feat: shields.io endpoint badge (#652)

* feat: shields.io endpoint badge

Signed-off-by: Steven Kreitzer <skre@skre.me>

* chore: update readme to include new shields.io badge

Signed-off-by: Steven Kreitzer <skre@skre.me>

---------

Signed-off-by: Steven Kreitzer <skre@skre.me>
Co-authored-by: TwiN <twin@linux.com>

README.md

@@ -107,6 +107,7 @@ Have any feedback or questions? [Create a discussion](https://github.com/TwiN/ga
   - [Badges](#badges)
     - [Uptime](#uptime)
     - [Health](#health)
+    - [Health (Shields.io)](#health-shieldsio)
     - [Response time](#response-time)
       - [How to change the color thresholds of the response time badge](#how-to-change-the-color-thresholds-of-the-response-time-badge)
   - [API](#api)
@@ -1958,6 +1959,25 @@ https://example.com/api/v1/endpoints/core_frontend/health/badge.svg
 ```
 
 
+#### Health (Shields.io)
+![Health](https://img.shields.io/endpoint?url=https%3A%2F%2Fstatus.twin.sh%2Fapi%2Fv1%2Fendpoints%2Fcore_blog-external%2Fhealth%2Fbadge.shields)
+
+The path to generate a badge is the following:
+```
+/api/v1/endpoints/{key}/health/badge.shields
+```
+Where:
+- `{key}` has the pattern `<GROUP_NAME>_<ENDPOINT_NAME>` in which both variables have ` `, `/`, `_`, `,` and `.` replaced by `-`.
+
+For instance, if you want the current status of the endpoint `frontend` in the group `core`,
+the URL would look like this:
+```
+https://example.com/api/v1/endpoints/core_frontend/health/badge.shields
+```
+
+See more information about the Shields.io badge endpoint [here](https://shields.io/badges/endpoint-badge).
+
+
 #### Response time
 ![Response time 1h](https://status.twin.sh/api/v1/endpoints/core_blog-external/response-times/1h/badge.svg)
 ![Response time 24h](https://status.twin.sh/api/v1/endpoints/core_blog-external/response-times/24h/badge.svg)

api/api.go

@@ -66,6 +66,7 @@ func (a *API) createRouter(cfg *config.Config) *fiber.App {
 	unprotectedAPIRouter := apiRouter.Group("/")
 	unprotectedAPIRouter.Get("/v1/config", ConfigHandler{securityConfig: cfg.Security}.GetConfig)
 	unprotectedAPIRouter.Get("/v1/endpoints/:key/health/badge.svg", HealthBadge)
+	unprotectedAPIRouter.Get("/v1/endpoints/:key/health/badge.shields", HealthBadgeShields)
 	unprotectedAPIRouter.Get("/v1/endpoints/:key/uptimes/:duration/badge.svg", UptimeBadge)
 	unprotectedAPIRouter.Get("/v1/endpoints/:key/response-times/:duration/badge.svg", ResponseTimeBadge(cfg))
 	unprotectedAPIRouter.Get("/v1/endpoints/:key/response-times/:duration/chart.svg", ResponseTimeChart)

api/badge.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"encoding/json"
 	"fmt"
 	"strconv"
 	"strings"
@@ -125,6 +126,36 @@ func HealthBadge(c *fiber.Ctx) error {
 	return c.Status(200).Send(generateHealthBadgeSVG(healthStatus))
 }
 
+func HealthBadgeShields(c *fiber.Ctx) error {
+	key := c.Params("key")
+	pagingConfig := paging.NewEndpointStatusParams()
+	status, err := store.Get().GetEndpointStatusByKey(key, pagingConfig.WithResults(1, 1))
+	if err != nil {
+		if err == common.ErrEndpointNotFound {
+			return c.Status(404).SendString(err.Error())
+		} else if err == common.ErrInvalidTimeRange {
+			return c.Status(400).SendString(err.Error())
+		}
+		return c.Status(500).SendString(err.Error())
+	}
+	healthStatus := HealthStatusUnknown
+	if len(status.Results) > 0 {
+		if status.Results[0].Success {
+			healthStatus = HealthStatusUp
+		} else {
+			healthStatus = HealthStatusDown
+		}
+	}
+	c.Set("Content-Type", "application/json")
+	c.Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	c.Set("Expires", "0")
+	jsonData, err := generateHealthBadgeShields(healthStatus)
+	if err != nil {
+		return c.Status(500).SendString(err.Error())
+	}
+	return c.Status(200).Send(jsonData)
+}
+
 func generateUptimeBadgeSVG(duration string, uptime float64) []byte {
 	var labelWidth, valueWidth, valueWidthAdjustment int
 	switch duration {
@@ -299,6 +330,17 @@ func generateHealthBadgeSVG(healthStatus string) []byte {
 	return svg
 }
 
+func generateHealthBadgeShields(healthStatus string) ([]byte, error) {
+	color := getBadgeShieldsColorFromHealth(healthStatus)
+	data := map[string]interface{}{
+		"schemaVersion": 1,
+		"label":         "gatus",
+		"message":       healthStatus,
+		"color":         color,
+	}
+	return json.Marshal(data)
+}
+
 func getBadgeColorFromHealth(healthStatus string) string {
 	if healthStatus == HealthStatusUp {
 		return badgeColorHexAwesome
@@ -307,3 +349,12 @@ func getBadgeColorFromHealth(healthStatus string) string {
 	}
 	return badgeColorHexPassable
 }
+
+func getBadgeShieldsColorFromHealth(healthStatus string) string {
+	if healthStatus == HealthStatusUp {
+		return "brightgreen"
+	} else if healthStatus == HealthStatusDown {
+		return "red"
+	}
+	return "yellow"
+}

api/badge_test.go

@@ -110,6 +110,21 @@ func TestBadge(t *testing.T) {
 			Path:         "/api/v1/endpoints/invalid_key/health/badge.svg",
 			ExpectedCode: http.StatusNotFound,
 		},
+		{
+			Name:         "badge-shields-health-up",
+			Path:         "/api/v1/endpoints/core_frontend/health/badge.shields",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-shields-health-down",
+			Path:         "/api/v1/endpoints/core_backend/health/badge.shields",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-shields-health-for-invalid-key",
+			Path:         "/api/v1/endpoints/invalid_key/health/badge.shields",
+			ExpectedCode: http.StatusNotFound,
+		},
 		{
 			Name:         "chart-response-time-24h",
 			Path:         "/api/v1/endpoints/core_backend/response-times/24h/chart.svg",