Add format=badge which directly serves badges (#67)

* feat: Add format=badge

Adds /kromgo/Verdana.ttf to the container which is the font that
shields.io uses for spacing calculations of the svg

* Update README endpoint examples

* docs: render json schema

---------

Co-authored-by: vaskozl <vaskozl@users.noreply.github.com>

Dockerfile

@@ -6,11 +6,19 @@ WORKDIR /build
 COPY . .
 RUN go build -ldflags "-s -w -X main.Version=${VERSION} -X main.Gitsha=${REVISION}" ./cmd/kromgo
 
+
+FROM alpine as fonts
+
+RUN apk add --no-cache msttcorefonts-installer
+RUN update-ms-fonts
+
 FROM gcr.io/distroless/static-debian12:nonroot
 USER nonroot:nonroot
 COPY --from=build --chmod=555 /build/kromgo /kromgo/kromgo
+COPY --from=fonts --chmod=555 /usr/share/fonts/truetype/msttcorefonts/Verdana.ttf /kromgo/
 EXPOSE 8080/tcp 8888/tcp
+WORKDIR /kromgo
 LABEL \
     org.opencontainers.image.title="kromgo" \
     org.opencontainers.image.source="https://github.com/kashalls/kromgo"
-ENTRYPOINT ["/kromgo/kromgo"]
+ENTRYPOINT ["/kromgo/kromgo"]

README.md

@@ -22,7 +22,7 @@ Queries take around 5ms ~ 75ms to complete depending on how many breaks my prome
 
 This format is provided to support Shield.io's [Endpoint Badge](https://shields.io/badges/endpoint-badge) endpoint.
 
-`HTTP GET localhost:8080/query?format=endpoint&metric=node_cpu_usage`
+`HTTP GET localhost:8080/node_cpu_usage`
 
 ```json
 {
@@ -35,7 +35,7 @@ This format is provided to support Shield.io's [Endpoint Badge](https://shields.
 
 ### Raw Response
 
-`HTTP GET localhost:8080/query?metric=node_cpu_usage`
+`HTTP GET localhost:8080/node_cpu_usage?format=raw`
 
 ```json
 [
@@ -49,6 +49,17 @@ This format is provided to support Shield.io's [Endpoint Badge](https://shields.
 ]
 ```
 
+### Badge Response
+
+Like the `endpoint` format but serves an svg badge with `label` and `message`
+
+`HTTP GET localhost:8080/node_cpu_usage?format=badge`
+
+```
+content-type: image/svg+xml
+<svg xmlns="http://www.w3.org/2000/svg" ...
+```
+
 ### 🤝 Gratitude and Thanks
 
 Thanks to all of the people at the [Home Operations](https://discord.gg/home-operations) Discord community. Be sure to check it out, its a blast!

cmd/kromgo/init/configuration/configuration.go

@@ -32,6 +32,7 @@ type ServerConfig struct {
 type KromgoConfig struct {
 	Prometheus string   `yaml:"prometheus,omitempty" json:"prometheus,omitempty"`
 	Metrics    []Metric `yaml:"metrics" json:"metrics"`
+	Badge      Badge    `yaml:"badge,omitempty" json:"badge,omitempty"`
 }
 
 type Metric struct {
@@ -50,6 +51,11 @@ type MetricColor struct {
 	ValueOverride string  `yaml:"valueOverride,omitempty" json:"valueOverride,omitempty"`
 }
 
+type Badge struct {
+	Font string `yaml:"font" json:"font"`
+	Size int    `yaml:"size" json:"size"`
+}
+
 var ConfigPath = "/kromgo/config.yaml" // Default config file path
 var ProcessedMetrics map[string]Metric
 

cmd/kromgo/init/server/server.go

@@ -49,9 +49,12 @@ func Init(config configuration.KromgoConfig, serverConfig configuration.ServerCo
 		}
 	}
 
-	mainRouter.Get("/{metric}", func(w http.ResponseWriter, r *http.Request) {
-		kromgo.KromgoRequestHandler(w, r, config)
-	})
+	kromgoHandler, err := kromgo.NewKromgoHandler(config)
+	if err != nil {
+		log.Fatal("Failed to initialize KromgoHandler", zap.Error(err))
+	}
+
+	mainRouter.Get("/{metric}", kromgoHandler.ServeHTTP)
 
 	mainServer := createHTTPServer(fmt.Sprintf("%s:%d", serverConfig.ServerHost, serverConfig.ServerPort), mainRouter, serverConfig.ServerReadTimeout, serverConfig.ServerWriteTimeout)
 	go func() {

config.schema.json

@@ -3,6 +3,22 @@
   "$id": "https://github.com/kashalls/kromgo/cmd/kromgo/init/configuration/kromgo-config",
   "$ref": "#/$defs/KromgoConfig",
   "$defs": {
+    "Badge": {
+      "properties": {
+        "font": {
+          "type": "string"
+        },
+        "size": {
+          "type": "integer"
+        }
+      },
+      "additionalProperties": false,
+      "type": "object",
+      "required": [
+        "font",
+        "size"
+      ]
+    },
     "KromgoConfig": {
       "properties": {
         "prometheus": {
@@ -13,6 +29,9 @@
             "$ref": "#/$defs/Metric"
           },
           "type": "array"
+        },
+        "badge": {
+          "$ref": "#/$defs/Badge"
         }
       },
       "additionalProperties": false,

config.yaml.example

@@ -1,5 +1,8 @@
 ---
 # yaml-language-server: $schema=https://raw.githubusercontent.com/kashalls/kromgo/main/config.schema.json
+badge:
+  font: Verdana.ttf # Relative to /kromgo - Verdana.ttf is available in the container
+  size: 12
 metrics:
   - name: node_cpu_usage
     query: "round(cluster:node_cpu:ratio_rate5m * 100, 0.1)"
@@ -23,4 +26,4 @@ metrics:
     colors:
       - { valueOverride: 'Ok', color: "green", min: 0, max: 0 }
       - { valueOverride: 'Not good', color: "orange", min: 1, max: 1 }
-      - { valueOverride: 'Whoops', color: "red", min: 2, max: 2 }
+      - { valueOverride: 'Whoops', color: "red", min: 2, max: 2 }

go.mod

@@ -4,6 +4,7 @@ go 1.22.1
 
 require (
 	github.com/caarlos0/env/v11 v11.2.2
+	github.com/essentialkaos/go-badge v1.4.1
 	github.com/go-chi/chi/v5 v5.1.0
 	github.com/go-chi/httprate v0.12.1
 	github.com/invopop/jsonschema v0.12.0
@@ -20,6 +21,7 @@ require (
 	github.com/buger/jsonparser v1.1.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
@@ -30,6 +32,7 @@ require (
 	github.com/prometheus/procfs v0.15.1 // indirect
 	github.com/wk8/go-ordered-map/v2 v2.1.8 // indirect
 	go.uber.org/multierr v1.10.0 // indirect
+	golang.org/x/image v0.18.0 // indirect
 	golang.org/x/sys v0.21.0 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
 )

go.sum

@@ -4,21 +4,23 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/buger/jsonparser v1.1.1 h1:2PnMjfWD7wBILjqQbt530v576A/cAbQvEW9gGIpYMUs=
 github.com/buger/jsonparser v1.1.1/go.mod h1:6RYKKt7H4d4+iWqouImQ9R2FZql3VbhNgx27UK13J/0=
-github.com/caarlos0/env/v11 v11.2.0 h1:kvB1ZmwdWgI3JsuuVUE7z4cY/6Ujr03D0w2WkOOH4Xs=
-github.com/caarlos0/env/v11 v11.2.0/go.mod h1:LwgkYk1kDvfGpHthrWWLof3Ny7PezzFwS4QrsJdHTMo=
 github.com/caarlos0/env/v11 v11.2.2 h1:95fApNrUyueipoZN/EhA8mMxiNxrBwDa+oAZrMWl3Kg=
 github.com/caarlos0/env/v11 v11.2.2/go.mod h1:JBfcdeQiBoI3Zh1QRAWfe+tpiNTmDtcCj/hHHHMx0vc=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/essentialkaos/check v1.4.0 h1:kWdFxu9odCxUqo1NNFNJmguGrDHgwi3A8daXX1nkuKk=
+github.com/essentialkaos/check v1.4.0/go.mod h1:LMKPZ2H+9PXe7Y2gEoKyVAwUqXVgx7KtgibfsHJPus0=
+github.com/essentialkaos/go-badge v1.4.1 h1:ZtPY1VzukuK51ryYnOrh8vIUBcSdsNJRL8GG+5QxdFg=
+github.com/essentialkaos/go-badge v1.4.1/go.mod h1:CwkvOc0vEK7OnTPNsl9Jx2nxzPakzZl9/ak6GvRFyQA=
 github.com/go-chi/chi/v5 v5.1.0 h1:acVI1TYaD+hhedDJ3r54HyA6sExp3HfXq7QWEEY/xMw=
 github.com/go-chi/chi/v5 v5.1.0/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
-github.com/go-chi/httprate v0.12.0 h1:08D/te3pOTJe5+VAZTQrHxwdsH2NyliiUoRD1naKaMg=
-github.com/go-chi/httprate v0.12.0/go.mod h1:TUepLXaz/pCjmCtf/obgOQJ2Sz6rC8fSf5cAt5cnTt0=
 github.com/go-chi/httprate v0.12.1 h1:55l3IWrPcipqKb72yBzH+grF51z5w+2Bb/Qmu1bos/E=
 github.com/go-chi/httprate v0.12.1/go.mod h1:TUepLXaz/pCjmCtf/obgOQJ2Sz6rC8fSf5cAt5cnTt0=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
@@ -68,6 +70,8 @@ go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
 go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
 go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
 go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
+golang.org/x/image v0.18.0 h1:jGzIakQa/ZXI1I0Fxvaa9W7yP25TqT6cHIHn+6CqvSQ=
+golang.org/x/image v0.18.0/go.mod h1:4yyo5vMFQjVjUcVk4jEQcU9MGy/rulF5WvUILseCM2E=
 golang.org/x/net v0.26.0 h1:soB7SVo0PWrY4vPW/+ay0jKDNScG2X9wFeYlXIvJsOQ=
 golang.org/x/net v0.26.0/go.mod h1:5YKkiSynbBIh3p6iOc/vibscux0x38BZDkn8sCUPxHE=
 golang.org/x/oauth2 v0.21.0 h1:tsimM75w1tF/uws5rbeHzIWxEqElMehnc+iW793zsZs=

pkg/kromgo/kromgo.go

@@ -4,8 +4,10 @@ import (
 	"encoding/json"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
+	"github.com/essentialkaos/go-badge"
 	"github.com/go-chi/chi/v5"
 	"github.com/kashalls/kromgo/cmd/kromgo/init/configuration"
 	"github.com/kashalls/kromgo/cmd/kromgo/init/log"
@@ -14,13 +16,44 @@ import (
 	"go.uber.org/zap"
 )
 
-func KromgoRequestHandler(w http.ResponseWriter, r *http.Request, config configuration.KromgoConfig) {
+type KromgoHandler struct {
+	Config         configuration.KromgoConfig
+	BadgeGenerator *badge.Generator
+}
+
+// NewKromgoHandler initializes the handler with the necessary dependencies
+func NewKromgoHandler(config configuration.KromgoConfig) (*KromgoHandler, error) {
+	var badgeGenerator *badge.Generator
+	if config.Badge.Font != "" {
+		size := 11
+		if config.Badge.Size != 0 {
+			size = config.Badge.Size
+		}
+		ptr, err := badge.NewGenerator(config.Badge.Font, size)
+		badgeGenerator = ptr
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &KromgoHandler{
+		Config:         config,
+		BadgeGenerator: badgeGenerator,
+	}, nil
+}
+
+func (h *KromgoHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	requestMetric := chi.URLParam(r, "metric")
 	if requestMetric == "query" {
 		requestMetric = r.URL.Query().Get("metric")
 	}
 	requestFormat := r.URL.Query().Get("format")
 
+	if requestFormat == "badge" && h.BadgeGenerator == nil {
+		HandleError(w, r, requestMetric, "Format badge is not configured", http.StatusInternalServerError)
+		return
+	}
+
 	metric, exists := configuration.ProcessedMetrics[requestMetric]
 
 	if !exists {
@@ -80,10 +113,20 @@ func KromgoRequestHandler(w http.ResponseWriter, r *http.Request, config configu
 		customResponse = colorConfig.ValueOverride
 	}
 
+	message := metric.Prefix + customResponse + metric.Suffix
+
+	if requestFormat == "badge" {
+		hex := colorNameToHex(colorConfig.Color)
+
+		w.Header().Set("Content-Type", "image/svg+xml")
+		w.Write(h.BadgeGenerator.GenerateFlat(metric.Name, message, hex))
+		return
+	}
+
 	data := map[string]interface{}{
 		"schemaVersion": 1,
 		"label":         metric.Name,
-		"message":       metric.Prefix + customResponse + metric.Suffix,
+		"message":       message,
 	}
 
 	if colorConfig.Color != "" {
@@ -106,4 +149,45 @@ func requestLog(r *http.Request) *zap.Logger {
 	requestFormat := r.URL.Query().Get("format")
 
 	return log.With(zap.String("req_method", r.Method), zap.String("req_path", r.URL.Path), zap.String("metric", requestMetric), zap.String("format", requestFormat))
-}
+}
+
+func colorNameToHex(colorName string) (string) {
+	if strings.HasPrefix(colorName, "#") {
+		return colorName
+	}
+
+	switch colorName {
+	case "":
+		return badge.COLOR_BLUE
+	case "blue":
+		return badge.COLOR_BLUE
+	case "brightgreen":
+		return badge.COLOR_BRIGHTGREEN
+	case "green":
+		return badge.COLOR_GREEN
+	case "grey":
+		return badge.COLOR_GREY
+	case "lightgrey":
+		return badge.COLOR_LIGHTGREY
+	case "orange":
+		return badge.COLOR_ORANGE
+	case "red":
+		return badge.COLOR_RED
+	case "yellow":
+		return badge.COLOR_YELLOW
+	case "yellowgreen":
+		return badge.COLOR_YELLOWGREEN
+	case "success":
+		return badge.COLOR_SUCCESS
+	case "important":
+		return badge.COLOR_IMPORTANT
+	case "critical":
+		return badge.COLOR_CRITICAL
+	case "informational":
+		return badge.COLOR_INFORMATIONAL
+	case "inactive":
+		return badge.COLOR_INACTIVE
+	default:
+		return badge.COLOR_GREEN
+	}
+}