Configuration

EmailEngine uses two types of configurations:

1. Application Configuration: This is loaded when the application starts and includes settings such as the HTTP port number.
2. Runtime Configuration: This can be updated at any time via the Settings API endpoint or through the built-in web interface. Examples include the webhook destination URL.

You can configure the application using either command-line arguments or environment variables. If both are provided for the same setting, the environment variable will take precedence over the command-line argument.

You can set a fixed number of worker threads (the default is 4), or use the special value "cpus", which automatically matches the number of worker threads to the available CPU cores.

Example:

$ emailengine --workers.imap=cpus

If you run multiple EmailEngine instances on the same Redis server, ensure that you use a different database number or unique key prefixes to prevent conflicts.

For non-default Redis configurations, such as when your Redis instance is hosted remotely or requires authentication, provide the Redis connection details 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"

To specify multiple CORS origins, use a space-separated string value, or add a separate --cors.origin argument for each origin.

Note: Use HTTPS only if your reverse proxy and EmailEngine instances are on different servers. For localhost connections, prefer HTTP.

By default, a queue worker processes one job at a time. If your queues are being processed too slowly, you can increase the concurrency values. However, increasing concurrency may result in events being processed out of order when the concurrency count is set higher than 1. Therefore, only increase these values if event order is not a critical concern.

If the working directory contains a "dotenv" file (named .env), EmailEngine will use it to set environment variables.

The dotenv file follows the KEY=VALUE format, with each entry on a separate line, like this:

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

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

You can also set individual environment variables by specifying a file that contains the value. To do this, use an environment key with a _FILE suffix and provide the path to the file.

If an environment variable is not set directly, EmailEngine will check if a corresponding file path variable exists. If it finds one, EmailEngine will attempt to read the value from the specified file.

In the example below, the value for EENGINE_SECRET is provided from a file located at "/path/to/secret.txt":

$ echo 'secretpass' > /path/to/secret.txt
$ export EENGINE_SECRET_FILE=/path/to/secret.txt
$ emailengine