Files
ThothII/harness/tht/jobs/runner.py
T

268 lines
9.9 KiB
Python

"""Resumable stage runner with durable atomic checkpoints and reports."""
from __future__ import annotations
import json
import hashlib
import os
import uuid
import stat
from collections.abc import Callable, Sequence
from dataclasses import dataclass
from pathlib import Path
from typing import Any
from pydantic import ValidationError
from tht.jobs.locking import WorkspaceJobLock
from tht.jobs.models import JobReport, JobRun, JobSpec, StageError, StageRun, utc_now
class CorruptCheckpointError(RuntimeError):
pass
@dataclass(frozen=True)
class JobContext:
run_id: str
job_type: str
dry_run: bool
workspace_root: Path
run_dir: Path
Stage = Callable[[JobContext], Any]
def _atomic_write(path: Path, payload: str) -> None:
temporary = path.with_name(f".{path.name}.{uuid.uuid4().hex}.tmp")
fd = os.open(temporary, os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0o600)
try:
with os.fdopen(fd, "w", encoding="utf-8") as stream:
stream.write(payload)
stream.flush()
os.fsync(stream.fileno())
os.replace(temporary, path)
directory_fd = os.open(path.parent, os.O_RDONLY)
try:
os.fsync(directory_fd)
finally:
os.close(directory_fd)
except BaseException:
try:
temporary.unlink()
except FileNotFoundError:
pass
raise
def _persist(path: Path, run: JobRun) -> None:
_atomic_write(path, run.model_dump_json(indent=2) + "\n")
def _load_checkpoint(path: Path) -> JobRun:
try:
return JobRun.model_validate_json(path.read_text(encoding="utf-8"))
except (OSError, ValidationError, ValueError, json.JSONDecodeError) as error:
raise CorruptCheckpointError("checkpoint is invalid and cannot be resumed") from error
def _new_run(spec: JobSpec, run_id: str, stages: Sequence[Stage]) -> JobRun:
names = list(spec.stage_ids)
if len(names) != len(stages):
raise ValueError("stage_ids must identify every stage exactly once")
if len(names) != len(set(names)):
raise ValueError("stage names must be unique")
return JobRun(
run_id=run_id,
compatibility_fingerprint=_compatibility_fingerprint(spec, names),
workspace_fingerprint=_value_fingerprint(spec.workspace_id),
job_type=spec.job_type,
spec_version=spec.spec_version,
pipeline_version=spec.pipeline_version,
config_fingerprint=spec.config_fingerprint,
input_fingerprint=spec.input_fingerprint,
dry_run=spec.dry_run,
status="running",
started_at=utc_now(),
resumed_from=spec.resume_run_id,
stages=tuple(StageRun(name=name) for name in names),
)
def _resume_run(spec: JobSpec, run_id: str, stages: Sequence[Stage], source: JobRun) -> JobRun:
requested_names = list(spec.stage_ids)
if len(requested_names) != len(stages) or len(requested_names) != len(set(requested_names)):
raise CorruptCheckpointError("resume checkpoint is incompatible with requested stages")
source_fingerprint = _source_compatibility_fingerprint(source)
if source.compatibility_fingerprint != source_fingerprint:
raise CorruptCheckpointError("resume checkpoint compatibility fingerprint is invalid")
expected = _compatibility_fingerprint(spec, requested_names)
if source_fingerprint != expected or [stage.name for stage in source.stages] != requested_names:
raise CorruptCheckpointError(
"resume checkpoint is incompatible; start an intentional new run without resume"
)
source_by_name = {stage.name: stage for stage in source.stages}
resumed_stages = []
for name in requested_names:
previous = source_by_name.get(name)
resumed_stages.append(
previous
if previous is not None and previous.status == "succeeded"
else StageRun(name=name)
)
return JobRun(
run_id=run_id,
compatibility_fingerprint=source.compatibility_fingerprint,
workspace_fingerprint=source.workspace_fingerprint,
job_type=spec.job_type,
spec_version=spec.spec_version,
pipeline_version=spec.pipeline_version,
config_fingerprint=spec.config_fingerprint,
input_fingerprint=spec.input_fingerprint,
dry_run=spec.dry_run,
status="running",
started_at=utc_now(),
resumed_from=source.run_id,
stages=tuple(resumed_stages),
)
def run_job(spec: JobSpec, stages: Sequence[Stage]) -> JobReport:
"""Run stages once, returning a terminal report instead of leaking stage exceptions."""
with WorkspaceJobLock(spec.workspace_root, spec.workspace_id, spec.job_type):
jobs_root = spec.workspace_root / ".tht-jobs" / spec.job_type / "runs"
if spec.resume_run_id is None:
source = None
else:
source_path = jobs_root / spec.resume_run_id / "checkpoint.json"
if not source_path.exists():
matches = list(
(spec.workspace_root / ".tht-jobs").glob(
f"*/runs/{spec.resume_run_id}/checkpoint.json"
)
)
if len(matches) == 1:
source_path = matches[0]
source = _load_checkpoint(source_path)
_validate_resume_source(spec, stages, source)
run_id = uuid.uuid4().hex
run_dir = jobs_root / run_id
_prepare_run_directory(spec.workspace_root, spec.job_type, run_id)
checkpoint_path = run_dir / "checkpoint.json"
if source is None:
run = _new_run(spec, run_id, stages)
else:
run = _resume_run(spec, run_id, stages, source)
_persist(checkpoint_path, run)
context = JobContext(run_id, spec.job_type, spec.dry_run, spec.workspace_root, run_dir)
for index, stage_callable in enumerate(stages):
if run.stages[index].status == "succeeded":
continue
stage = run.stages[index].model_copy(
update={"status": "running", "started_at": utc_now()}
)
run = run.model_copy(
update={"stages": run.stages[:index] + (stage,) + run.stages[index + 1 :]}
)
_persist(checkpoint_path, run)
try:
stage_callable(context)
except Exception:
failed = stage.model_copy(
update={
"status": "failed",
"finished_at": utc_now(),
"error": StageError(),
}
)
run = run.model_copy(
update={
"status": "failed",
"finished_at": utc_now(),
"stages": run.stages[:index] + (failed,) + run.stages[index + 1 :],
}
)
_persist(checkpoint_path, run)
break
succeeded = stage.model_copy(update={"status": "succeeded", "finished_at": utc_now()})
run = run.model_copy(
update={"stages": run.stages[:index] + (succeeded,) + run.stages[index + 1 :]}
)
_persist(checkpoint_path, run)
else:
run = run.model_copy(update={"status": "succeeded", "finished_at": utc_now()})
_persist(checkpoint_path, run)
report = JobReport.model_validate(run.model_dump())
_atomic_write(run_dir / "report.json", report.model_dump_json(indent=2) + "\n")
return report
def _value_fingerprint(value: str) -> str:
return "sha256:" + hashlib.sha256(value.encode("utf-8")).hexdigest()
def _compatibility_fingerprint(spec: JobSpec, stage_ids: list[str]) -> str:
payload = {
"schema_version": 1,
"workspace": _value_fingerprint(spec.workspace_id),
"job_type": spec.job_type,
"dry_run": spec.dry_run,
"spec_version": spec.spec_version,
"pipeline_version": spec.pipeline_version,
"config_fingerprint": spec.config_fingerprint,
"input_fingerprint": spec.input_fingerprint,
"stage_ids": stage_ids,
}
canonical = json.dumps(payload, sort_keys=True, separators=(",", ":"))
return _value_fingerprint(canonical)
def _source_compatibility_fingerprint(source: JobRun) -> str:
payload = {
"schema_version": source.schema_version,
"workspace": source.workspace_fingerprint,
"job_type": source.job_type,
"dry_run": source.dry_run,
"spec_version": source.spec_version,
"pipeline_version": source.pipeline_version,
"config_fingerprint": source.config_fingerprint,
"input_fingerprint": source.input_fingerprint,
"stage_ids": [stage.name for stage in source.stages],
}
canonical = json.dumps(payload, sort_keys=True, separators=(",", ":"))
return _value_fingerprint(canonical)
def _validate_resume_source(spec: JobSpec, stages: Sequence[Stage], source: JobRun) -> None:
_resume_run(spec, "0" * 32, stages, source)
def _prepare_run_directory(workspace_root: Path, job_type: str, run_id: str) -> None:
parent_fd = os.open(workspace_root, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW)
try:
for component in (".tht-jobs", job_type, "runs", run_id):
try:
os.mkdir(component, 0o700, dir_fd=parent_fd)
os.fsync(parent_fd)
except FileExistsError:
pass
child_fd = os.open(
component,
os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW,
dir_fd=parent_fd,
)
info = os.fstat(child_fd)
if not stat.S_ISDIR(info.st_mode) or info.st_uid != os.getuid():
os.close(child_fd)
raise OSError("unsafe job run directory")
os.fchmod(child_fd, 0o700)
os.close(parent_fd)
parent_fd = child_fd
os.fsync(parent_fd)
finally:
os.close(parent_fd)