Send email through multiple email service providers
All about sending emails. Exposes API to enable any other service/client to be able to send emails. In a usual setup both email service providers will be able to pick up requests and process. In the event of single service/email provider failure, the message will be returned to the queue for other email provider to process.
A slight variation to the solution implmented is: instead of being one service provider on standby and activates when other is down, in current implmentation both the service providers are always active and ready to send emails ( mailgun needs to be out of sandbox to make it production ready ). Either one of the service failure doesn't impact the system because in the case of one provider failure the request will be visible and returned to the queue for other email provider to pick it up and send.
With DLQ ( Dead letter queue ), each failed request can be visible. Audit can be done via cloudwatch logs.
These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.
AWS account and credentials with proper IAM roles and policies to be able to deploy this service.
- Serverless (sls) installed gobally
serverless.ymlfile to be edited with appropriate env variables
npm install
You can simple run:
npm run test
Which in the backend executes:
nyc --reporter=html --reporter=text sls invoke test --stage=dev
To check for coverage
npm run coverage
The system is using aws lambda and exposes RESTful HTTP API, for API schema please check schemas/sendMail.schema.js file. Use an online tool like: https://www.jsonschemavalidator.net/ to get a proper payload.
A simple payload will look like this:
{
"personalizations": [{
"to": [
{
"name": "Dear Doe",
"email":"doe@doe.com"
}
]
}],
"from": {
"email": "support@siteminder.com"
},
"subject": "Test Subject",
"content":[
{
"type": "text/plain",
"value": "Email content in plain text"
}]
}
Another example payload with cc and bcc:
{
"personalizations": [{
"to": [
{
"name": "Tetris",
"email":"example@tetris.com"
}
], "cc":[
{
"name": "Test",
"email": "test@test.com"
}
],
"bcc":[
{"email": "bcc@email.com"}]
}],
"from": {
"email": "support@sitminder.com"
},
"subject": "Test Subject",
"content":[
{
"type": "text/plain",
"value": "Email content in plain text"
}]
}
Once you setup the AWS credentials, please deploy via below command:
serverless deploy --stage ${stage} --region ap-southeast-1
provide appropriate stage to deploy. For example to deploy in dev env, use dev
- Wonderful people of open sourced nodejs community.
- Reference the queue url automatically from cloudformation stack
- DLQ need to be setup
- Add support for CC and BCC (mailgun)
- Write more tests
- Produce swagger/openapi document as API doc.
- Mailgun is still in sandbox; hence currently there are no emails going out that are not pre-registered.
- No authentication