A simple microservice designed in GO using Echo Microframework for sending emails and/or calendar invitations to users.
- Send emails using your Mailgun API credentials.
- Send using a standar SMTP server.
- Support for HTML and Plain Text emails.
- Calendar invitation with RSVP.
- Docker image is built using multistage and alpine image to keep it as small and secure as possible.
Download the repo and build the docker image:
$ git clone https://github.com/gdi3d/calenvite
$ docker build -t calenvite_svc:latest .
and use provided docker-compose files for more info.
$ git clone https://github.com/gdi3d/calenvite
$ go get -d -v
$ go mod download
$ go mod verify
$ go build -a -o calenvite
# run de service
$ ./calenvite
There's a few env vars that you need to set when you launch the container in order to work:
# If you want use Mailgun API:
CALENVITE_SVC_MAILGUN_DOMAIN: The domain from which the email are going to be sent
CALENVITE_SVC_MAILGUN_KEY: The Mailgun API secret key
# If you want to use SMTP:
CALENVITE_SVC_SMTP_HOST: The host/ip of the SMTP server
CALENVITE_SVC_SMTP_PORT: The port of the SMTP server
CALENVITE_SVC_SMTP_USER: The username to authenticate to the SMTP server
CALENVITE_SVC_SMTP_PASSWORD: The password to authenticate to the SMTP server
# common to both options
CALENVITE_SVC_EMAIL_SENDER_ADDRESS: The email address that would be used to send the email (this value will be used in the FROM part of the email)
CALENVITE_SVC_SEND_USING: MAILGUN or SMTP
CALENVITE_SVC_PORT: Port to expose (optional, default: 8000)
# mailgun-docker-compose.yml
version: "3.9"
services:
app_backend:
image: calenvite_svc:latest
ports:
- "8080:8000"
environment:
- CALENVITE_SVC_MAILGUN_DOMAIN=mycooldomain.com
- CALENVITE_SVC_MAILGUN_KEY=abcd1234
- [email protected]
- CALENVITE_SVC_SEND_USING=MAILGUN
# smtp-docker-compose.yml
version: "3.9"
services:
app_backend:
image: calenvite_svc:latest
ports:
- "8080:8000"
environment:
- CALENVITE_SVC_SMTP_HOST=smtp.mailprovider.com
- CALENVITE_SVC_SMTP_PORT=587
- CALENVITE_SVC_SMTP_USER=mysmtpuser
- CALENVITE_SVC_SMTP_PASSWORD=shhhh.is.secret
- [email protected]
- CALENVITE_SVC_SEND_USING=SMTP
A healthcheck endpoint to test if the service is up and running and a valid configuration is present.
Note: This healthcheck is only going to check that the environment vars are defined. It will not check if the credentials are valid or not
/healthcheck/
curl --location --request GET 'http:https://127.0.0.1:8080/healthcheck'
Service ok
HTTP/1.1 200
Content-Type: application/json; charset=UTF-8
Vary: Accept-Encoding
null
Service not working
HTTP/1.1 500 Internal Server Error
Content-Type: application/json; charset=UTF-8
Vary: Accept-Encoding
{
"message": "Internal Server Error"
}
Send email, and optionally, an calendar invitation with RSVP to the users.
/invite/
{
"users": [
{
"full_name": "Eric Cartman",
"email": "[email protected]"
},
{
"full_name": "Tina belcher",
"email": "[email protected]"
}
],
"invitation": {
"start_at": "2030-10-12T07:20:50.52Z",
"end_at": "2030-10-12T08:20:50.52Z",
"organizer_email": "[email protected]",
"organizer_full_name": "Mr. Mojo Rising",
"summary": "This meeting will be about...",
"location": "https://zoom.us/332324342",
"description": "Voluptatum ut quis ut. Voluptas qui pariatur quo. Omnis enim rerum dolorum. Qui aut est sed qui voluptatem harum. Consequuntur et accusantium culpa est fuga molestiae in ut. Numquam harum"
},
"email_subject": "You've just been invited!",
"email_body": "<html><body><h1>email body about the invitation/event</h1></body></html>",
"email_is_html": true
}
Notes about fields:
- If you don't need to send a calendar invitation you can omit the field
invitation - If you want to send plain text messages set the key
email_is_htmltofalse
curl --location --request POST 'http:https://127.0.0.1:8080/invite/' \
--header 'Content-Type: application/json' \
--data-raw '{"users":[{"full_name":"Eric Cartman","email":"[email protected]"},{"full_name":"Tina belcher","email":"[email protected]"}],"invitation":{"start_at":"2030-10-12T07:20:50.52Z","end_at":"2030-10-12T08:20:50.52Z","organizer_email":"[email protected]","organizer_full_name":"Mr. Mojo Rising","summary":"This meeting will be about...","location":"https://zoom.us/332324342","description":"Voluptatum ut quis ut. Voluptas qui pariatur quo. Omnis enim rerum dolorum. Qui aut est sed qui voluptatem harum. Consequuntur et accusantium culpa est fuga molestiae in ut. Numquam harum"},"email_subject":"You'\''ve just been invited!","email_body":"<html><body><h1>email body about the invitation/event</h1></body></html>","email_is_html":true}'
Successful
HTTP/1.1 200
Content-Type: application/json; charset=UTF-8
Vary: Accept-Encoding
{
"message": "SENT_OK",
"status_code": 200,
"error_fields": null
}
Field missing/invalid
HTTP/1.1 400 BAD REQUEST
Content-Type: application/json; charset=UTF-8
Vary: Accept-Encoding
{
"message": "INVALID_PAYLOAD",
"status_code": 400,
"error_fields": [
{
"field": "email_body",
"message": "",
"code": "required"
}
]
}
Error
HTTP/1.1 500 Internal Server Error
Content-Type: application/json; charset=UTF-8
Vary: Accept-Encoding
{
"message": "ERROR",
"status_code": 500,
"error_fields": null
}
You can Contact me 🙋🏻♂️ on LinkedIn if you have any questions. Otherwise you can open a ticket 😉