mCaptcha/docs/CONFIGURATION.md

Configuration

mCaptcha is highly configurable.

Configuration is applied/merged in the following order:

1. path to configuration file passed in via MCAPTCHA_CONFIG
2. ./config/default.toml
3. /etc/mcaptcha/config.toml
4. environment variables.

Setup

Environment variables

Setting environment variables are optional. The configuration files have all the necessary parameters listed. By setting environment variables, you will be overriding the values set in the configuration files.

General

Name	Value
MCAPTCHA_debug	Enable debug logging
MCAPTCHA_config	Path to configuration file
MCAPTCHA_commercial	Does this instance offer commercial plans? Please consider donating if it does :D
MCAPTCHA_source_code	Link to the source code of this instance
MCAPTCHA_allow_registration	Is registration allowed on this instance?
MCAPTCHA_allow_demo	Allow demo access to the server? If registration(previous option) is disabled then demo users will not be allowed

Database

Name	Value
MCAPTCHA_database_DATEBASE_POOL	database connection pool size
DATABASE_URL (overrides above vars)	database URL in postgres://user:pass@host:port/dbname format

Redis

Name	Value
MCAPTCHA_redis_URL	Redis URL
MCAPTCHA_redis_POOL	Redis connection pool size

Server

Name	Value
PORT	The port on which you want mCaptcha to listen to
MCAPTCHA_server_IP	The IP address on which you want mCaptcha to listen to
MCAPTCHA_server_DOMAIN	Domain under which mCaptcha will be*
MCAPTCHA_server_COOKIE_SECRET	Cookie secret, must be long and random
MCAPTCHA_server_PROXY_HAS_TLS	Is mCaptcha behind a proxy? If yes, mCaptcha can send additional headers like HSTS

* Authentication doesn't work without MCAPTCHA_DOMAIN set to the correct domain

Captcha

Name	Value
MCAPTCHA_captcha_SALT	Salt has to be long and random
MCAPTCHA_captcha_GC	Garbage collection duration in seconds, requires tuning but 30 is a good starting point
MCAPTCHA_captcha_RUNNERS	[Performance] Number of runners to use for PoW validation. Defaults to number of CPUs available
MCAPTCHA_captcha_QUEUE_LENGTH	[Performance] PoW Validation queue length, controls how many pending validation jobs can be held in queue
MCAPTCHA_captcha_ENABLE_STATS	Record for CAPTCHA events like configuration fetch, solves and authentication of validation token. Useful for commercial deployments.
MCAPTCHA_captcha_DEFAULT_DIFFICULTY_STRATEGY_avg_traffic_difficulty%	Default difficulty factor to use in easy mode CAPTCHA configuration estimation for average traffic metric
MCAPTCHA_captcha_DEFAULT_DIFFICULTY_STRATEGY_peak_sustainable_traffic_difficulty%	Default difficulty factor to use in easy mode CAPTCHA configuration estimation for peak traffic metric
MCAPTCHA_captcha_DEFAULT_DIFFICULTY_STRATEGY_broke_my_site_traffic_difficulty%	Default difficulty factor to use in easy mode CAPTCHA configuration estimation for traffic that took the website down
MCAPTCHA_captcha_DEFAULT_DIFFICULTY_STRATEGY_duration%	Default duration to use in CAPTCHA configuration in easy mode

% See commits 54b14291ec140e and 42544ec421e0 for more info.

SMTP

Name	Value
MCAPTCHA_smtp_FROM	email address from which the email will be sent
MCAPTCHA_smtp_URL	SMTP server URL
MCAPTCHA_smtp_PORT	SMTP server port
MCAPTCHA_smtp_USERNAME	SMTP username
MCAPTCHA_smtp_PASSWORD	SMTP password