Prometheus metrics

handlers.go

@@ -1,9 +1,11 @@
 package main
 
 import (
+	"fmt"
 	"io/ioutil"
 	"log"
 	"net/http"
+	"os"
 
 	"github.com/labstack/echo"
 	"github.com/rosti-cz/node-api/apps"
@@ -485,3 +487,39 @@ func getAppProcessesHandler(c echo.Context) error {
 
 	return c.JSON(http.StatusOK, processes)
 }
+
+// Return metrics that are available for running node
+func metricsHandler(c echo.Context) error {
+	var metrics string
+
+	// Node indexes
+	node, err := node.GetNodeInfo()
+	if err != nil {
+		return c.JSONPretty(http.StatusInternalServerError, Message{Message: err.Error()}, JSONIndent)
+	}
+
+	hostname, err := os.Hostname()
+	if err != nil {
+		return c.JSONPretty(http.StatusInternalServerError, Message{Message: err.Error()}, JSONIndent)
+	}
+
+	metrics += fmt.Sprintf("rosti_node_index{hostname=\"%s\"} %f\n", hostname, node.Index)
+	metrics += fmt.Sprintf("rosti_node_disk_space_index{hostname=\"%s\"} %f\n", hostname, node.DiskSpaceIndex)
+	metrics += fmt.Sprintf("rosti_node_load1_index{hostname=\"%s\"} %f\n", hostname, node.Load1Index)
+	metrics += fmt.Sprintf("rosti_node_load5_index{hostname=\"%s\"} %f\n", hostname, node.Load5Index)
+	metrics += fmt.Sprintf("rosti_node_load15_index{hostname=\"%s\"} %f\n", hostname, node.Load15Index)
+	metrics += fmt.Sprintf("rosti_node_memory_index{hostname=\"%s\"} %f\n", hostname, node.MemoryIndex)
+	metrics += fmt.Sprintf("rosti_node_sold_memory{hostname=\"%s\"} %d\n", hostname, node.SoldMemory)
+
+	apps, err := apps.List()
+	if err != nil {
+		return c.JSONPretty(http.StatusInternalServerError, Message{Message: err.Error()}, JSONIndent)
+	}
+
+	for _, app := range *apps {
+		metrics += fmt.Sprintf("rosti_node_app_disk_usage_bytes{hostname=\"%s\", app=\"%s\"} %d\n", hostname, app.Name, app.DiskUsageBytes)
+		metrics += fmt.Sprintf("rosti_node_app_disk_usage_inodes{hostname=\"%s\", app=\"%s\"} %d\n", hostname, app.Name, app.DiskUsageInodes)
+	}
+
+	return c.String(http.StatusOK, metrics)
+}

main.go

@@ -55,6 +55,9 @@ func main() {
 	// UI
 	e.GET("/", homeHandler)
 
+	// Prometheus metrics
+	e.GET("/metrics", metricsHandler)
+
 	// Returns list of apps
 	e.GET("/v1/apps", listAppsHandler)