motion_report: Add support for dumping steps/trapq via API server

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 43 insertions, 0 deletions

diff --git a/docs/API_Server.md b/docs/API_Server.md
index b8419a8d..77470137 100644
--- a/docs/API_Server.md
+++ b/docs/API_Server.md
@@ -278,6 +278,49 @@ window" interface. Parsing content from the G-Code terminal output is
 discouraged. Use the "objects/subscribe" endpoint to obtain updates on
 Klipper's state.
 
+### motion_report/dump_stepper
+
+This endpoint is used to subscribe to Klipper's internal stepper
+queue_step command stream for a stepper. Obtaining these low-level
+motion updates may be useful for diagnostic and debugging
+purposes. Using this endpoint may increase Klipper's system load.
+
+A request may look like:
+`{"id": 123, "method":"motion_report/dump_stepper",
+"params": {"name": "stepper_x", "response_template": {}}}`
+and might return:
+`{"id": 123, "result": {"header": ["interval", "count", "add"]}}`
+and might later produce asynchronous messages such as:
+`{"params": {"first_clock": 179601081, "first_time": 8.98,
+"first_position": 0, "last_clock": 219686097, "last_time": 10.984,
+"data": [[179601081, 1, 0], [29573, 2, -8685], [16230, 4, -1525],
+[10559, 6, -160], [10000, 976, 0], [10000, 1000, 0], [10000, 1000, 0],
+[10000, 1000, 0], [9855, 5, 187], [11632, 4, 1534], [20756, 2, 9442]]}}`
+
+The "header" field in the initial query response is used to describe
+the fields found in later "data" responses.
+
+### motion_report/dump_trapq
+
+This endpoint is used to subscribe to Klipper's internal "trapezoid
+motion queue". Obtaining these low-level motion updates may be useful
+for diagnostic and debugging purposes. Using this endpoint may
+increase Klipper's system load.
+
+A request may look like:
+`{"id": 123, "method": "motion_report/dump_trapq", "params":
+{"name": "toolhead", "response_template":{}}}`
+and might return:
+`{"id": 1, "result": {"header": ["time", "duration",
+"start_velocity", "acceleration", "start_position", "direction"]}}`
+and might later produce asynchronous messages such as:
+`{"params": {"data": [[4.05, 1.0, 0.0, 0.0, [300.0, 0.0, 0.0],
+[0.0, 0.0, 0.0]], [5.054, 0.001, 0.0, 3000.0, [300.0, 0.0, 0.0],
+[-1.0, 0.0, 0.0]]]}}`
+
+The "header" field in the initial query response is used to describe
+the fields found in later "data" responses.
+
 ### pause_resume/cancel
 
 This endpoint is similar to running the "PRINT_CANCEL" G-Code command.