Infrastructure · Data Structures

Queue

Ordered container with FIFO/LIFO/priority discipline and explicit dequeue semantics

Definition

Mechanism

A linear container holding Tasks or Messages under an explicit ordering discipline (FIFO, LIFO, or Priority). Consumers dequeue one element at a time; producers enqueue at the discipline-dictated position. Distinct from a Stream (continuous, unbounded, with no single consumer) and from a plain list (no consumer semantics).

Invariants

None stated.

Risks

Failure modes

None stated.

Relationships

Builds on

References

Task

The atomic unit of intent

Used by

References

Reference

Data schema

{
  "type": "object",
  "required": [
    "queue_id",
    "items",
    "policy"
  ],
  "properties": {
    "queue_id": {
      "type": "string"
    },
    "items": {
      "type": "array",
      "items": {
        "type": "object",
        "description": "Enqueued Task or Message objects"
      }
    },
    "policy": {
      "type": "string",
      "enum": [
        "FIFO",
        "LIFO",
        "Priority"
      ],
      "default": "FIFO"
    },
    "capacity": {
      "type": "integer"
    },
    "metrics": {
      "type": "object",
      "properties": {
        "depth": {
          "type": "integer"
        },
        "average_wait_time": {
          "type": "number"
        }
      }
    }
  }
}

Identity

Ref
Queue#5689
Sema ID
sema:Queue#mh:SHA-256:5689d2db87dd8752019da54910f7be96929ff84baf09cdadd2c6826b01ea5420
Ring
0
Tier
1
Updated
2026-11-11
Supersedes
  • sema:Queue#mh:SHA-256:2ec3531a8c5711e281ab2913646d9f46dad05140fea7ceb6966bfa62d745bc9b
  • sema:Queue#mh:SHA-256:52224702509927c0b69df5580e0554e4ca381f93d291a08d7b2e8d4eaf04cdb2