syntax¶

SNS Syntax Reference¶

x-sns:
  QueueA:
    Properties: {}
    Settings: {}
    Services: []

Properties¶

Mandatory Properties¶

SQS does not require any properties to be set in order to create the queue. No settings are mandatory.

Special properties¶

It is possible to define Dead Letter Queues for SQS messages (DLQ). It is possible to easily define this in ECS ComposeX simply by referring to the name of the queue, deployed in this same deployment.

Warning

It won’t be possible to import a queue ARN at this time in ECS ComposeX that exists outside of the stack today.

Services¶

Similar to all other modules, we have a list of dictionaries, with two keys of interest:

name: the name of the service as defined in services
access: the type of access to the resource.
scaling: Allow to define the scaling behaviour of the service based on SQS Approximate Messages Visible.

IAM Permissions¶

RO - read only
RWMessages - read/write messages on the queue
RWPermissions - read/write messages and grants access to modify some queue attributes

Tip

IAM policies, are defined in sqs/sqs_perms.json

Hint

You can also use AWS SAM Permissions as defined in AWS Documentation

SAM Policy Example¶

services:
  serviceA: {}
x-sqs:
  QueueA:
    Services:
      - name: serviceA
        access: SQSPollerPolicy

Lookup¶

See Lookup for more details about Lookup.

x-sqs:
  QueueA:
    Lookup:
      Tags:
        - Name: queue-a-123
        - owner: app01

Scaling¶

You can now defined StepScaling on the ECS Service based on the number of messages in the queue!

Scaling Syntax¶

scaling:
  steps:
    - lower_bound: int
      upper_bound: int
      count: int
  scaling_in_cooldown: int
  scaling_out_cooldown: int

Tip

You can define scaling rules on SQS Queues that you are importing via Lookup

Attention

If you already setup other Scaling policies for the service, beware of race conditions!

Special Features¶

Redrive policy¶

The redrive policy works exactly as you would expect it and is defined in the exact same way as for within the SQS proprties. Only, here, you only need to put the queue name of the DLQ. The generated ARN etc. will be fetched via exports (which also implicitly adds a lock on it).

Example with DLQ:

x-sqs:
  DLQ:
    Properties: {}
    Settings: {}
    Services: []

AppQueue:
  Properties:
    RedrivePolicy:
      deadLetterTargetArn: DLQ
      maxReceiveCount: 10
  Settings:
    EnvNames:
      - APPQUEUE01

Settings¶

Refer to Settings

Examples¶

Simple SQS Queues with DLQ configured¶

x-sqs:
  Queue02:
    Services:
      - name: app02
        access: RWPermissions
      - name: app03
        access: RO
    Properties:
      RedrivePolicy:
        deadLetterTargetArn: Queue01
        maxReceiveCount: 10
    Settings:
      EnvNames:
        - APP_QUEUE
        - AppQueue

  Queue01:
    Services:
      - name: app03
        access: RWMessages
    Properties: {}
    Settings:
      EnvNames:
        - DLQ
        - dlq

SQS Queue with scaling definition¶

x-sqs:
  QueueA:
    Services:
      - name: abcd
        access: RWMessages
        scaling:
          ScaleInCooldown: 120
          ScaleOutCooldown: 60
          steps:
            - lower_bound: 0
              upper_bound: 10
              count: 1 # Gives you 1 container if there is between 0 and 10 messages in the queue.
            - lower_bound: 10
              upper_bound: 100
              count: 10 # Gives you 10 containers if you have between 10 and 100 messages in the queue.
            - lower_bound: 100
              count: 20 # Gives you 20 containers if there is 100+ messages in the queue

Note

The last step cannot have defined a upper_bound. If you set one, it will be automatically be removed.

Note

You need to have defined x-configs/scaling/Range to enable step scaling on the ECS Service.