Group related command line options together

[heyman]

This PR (for #1282) does the following

• Group related command line options together using Argument Groups from argparse, resulting in a much better --help message
• Removes deprecated --no-reset-stats options.

This PR is work in progress. Here's the current help output:

Usage: locust [OPTIONS] [LocustClass ...]

Common options:
  -h, --help            show this help message and exit
  -f LOCUSTFILE, --locustfile LOCUSTFILE
                        Python module file to import, e.g. '../other.py'. Default: locustfile
  -H HOST, --host HOST  Host to load test in the following format: http://10.21.32.33
  -c NUM_CLIENTS, --clients NUM_CLIENTS
                        Number of concurrent Locust users. Only used together with --headless
  -r HATCH_RATE, --hatch-rate HATCH_RATE
                        The rate per second in which clients are spawned. Only used together with --headless
  -t RUN_TIME, --run-time RUN_TIME
                        Stop after the specified amount of time, e.g. (300s, 20m, 3h, 1h30m, etc.). Only used together with --headless
  -l, --list            Show list of possible locust classes and exit

Web UI options:
  --web-host WEB_HOST   Host to bind the web interface to. Defaults to '' (all interfaces)
  --web-port WEB_PORT, -P WEB_PORT
                        Port on which to run web host
  --headless            Disable the web interface, and instead start the load test immediately. Requires -c and -t to be specified.

Master options:
  Options for running a Locust Master node when running Locust distributed. A Master node need Worker nodes that connect to it before it can run load tests.

  --master              Set locust to run in distributed mode with this process as master
  --master-bind-host MASTER_BIND_HOST
                        Interfaces (hostname, ip) that locust master should bind to. Only used when running with --master. Defaults to * (all available interfaces).
  --master-bind-port MASTER_BIND_PORT
                        Port that locust master should bind to. Only used when running with --master. Defaults to 5557.
  --expect-workers EXPECT_WORKERS
                        How many workers master should expect to connect before starting the test (only when --headless used).

Worker options:

  Options for running a Locust Worker node when running Locust distributed.
  Only the LOCUSTFILE (-f option) need to be specified when starting a Worker, since other options such as -c, -r, -t are specified on the Master node.

  --worker              Set locust to run in distributed mode with this process as worker
  --master-host MASTER_HOST
                        Host or IP address of locust master for distributed load testing. Only used when running with --worker. Defaults to 127.0.0.1.
  --master-port MASTER_PORT
                        The port to connect to that is used by the locust master for distributed load testing. Only used when running with --worker. Defaults to 5557.

Request statistics options:
  --csv CSVFILEBASE, --csv-base-name CSVFILEBASE
                        Store current request stats to files in CSV format.
  --csv-full-history    Store each stats entry in CSV format to _stats_history.csv file
  --print-stats         Print stats in the console
  --only-summary        Only print the summary stats
  --reset-stats         Reset statistics once hatching has been completed. Should be set on both master and workers when running in distributed mode

Logging options:
  --skip-log-setup      Disable Locust's logging setup. Instead, the configuration is provided by the Locust test or Python defaults.
  --loglevel LOGLEVEL, -L LOGLEVEL
                        Choose between DEBUG/INFO/WARNING/ERROR/CRITICAL. Default is INFO.
  --logfile LOGFILE     Path to log file. If not set, log will go to stdout/stderr

Step load options:
  --step-load           Enable Step Load mode to monitor how performance metrics varies when user load increases. Requires --step-clients and --step-time to be specified.
  --step-clients STEP_CLIENTS
                        Client count to increase by step in Step Load mode. Only used together with --step-load
  --step-time STEP_TIME
                        Step duration in Step Load mode, e.g. (300s, 20m, 3h, 1h30m, etc.). Only used together with --step-load

Other options:
  --show-task-ratio     Print table of the locust classes' task execution ratio
  --show-task-ratio-json
                        Print json data of the locust classes' task execution ratio
  --version, -V         Show program's version number and exit
  --exit-code-on-error EXIT_CODE_ON_ERROR
                        Sets the process exit code to use when a test result contain any failure or error
  -s STOP_TIMEOUT, --stop-timeout STOP_TIMEOUT
                        Number of seconds to wait for a simulated user to complete any executing task before exiting. Default is to terminate immediately. This parameter only needs to be specified for
                        the master process when running Locust distributed.

Locust user classes:
  LocustClass           Optionally specify which Locust classes that should be used (available Locust classes can be listed with -l or --list)

[codecov]

Codecov Report

Merging #1311 into master will increase coverage by 0.12%.
The diff coverage is 90.00%.

@@            Coverage Diff             @@
##           master    #1311      +/-   ##
==========================================
+ Coverage   80.36%   80.49%   +0.12%     
==========================================
  Files          23       23              
  Lines        2139     2148       +9     
  Branches      322      323       +1     
==========================================
+ Hits         1719     1729      +10     
+ Misses        342      340       -2     
- Partials       78       79       +1     

Impacted Files	Coverage Δ
locust/contrib/fasthttp.py	89.83% <ø> (ø)
locust/stats.py	88.19% <ø> (ø)
locust/main.py	22.77% <28.57%> (-0.43%)	⬇️
locust/argument_parser.py	74.75% <100.00%> (+2.71%)	⬆️
locust/runners.py	76.65% <0.00%> (+0.22%)	⬆️

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[cyberw]

Awesome! Dump the descriptions that just repeat the headers though (e.g "Logging options: Options related to logging")

[heyman]

Dump the descriptions that just repeat the headers though (e.g "Logging options: Options related to logging")

Done!

I've also renamed --no-web to --headless.

[cyberw]

"Enable Step Load mode to monitor how performance metrics varies when user load increases. Requires --step-clients and --step-time to be specified." This description is weird, sounds like it has something to do with monitoring...

[cyberw]

What is master_bind_port? It doesnt appear to be used anywhere (only master_port seems to actually be used)

[cyberw]

Oh, and we might want to change LocustClass to UserClass.

[cyberw]

We should probably add the output of locust --help to the docs somewhere (to help people who are googling/searching the docs). If that could be automated it would be really nice.

[heyman]

"Enable Step Load mode to monitor how performance metrics varies when user load increases. Requires --step-clients and --step-time to be specified." This description is weird, sounds like it has something to do with monitoring...

I agree. TBH, the "step load" implementation feels a bit half-baked to me, and I'm not very fond of it, but I think that should be a separate issue.

What is master_bind_port? It doesnt appear to be used anywhere (only master_port seems to actually be used)

It's the port that the master node listen to for incoming worker connections. It's used in main.py.

Oh, and we might want to change LocustClass to UserClass.

Yeah, I figured we could do that in the Locust -> User change.

We should probably add the output of locust --help to the docs somewhere (to help people who are googling/searching the docs). If that could be automated it would be really nice.

Great idea! I'll look into if we can get it into the documentation build flow.

[cyberw]

What is master_bind_port? It doesnt appear to be used anywhere (only master_port seems to actually be used)

It's the port that the master node listen to for incoming worker connections. It's used in main.py.

Ah, I tried searching for it in the project and was unable to find anyone reading the value, but I was accidentally searching for master_bind_port (space at the end). Sorry!

But it made me think: Perhaps splitting master settings and slave settings into their own groups would make it more clear?

[heyman]

But it made me think: Perhaps splitting master settings and slave settings into their own groups would make it more clear?

I tried it out and I think it's an improvement!

[heyman]

We should probably add the output of locust --help to the docs somewhere (to help people who are googling/searching the docs). If that could be automated it would be really nice.

Fixed in 51547a0. Here's how it looks in the docs: https://docs.locust.io/en/latest/quickstart.html#locust-command-line-interface