Better /metrics handling

config/configuration.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"reflect"
+	"strings"
 	"time"
 
 	"github.com/heetch/confita"
@@ -64,6 +65,20 @@ func Load() (*EnvConfig, []Config) {
 	return cfg, cfg.Split()
 }
 
+func (c *Config) String() string {
+	ref := reflect.ValueOf(c)
+	fields := ref.Elem()
+
+	buffer := make([]string, fields.NumField(), fields.NumField())
+	for i := 0; i < fields.NumField(); i++ {
+		valueField := fields.Field(i)
+		typeField := fields.Type().Field(i)
+		buffer[i] = fmt.Sprintf("%s=%v", typeField.Name, valueField.Interface())
+	}
+
+	return fmt.Sprintf("<Config@%X %s>", &c, strings.Join(buffer, ", "))
+}
+
 //Validate check if the config is valid
 func (c Config) Validate() error {
 	if c.PIHoleProtocol != "http" && c.PIHoleProtocol != "https" {

internal/pihole/client.go

@@ -14,7 +14,6 @@ import (
 
 	"github.com/eko/pihole-exporter/config"
 	"github.com/eko/pihole-exporter/internal/metrics"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 // Client struct is a PI-Hole client to request an instance of a PI-Hole ad blocker.
@@ -34,7 +33,7 @@ func NewClient(config *config.Config) *Client {
 
 	fmt.Printf("Creating client with config %s\n", config)
 
-	client := &Client{
+	return &Client{
 		config: config,
 		httpClient: http.Client{
 			CheckRedirect: func(req *http.Request, via []*http.Request) error {
@@ -42,16 +41,13 @@ func NewClient(config *config.Config) *Client {
 			},
 		},
 	}
-
-	fmt.Printf("Client created with config %s\n", client)
-
-	return client
 }
 
 func (c *Client) String() string {
 	return c.config.PIHoleHostname
 }
 
+/*
 // Metrics scrapes pihole and sets them
 func (c *Client) Metrics() http.HandlerFunc {
 	return func(writer http.ResponseWriter, request *http.Request) {
@@ -66,19 +62,18 @@ func (c *Client) Metrics() http.HandlerFunc {
 		log.Printf("New tick of statistics: %s", stats.ToString())
 		promhttp.Handler().ServeHTTP(writer, request)
 	}
-}
+}*/
+
+func (c *Client) CollectMetrics(writer http.ResponseWriter, request *http.Request) error {
 
-func (c *Client) CollectMetrics(writer http.ResponseWriter, request *http.Request) {
 	stats, err := c.getStatistics()
 	if err != nil {
-		writer.WriteHeader(http.StatusBadRequest)
-		_, _ = writer.Write([]byte(err.Error()))
-		return
+		return err
 	}
 	c.setMetrics(stats)
 
-	log.Printf("New tick of statistics: %s", stats.ToString())
-	promhttp.Handler().ServeHTTP(writer, request)
+	log.Printf("New tick of statistics from %s: %s", c, stats)
+	return nil
 }
 
 func (c *Client) GetHostname() string {

internal/pihole/model.go

@@ -31,6 +31,6 @@ type Stats struct {
 }
 
 // ToString method returns a string of the current statistics struct.
-func (s *Stats) ToString() string {
+func (s *Stats) String() string {
 	return fmt.Sprintf("%d ads blocked / %d total DNS queries", s.AdsBlockedToday, s.DNSQueriesAllTypes)
 }

internal/server/server.go

@@ -5,9 +5,11 @@ import (
 	"log"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/eko/pihole-exporter/internal/pihole"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"golang.org/x/net/context"
 )
 
@@ -33,10 +35,22 @@ func NewServer(port uint16, clients []*pihole.Client) *Server {
 
 	mux.HandleFunc("/metrics",
 		func(writer http.ResponseWriter, request *http.Request) {
-			for i, client := range clients {
-				fmt.Printf("Idx: %d, Hostname: %s\n", i, client)
-				client.CollectMetrics(writer, request)
+			errors := make([]string, 0)
+
+			for _, client := range clients {
+				if err := client.CollectMetrics(writer, request); err != nil {
+					errors = append(errors, err.Error())
+					fmt.Printf("Error %s\n", err)
 				}
+			}
+
+			if len(errors) == len(clients) {
+				writer.WriteHeader(http.StatusBadRequest)
+				body := strings.Join(errors, "\n")
+				_, _ = writer.Write([]byte(body))
+			}
+
+			promhttp.Handler().ServeHTTP(writer, request)
 		},
 	)
 

main.go

@@ -16,12 +16,8 @@ func main() {
 	metrics.Init()
 
 	serverDead := make(chan struct{})
-	clients := make([]*pihole.Client, 0, len(clientConfigs))
-	for i, _ := range clientConfigs {
-		client := pihole.NewClient(&clientConfigs[i])
-		clients = append(clients, client)
-		fmt.Printf("Append client %s\n", clients)
-	}
+
+	clients := buildClients(clientConfigs)
 
 	s := server.NewServer(envConf.Port, clients)
 	go func() {
@@ -43,3 +39,14 @@ func main() {
 
 	fmt.Println("pihole-exporter HTTP server stopped")
 }
+
+func buildClients(clientConfigs []config.Config) []*pihole.Client {
+	clients := make([]*pihole.Client, 0, len(clientConfigs))
+	for i := range clientConfigs {
+		clientConfig := &clientConfigs[i]
+
+		client := pihole.NewClient(clientConfig)
+		clients = append(clients, client)
+	}
+	return clients
+}