gatus/README.md

Gatus is a health dashboard that gives you the ability to monitor your services using HTTP, ICMP, TCP, and even DNS queries as well as evaluate the result of said queries by using a list of conditions on values like the status code, the response time, the certificate expiration, the body and many others. The icing on top is that each of these health checks can be paired with alerting via Slack, PagerDuty, Discord and even Twilio.

I personally deploy it in my Kubernetes cluster and let it monitor the status of my core applications: https://status.twinnation.org/

Quick start

docker run -p 8080:8080 --name gatus twinproduction/gatus

For more details, see Usage

Table of Contents

• Why Gatus?
• Features
• Usage
• Configuration
  • Conditions
    • Placeholders
    • Functions
  • Alerting
    • Configuring Slack alerts
    • Configuring Discord alerts
    • Configuring PagerDuty alerts
    • Configuring Twilio alerts
    • Configuring Mattermost alerts
    • Configuring Messagebird alerts
    • Configuring Telegram alerts
    • Configuring custom alerts
  • Kubernetes (ALPHA)
    • Auto Discovery
    • Deploying
• Docker
• Helm Chart
• Running the tests
• Using in Production
• FAQ
  • Sending a GraphQL request
  • Recommended interval
  • Default timeouts
  • Monitoring a TCP service
  • Monitoring a service using ICMP
  • Monitoring a service using DNS queries
  • Monitoring a service using STARTTLS
  • Basic authentication
  • disable-monitoring-lock
  • Reloading configuration on the fly
  • Service groups
  • Exposing Gatus on a custom port
  • Uptime Badges (ALPHA)
  • API

Why Gatus?

Before getting into the specifics, I want to address the most common question:

Why would I use Gatus when I can just use Prometheus’ Alertmanager, Cloudwatch or even Splunk?

Neither of these can tell you that there’s a problem if there are no clients actively calling the endpoint. In other words, it's because monitoring metrics mostly rely on existing traffic, which effectively means that unless your clients are already experiencing a problem, you won't be notified.

Gatus, on the other hand, allows you to configure health checks for each of your features, which in turn allows it to monitor these features and potentially alert you before any clients are impacted.

A sign you may want to look into Gatus is by simply asking yourself whether you'd receive an alert if your load balancer was to go down right now. Will any of your existing alerts by triggered? Your metrics won’t report an increase in errors if there’s no traffic that makes it to your applications. This puts you in a situation where your clients are the ones that will notify you about the degradation of your services rather than you reassuring them that you're working on fixing the issue before they even know about it.

Features

The main features of Gatus are:

• Highly flexible health check conditions: While checking the response status may be enough for some use cases, Gatus goes much further and allows you to add conditions on the response time, the response body and even the IP address.
• Ability to use Gatus for user acceptance tests: Thanks to the point above, you can leverage this application to create automated user acceptance tests.
• Very easy to configure: Not only is the configuration designed to be as readable as possible, it's also extremely easy to add a new service or a new endpoint to monitor.
• Alerting: While having a pretty visual dashboard is useful to keep track of the state of your application(s), you probably don't want to stare at it all day. Thus, notifications via Slack, Mattermost, Messagebird, PagerDuty and Twilio are supported out of the box with the ability to configure a custom alerting provider for any needs you might have, whether it be a different provider or a custom application that manages automated rollbacks.
• Metrics
• Low resource consumption: As with most Go applications, the resource footprint that this application requires is negligibly small.
• GitHub uptime badges:

Usage

By default, the configuration file is expected to be at config/config.yaml.

You can specify a custom path by setting the GATUS_CONFIG_FILE environment variable.

Here's a simple example:

metrics: true         # Whether to expose metrics at /metrics
services:
  - name: twinnation  # Name of your service, can be anything
    url: "https://twinnation.org/health"
    interval: 30s     # Duration to wait between every status check (default: 60s)
    conditions:
      - "[STATUS] == 200"         # Status must be 200
      - "[BODY].status == UP"     # The json path "$.status" must be equal to UP
      - "[RESPONSE_TIME] < 300"   # Response time must be under 300ms
  - name: example
    url: "https://example.org/"
    interval: 5m
    conditions:
      - "[STATUS] == 200"

This example would look like this:

Note that you can also use environment variables in the configuration file (e.g. $DOMAIN, ${DOMAIN})

If you want to test it locally, see Docker.

Configuration

Parameter	Description	Default
debug	Whether to enable debug logs	false
metrics	Whether to expose metrics at /metrics	false
storage	Storage configuration	{}
storage.file	File to persist the data in. If not set, storage is in-memory only.	""
services	List of services to monitor	Required []
services[].name	Name of the service. Can be anything.	Required ""
services[].group	Group name. Used to group multiple services together on the dashboard. See Service groups.	""
services[].url	URL to send the request to	Required ""
services[].method	Request method	GET
services[].insecure	Whether to skip verifying the server's certificate chain and host name	false
services[].conditions	Conditions used to determine the health of the service. See Conditions.	[]
services[].interval	Duration to wait between every status check	60s
services[].graphql	Whether to wrap the body in a query param ({"query":"$body"})	false
services[].body	Request body	""
services[].headers	Request headers	{}
services[].dns	Configuration for a service of type DNS. See Monitoring a service using DNS queries.	""
services[].dns.query-type	Query type for DNS service	""
services[].dns.query-name	Query name for DNS service	""
services[].alerts[].type	Type of alert. Valid types: slack, discord, pagerduty, twilio, mattermost, messagebird, custom	Required ""
services[].alerts[].enabled	Whether to enable the alert	false
services[].alerts[].failure-threshold	Number of failures in a row needed before triggering the alert	3
services[].alerts[].success-threshold	Number of successes in a row before an ongoing incident is marked as resolved	2
services[].alerts[].send-on-resolved	Whether to send a notification once a triggered alert is marked as resolved	false
services[].alerts[].description	Description of the alert. Will be included in the alert sent	""
alerting	Configuration for alerting. See Alerting.	{}
security	Security configuration	{}
security.basic	Basic authentication security configuration	{}
security.basic.username	Username for Basic authentication	Required ""
security.basic.password-sha512	Password's SHA512 hash for Basic authentication	Required ""
disable-monitoring-lock	Whether to disable the monitoring lock	false
skip-invalid-config-update	Whether to ignore invalid configuration update. See Reloading configuration on the fly.
web	Web configuration	{}
web.address	Address to listen on	0.0.0.0
web.port	Port to listen on	8080

• For Kubernetes configuration, see Kubernetes.
• For alerting configuration, see Alerting.

Conditions

Here are some examples of conditions you can use:

Condition	Description	Passing values	Failing values
[STATUS] == 200	Status must be equal to 200	200	201, 404, ...
[STATUS] < 300	Status must lower than 300	200, 201, 299	301, 302, ...
[STATUS] <= 299	Status must be less than or equal to 299	200, 201, 299	301, 302, ...
[STATUS] > 400	Status must be greater than 400	401, 402, 403, 404	400, 200, ...
[STATUS] == any(200, 429)	Status must be either 200 or 429	200, 429	201, 400, ...
[CONNECTED] == true	Connection to host must've been successful	true, false
[RESPONSE_TIME] < 500	Response time must be below 500ms	100ms, 200ms, 300ms	500ms, 501ms
[IP] == 127.0.0.1	Target IP must be 127.0.0.1	127.0.0.1	0.0.0.0
[BODY] == 1	The body must be equal to 1	1	{}, 2, ...
[BODY].user.name == john	JSONPath value of $.user.name is equal to john	{"user":{"name":"john"}}
[BODY].data[0].id == 1	JSONPath value of $.data[0].id is equal to 1	{"data":[{"id":1}]}
[BODY].age == [BODY].id	JSONPath value of $.age is equal JSONPath $.id	{"age":1,"id":1}
len([BODY].data) < 5	Array at JSONPath $.data has less than 5 elements	{"data":[{"id":1}]}
len([BODY].name) == 8	String at JSONPath $.name has a length of 8	{"name":"john.doe"}	{"name":"bob"}
has([BODY].errors) == false	JSONPath $.errors does not exist	{"name":"john.doe"}	{"errors":[]}
has([BODY].users) == true	JSONPath $.users exists	{"users":[]}	{}
[BODY].name == pat(john*)	String at JSONPath $.name matches pattern john*	{"name":"john.doe"}	{"name":"bob"}
[BODY].id == any(1, 2)	Value at JSONPath $.id is equal to 1 or 2	1, 2	3, 4, 5
[CERTIFICATE_EXPIRATION] > 48h	Certificate expiration is more than 48h away	49h, 50h, 123h	1h, 24h, ...

Placeholders

Placeholder	Description	Example of resolved value
[STATUS]	Resolves into the HTTP status of the request	404
[RESPONSE_TIME]	Resolves into the response time the request took, in ms	10
[IP]	Resolves into the IP of the target host	192.168.0.232
[BODY]	Resolves into the response body. Supports JSONPath.	{"name":"john.doe"}
[CONNECTED]	Resolves into whether a connection could be established	true
[CERTIFICATE_EXPIRATION]	Resolves into the duration before certificate expiration	24h, 48h, 0 (if not using HTTPS)
[DNS_RCODE]	Resolves into the DNS status of the response	NOERROR

Functions

Function	Description	Example
len	Returns the length of the object/slice. Works only with the [BODY] placeholder.	len([BODY].username) > 8
has	Returns true or false based on whether a given path is valid. Works only with the [BODY] placeholder.	has([BODY].errors) == false
pat	Specifies that the string passed as parameter should be evaluated as a pattern. Works only with == and !=.	[IP] == pat(192.168.*)
any	Specifies that any one of the values passed as parameters is a valid value. Works only with == and !=.	[BODY].ip == any(127.0.0.1, ::1)

NOTE: Use pat only when you need to. [STATUS] == pat(2*) is a lot more expensive than [STATUS] < 300.

Alerting

Gatus supports multiple alerting providers, such as Slack and PagerDuty, and supports different alerts for each individual services with configurable descriptions and thresholds.

Note that if an alerting provider is not configured properly, all alerts configured with the provider's type will be ignored.

Parameter	Description	Default
alerting.slack	Configuration for alerts of type slack	{}
alerting.slack.webhook-url	Slack Webhook URL	Required ""
alerting.discord	Configuration for alerts of type discord	{}
alerting.discord.webhook-url	Discord Webhook URL	Required ""
alerting.pagerduty	Configuration for alerts of type pagerduty	{}
alerting.pagerduty.integration-key	PagerDuty Events API v2 integration key.	Required ""
alerting.twilio	Settings for alerts of type twilio	{}
alerting.twilio.sid	Twilio account SID	Required ""
alerting.twilio.token	Twilio auth token	Required ""
alerting.twilio.from	Number to send Twilio alerts from	Required ""
alerting.twilio.to	Number to send twilio alerts to	Required ""
alerting.mattermost	Configuration for alerts of type mattermost	{}
alerting.mattermost.webhook-url	Mattermost Webhook URL	Required ""
alerting.mattermost.insecure	Whether to skip verifying the server's certificate chain and host name	false
alerting.messagebird	Settings for alerts of type messagebird	{}
alerting.messagebird.access-key	Messagebird access key	Required ""
alerting.messagebird.originator	The sender of the message	Required ""
alerting.messagebird.recipients	The recipients of the message	Required ""
alerting.telegram	Configuration for alerts of type telegram	{}
alerting.telegram.token	Telegram Bot Token	Required ""
alerting.telegram.id	Telegram User ID	Required ""
alerting.custom	Configuration for custom actions on failure or alerts	{}
alerting.custom.url	Custom alerting request url	Required ""
alerting.custom.method	Request method	GET
alerting.custom.insecure	Whether to skip verifying the server's certificate chain and host name	false
alerting.custom.body	Custom alerting request body.	""
alerting.custom.headers	Custom alerting request headers	{}
alerting.*.default-alert.enabled	Whether to enable the alert	N/A
alerting.*.default-alert.failure-threshold	Number of failures in a row needed before triggering the alert	N/A
alerting.*.default-alert.success-threshold	Number of successes in a row before an ongoing incident is marked as resolved	N/A
alerting.*.default-alert.send-on-resolved	Whether to send a notification once a triggered alert is marked as resolved	N/A
alerting.*.default-alert.description	Description of the alert. Will be included in the alert sent	N/A

Configuring Slack alerts

alerting:
  slack: 
    webhook-url: "https://hooks.slack.com/services/**********/**********/**********"

services:
  - name: twinnation
    url: "https://twinnation.org/health"
    interval: 30s
    alerts:
      - type: slack
        enabled: true
        description: "healthcheck failed 3 times in a row"
        send-on-resolved: true
      - type: slack
        enabled: true
        failure-threshold: 5
        description: "healthcheck failed 5 times in a row"
        send-on-resolved: true
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"
      - "[RESPONSE_TIME] < 300"

Here's an example of what the notifications look like:

Configuring Discord alerts

alerting:
  discord: 
    webhook-url: "https://discord.com/api/webhooks/**********/**********"

services:
  - name: twinnation
    url: "https://twinnation.org/health"
    interval: 30s
    alerts:
      - type: discord
        enabled: true
        description: "healthcheck failed"
        send-on-resolved: true
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"
      - "[RESPONSE_TIME] < 300"

Configuring PagerDuty alerts

It is highly recommended to set services[].alerts[].send-on-resolved to true for alerts of type pagerduty, because unlike other alerts, the operation resulting from setting said parameter to true will not create another incident, but mark the incident as resolved on PagerDuty instead.

alerting:
  pagerduty: 
    integration-key: "********************************"

services:
  - name: twinnation
    url: "https://twinnation.org/health"
    interval: 30s
    alerts:
      - type: pagerduty
        enabled: true
        failure-threshold: 3
        success-threshold: 5
        send-on-resolved: true
        description: "healthcheck failed"
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"
      - "[RESPONSE_TIME] < 300"

Configuring Twilio alerts

alerting:
  twilio:
    sid: "..."
    token: "..."
    from: "+1-234-567-8901"
    to: "+1-234-567-8901"

services:
  - name: twinnation
    interval: 30s
    url: "https://twinnation.org/health"
    alerts:
      - type: twilio
        enabled: true
        failure-threshold: 5
        send-on-resolved: true
        description: "healthcheck failed"
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"
      - "[RESPONSE_TIME] < 300"

Configuring Mattermost alerts

alerting:
  mattermost: 
    webhook-url: "http://**********/hooks/**********"
    insecure: true

services:
  - name: twinnation
    url: "https://twinnation.org/health"
    interval: 30s
    alerts:
      - type: mattermost
        enabled: true
        description: "healthcheck failed"
        send-on-resolved: true
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"
      - "[RESPONSE_TIME] < 300"

Here's an example of what the notifications look like:

Configuring Messagebird alerts

Example of sending SMS text message alert using Messagebird:

alerting:
  messagebird:
    access-key: "..."
    originator: "31619191918"
    recipients: "31619191919,31619191920"
services:
  - name: twinnation
    interval: 30s
    url: "https://twinnation.org/health"
    alerts:
      - type: messagebird
        enabled: true
        failure-threshold: 3
        send-on-resolved: true
        description: "healthcheck failed"
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"
      - "[RESPONSE_TIME] < 300"

Configuring Telegram alerts

alerting:
  telegram: 
    token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11"
    id: "0123456789"

services:
  - name: twinnation
    url: "https://twinnation.org/health"
    interval: 30s
    alerts:
      - type: telegram
        enabled: true
        send-on-resolved: true
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"

Here's an example of what the notifications look like:

Configuring custom alerts

While they're called alerts, you can use this feature to call anything.

For instance, you could automate rollbacks by having an application that keeps tracks of new deployments, and by leveraging Gatus, you could have Gatus call that application endpoint when a service starts failing. Your application would then check if the service that started failing was recently deployed, and if it was, then automatically roll it back.

The placeholders [ALERT_DESCRIPTION] and [SERVICE_NAME] are automatically substituted for the alert description and the service name. These placeholders can be used in the body (alerting.custom.body) and in the url (alerting.custom.url).

If you have an alert using the custom provider with send-on-resolved set to true, you can use the [ALERT_TRIGGERED_OR_RESOLVED] placeholder to differentiate the notifications. The aforementioned placeholder will be replaced by TRIGGERED or RESOLVED accordingly, though it can be modified (details at the end of this section).

For all intents and purpose, we'll configure the custom alert with a Slack webhook, but you can call anything you want.

alerting:
  custom:
    url: "https://hooks.slack.com/services/**********/**********/**********"
    method: "POST"
    insecure: true
    body: |
      {
        "text": "[ALERT_TRIGGERED_OR_RESOLVED]: [SERVICE_NAME] - [ALERT_DESCRIPTION]"
      }      
services:
  - name: twinnation
    url: "https://twinnation.org/health"
    interval: 30s
    alerts:
      - type: custom
        enabled: true
        failure-threshold: 10
        success-threshold: 3
        send-on-resolved: true
        description: "healthcheck failed"
    conditions:
      - "[STATUS] == 200"
      - "[BODY].status == UP"
      - "[RESPONSE_TIME] < 300"

Note that you can customize the resolved values for the [ALERT_TRIGGERED_OR_RESOLVED] placeholder like so:

alerting:
  custom:
    placeholders:
      ALERT_TRIGGERED_OR_RESOLVED:
        TRIGGERED: "partial_outage"
        RESOLVED: "operational"

As a result, the [ALERT_TRIGGERED_OR_RESOLVED] in the body of first example of this section would be replaced by partial_outage when an alert is triggered and operational when an alert is resolved.

Setting a default provider alert

While you can specify the alert configuration directly in the service definition, it's tedious and may lead to a very long configuration file.

To avoid such problem, you can use the default-alert parameter present in each provider configuration:

alerting:
  slack: 
    webhook-url: "https://hooks.slack.com/services/**********/**********/**********"
    default-alert:
      enabled: true
      description: "healthcheck failed"
      send-on-resolved: true
      failure-threshold: 5
      success-threshold: 5

As a result, your service configuration looks a lot tidier:

services:
  - name: example
    url: "https://example.org"
    alerts:
      - type: slack
    conditions:
      - "[STATUS] == 200"

  - name: other-example
    url: "https://example.com"
    alerts:
      - type: slack
    conditions:
      - "[STATUS] == 200"

It also allows you to do things like this:

services:
  - name: twinnation
    url: "https://twinnation.org/health"
    alerts:
      - type: slack
        failure-threshold: 5
      - type: slack
        failure-threshold: 10
      - type: slack
        failure-threshold: 15
    conditions:
      - "[STATUS] == 200"

Kubernetes (ALPHA)

Warning

: This feature is in ALPHA. This means that it is very likely to change in the near future, which means that while you can use this feature as you see fit, there may be breaking changes in future releases.

Parameter	Description	Default
kubernetes	Kubernetes configuration	{}
kubernetes.auto-discover	Whether to enable auto discovery	false
kubernetes.cluster-mode	Cluster mode to use for authenticating. Supported values: in, out	Required ""
kubernetes.service-template	Service template. See services[] in Configuration	Required nil
kubernetes.excluded-service-suffixes	List of service suffixes to not monitor (e.g. canary)	[]
kubernetes.namespaces	List of configurations for the namespaces from which services will be discovered	[]
kubernetes.namespaces[].name	Namespace name	Required ""
kubernetes.namespaces[].hostname-suffix	Suffix to append to the service name before calling target-path	Required ""
kubernetes.namespaces[].target-path	Path that will be called on the discovered service for the health check	""
kubernetes.namespaces[].excluded-services	List of services to not monitor in the given namespace	[]

Auto Discovery

Auto discovery works by reading all Service resources from the configured namespaces and appending the hostname-suffix as well as the configured target-path to the service name and making an HTTP call.

All auto-discovered services will have the service configuration populated from the service-template.

You can exclude certain services from the dashboard by using kubernetes.excluded-service-suffixes or kubernetes.namespaces[].excluded-services.

kubernetes:
  auto-discover: true
  # out: Gatus is deployed outside of the K8s cluster.
  # in: Gatus is deployed in the K8s cluster
  cluster-mode: "out"                                              
  excluded-service-suffixes:
    - canary
  service-template:
    interval: 30s
    conditions:
      - "[STATUS] == 200"
  namespaces:
    - name: default
      # If cluster-mode is out, you should use an externally accessible hostname suffix (e.g.. .example.com)
      # This will result in gatus generating services with URLs like <service-name>.example.com
      # If cluster-mode is in, you can use either an externally accessible hostname suffix (e.g.. .example.com)
      # or an internally accessible hostname suffix (e.g. .default.svc.cluster.local)
      hostname-suffix: ".default.svc.cluster.local"
      target-path: "/health"
      # If some services cannot be or do not need to be monitored, you can exclude them by explicitly defining them
      # in the following list.
      excluded-services:
        - gatus
        - kubernetes

Note that hostname-suffix could also be something like .yourdomain.com, in which case the endpoint that would be monitored would be potato.example.com/health, assuming you have a service named potato and a matching ingress to map potato.example.com to the potato service.

Deploying

See example/kubernetes-with-auto-discovery

Docker

To run Gatus locally with Docker:

docker run -p 8080:8080 --name gatus twinproduction/gatus

Other than using one of the examples provided in the examples folder, you can also try it out locally by creating a configuration file, we'll call it config.yaml for this example, and running the following command:

docker run -p 8080:8080 --mount type=bind,source="$(pwd)"/config.yaml,target=/config/config.yaml --name gatus twinproduction/gatus

If you're on Windows, replace "$(pwd)" by the absolute path to your current directory, e.g.:

docker run -p 8080:8080 --mount type=bind,source=C:/Users/Chris/Desktop/config.yaml,target=/config/config.yaml --name gatus twinproduction/gatus

To build the image locally:

docker build . -t twinproduction/gatus

Helm Chart

Helm must be installed to use the chart. Please refer to Helm's documentation to get started.

Once Helm is set up properly, add the repo as follows:

helm repo add gatus https://avakarev.github.io/gatus-chart

To get more details, please check chart's configuration and helmfile example

Running the tests

go test ./... -mod vendor

Using in Production

See the example folder.

FAQ

Sending a GraphQL request

By setting services[].graphql to true, the body will automatically be wrapped by the standard GraphQL query parameter.

For instance, the following configuration:

services:
  - name: filter-users-by-gender
    url: http://localhost:8080/playground
    method: POST
    graphql: true
    body: |
      {
        users(gender: "female") {
          id
          name
          gender
          avatar
        }
      }      
    conditions:
      - "[STATUS] == 200"
      - "[BODY].data.users[0].gender == female"

will send a POST request to http://localhost:8080/playground with the following body:

{"query":"      {\n        users(gender: \"female\") {\n          id\n          name\n          gender\n          avatar\n        }\n      }"}

Recommended interval

NOTE: This does not really apply if disable-monitoring-lock is set to true, as the monitoring lock is what tells Gatus to only evaluate one service at a time.

To ensure that Gatus provides reliable and accurate results (i.e. response time), Gatus only evaluates one service at a time In other words, even if you have multiple services with the exact same interval, they will not execute at the same time.

You can test this yourself by running Gatus with several services configured with a very short, unrealistic interval, such as 1ms. You'll notice that the response time does not fluctuate - that is because while services are evaluated on different goroutines, there's a global lock that prevents multiple services from running at the same time.

Unfortunately, there is a drawback. If you have a lot of services, including some that are very slow or prone to time out (the default time out is 10s for HTTP and 5s for TCP), then it means that for the entire duration of the request, no other services can be evaluated.

This does mean that Gatus will be unable to evaluate the health of other services. The interval does not include the duration of the request itself, which means that if a service has an interval of 30s and the request takes 2s to complete, the timestamp between two evaluations will be 32s, not 30s.

While this does not prevent Gatus' from performing health checks on all other services, it may cause Gatus to be unable to respect the configured interval, for instance:

• Service A has an interval of 5s, and times out after 10s to complete
• Service B has an interval of 5s, and takes 1ms to complete
• Service B will be unable to run every 5s, because service A's health evaluation takes longer than its interval

To sum it up, while Gatus can really handle any interval you throw at it, you're better off having slow requests with higher interval.

As a rule of the thumb, I personally set interval for more complex health checks to 5m (5 minutes) and simple health checks used for alerting (PagerDuty/Twilio) to 30s.

Default timeouts

Protocol	Timeout
HTTP	10s
TCP	5s

Monitoring a TCP service

By prefixing services[].url with tcp:\\, you can monitor TCP services at a very basic level:

services:
  - name: redis
    url: "tcp://127.0.0.1:6379"
    interval: 30s
    conditions:
      - "[CONNECTED] == true"

Placeholders [STATUS] and [BODY] as well as the fields services[].body, services[].insecure, services[].headers, services[].method and services[].graphql are not supported for TCP services.

NOTE: [CONNECTED] == true does not guarantee that the service itself is healthy - it only guarantees that there's something at the given address listening to the given port, and that a connection to that address was successfully established.

Monitoring a service using ICMP

By prefixing services[].url with icmp:\\, you can monitor services at a very basic level using ICMP, or more commonly known as "ping" or "echo":

services:
  - name: ping-example
    url: "icmp://example.com"
    conditions:
      - "[CONNECTED] == true"

Only the placeholders [CONNECTED], [IP] and [RESPONSE_TIME] are supported for services of type ICMP. You can specify a domain prefixed by icmp://, or an IP address prefixed by icmp://.

Monitoring a service using DNS queries

Defining a dns configuration in a service will automatically mark that service as a service of type DNS:

services:
  - name: example-dns-query
    url: "8.8.8.8" # Address of the DNS server to use
    interval: 30s
    dns:
      query-name: "example.com"
      query-type: "A"
    conditions:
      - "[BODY] == 93.184.216.34"
      - "[DNS_RCODE] == NOERROR"

There are two placeholders that can be used in the conditions for services of type DNS:

• The placeholder [BODY] resolves to the output of the query. For instance, a query of type A would return an IPv4.
• The placeholder [DNS_RCODE] resolves to the name associated to the response code returned by the query, such as NOERROR, FORMERR, SERVFAIL, NXDOMAIN, etc.

Monitoring a service using STARTTLS

If you have an email server that you want to ensure there are no problems with, monitoring it through STARTTLS will serve as a good initial indicator:

services:
  - name: starttls-smtp-example
    url: "starttls://smtp.gmail.com:587"
    interval: 30m
    conditions:
      - "[CONNECTED] == true"
      - "[CERTIFICATE_EXPIRATION] > 48h"

Basic authentication

You can require Basic authentication by leveraging the security.basic configuration:

security:
  basic:
    username: "john.doe"
    password-sha512: "6b97ed68d14eb3f1aa959ce5d49c7dc612e1eb1dafd73b1e705847483fd6a6c809f2ceb4e8df6ff9984c6298ff0285cace6614bf8daa9f0070101b6c89899e22"

The example above will require that you authenticate with the username john.doe as well as the password hunter2.

disable-monitoring-lock

Setting disable-monitoring-lock to true means that multiple services could be monitored at the same time.

While this behavior wouldn't generally be harmful, conditions using the [RESPONSE_TIME] placeholder could be impacted by the evaluation of multiple services at the same time, therefore, the default value for this parameter is false.

There are three main reasons why you might want to disable the monitoring lock:

• You're using Gatus for load testing (each services are periodically evaluated on a different goroutine, so technically, if you create 100 services with a 1 seconds interval, Gatus will send 100 requests per second)
• You have a lot of services to monitor
• You want to test multiple services at very short interval (< 5s)

Reloading configuration on the fly

For the sake on convenience, Gatus automatically reloads the configuration on the fly if the loaded configuration file is updated while Gatus is running.

By default, the application will exit if the updating configuration is invalid, but you can configure Gatus to continue running if the configuration file is updated with an invalid configuration by setting skip-invalid-config-update to true.

Keep in mind that it is in your best interest to ensure the validity of the configuration file after each update you apply to the configuration file while Gatus is running by looking at the log and making sure that you do not see the following message:

The configuration file was updated, but it is not valid. The old configuration will continue being used.

Failure to do so may result in Gatus being unable to start if the application is restarted for whatever reason.

I recommend not setting skip-invalid-config-update to true to avoid a situation like this, but the choice is yours to make.

Note that if you are not using a file storage, updating the configuration while Gatus is running is effectively the same as restarting the application.

Service groups

Service groups are used for grouping multiple services together on the dashboard.

services:
  - name: frontend
    group: core
    url: "https://example.org/"
    interval: 5m
    conditions:
      - "[STATUS] == 200"

  - name: backend
    group: core
    url: "https://example.org/"
    interval: 5m
    conditions:
      - "[STATUS] == 200"

  - name: monitoring
    group: internal
    url: "https://example.org/"
    interval: 5m
    conditions:
      - "[STATUS] == 200"

  - name: nas
    group: internal
    url: "https://example.org/"
    interval: 5m
    conditions:
      - "[STATUS] == 200"

  - name: random service that isn't part of a group
    url: "https://example.org/"
    interval: 5m
    conditions:
      - "[STATUS] == 200"

The configuration above will result in a dashboard that looks like this:

Exposing Gatus on a custom port

By default, Gatus is exposed on port 8080, but you may specify a different port by setting the web.port parameter:

web:
  port: 8081

If you're using a PaaS like Heroku that doesn't let you set a custom port and exposes it through an environment variable instead, you can use that environment variable directly in the configuration file:

web:
  port: ${PORT}

Uptime badges

Gatus can automatically generate a SVG badge for one of your monitored services. This allows you to put badges in your individual services' README or even create your own status page, if you desire.

The endpoint to generate a badge is the following:

/api/v1/badges/uptime/{duration}/{identifier}.svg

Where:

• {duration} is 7d, 24h or 1h
• {identifier} has the pattern <GROUP_NAME>_<SERVICE_NAME>.svg in which both variables have , /, _, , and . replaced by -.

For instance, if you want the uptime during the last 24 hours from the service frontend in the group core, the URL would look like this:

http://example.com/api/v1/badges/uptime/7d/core_frontend.svg

If you want to display a service that is not part of a group, you must leave the group value empty:

http://example.com/api/v1/badges/uptime/7d/_frontend.svg

Example:

![Uptime 24h](https://status.twinnation.org/api/v1/badges/uptime/24h/core_twinnation-external.svg)

If you'd like to see a visual example of each badges available, you can simply navigate to the service's detail page.

API

Gatus provides a simple read-only API which can be queried in order to programmatically determine service status and history.

All services are available via a GET request to the following endpoint:

/api/v1/statuses

Example: https://status.twinnation.org/api/v1/statuses

Specific services can also be queried by using the following pattern:

/api/v1/statuses/{group}_{service}

Example: https://status.twinnation.org/api/v1/statuses/core_twinnation-home

Gzip compression will be used if the Accept-Encoding HTTP header contains gzip.

The API will return a JSON payload with the Content-Type response header set to application/json. No such header is required to query the API.