seatrial: situational-mock-based load testing

seatrial is a load generation tool for HTTP/1.1 services built to simulate traffic on known-common flows, particularly in monolith-ish applications. It operates under the model of: one or more Situations are executed in parallel, involving one or more Grunts who will go through the flows of using the backing service(s) based on the rules defined in their associated Persona. This makes seatrial a decent fit for testing otherwise constant-traffic applications' behaviors under fairly-predictably-bursty load.

This tool is technically capable of performing tests like "just attack this endpoint until it falls over", but is not designed around them. It's also not (yet?) well-suited to unpredictable loads - it can probably be used in a fuzzing manner to discover such breaking points, but seatrial is currently optimized for taking historical learnings plus data gleamed from the rest of your observability stack, and preventing repeats of the same outages (and indeed, for helping developers make such scale events, Non-Events).

Usage

Usage: seatrial <base_url> <req_situation> [<situations...>] [-m <multiplier>]

situational-mock-based load testing

Positional Arguments:
  base_url          base URL for all situations in this run
  req_situation     path to a RON file in seatrial(5) situation config format
  situations        optional paths to additional RON files in seatrial(5)
                    situation config format

Options:
  -m, --multiplier  integral multiplier for grunt counts (minimum 1)
  --help            display usage information

Further detail, commentary, API documentation, etc. are provided in scdoc format in the source repo, and in Unix manual page format in installed copies of seatrial.

• seatrial(1) documents the CLI application itself
• seatrial(5) documents the configuration format
• seatrial.lua(3) documents the Lua API to implement dynamic values and validators

In an installed copy of seatrial, including the Docker container, these are accessible with man <section> <name>, for example man 3 seatrial.lua or docker run --rm -it <container tag> man 3 seatrial.lua. From this source tree, provided scdoc is installed, you can instead run, for example, ./read_manual_page 'seatrial.lua(3)'.

Development and Packaging

Minimum Supported Rust Version is 1.58, as specified in Cargo.toml. Compilation requires nothing particularly special on the host OS beyond a standard Rust compiler stack; see Dockerfile for an example build. Documentation is in scdoc format, and should be compiled to roff by packagers (if you further process the roff into HTML or GNU Info or whatever, cool, but at least ship the manual pages).

The source must pass rustfmt and clippy without errors. It should also pass without warnings, unless there's good reason to leave the warnings in place.

MacOS users can use brew bundle to install the development dependencies as found in Brewfile (note that this will install Docker Desktop via its Cask; if you've installed Docker Desktop via some other means you may need to either uninstall your existing copy, or remove this line from Brewfile. Take care not to submit a PR with such a change in place!). Linux users should install rustup and scdoc via their distribution package manager. If rustup isn't available but a Rust of at least the MSRV is, then system-wide Rust is fine.

If you've never worked with Rust before and rustup is freshly installed, you'll need to run rustup-init to pull Cargo, the Rust toolchain, etc.

Tangentially to all of this, a Dockerfile is provided if preferred.

Legal

This is released under the terms of the ISC License:

Copyright 2022 The Wanderlust Group

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.