Configuration

EmailEngine uses two kinds of configurations:

1. Application configuration that is loaded when the application starts (e.g., the port number to listen on)
2. Runtime configuration that is updated via the Settings API endpoint and can be modified at any time (e.g., webhooks destination URL). You can also change most of these settings via the built-in web interface.

You can set application configuration either via command-line arguments or environment variables. If both are specified, then the environment variable for the same thing overrides the value from the command-line argument.

If the working directory contains a "dotenv" file (a file named .env) then EmailEngine uses it to populate environment variables.

Dotenv file uses KEY=VALUE syntax with each entry on a separate line, for example like this:

EENGINE_WORKERS=2
EENGINE_REDIS="redis://127.0.0.1:6379/8"

Lines starting with # are treated as comments, and empty lines are ignored.

These are the main application settings

IMAP Worker Count

You can specify a fixed number of threads to start (worker count defaults to 4), or you can use a special value "cpus" that maps to the count of CPU threads.

Example:

$ emailengine --workers.imap=cpus

Redis configuration

If you are using a non-default Redis configuration, for example, if your Redis instance is not installed locally or requires authentication, then you can provide Redis configuration as a connection string in the following format:

redis://:password@hostname:port/db-number

Example:

$ emailengine --dbs.redis="redis://:supersecret@178.32.207.71:6379/8"

Web server settings for the API and web UI

By default, a queue worker processes a single job at a time. If your queues are processed too slowly, you can increase the concurrency counters. The downside is that events are not guaranteed to be processed in the correct order when having concurrency higher than 1, so grow these values only when you do not care about ordering too much.