create tasks with dependencies

One _batch cannot link rows it creates (recipe 002), so the Tasks go in the first call and the TaskDependency rows in the second. Writing the edges as rows is the one route that takes a dependency_type and an offset_days and reschedules the dependents; upstream_tasks in a create body links without moving any date (probe 086).

Call

import json
import sys

sys.path.insert(0, "src")                       # or PYTHONPATH=src
from sg_groundtruth.client import FPT
from sg_groundtruth.env import load

c = FPT.from_env(load("."))
PROJECT_ID = 1234


def batch(requests_):
    r = c.post("/entity/_batch", json={"requests": requests_})
    if not r.ok:
        raise SystemExit(json.dumps(r.json()["errors"], indent=2))   # nothing was applied
    return r.json()["data"]


def create_tasks(entity, tasks, edges):
    """tasks: {name: fields}. edges: [(downstream, upstream, dependency_type, offset_days)]."""
    project = {"type": "Project", "id": PROJECT_ID}
    names = list(tasks)
    # 1. The Tasks. A batch cannot name a row it creates (recipe 002), so the links wait for call 2.
    rows = batch([{"request_type": "create", "entity": "Task",
                   "data": {"project": project, "entity": entity, "content": n, **tasks[n]}}
                  for n in names])
    ids = {n: row["data"]["id"] for n, row in zip(names, rows)}
    # 2. The edges, as TaskDependency rows: the one route that takes a type and an offset and
    #    reschedules the dependents (probe 086). `task` is downstream, `dependent_task` upstream.
    batch([{"request_type": "create", "entity": "TaskDependency",
            "data": {"task": {"type": "Task", "id": ids[down]},
                     "dependent_task": {"type": "Task", "id": ids[up]},
                     "dependency_type": typ, "offset_days": offset}}
           for down, up, typ, offset in edges])
    return ids


create_tasks({"type": "Shot", "id": 5678}, {
    "layout": {"start_date": "2026-03-02", "due_date": "2026-03-03"},
    "anim":   {"duration": 2400},
    "light":  {"duration": 960},
    "comp":   {"duration": 960},
}, [("anim", "layout", "finish-to-start-next-day", None),
    ("light", "anim", "start-to-start", 2),
    ("comp", "light", "finish-to-start-next-day", None)])

Response

call 1 -> 200, 4 create rows    {'layout': 47299, 'anim': 47300, 'light': 47301, 'comp': 47302}
call 2 -> 200, 3 create rows
read back
  layout  2026-03-02..2026-03-03  duration 960
  anim    2026-03-04..2026-03-10  duration 2400  upstream [layout]   finish-to-start-next-day
  light   2026-03-06..2026-03-09  duration 960   upstream [anim]     start-to-start, offset_days 2
  comp    2026-03-10..2026-03-11  duration 960   upstream [light]    finish-to-start-next-day

Notes

• A Task sent with only duration gets its dates from its dependency in call 2: anim started the working day after layout ended and ran its 2400 minutes, five 8-hour days on the probed site.
• offset_days is working days: light starts two working days after anim starts (probe 085).
• The four dependency_type values, and the error that lists them, are in probe 085. Omitting the type stores finish-to-start-next-day.
• A loop or a repeated pair in call 2 is a 400 and rolls the whole call back; the Tasks from call 1 stay. Delete them, or resend call 2 fixed.
• Keep each call under about 200 requests (recipe 002, size note).