mirror of https://github.com/dirtbags/moth.git
176 lines
6.3 KiB
Markdown
176 lines
6.3 KiB
Markdown
Overview of MOTH
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================
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Monarch Of The Hill (MOTH) is a framework for running puzzle-based events for teams.
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Each team is assigned a token which they use to identify themselves.
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Teams are presented with a number of *categories*,
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each containing a sequence of *puzzles* of increasing point value.
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When the event starts, only the lowest-point puzzle in each category is available.
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As soon as any team enters the correct solution to the puzzle,
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the next puzzle is opened up for all teams.
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A scoreboard tracks team rankings,
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indicating score within each category,
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and overall ranking.
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How Scores are Calculated
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-------------------------
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The per-category score for team `t` is computed as:
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* Let `m` be the sum of all points in currently-visible puzzles in this category
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* Let `s` be the sum of all points team `t` has won in this category
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* Team `t`'s score is `s`/`m`
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Therefore, the maximum number of points a team can have in a category is 1.0.
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Put another way, a team's per-category score is the percentage of points they've made so far in that category.
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The total score for team `t` is the sum of all per-category points.
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Therefore, the maximum number of points a team can have in a 7-category event is 7.0.
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This point system has proven both easy to explain (if not immediately obvious),
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and acceptable by participants.
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Because we don't award extra points for quick responses,
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teams always feel like they have the possibility to catch up if they are skilled enough.
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Requirements
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-------------
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MOTH was written to run on a wide range of Linux systems.
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We are very careful not to require exotic extensions:
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you can run MOTH equally well on OpenWRT and Ubuntu Server.
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It might even run on BSD: if you've tried this, please email us!
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Its architecture also limits permissions,
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to make it easier to lock things down very tight.
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Since it writes to the filesystem slowly and atomically,
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it can be run from a USB flash drive formatted with VFAT.
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On the server, it requires:
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* Bourne shell (POSIX 1003.2: BASH is okay but not required)
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* Awk (POSIX 1003.2: gawk is okay but not required)
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* Lua 5.1
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On the client, it requires:
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* A modern web browser with JavaScript
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* Categories might add other requirements (like domain-specific tools to solve the puzzles)
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Filesystem Layout
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=================
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The system is set up to make it simple to run one or more contests on a single machine.
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I like to use `/srv/moth` as the base directory for all instances.
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So if I were running an instance called "hack",
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the instance directory would be `/srv/moth/hack`.
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There are five entries in each instance directory, described in detail below:
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/srv/moth/hack # (r-x) Instance directory
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/srv/moth/hack/assigned.txt # (r--) List of assigned team tokens
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/srv/moth/hack/bin/ # (r-x) Per-instance binaries
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/srv/moth/hack/categories/ # (r-x) Installed categories
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/srv/moth/hack/state/ # (rwx) Contest state
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/srv/moth/hack/www/ # (r-x) Web server documentroot
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`state/assigned.txt`
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----------------
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This is just a list of tokens that have been assigned.
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One token per line, and tokens can be anything you want.
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For my middle school events, I make tokens all possible 4-digit numbers,
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and tell kids to use any number they want: it makes it quicker to start.
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For more advanced events,
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this doesn't work as well because people start guessing other teams' numbers to confuse each other.
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So I use hex representations of random 32-bit ints.
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But you could use anything you want in here (for specifics on allowed characters, read the registration CGI).
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The registration CGI checks this list to see if a token has already assigned to a team name.
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Teams enter points by token,
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which lets them use any text they want for a team name.
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Since we don't read their team name anywhere else than the registration and scoreboard generator,
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it allows some assumptions about what kind of strings tokens can be,
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resulting in simpler code.
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`categories/`
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--------------
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`categories/` contains read-only category packages.
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Within each subdirectory there is:
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* `map.txt` mapping point values to directory names
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* `answers.txt` a list of answers for each point value
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* `salt` used to generate directory names (so people can't guess them to skip ahead)
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* `summary.txt` a compliation of `00summary.txt` files for puzzles, to give you a quick reference point when someone says "I need help on js 40".
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* `puzzles` is all the HTML that needs to be served up for the category
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`bin/`
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------
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Contains all the binaries you'll need to run an event.
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These are probably just copies from the `base` package (where this README lives).
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They're copied over in case you need to hack on them during an event.
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`bin/once` is of particular interest:
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it gets run periodically to do everything, including:
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* Gather points from `points.new` and append them to the points log.
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* Generate a new `puzzles.html` listing all open puzzles.
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* Generate a new `points.json` for the scoreboard
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### Pausing `once`
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You can pause everything `bin/once` does by touching a file in the root directory
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called `disabled`.
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This doesn't stop the game:
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it just stops points collection and generation of the files listed above.
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This is extremely helpful when, inevitably,
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you need to hack the points log,
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or do other maintenance tasks.
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Most times you don't even need to announce that you're doing anything:
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people can keep playing the game and their points keep collecting,
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ready to be appended to the log when you're done and you re-enable `once`.
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`www/`
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-----------
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HTML root for an event.
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It is possible to make this read-only,
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after you've set up your packages.
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You will need to symlink a few things into the `state` directory, though.
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`state/`
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---------
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Where all game state is stored.
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This is the only part of the contest directory setup that needs to be writable,
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and tarring it up preserves exactly the entire contest.
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Notable, it contains the mapping from team hash to name,
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and the points log.
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`points.log` is replayed by the scoreboard generator to calculate the current score for each team.
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New points are written to `points.new`, and picked up by `bin/once` to append to `points.log`.
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When `once` is disabled (by touching a file called `disabled` at the top level for a game),
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the various points-awarding things can keep writing files into `points.new`,
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with no need for locking or "bringing down the game for maintenance".
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