Emailer

Emailer's function is to receive email requests in the form of an EmailMsg, queue them, and then forward them to a service that will send the email. Currently Emailer is configured to use the MailGun api, but Emailer can be configured for other services' apis such as SendGrid.

Emailer listens to the messaging service set up with the Leverege Platform. The default message reading configuration is NSQ, and the topic that emailer listens to is email. The format of the message is an EmailMsg, which can be found in the Messages library, and an example is given below.

A message starts by invoking the route method on an instance of a writer created by Message Queue with the email topic and an instance of an EmailMsg. Message Queue writes the message to the Transponder service, which then routes it to this service (Emailer). Emailer does a validation check to make sure the message received is an instance of an EmailMsg. If there is a templateId provided, Emailer fetches the HTML template, and Handlebars is used to insert values from the context into the template. The Message is then sent to Mailgun for the email to be sent to the client.

Configuration

Required

There are 4 config variable that are required to run this service.

Name	Description
MAIL_GUN_API_KEY	Mailgun Api Key
MAIL_GUN_DOMAIN	Mailgun domain to send emails from
MODEL_FIREBASE_SERVICE_ACCOUNT	service account key to firebase database
MODEL_FIREBASE_DATABASE_URL	url to firebase database

Optional

There are 11 config variables that have defaults set that will need to be specified in the environment if the default is incorrect.

Name	Description	Default
EMAIL_TEMPLATES_DIR	file path to where email templates are stored	null
TRANSPORT_CONFIG	config for readers and writers	{ type, host, port }
NSQ_HOST_ADDR	host address for NSQ, not needed if TRANSPORT_CONFIG is specified	'127.0.0.1'
NSQ_HOST_PORT	port for NSQ, not needed if TRANSPORT_CONFIG is specified	4150
CACHE_CONFIG	configuration for the cache db	{ type, connection : { host, port } }
LIMIT_CONFIG	configuration for the limit db	Limit
MAIL_ATTEMPTS	maximum number of delivery attempts before aborting	3
MAIL_ATTEMPT_DELAY	delay enforced between email attempts	30000
MAIL_GUN_TEMPLATES	string representing the path to the Mailgun templates	'./templates/email/'
MAIL_GUN_DEFAULT_SENDER	default sender email address	'[email protected]'
API_SERVER	url of the Leverege api	'https://imagine.leverege.com:8181'

EmailMsg

A more detailed message spec can be found in the Messages library.

Name	Type	Description
to	string or array	recipients' email addresses
cc	string or array	carbon copy email list
bcc	string or array	blind carbon copy email list
subject	string	subject line
text	string	optional message in plain text format
html	string	optional message in html format
template	string	id of the template to use
context	object	object to give to the template
attachments	array	attachment list
attachments[n].filename	string	name of the attachment that the recipients will see
attachments[n].url	string	source of a file to send as attachment
attachments[n].content	string	base64 encoded content. Don't use this if url is specified
attachments[n].encoding	string	normally "base64"