Mission Nav2 (NavigateToPose)

Description

The nav2 adapter of the Mission Measurement for nav2's NavigateToPose action -- a single-pose navigation goal, the base case the mission lifecycle contract (#305, recorded in ADR-0010) was agreed against. Emits a mission_start Record when a goal is accepted and a mission_end Record once it reaches a terminal state. NavigateThroughPoses and FollowWaypoints are its siblings (#388/#389): same Record schema, same mission_id/sequence conventions, each with its own mission_type.

This Measurement is a passive watcher: it never sends a NavigateToPose goal itself. Whatever already dispatches navigation missions on the robot -- nav2's bt_navigator, a fleet orchestrator, an operator command -- keeps doing exactly that; this Measurement only observes. That is a deliberate match to every other Measurement's read-only relationship to the systems it reports on, and it is also why it does not use rclcpp_action::Client's typed goal-tracking API: that API only reports on goals the client itself sent. Instead it subscribes directly to the action's _action/status (action_msgs/msg/GoalStatusArray, the same message type for every action) and _action/feedback topics to see a goal get accepted, pick up its recovery count, and reach a terminal state, and calls the action's _action/get_result service directly once it does, to fetch the Result -- all standard, public parts of the ROS 2 action wire protocol that any client may use, sender or not.

nav2's NavigateToPose action server processes one goal at a time, so this Measurement only ever tracks one mission at once. A second goal accepted before the first reaches a terminal state is logged and otherwise ignored -- it produces no Record of its own, and the mission already being tracked is unaffected.

outcome on the end Record is one of succeeded, failed, cancelled, aborted: CANCELED maps to cancelled, ABORTED to aborted (both carrying nav2's own error_msg/error_code as reason/error_code), and SUCCEEDED maps to succeeded unless NavigateToPose::Result.error_code is non-zero, in which case it is failed -- an application-level failure nav2 reported without aborting the goal status itself.

recoveries (from NavigateToPose::Feedback.number_of_recoveries, when feedback was seen before completion) is carried on the end Record when available.

A mission still running when collection stops simply never gets a matching mission_end Record: nothing downstream can average an interval that was never closed as a zero, because there is no mission_end Record to average. sequence is a monotonically increasing counter across every Record this Measurement instance emits (start and end alike, not per mission_id), so a dropped Record shows up as a gap rather than silently corrupting a duration or a mission-success-rate denominator.

Parameters

Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "MissionNav2",
  "properties": {
    "event": { "type": "string", "enum": ["mission_start", "mission_end"] },
    "mission_id": { "type": "string" },
    "mission_type": { "type": "string", "const": "navigate_to_pose" },
    "sequence": { "type": "integer", "minimum": 1 },
    "outcome": { "type": "string", "enum": ["succeeded", "failed", "cancelled", "aborted"] },
    "reason": { "type": "string" },
    "error_code": { "type": "integer", "minimum": 0 },
    "duration_sec": { "type": "number", "minimum": 0 },
    "recoveries": { "type": "integer", "minimum": 0 }
  },
  "required": ["event", "mission_id", "mission_type", "sequence"],
  "type": "object"
}

outcome and duration_sec are required on mission_end only. reason and error_code are required on mission_end when outcome is failed or aborted.

Configuration

...
mission:
  plugin: "dc_measurements/MissionNav2"
  topic_output: "/dc/measurement/mission"
  group_key: "mission"
  action_name: "navigate_to_pose"

Example output

Start:

{
  "event": "mission_start",
  "mission_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "mission_type": "navigate_to_pose",
  "sequence": 7
}

and end (succeeded):

{
  "event": "mission_end",
  "mission_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "mission_type": "navigate_to_pose",
  "sequence": 8,
  "outcome": "succeeded",
  "duration_sec": 96.4,
  "recoveries": 1
}

and end (aborted):

{
  "event": "mission_end",
  "mission_id": "6c9f6a3e-2d1a-4e3a-9f7a-1b2c3d4e5f60",
  "mission_type": "navigate_to_pose",
  "sequence": 10,
  "outcome": "aborted",
  "reason": "tf timeout",
  "error_code": 9102,
  "duration_sec": 12.1
}