Sendgrid Event Logger

Small, fast http server to log Sendgrid Event Webhook callback to Elasticsearch

Monitoring sendgrid events on Kibana dashboard

Installing

Just install globally with npm:

npm install -g sendgrid-event-logger

Setup

Install and run Elasticsearch. Refer to the docs for details: https://www.elastic.co/guide/en/elasticsearch/reference/current/_installation.html
Install the default config file by running:
```
 sendgrid-event-logger install
```
If you're running elasticsearch on a port other than 9200 the above command will generate an error. Don't worry about it for now.
Check /etc/sendgrid-event-logger.json and edit if necessary.
To run the server, simply type:
```
 sendgrid-event-logger
```
It is highly recommended that you run the server using a process manager like PM2 or forever.
Configure your Sendgrid account to point the Event Webhook to:
```
 http://your.server.address:port/logger
```
Refer to the docs for how to set up the Event Webhook: https://sendgrid.com/docs/API_Reference/Webhooks/event.html

Note: If you enable basic auth then set the URL to:
```
 http://username:password@your.server.address:port/logger
```

Integrating with Kibana

Install Kibana. Refer to the docs for details: https://www.elastic.co/guide/en/kibana/current/setup.html
Configure a new index pattern.
- Select "Index contains time-based events" checkbox
- In the "Index name or pattern" entry type: mail-*
- In the "Time-field name" entry select "timestamp"
- Press "Create"

Configuration

The config file is located at: /etc/sendgrid-event-logger.json. The following are the configurations available:

elasticsearch_host Location of the elasticsearch server.
port The port the server listens on
use_basicauth Enable or disable basic authentication
basicauth.user Login username if basicauth is enabled
basicauth.password Login password if basicauth is enabled
use_https Enable or disable TLS
https.key_file Location of TLS key file on disk
https.cert_file Location of TLS certificate file on disk
days_to_retain_log Number of days to keep logs. Logs older than this will be deleted periodically. Set to 0 or false to disable automatic deletion of old logs.

Note: I've personally found that elasticsearch takes up roughly 200MB of disk space for every 100000 emails delivered by Sendgrid. So you can use it as a rough guideline to calculate how much disk you need. For example, if you send 200k emails per month on average then you'd need 400MB per month or roughly 5GB per year. You can then set days_to_retain_log appropriately depending on how much disk space you have.

Implementation details

All sendgrid events are logged to a time-series index with the prefix mail-. The server logs events to a new index each day similar to how logstash works.

By default the server listens to port 8080 but this can be changed in the config file.

The server exposes 4 URL endpoints:

POST /logger This receives data from Sendgrid Event Webhook callback It expects the data to be an array of events. At minimum, the data format must be at least:
```
  [
      {
          timestamp: ${unix_timestamp}
      }
  ]
```
The only mandatory field is timestamp. Which means you can also post your own events to this URL if you want to correlate your data with sendgrid events.
GET /status This simply returns {status:'ok'}. This URL may be used to check if the server is still alive.
GET /copyright Returns copyright and license information.
GET /version Returns version information.

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 (GPL-2.0) as published bythe Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.