> ## Documentation Index
> Fetch the complete documentation index at: https://headgate.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Return queue history for backlog and throughput trends.

> The UI leads with time-to-drain rather than depth. That is a rate, and
a rate needs history — which the first draft of this spec had no way to serve.
Backed by incrementally maintained counters, never by a queue-depth scan.




## OpenAPI

````yaml /api/headgate.openapi.yaml get /queues/{queue}/history
openapi: 3.1.0
info:
  title: headgate control API
  version: 0.1.0
  description: >
    The web UI is one client of this control API and gets no

    privileged access — asynqmon reads Redis directly, which is why its
    compatibility

    note is three minor versions stale.


    Both the Go and Rust implementations serve this spec, and the conformance
    suite

    asserts identical responses. Every list endpoint is bounded to prevent
    inspection

    from becoming an unbounded store operation: asynq's

    GetQueueInfo is O(number of groups) and has pinned Redis CPU for seconds in

    production. Monitoring caused the outage.


    DERIVED FROM THE ARCHITECTURE, NOT FROM A PREDECESSOR'S UI. The first draft
    of this

    spec was the asynq Inspector surface -- list by state, act on one job, pause
    a queue

    -- with new nouns bolted on. That inherited three problems: it omitted bulk

    operations, history, and enqueue (which asynq and apalis-board respectively
    DO have),

    and more importantly it had no endpoint for the question this system's own
    design

    creates. When dequeue is an admission decision, the operator's first
    question is not

    "what is in the queue" but "why is THIS job not running" -- see
    /jobs/{id}/admission.

    No predecessor needs that endpoint because no predecessor has a gate.
servers:
  - url: /api/v1
security: []
paths:
  /queues/{queue}/history:
    get:
      summary: Return queue history for backlog and throughput trends.
      description: >
        The UI leads with time-to-drain rather than depth. That is a rate, and

        a rate needs history — which the first draft of this spec had no way to
        serve.

        Backed by incrementally maintained counters, never by a queue-depth
        scan.
      parameters:
        - $ref: '#/components/parameters/Queue'
        - name: since_ms
          in: query
          schema:
            type: integer
        - name: bucket_ms
          in: query
          schema:
            type: integer
            default: 60000
      responses:
        '200':
          description: Queue history buckets.
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
                  properties:
                    at_ms:
                      type: integer
                    arrived:
                      type: integer
                    completed:
                      type: integer
                    failed:
                      type: integer
                    depth:
                      type: integer
                    admission_rejections:
                      type: object
                      description: >-
                        Rejections grouped by policy. Without this, a
                        misconfigured limit looks exactly like a slow worker.
                      additionalProperties:
                        type: integer
components:
  parameters:
    Queue:
      name: queue
      in: path
      required: true
      schema:
        type: string

````