Delivery groups

A destination has one queue. If one of your tenants triggers a flood, everyone behind it waits. Delivery groups split that queue by a value in each request, and give every group its own rate and its own concurrency.

Configure it

Set groups on a URL destination:

{
  "groups": {
    "key": "body.customer_id",
    "rate": 5,
    "period": "second",
    "max_in_flight": 2,
    "overrides": {
      "cus_priority": { "rate": 50, "period": "second" }
    }
  }
}

Field	Meaning
key	One path into the request as received: body.<path>, headers.<name> or query.<name>.
rate, period	The default cap for every group: 1 to 1,000 per second, minute or hour.
max_in_flight	Optional. Requests out at once per group, 1 to 50.
overrides	Up to 100 group values with their own rate, period and max_in_flight.

How it behaves

• Each group has its own rate. Busy groups take turns, and idle groups hold nothing back.
• The destination’s own max_in_flight and rate_per_second remain the ceiling over all groups.
• An event with no value at the key goes into the unknown group, which has the default rate.
• The group is worked out once, when the event reaches the destination. Changing the rule affects new events; a redrive works it out again.

See what is happening

GET /v1/destinations/:id/groups lists the groups seen on a destination. In Events you can filter by delivery_group. If a group’s oldest unsent event has waited 15 minutes, Ensue sends a destination.group_backlog notification, and destination.group_backlog_cleared once they catch up.