diff options
Diffstat (limited to 'uploader/background_jobs.py')
| -rw-r--r-- | uploader/background_jobs.py | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/uploader/background_jobs.py b/uploader/background_jobs.py new file mode 100644 index 0000000..a71dd44 --- /dev/null +++ b/uploader/background_jobs.py @@ -0,0 +1,225 @@ +"""Generic views and utilities to handle background jobs.""" +import uuid +import datetime +import importlib +from typing import Callable +from functools import partial + +from werkzeug.wrappers.response import Response +from flask import ( + flash, + request, + redirect, + Blueprint, + current_app as app) + +from gn_libs import jobs +from gn_libs import sqlite3 +from gn_libs.jobs.jobs import JobNotFound + +from uploader import session +from uploader.authorisation import require_login +from uploader.flask_extensions import url_for, render_template + +background_jobs_bp = Blueprint("background-jobs", __name__) +HandlerType = Callable[[dict], Response] + + +def make_datetime_formatter(dtformat: str = "%A, %d %B %Y at %H:%M %Z") -> Callable[[str], str]: + """Make a datetime formatter with the provided `dtformat`""" + def __formatter__(val: str) -> str: + dt = datetime.datetime.fromisoformat(val) + return dt.strftime(dtformat.strip()) + + return __formatter__ + +__default_datetime_formatter__ = make_datetime_formatter() + + +def __default_handler__(_job): + return render_template("background-jobs/job-summary.html", + job=_job, + display_datetime=__default_datetime_formatter__) + +def register_handlers( + job_type: str, + success_handler: HandlerType, + # pylint: disable=[redefined-outer-name] + error_handler: HandlerType = __default_handler__ + # pylint: disable=[redefined-outer-name] +) -> str: + """Register success and error handlers for each job type.""" + if not bool(app.config.get("background-jobs")): + app.config["background-jobs"] = {} + + if not bool(app.config["background-jobs"].get(job_type)): + app.config["background-jobs"][job_type] = { + "success": success_handler, + "error": error_handler + } + + return job_type + + +def register_job_handlers(job: dict): + """Related to register handlers above.""" + def __load_handler__(absolute_function_path): + _parts = absolute_function_path.split(".") + app.logger.debug("THE PARTS ARE: %s", _parts) + assert len(_parts) > 1, f"Invalid path: {absolute_function_path}" + module = importlib.import_module(f".{_parts[-2]}", + package=".".join(_parts[0:-2])) + return getattr(module, _parts[-1]) + + metadata = job["metadata"] + if metadata.get("success_handler"): + _success_handler = __load_handler__(metadata["success_handler"]) + try: + _error_handler = __load_handler__(metadata["error_handler"]) + except Exception as _exc:# pylint: disable=[broad-exception-caught] + _error_handler = __default_handler__ + register_handlers( + metadata["job-type"], _success_handler, _error_handler) + + +def handler(job: dict, handler_type: str) -> HandlerType: + """Fetch a handler for the job.""" + _job_type = job["metadata"]["job-type"] + _handler = app.config.get( + "background-jobs", {} + ).get( + _job_type, {} + ).get(handler_type) + if bool(_handler): + return _handler(job) + + return __default_handler__(job) + + +error_handler = partial(handler, handler_type="error") +success_handler = partial(handler, handler_type="success") + + +@background_jobs_bp.route("/status/<uuid:job_id>") +@require_login +def job_status(job_id: uuid.UUID): + """View the job status.""" + with sqlite3.connection(app.config["ASYNCHRONOUS_JOBS_SQLITE_DB"]) as conn: + try: + job = jobs.job(conn, job_id, fulldetails=True) + status = job["metadata"]["status"] + + register_job_handlers(job) + if status in ("error", "stopped"): + return error_handler(job) + + if status == "completed": + return success_handler(job) + + return render_template("background-jobs/job-status.html", + job=job, + display_datetime=__default_datetime_formatter__) + except JobNotFound as _jnf: + return render_template("jobs/job-not-found.html", job_id=job_id) + + +@background_jobs_bp.route("/error/<uuid:job_id>") +@require_login +def job_error(job_id: uuid.UUID): + """Handle job errors in a generic manner.""" + with sqlite3.connection(app.config["ASYNCHRONOUS_JOBS_SQLITE_DB"]) as conn: + try: + job = jobs.job(conn, job_id, fulldetails=True) + return render_template("jobs/job-error.html", job=job) + except JobNotFound as _jnf: + return render_template("jobs/job-not-found.html", job_id=job_id) + + +@background_jobs_bp.route("/list") +@require_login +def list_jobs(): + """List background jobs.""" + with sqlite3.connection(app.config["ASYNCHRONOUS_JOBS_SQLITE_DB"]) as conn: + return render_template( + "background-jobs/list-jobs.html", + jobs=jobs.jobs_by_external_id( + conn, session.user_details()["user_id"]), + display_datetime=__default_datetime_formatter__) + + +@background_jobs_bp.route("/summary/<uuid:job_id>") +@require_login +def job_summary(job_id: uuid.UUID): + """Provide a summary for completed jobs.""" + with sqlite3.connection(app.config["ASYNCHRONOUS_JOBS_SQLITE_DB"]) as conn: + try: + job = jobs.job(conn, job_id, fulldetails=True) + status = job["metadata"]["status"] + + if status in ("completed", "error", "stopped"): + return render_template("background-jobs/job-summary.html", + job=job, + display_datetime=__default_datetime_formatter__) + return redirect(url_for( + "background-jobs.job_status", job_id=job["job_id"])) + except JobNotFound as _jnf: + return render_template("jobs/job-not-found.html", job_id=job_id) + + +@background_jobs_bp.route("/delete/<uuid:job_id>", methods=["GET", "POST"]) +@require_login +def delete_single(job_id: uuid.UUID): + """Delete a single job.""" + with sqlite3.connection(app.config["ASYNCHRONOUS_JOBS_SQLITE_DB"]) as conn: + try: + job = jobs.job(conn, job_id, fulldetails=True) + status = job["metadata"]["status"] + if status not in ("completed", "error", "stopped"): + flash("We cannot delete a running job.", "alert alert-danger") + return redirect(url_for( + "background-jobs.job_summary", job_id=job_id)) + + if request.method == "GET": + return render_template("background-jobs/delete-job.html", + job=job, + display_datetime=__default_datetime_formatter__) + + if request.form["btn-confirm-delete"] == "delete": + jobs.delete_job(conn, job_id) + flash("Job was deleted successfully.", "alert alert-success") + return redirect(url_for("background-jobs.list_jobs")) + flash("Delete cancelled.", "alert alert-info") + return redirect(url_for( + "background-jobs.job_summary", job_id=job_id)) + except JobNotFound as _jnf: + return render_template("jobs/job-not-found.html", job_id=job_id) + + +@background_jobs_bp.route("/stop/<uuid:job_id>", methods=["GET", "POST"]) +@require_login +def stop_job(job_id: uuid.UUID): + """Stop a running job.""" + with sqlite3.connection(app.config["ASYNCHRONOUS_JOBS_SQLITE_DB"]) as conn: + try: + job = jobs.job(conn, job_id, fulldetails=True) + status = job["metadata"]["status"] + if status != "running": + flash("Cannot stop a job that is not running.", "alert alert-danger") + return redirect(url_for( + "background-jobs.job_summary", job_id=job_id)) + + if request.method == "GET": + return render_template("background-jobs/stop-job.html", + job=job, + display_datetime=__default_datetime_formatter__) + + if request.form["btn-confirm-stop"] == "stop": + jobs.kill_job(conn, job_id) + flash("Job was stopped successfully.", "alert alert-success") + return redirect(url_for( + "background-jobs.job_summary", job_id=job_id)) + flash("Stop cancelled.", "alert alert-info") + return redirect(url_for( + "background-jobs.job_summary", job_id=job_id)) + except JobNotFound as _jnf: + return render_template("jobs/job-not-found.html", job_id=job_id) |