Added prometheus exporter support for Bedrock servers

README.md

@@ -89,18 +89,30 @@ minecraft_status,host=mc.hypixel.net,port=25565,status=success response_time=0.2
 
 ### Monitoring a server with Prometheus
 
-When using the `export-for-prometheus` subcommand, mc-monitor will serve a Prometheus exporter that collects the Minecraft server metrics during each scrape of the path `/metrics`.
+When using the `export-for-prometheus` subcommand, mc-monitor will serve a Prometheus exporter on port 8080, by default, that collects Minecraft server metrics during each scrape of `/metrics`.
 
-Labels
-- `server_host`
-- `server_port`
-- `server_edition` : `java` or `bedrock`
-Metrics
+The sub-command accepts the following arguments, which can also be viewed using `--help`:
+```
+  -edition string
+    	The edition of Minecraft server, java or bedrock (env EXPORT_EDITION) (default "java")
+  -port int
+    	HTTP port where Prometheus metrics are exported (env EXPORT_PORT) (default 8080)
+  -servers host:port
+    	one or more host:port addresses of servers to monitor, when port is omitted 19132 is used (env EXPORT_SERVERS)
+```
+
+The following metrics are exported
 - `minecraft_status_healthy`
 - `minecraft_status_response_time_seconds`
 - `minecraft_status_players_online_count`
 - `minecraft_status_players_max_count`
 
+with the labels
+- `server_host`
+- `server_port`
+- `server_edition` : `java` or `bedrock`
+
 An example Docker composition is provided in [examples/mc-monitor-prom](examples/mc-monitor-prom), which was used to grab the following screenshot:
 
-![Prometheus Chart](docs/prometheus_online_count_chart.png)
+![Prometheus Chart](docs/prometheus_online_count_chart.png)
+

prom_cmd.go

@@ -3,25 +3,23 @@ package main
 import (
 	"context"
 	"flag"
-	"fmt"
 	"github.com/google/subcommands"
 	"github.com/itzg/go-flagsfiller"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.uber.org/zap"
 	"log"
 	"net/http"
-	"os"
 	"strconv"
 )
 
 const promExportPath = "/metrics"
 
 type exportPrometheusCmd struct {
-	Servers    []string `usage:"one or more [host:port] addresses of servers to monitor"`
-	ExportPort int      `usage:"HTTP port where Prometheus metrics are exported" default:"8080"`
-	Edition    string   `usage:"The type of Minecraft server, java or bedrock" default:"java"`
-	logger     *zap.Logger
+	Servers []string `usage:"one or more [host:port] addresses of servers to monitor, when port is omitted 19132 is used"`
+	Port    int      `usage:"HTTP port where Prometheus metrics are exported" default:"8080"`
+	Edition string   `usage:"The edition of Minecraft server, java or bedrock" default:"java"`
+	logger  *zap.Logger
 }
 
 func (c *exportPrometheusCmd) Name() string {
@@ -46,11 +44,11 @@ func (c *exportPrometheusCmd) SetFlags(f *flag.FlagSet) {
 
 func (c *exportPrometheusCmd) Execute(_ context.Context, _ *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
 	if len(c.Servers) == 0 {
-		_, _ = fmt.Fprintln(os.Stderr, "requires at least one server")
+		printUsageError("requires at least one server")
 		return subcommands.ExitUsageError
 	}
 	if !ValidEdition(c.Edition) {
-		_, _ = fmt.Fprintln(os.Stderr, "invalid edition")
+		printUsageError("invalid edition")
 		return subcommands.ExitUsageError
 	}
 
@@ -66,7 +64,7 @@ func (c *exportPrometheusCmd) Execute(_ context.Context, _ *flag.FlagSet, args .
 		log.Fatal(err)
 	}
 
-	exportAddress := ":" + strconv.Itoa(c.ExportPort)
+	exportAddress := ":" + strconv.Itoa(c.Port)
 
 	logger.Info("exporting metrics for prometheus",
 		zap.String("address", exportAddress),

prom_collector.go

@@ -5,6 +5,7 @@ import (
 	mcpinger "github.com/Raqbit/mc-pinger"
 	"github.com/prometheus/client_golang/prometheus"
 	"go.uber.org/zap"
+	"net"
 	"strconv"
 	"time"
 )
@@ -61,12 +62,20 @@ func newPromCollectors(servers []string, edition ServerEdition, logger *zap.Logg
 func createPromCollectors(servers []string, edition ServerEdition, logger *zap.Logger) (collectors []specificPromCollector, err error) {
 	for _, server := range servers {
 		switch edition {
+
 		case JavaEdition:
 			host, port, err := SplitHostPort(server, DefaultJavaPort)
 			if err != nil {
 				return nil, fmt.Errorf("failed to process server entry '%s': %w", server, err)
 			}
 			collectors = append(collectors, newPromJavaCollector(host, port, logger))
+
+		case BedrockEdition:
+			host, port, err := SplitHostPort(server, DefaultBedrockPort)
+			if err != nil {
+				return nil, fmt.Errorf("failed to process server entry '%s': %w", server, err)
+			}
+			collectors = append(collectors, newPromBedrockCollector(host, port, logger))
 		}
 	}
 	return
@@ -118,3 +127,37 @@ func (c *promJavaCollector) sendMetric(metrics chan<- prometheus.Metric, desc *p
 		metrics <- metric
 	}
 }
+
+type promBedrockCollector struct {
+	host   string
+	port   string
+	logger *zap.Logger
+}
+
+func newPromBedrockCollector(host string, port uint16, logger *zap.Logger) *promBedrockCollector {
+	return &promBedrockCollector{host: host, port: strconv.Itoa(int(port)), logger: logger}
+}
+
+func (c *promBedrockCollector) Collect(metrics chan<- prometheus.Metric) {
+	c.logger.Debug("pinging", zap.String("host", c.host), zap.String("port", c.port))
+
+	info, err := PingBedrockServer(net.JoinHostPort(c.host, c.port))
+	if err != nil {
+		c.sendMetric(metrics, promDescHealthy, 0)
+	} else {
+		c.sendMetric(metrics, promDescResponseTime, info.Rtt.Seconds())
+		c.sendMetric(metrics, promDescHealthy, 1)
+		c.sendMetric(metrics, promDescPlayersOnline, float64(info.Players))
+		c.sendMetric(metrics, promDescPlayersMax, float64(info.MaxPlayers))
+	}
+}
+
+func (c *promBedrockCollector) sendMetric(metrics chan<- prometheus.Metric, desc *prometheus.Desc, value float64) {
+	metric, err := prometheus.NewConstMetric(desc, prometheus.GaugeValue, value,
+		c.host, c.port, string(JavaEdition))
+	if err != nil {
+		c.logger.Error("failed to build metric", zap.Error(err), zap.String("name", desc.String()))
+	} else {
+		metrics <- metric
+	}
+}

constants.go → shared.go

@@ -1,5 +1,10 @@
 package main
 
+import (
+	"fmt"
+	"os"
+)
+
 const (
 	DefaultJavaPort    uint16 = 25565
 	DefaultBedrockPort uint16 = 19132
@@ -19,3 +24,7 @@ func ValidEdition(v string) bool {
 	}
 	return false
 }
+
+func printUsageError(msg string) {
+	_, _ = fmt.Fprintln(os.Stderr, msg)
+}