Fix #117: Implement email alerts

README.md

@@ -40,6 +40,7 @@ Have any feedback or want to share your good/bad experience with Gatus? Feel fre
   - [Client configuration](#client-configuration)
   - [Alerting](#alerting)
     - [Configuring Discord alerts](#configuring-discord-alerts)
+    - [Configuring Email alerts](#configuring-email-alerts)
     - [Configuring Mattermost alerts](#configuring-mattermost-alerts)
     - [Configuring Messagebird alerts](#configuring-messagebird-alerts)
     - [Configuring PagerDuty alerts](#configuring-pagerduty-alerts)
@@ -348,6 +349,44 @@ endpoints:
 ```
 
 
+#### Configuring Email alerts
+| Parameter                          | Description                                       | Default        |
+|:---------------------------------- |:------------------------------------------------- |:-------------- |
+| `alerting.email`                   | Configuration for alerts of type `email`          | `{}`           |
+| `alerting.email.from`              | Email used to send the alert                      | Required `""`  |
+| `alerting.email.password`          | Password of the email used to send the alert      | Required `""`  |
+| `alerting.email.host`              | Host of the mail server (e.g. `smtp.gmail.com`)   | Required `""`  |
+| `alerting.email.port`              | Port the mail server is listening to (e.g. `587`) | Required `0`   |
+| `alerting.email.to`                | Email(s) to send the alerts to                    | Required `""`  |
+| `alerting.email.default-alert`     | Default alert configuration. <br />See [Setting a default alert](#setting-a-default-alert) | N/A |
+
+```yaml
+alerting:
+  email:
+    from: "from@example.com"
+    password: "hunter2"
+    host: "mail.example.com"
+    port: 587
+    to: "recipient1@example.com,recipient2@example.com"
+
+endpoints:
+  - name: website
+    url: "https://twin.sh/health"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+      - "[BODY].status == UP"
+      - "[RESPONSE_TIME] < 300"
+    alerts:
+      - type: email
+        enabled: true
+        description: "healthcheck failed"
+        send-on-resolved: true
+```
+
+**NOTE:** Some mail servers are painfully slow.
+
+
 #### Configuring Mattermost alerts
 | Parameter                           | Description                                                                                 | Default        |
 |:----------------------------------- |:------------------------------------------------------------------------------------------- |:-------------- |