from __future__ import annotations
import csv
import json
import logging
import os.path
from functools import wraps
from html import escape
from io import StringIO
from itertools import chain
from json import dumps
from time import time
from typing import TYPE_CHECKING, Any
import gevent
from flask import (
Flask,
Response,
jsonify,
make_response,
redirect,
render_template,
request,
send_file,
send_from_directory,
url_for,
)
from flask_cors import CORS
from flask_login import LoginManager, login_required
from gevent import pywsgi
from . import __version__ as version
from . import argument_parser
from . import stats as stats_module
from .html import get_html_report
from .log import greenlet_exception_logger
from .runners import STATE_MISSING, STATE_RUNNING, MasterRunner
from .stats import StatsCSV, StatsCSVFileWriter, StatsErrorDict, sort_stats
from .user.inspectuser import get_ratio
from .util.cache import memoize
from .util.timespan import parse_timespan
if TYPE_CHECKING:
from .env import Environment
logger = logging.getLogger(__name__)
greenlet_exception_handler = greenlet_exception_logger(logger)
DEFAULT_CACHE_TIME = 2.0
[docs]class WebUI:
"""
Sets up and runs a Flask web app that can start and stop load tests using the
:attr:`environment.runner <locust.env.Environment.runner>` as well as show the load test statistics
in :attr:`environment.stats <locust.env.Environment.stats>`
"""
app: Flask | None = None
"""
Reference to the :class:`flask.Flask` app. Can be used to add additional web routes and customize
the Flask app in other various ways. Example::
from flask import request
@web_ui.app.route("/my_custom_route")
def my_custom_route():
return "your IP is: %s" % request.remote_addr
"""
greenlet: gevent.Greenlet | None = None
"""
Greenlet of the running web server
"""
server: pywsgi.WSGIServer | None = None
"""Reference to the :class:`pyqsgi.WSGIServer` instance"""
template_args: dict[str, Any]
"""Arguments used to render index.html for the web UI. Must be used with custom templates
extending index.html."""
auth_args: dict[str, Any]
"""Arguments used to render auth.html for the web UI auth page. Must be used when configuring auth"""
def __init__(
self,
environment: Environment,
host: str,
port: int,
web_login: bool = False,
tls_cert: str | None = None,
tls_key: str | None = None,
stats_csv_writer: StatsCSV | None = None,
delayed_start=False,
userclass_picker_is_active=False,
modern_ui=False,
):
"""
Create WebUI instance and start running the web server in a separate greenlet (self.greenlet)
Arguments:
environment: Reference to the current Locust Environment
host: Host/interface that the web server should accept connections to
port: Port that the web server should listen to
web_login: Enables a login page for the modern UI
tls_cert: A path to a TLS certificate
tls_key: A path to a TLS private key
delayed_start: Whether or not to delay starting web UI until `start()` is called. Delaying web UI start
allows for adding Flask routes or Blueprints before accepting requests, avoiding errors.
"""
environment.web_ui = self
self.stats_csv_writer = stats_csv_writer or StatsCSV(environment, stats_module.PERCENTILES_TO_REPORT)
self.environment = environment
self.host = host
self.port = port
self.tls_cert = tls_cert
self.tls_key = tls_key
self.userclass_picker_is_active = userclass_picker_is_active
self.modern_ui = modern_ui
self.web_login = web_login
app = Flask(__name__)
CORS(app)
self.app = app
app.jinja_env.add_extension("jinja2.ext.do")
app.debug = True
root_path = os.path.dirname(os.path.abspath(__file__))
app.root_path = root_path
self.webui_build_path = os.path.join(root_path, "webui", "dist")
self.greenlet: gevent.Greenlet | None = None
self._swarm_greenlet: gevent.Greenlet | None = None
self.template_args = {}
self.auth_args = {}
if self.web_login:
self.login_manager = LoginManager()
self.login_manager.init_app(app)
self.login_manager.login_view = "login"
if environment.runner:
self.update_template_args()
if not delayed_start:
self.start()
@app.errorhandler(Exception)
def handle_exception(error):
error_message = str(error)
logger.log(logging.CRITICAL, error_message)
return make_response(error_message, 500)
@app.route("/assets/<path:path>")
def send_assets(path):
return send_from_directory(os.path.join(self.webui_build_path, "assets"), path)
@app.route("/")
@self.auth_required_if_enabled
def index() -> str | Response:
if not environment.runner:
return make_response("Error: Locust Environment does not have any runner", 500)
self.update_template_args()
if self.modern_ui:
self.set_static_modern_ui()
return render_template("index.html", template_args=self.template_args)
return render_template("index.html", **self.template_args)
@app.route("/swarm", methods=["POST"])
@self.auth_required_if_enabled
def swarm() -> Response:
assert request.method == "POST"
# Loading UserClasses & ShapeClasses if Locust is running with UserClass Picker
if self.userclass_picker_is_active:
if not self.environment.available_user_classes:
err_msg = "UserClass picker is active but there are no available UserClasses"
return jsonify({"success": False, "message": err_msg, "host": environment.host})
# Getting Specified User Classes
form_data_user_class_names = request.form.getlist("user_classes")
# Updating UserClasses
if form_data_user_class_names:
user_classes = {}
for user_class_name, user_class_object in self.environment.available_user_classes.items():
if user_class_name in form_data_user_class_names:
user_classes[user_class_name] = user_class_object
else:
if self.environment.runner and self.environment.runner.state == STATE_RUNNING:
# Test is already running
# Using the user classes that have already been selected
user_classes = {
key: value
for (key, value) in self.environment.available_user_classes.items()
if value in self.environment.user_classes
}
else:
# Starting test with no user class selection
# Defaulting to using all available user classes
user_classes = self.environment.available_user_classes
self._update_user_classes(user_classes)
# Updating ShapeClass if specified in WebUI Form
form_data_shape_class_name = request.form.get("shape_class", "Default")
if form_data_shape_class_name == "Default":
self._update_shape_class(None)
else:
self._update_shape_class(form_data_shape_class_name)
parsed_options_dict = vars(environment.parsed_options) if environment.parsed_options else {}
run_time = None
for key, value in request.form.items():
if key == "user_count": # if we just renamed this field to "users" we wouldn't need this
user_count = int(value)
elif key == "spawn_rate":
spawn_rate = float(value)
elif key == "host":
# Replace < > to guard against XSS
environment.host = str(request.form["host"]).replace("<", "").replace(">", "")
elif key == "user_classes":
# Set environment.parsed_options.user_classes to the selected user_classes
parsed_options_dict[key] = request.form.getlist("user_classes")
elif key == "run_time":
if not value:
continue
try:
run_time = parse_timespan(value)
except ValueError:
err_msg = "Valid run_time formats are : 20, 20s, 3m, 2h, 1h20m, 3h30m10s, etc."
logger.error(err_msg)
return jsonify({"success": False, "message": err_msg, "host": environment.host})
elif key in parsed_options_dict:
# update the value in environment.parsed_options, but dont change the type.
parsed_options_value = parsed_options_dict[key]
if isinstance(parsed_options_value, bool):
parsed_options_dict[key] = value == "true"
elif parsed_options_value is None:
parsed_options_dict[key] = parsed_options_value
else:
parsed_options_dict[key] = type(parsed_options_dict[key])(value)
if environment.shape_class and environment.runner is not None:
environment.runner.start_shape()
return jsonify(
{
"success": True,
"message": f"Swarming started using shape class '{type(environment.shape_class).__name__}'",
"host": environment.host,
}
)
if self._swarm_greenlet is not None:
self._swarm_greenlet.kill(block=True)
self._swarm_greenlet = None
if environment.runner is not None:
self._swarm_greenlet = gevent.spawn(environment.runner.start, user_count, spawn_rate)
self._swarm_greenlet.link_exception(greenlet_exception_handler)
response_data = {
"success": True,
"message": "Swarming started",
"host": environment.host,
}
if run_time:
gevent.spawn_later(run_time, self._stop_runners).link_exception(greenlet_exception_handler)
response_data["run_time"] = run_time
if self.userclass_picker_is_active:
response_data["user_classes"] = sorted(user_classes.keys())
return jsonify(response_data)
else:
return jsonify({"success": False, "message": "No runner", "host": environment.host})
@app.route("/stop")
@self.auth_required_if_enabled
def stop() -> Response:
if self._swarm_greenlet is not None:
self._swarm_greenlet.kill(block=True)
self._swarm_greenlet = None
if environment.runner is not None:
environment.runner.stop()
return jsonify({"success": True, "message": "Test stopped"})
@app.route("/stats/reset")
@self.auth_required_if_enabled
def reset_stats() -> str:
environment.events.reset_stats.fire()
if environment.runner is not None:
environment.runner.stats.reset_all()
environment.runner.exceptions = {}
return "ok"
@app.route("/stats/report")
@self.auth_required_if_enabled
def stats_report() -> Response:
theme = request.args.get("theme", "")
res = get_html_report(
self.environment,
show_download_link=not request.args.get("download"),
use_modern_ui=self.modern_ui,
theme=theme,
)
if request.args.get("download"):
res = app.make_response(res)
res.headers["Content-Disposition"] = f"attachment;filename=report_{time()}.html"
return res
def _download_csv_suggest_file_name(suggest_filename_prefix: str) -> str:
"""Generate csv file download attachment filename suggestion.
Arguments:
suggest_filename_prefix: Prefix of the filename to suggest for saving the download. Will be appended with timestamp.
"""
return f"{suggest_filename_prefix}_{time()}.csv"
def _download_csv_response(csv_data: str, filename_prefix: str) -> Response:
"""Generate csv file download response with 'csv_data'.
Arguments:
csv_data: CSV header and data rows.
filename_prefix: Prefix of the filename to suggest for saving the download. Will be appended with timestamp.
"""
response = make_response(csv_data)
response.headers["Content-type"] = "text/csv"
response.headers["Content-disposition"] = (
f"attachment;filename={_download_csv_suggest_file_name(filename_prefix)}"
)
return response
@app.route("/stats/requests/csv")
@self.auth_required_if_enabled
def request_stats_csv() -> Response:
data = StringIO()
writer = csv.writer(data)
self.stats_csv_writer.requests_csv(writer)
return _download_csv_response(data.getvalue(), "requests")
@app.route("/stats/requests_full_history/csv")
@self.auth_required_if_enabled
def request_stats_full_history_csv() -> Response:
options = self.environment.parsed_options
if options and options.stats_history_enabled and isinstance(self.stats_csv_writer, StatsCSVFileWriter):
return send_file(
os.path.abspath(self.stats_csv_writer.stats_history_file_name()),
mimetype="text/csv",
as_attachment=True,
download_name=_download_csv_suggest_file_name("requests_full_history"),
etag=True,
max_age=0,
conditional=True,
last_modified=None,
)
return make_response("Error: Server was not started with option to generate full history.", 404)
@app.route("/stats/failures/csv")
@self.auth_required_if_enabled
def failures_stats_csv() -> Response:
data = StringIO()
writer = csv.writer(data)
self.stats_csv_writer.failures_csv(writer)
return _download_csv_response(data.getvalue(), "failures")
@app.route("/stats/requests")
@self.auth_required_if_enabled
@memoize(timeout=DEFAULT_CACHE_TIME, dynamic_timeout=True)
def request_stats() -> Response:
stats: list[dict[str, Any]] = []
errors: list[StatsErrorDict] = []
if environment.runner is None:
report = {
"stats": stats,
"errors": errors,
"total_rps": 0.0,
"total_fail_per_sec": 0.0,
"fail_ratio": 0.0,
"current_response_time_percentile_1": None,
"current_response_time_percentile_2": None,
"state": STATE_MISSING,
"user_count": 0,
}
if isinstance(environment.runner, MasterRunner):
report.update({"workers": []})
return jsonify(report)
for s in chain(sort_stats(environment.runner.stats.entries), [environment.runner.stats.total]):
stats.append(s.to_dict())
for e in environment.runner.errors.values():
err_dict = e.serialize()
err_dict["name"] = escape(err_dict["name"])
err_dict["error"] = escape(err_dict["error"])
errors.append(err_dict)
# Truncate the total number of stats and errors displayed since a large number of rows will cause the app
# to render extremely slowly. Aggregate stats should be preserved.
truncated_stats = stats[:500]
if len(stats) > 500:
truncated_stats += [stats[-1]]
report = {"stats": truncated_stats, "errors": errors[:500]}
total_stats = stats[-1]
if stats:
report["total_rps"] = total_stats["current_rps"]
report["total_fail_per_sec"] = total_stats["current_fail_per_sec"]
report["total_avg_response_time"] = total_stats["avg_response_time"]
report["fail_ratio"] = environment.runner.stats.total.fail_ratio
if self.modern_ui:
report["current_response_time_percentiles"] = {
f"response_time_percentile_{percentile}": environment.runner.stats.total.get_current_response_time_percentile(
percentile
)
for percentile in stats_module.MODERN_UI_PERCENTILES_TO_CHART
}
else:
report["current_response_time_percentile_1"] = (
environment.runner.stats.total.get_current_response_time_percentile(
stats_module.PERCENTILES_TO_CHART[0]
)
)
report["current_response_time_percentile_2"] = (
environment.runner.stats.total.get_current_response_time_percentile(
stats_module.PERCENTILES_TO_CHART[1]
)
)
if isinstance(environment.runner, MasterRunner):
workers = []
for worker in environment.runner.clients.values():
workers.append(
{
"id": worker.id,
"state": worker.state,
"user_count": worker.user_count,
"cpu_usage": worker.cpu_usage,
"memory_usage": worker.memory_usage,
}
)
report["workers"] = workers
report["state"] = environment.runner.state
report["user_count"] = environment.runner.user_count
return jsonify(report)
@app.route("/exceptions")
@self.auth_required_if_enabled
def exceptions() -> Response:
return jsonify(
{
"exceptions": [
{
"count": row["count"],
"msg": escape(row["msg"]),
"traceback": escape(row["traceback"]),
"nodes": ", ".join(row["nodes"]),
}
for row in (environment.runner.exceptions.values() if environment.runner is not None else [])
]
}
)
@app.route("/exceptions/csv")
@self.auth_required_if_enabled
def exceptions_csv() -> Response:
data = StringIO()
writer = csv.writer(data)
self.stats_csv_writer.exceptions_csv(writer)
return _download_csv_response(data.getvalue(), "exceptions")
@app.route("/tasks")
@self.auth_required_if_enabled
def tasks() -> dict[str, dict[str, dict[str, float]]]:
runner = self.environment.runner
user_spawned: dict[str, int]
if runner is None:
user_spawned = {}
else:
user_spawned = (
runner.reported_user_classes_count
if isinstance(runner, MasterRunner)
else runner.user_classes_count
)
task_data = {
"per_class": get_ratio(self.environment.user_classes, user_spawned, False),
"total": get_ratio(self.environment.user_classes, user_spawned, True),
}
return task_data
@app.route("/logs")
@self.auth_required_if_enabled
def logs():
log_reader_handler = [
handler for handler in logging.getLogger("root").handlers if handler.name == "log_reader"
]
if log_reader_handler:
logs = log_reader_handler[0].logs
else:
logs = []
return jsonify({"logs": logs})
@app.route("/login")
def login():
if not self.web_login:
return redirect(url_for("index"))
if self.modern_ui:
self.set_static_modern_ui()
return render_template(
"auth.html",
auth_args=self.auth_args,
)
else:
return "Web Auth is only available on the modern web ui."
@app.route("/user", methods=["POST"])
def update_user():
assert request.method == "POST"
user_settings = json.loads(request.data)
self.environment.update_user_class(user_settings)
return {}, 201
def start(self):
self.greenlet = gevent.spawn(self.start_server)
self.greenlet.link_exception(greenlet_exception_handler)
def start_server(self):
if self.tls_cert and self.tls_key:
self.server = pywsgi.WSGIServer(
(self.host, self.port), self.app, log=None, keyfile=self.tls_key, certfile=self.tls_cert
)
else:
self.server = pywsgi.WSGIServer((self.host, self.port), self.app, log=None)
self.server.serve_forever()
[docs] def stop(self):
"""
Stop the running web server
"""
self.server.stop()
[docs] def auth_required_if_enabled(self, view_func):
"""
Decorator that can be used on custom route methods that will turn on Flask Login
authentication if the ``--web-login`` flag is used. Example::
@web_ui.app.route("/my_custom_route")
@web_ui.auth_required_if_enabled
def my_custom_route():
return "custom response"
"""
@wraps(view_func)
def wrapper(*args, **kwargs):
if self.web_login:
try:
return login_required(view_func)(*args, **kwargs)
except Exception as e:
return f"Locust auth exception: {e} See https://docs.locust.io/en/stable/extending-locust.html#authentication for configuring authentication."
else:
return view_func(*args, **kwargs)
return wrapper
def set_static_modern_ui(self):
self.app.template_folder = self.webui_build_path
self.app.static_folder = os.path.join(self.webui_build_path, "assets")
self.app.static_url_path = "/assets/"
def update_template_args(self):
override_host_warning = False
if self.environment.host:
host = self.environment.host
elif self.environment.runner.user_classes:
all_hosts = {l.host for l in self.environment.runner.user_classes}
if len(all_hosts) == 1:
host = list(all_hosts)[0]
else:
# since we have multiple User classes with different host attributes, we'll
# inform that specifying host will override the host for all User classes
override_host_warning = True
host = None
else:
host = None
options = self.environment.parsed_options
if is_distributed := isinstance(self.environment.runner, MasterRunner):
worker_count = self.environment.runner.worker_count
else:
worker_count = 0
stats = self.environment.runner.stats
extra_options = argument_parser.ui_extra_args_dict()
available_user_classes = None
users = None
if self.environment.available_user_classes:
available_user_classes = sorted(self.environment.available_user_classes)
users = {
user_class_name: user_class.json()
for (user_class_name, user_class) in self.environment.available_user_classes.items()
}
available_shape_classes = ["Default"]
if self.environment.available_shape_classes:
available_shape_classes += sorted(self.environment.available_shape_classes.keys())
available_user_tasks = (
{
user_class_name: [task.__name__ for task in user_class]
for (user_class_name, user_class) in self.environment.available_user_tasks.items()
}
if self.environment.available_user_tasks
else None
)
if self.modern_ui:
percentiles = {
"percentiles_to_chart": stats_module.MODERN_UI_PERCENTILES_TO_CHART,
"percentiles_to_statistics": stats_module.PERCENTILES_TO_STATISTICS,
}
else:
percentiles = {
"percentile1": stats_module.PERCENTILES_TO_CHART[0],
"percentile2": stats_module.PERCENTILES_TO_CHART[1],
}
self.template_args = {
"locustfile": self.environment.locustfile,
"state": self.environment.runner.state,
"is_distributed": is_distributed,
"user_count": self.environment.runner.user_count,
"version": version,
"host": host if host else "",
"history": stats.history if stats.num_requests > 0 else {},
"override_host_warning": override_host_warning,
"num_users": options and options.num_users,
"spawn_rate": options and options.spawn_rate,
"worker_count": worker_count,
"hide_common_options": (
self.environment.shape_class
and not (self.userclass_picker_is_active or self.environment.shape_class.use_common_options)
),
"stats_history_enabled": options and options.stats_history_enabled,
"tasks": dumps({}),
"extra_options": extra_options,
"run_time": options and options.run_time,
"show_userclass_picker": self.userclass_picker_is_active,
"available_user_classes": available_user_classes,
"available_shape_classes": available_shape_classes,
"available_user_tasks": available_user_tasks,
"users": users,
**percentiles,
}
def _update_shape_class(self, shape_class_name):
if shape_class_name:
shape_class = self.environment.available_shape_classes[shape_class_name]
shape_class.runner = self.environment.runner
else:
shape_class = None
# Validating ShapeClass
self.environment.shape_class = shape_class
self.environment._validate_shape_class_instance()
def _update_user_classes(self, user_classes):
self.environment.user_classes = list(user_classes.values())
# populate the locustfile which used in web ui title only
if self.environment.locustfile is None:
self.environment.locustfile = ",".join(self.environment.user_classes_by_name.keys())
# Validating UserClasses
self.environment._remove_user_classes_with_weight_zero()
self.environment._validate_user_class_name_uniqueness()
def _stop_runners(self):
self.environment.runner.stop()