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app/scripts/seed_demo_training.py
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stroblmeandClaude Fable 5 52c0c5e2ce An example to evaluate: a training run, its dashboard, and two bugs it found
make seed-demo builds demo_training — prepare on the engine, a GPU-bound
train, evaluate back here — and a panel that draws the loss curve while the
training is still going. It is the session's whole argument in one flow: batch
runs with parameters and a result, a generator yielding on a declared port
rather than logging, fluksio.emit from inside a callback, artifacts carrying
the dataset and the weights between machines, and a sweep whose configs are
isolated from each other. The train node prefers its label rather than
requiring it, so it runs before a GPU box exists and says which machine and
which numeric backend it actually used.

Building it turned up two real bugs. A run waited for a worker its flow only
*preferred*, because required_labels ignored device_policy — so the example
hung on a label it did not need. And a run's seed never reached the flow, so
sweeping over seeds ran the same experiment N times; it now fills an input of
that name when the flow declares one, which is what the field looked like it
did all along.

Pressing Run on a batch flow now submits a run rather than taking the old
non-durable path — that button is the first thing anyone evaluating will press,
and it was quietly doing something else.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AD8SfVhzXBG2nAfFcVh3iD
2026-08-18 22:04:14 +02:00

458 lines
16 KiB
Python

#!/usr/bin/env python
"""Seed the ML-pipeline example: a batch flow, a dashboard, and a worker to try.
What it builds::
demo_training prepare -> train -> evaluate a batch flow, run on demand
demo_training a dashboard watching a run as it happens
The flow is a small supervised fit — recover ``y = 3x + 2`` from noisy samples
— chosen because it is a real training loop with none of the setup. What it is
actually demonstrating is the shape of an ML pipeline on this engine:
* **Batch runs.** ``mode: batch``, so nothing is activated and nothing fires
until a run asks. Its ``inputs`` are the run's parameters and its ``outputs``
are the run's result.
* **Streaming outputs.** ``train`` is a generator: every ``yield`` publishes on
the ``loss`` port the instant it happens, so the dashboard chart draws the
curve while the training is still running. There is no logging call — the
numbers are outputs, and the run keeps the whole series because ``loss``
declares ``stream: true``.
* **``fluksio.emit``** for where a yield cannot reach: ``progress`` is
published from inside a helper the loop calls, which is the shape a training
framework's callback has.
* **Artifacts.** The dataset and the trained weights are far too big to be
messages, so they travel as references into the content-addressed store and
are opened on the other side — including when the other side is a different
machine.
* **A GPU node beside CPU nodes.** ``train`` declares ``device: gpu``, so it
runs on an attached worker carrying that label. Its policy is ``prefer``, so
with no worker attached it runs on the engine instead — and it reports which
machine and which numeric backend it used, so the routing is visible in the
result rather than taken on trust.
* **Sweeps.** Runs of one flow are isolated from each other, so the same flow
can be swept over parameters and the runs compared.
Run it against a stack that is already up::
make -C app seed-demo
Then, from the dashboard or the API::
POST /api/v1/runs/flows/demo_training {"params": {"epochs": 40}}
POST /api/v1/runs/flows/demo_training/sweep {"runs": [...]}
Environment (the Makefile passes these):
API_URL, FIRST_SUPERUSER, FIRST_SUPERUSER_PASSWORD
"""
from __future__ import annotations
import os
import sys
from typing import Any
import httpx
API = os.environ.get("API_URL", "http://api.localhost")
EMAIL = os.environ.get("FIRST_SUPERUSER", "")
PASSWORD = os.environ.get("FIRST_SUPERUSER_PASSWORD", "")
FLOW = "demo_training"
PANEL = "demo_training"
PREPARE_SOURCE = '''"""Make the dataset, and hand it on as an artifact.
Runs on the engine: no device, so it goes to the local worker pool. Only the
standard library, because the engine's venv is its own and this node has no
business asking it for anything.
"""
import json
import random
import fluksio
#: The line the training is supposed to recover.
TRUE_SLOPE = 3.0
TRUE_INTERCEPT = 2.0
def process(seed, noise, samples, params):
rng = random.Random(int(seed))
rows = [
[x, TRUE_SLOPE * x + TRUE_INTERCEPT + rng.gauss(0.0, float(noise))]
for x in (rng.uniform(-1.0, 1.0) for _ in range(int(samples)))
]
payload = json.dumps(
{"rows": rows, "truth": {"slope": TRUE_SLOPE, "intercept": TRUE_INTERCEPT}}
).encode()
# Data between stages is an artifact, not a message: the reference is
# what travels, and it stays valid on whichever machine opens it.
return {
"dataset": fluksio.save_artifact(payload, "dataset.json", "application/json"),
"sample_count": len(rows),
}
'''
TRAIN_SOURCE = '''"""Fit the dataset, publishing the loss as it goes.
A generator, so this node produces values over time: every ``yield`` is a dict
keyed by output port and is published the moment it happens, and what the
function returns at the end is the node's result. Nothing here logs anything —
the loss is an output of the graph, which is why a chart can bind to it.
Bound to ``device: gpu``. With a worker carrying that label attached it runs
there; without one it falls back to the engine, and ``trained_on`` says which
happened. numpy is used when the machine it landed on has it, which is how the
two environments tell themselves apart.
"""
import json
import platform
import time
import fluksio
try:
import numpy as np
except ImportError: # The engine's own venv has no numpy; a GPU box will.
np = None
def process(dataset, learning_rate, epochs, pace, params):
with open(fluksio.load_artifact(dataset)) as handle:
data = json.load(handle)
xs = [row[0] for row in data["rows"]]
ys = [row[1] for row in data["rows"]]
count = len(xs)
total = int(epochs)
rate = float(learning_rate)
slope, intercept = 0.0, 0.0
if np is not None:
axis_x, axis_y = np.array(xs), np.array(ys)
def report(epoch):
# Published from inside a helper, where a yield cannot reach — the
# shape a training framework's callback has. Same port, same checking.
fluksio.emit(progress=round(100.0 * (epoch + 1) / total, 1))
loss = 0.0
for epoch in range(total):
if np is not None:
error = (slope * axis_x + intercept) - axis_y
loss = float((error**2).mean())
slope -= rate * float((2 * error * axis_x).mean())
intercept -= rate * float((2 * error).mean())
else:
error = [slope * x + intercept - y for x, y in zip(xs, ys)]
loss = sum(e * e for e in error) / count
slope -= rate * sum(2 * e * x for e, x in zip(error, xs)) / count
intercept -= rate * sum(2 * e for e in error) / count
yield {"loss": round(loss, 6)}
report(epoch)
# Only so the curve is watchable; a real epoch takes as long as it takes.
if float(pace) > 0:
time.sleep(float(pace))
weights = json.dumps({"slope": slope, "intercept": intercept}).encode()
return {
"weights": fluksio.save_artifact(weights, "weights.json", "application/json"),
"final_loss": round(loss, 6),
"trained_on": "{} ({})".format(
platform.node(),
"numpy " + np.__version__ if np is not None else "pure python",
),
}
'''
EVALUATE_SOURCE = '''"""Score the fit, back on the engine.
Opens two artifacts: the dataset this run prepared and the weights the
training produced — which may have been written on another machine entirely.
A reference names content, so where it came from does not matter.
"""
import json
import fluksio
def process(weights, dataset, params):
with open(fluksio.load_artifact(weights)) as handle:
fit = json.load(handle)
with open(fluksio.load_artifact(dataset)) as handle:
data = json.load(handle)
rows = data["rows"]
truth = data["truth"]
mean = sum(y for _x, y in rows) / len(rows)
total = sum((y - mean) ** 2 for _x, y in rows)
residual = sum((y - (fit["slope"] * x + fit["intercept"])) ** 2 for x, y in rows)
r2 = 1.0 - residual / total if total else 0.0
good = r2 > 0.9
return {
"accuracy": round(100.0 * max(0.0, r2), 2),
"report": {
"title": "Recovered {:.2f}x + {:.2f}".format(
fit["slope"], fit["intercept"]
),
"body": "Truth is {}x + {}. R² = {:.4f} over {} samples.".format(
truth["slope"], truth["intercept"], r2, len(rows)
),
"severity": "info" if good else "warning",
},
}
'''
NODES = [
{
"id": "prepare",
"type": "python",
"title": "Make the dataset",
"requires": [
{"name": "seed", "dtype": "int"},
{"name": "noise", "dtype": "float"},
{"name": "samples", "dtype": "int"},
],
"provides": [
{"name": "dataset", "dtype": "artifact"},
{"name": "sample_count", "dtype": "int"},
],
},
{
"id": "train",
"type": "python",
"title": "Fit it",
# Runs on a worker carrying this label; falls back here without one,
# which is what makes the example work before a GPU box is attached.
"device": "gpu",
"device_policy": "prefer",
# Generous, and an *idle* timeout: a node that keeps publishing keeps
# its deadline reset, so this is how long it may go quiet.
"timeout": 300,
"requires": [
{"name": "dataset", "dtype": "artifact"},
{"name": "learning_rate", "dtype": "float"},
{"name": "epochs", "dtype": "int"},
{"name": "pace", "dtype": "float"},
],
"provides": [
# The curve. `stream` says this port publishes repeatedly while the
# node runs, and is what makes a run keep every value it takes.
{"name": "loss", "dtype": "float", "stream": True},
{"name": "progress", "dtype": "float", "stream": True},
{"name": "weights", "dtype": "artifact"},
{"name": "final_loss", "dtype": "float"},
{"name": "trained_on", "dtype": "str"},
],
},
{
"id": "evaluate",
"type": "python",
"title": "Score it",
"requires": [
{"name": "weights", "dtype": "artifact"},
{"name": "dataset", "dtype": "artifact"},
],
"provides": [
{"name": "report", "dtype": "record"},
{"name": "accuracy", "dtype": "float"},
],
},
]
#: The run's parameters, with the values a run gets when it names none.
INPUTS = [
{"spec": {"name": "seed", "dtype": "int"}, "initial": 1},
{"spec": {"name": "noise", "dtype": "float"}, "initial": 0.25},
{"spec": {"name": "samples", "dtype": "int"}, "initial": 200},
{"spec": {"name": "learning_rate", "dtype": "float"}, "initial": 0.2},
{"spec": {"name": "epochs", "dtype": "int"}, "initial": 40},
# Only so a human can watch the curve arrive; set it to 0 for a sweep.
{"spec": {"name": "pace", "dtype": "float"}, "initial": 0.15},
]
#: What a run reports as its result. Everything else the flow computed stays
#: in the run's own state and is dropped with it.
OUTPUTS = ["report", "accuracy", "final_loss", "trained_on", "sample_count"]
WIDGETS = [
{
"id": "curve",
"type": "chart",
"title": "Training loss",
"layout": {"lg": {"x": 0, "y": 0, "w": 8, "h": 5}},
"config": {
# Bound to the port the node yields on — the same binding a
# temperature would use. Nothing here knows what a metric is.
"series": [{"message": f"{FLOW}.loss", "dtype": "float", "label": "loss"}],
"history": {"points": 600},
},
},
{
"id": "how",
"type": "markdown",
"title": "",
"layout": {"lg": {"x": 8, "y": 0, "w": 4, "h": 5}},
"config": {
"content": (
"## Try it\n"
"- Press Run on the flow, or POST /api/v1/runs/flows/demo_training\n"
"- The curve fills in while the training runs. It is a port"
" the node yields on, not a log.\n"
"- Sweep it: POST .../sweep with a list of params. Runs are"
" isolated, so they go in parallel.\n"
"- Attach a worker labelled gpu and 'Trained on' changes"
" machine.\n"
"- The finished series lives on the run:"
" GET /api/v1/runs/{id}/metrics?name=demo_training.loss"
)
},
},
{
"id": "progress",
"type": "gauge",
"title": "Progress",
"layout": {"lg": {"x": 0, "y": 5, "w": 3, "h": 3}},
"config": {
"message": f"{FLOW}.progress",
"dtype": "float",
"min": 0,
"max": 100,
"unit": "%",
},
},
{
"id": "accuracy",
"type": "gauge",
"title": "Fit quality (R²)",
"layout": {"lg": {"x": 3, "y": 5, "w": 3, "h": 3}},
"config": {
"message": f"{FLOW}.accuracy",
"dtype": "float",
"min": 0,
"max": 100,
"unit": "%",
},
},
{
"id": "loss_now",
"type": "stat",
"title": "Final loss",
"layout": {"lg": {"x": 6, "y": 5, "w": 3, "h": 3}},
"config": {"message": f"{FLOW}.final_loss", "dtype": "float", "precision": 4},
},
{
"id": "samples",
"type": "stat",
"title": "Samples",
"layout": {"lg": {"x": 9, "y": 5, "w": 3, "h": 3}},
"config": {"message": f"{FLOW}.sample_count", "dtype": "int"},
},
{
"id": "where",
"type": "stat",
"title": "Trained on",
"layout": {"lg": {"x": 0, "y": 8, "w": 5, "h": 3}},
"config": {"message": f"{FLOW}.trained_on", "dtype": "str"},
},
{
"id": "verdict",
"type": "notification",
"title": "Result",
"layout": {"lg": {"x": 5, "y": 8, "w": 7, "h": 3}},
"config": {"message": f"{FLOW}.report", "dtype": "record"},
},
]
class Api:
def __init__(self) -> None:
self.http = httpx.Client(base_url=f"{API}/api/v1", timeout=60)
token = self.http.post(
"/login/access-token",
data={"username": EMAIL, "password": PASSWORD},
).json()["access_token"]
self.http.headers["Authorization"] = f"Bearer {token}"
def __call__(self, method: str, path: str, body: Any = None) -> Any:
response = self.http.request(method, path, json=body)
response.raise_for_status()
return response.json() if response.content else None
def main() -> int:
if not EMAIL or not PASSWORD:
print("FIRST_SUPERUSER / FIRST_SUPERUSER_PASSWORD are unset.", file=sys.stderr)
return 1
api = Api()
try:
api("DELETE", f"/flows/{FLOW}")
except httpx.HTTPStatusError:
pass
api(
"PUT",
f"/flows/{FLOW}",
{
"name": FLOW,
"title": "Training run (example)",
"mode": "batch",
"outputs": OUTPUTS,
"nodes": NODES,
"inputs": INPUTS,
},
)
for node_id, code in (
("prepare", PREPARE_SOURCE),
("train", TRAIN_SOURCE),
("evaluate", EVALUATE_SOURCE),
):
api("PUT", f"/flows/{FLOW}/nodes/{node_id}/source", {"code": code})
version = api("GET", f"/flows/{FLOW}?draft=true")["definition"]["version"]
published = api("POST", f"/flows/{FLOW}/publish", {"version": version})
print(f" {FLOW}: {len(NODES)} nodes, published")
for issue in published.get("issues") or []:
print(f" ! {issue['message']}")
try:
api("DELETE", f"/dashboards/{PANEL}")
except httpx.HTTPStatusError:
pass
api("POST", f"/dashboards/{PANEL}", {"name": PANEL, "title": "Training"})
current = api("GET", f"/dashboards/{PANEL}")
api(
"PUT",
f"/dashboards/{PANEL}",
{
**current,
"pages": [
{
"id": "main",
"title": "Overview",
"sections": [{"id": "main", "widgets": WIDGETS}],
}
],
},
)
version = api("GET", f"/dashboards/{PANEL}?draft=true")["version"]
api("POST", f"/dashboards/{PANEL}/publish", {"version": version})
print(f" dashboard '{PANEL}': published")
print(
f"\nOpen /view/{PANEL}, then start a run:\n"
f' POST {API}/api/v1/runs/flows/{FLOW} {{"params": {{}}}}\n'
"The curve fills in as it trains. For a sweep, set pace to 0."
)
return 0
if __name__ == "__main__":
raise SystemExit(main())