From 13122275f6e6dddb4dbf3ad8db0cdcda9a785fdd Mon Sep 17 00:00:00 2001
From: Julian Kornberger <jk+github@digineo.de>
Date: Wed, 29 Nov 2023 21:18:39 +0100
Subject: [PATCH] Switch to log/slog package

---
 exporter/collector.go |  4 ++--
 exporter/exporter.go  |  6 +++---
 main.go               | 31 +++++++++++++++++++++++++++----
 triax/client.go       | 27 +++++++++------------------
 4 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/exporter/collector.go b/exporter/collector.go
index 6ede5af..bab2d29 100644
--- a/exporter/collector.go
+++ b/exporter/collector.go
@@ -3,7 +3,7 @@ package exporter
 import (
 	"context"
 	"fmt"
-	"log"
+	"log/slog"
 	"strconv"
 
 	"github.com/digineo/triax-eoc-exporter/triax"
@@ -72,7 +72,7 @@ func (t *triaxCollector) Collect(ch chan<- prometheus.Metric) {
 	ch <- prometheus.MustNewConstMetric(ctrlUp, prometheus.GaugeValue, boolToFloat(err == nil))
 
 	if err != nil {
-		log.Println("fetching failed:", err)
+		slog.Error("fetching failed", "error", err)
 	}
 }
 
diff --git a/exporter/exporter.go b/exporter/exporter.go
index c0cb5ae..ffa0427 100644
--- a/exporter/exporter.go
+++ b/exporter/exporter.go
@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"log"
+	"log/slog"
 	"net"
 	"net/http"
 	"text/template"
@@ -30,8 +30,8 @@ func (cfg *Config) Start(listenAddress, version string) {
 	router.GET("/controllers/:target/api/*path", cfg.targetMiddleware(cfg.apiHandler))
 	router.PUT("/controllers/:target/nodes/:mac", cfg.targetMiddleware(cfg.updateNodeHandler))
 
-	log.Printf("Starting exporter on http://%s/", listenAddress)
-	log.Fatal(http.ListenAndServe(listenAddress, router))
+	slog.Info("Starting exporter", "listenAddress", listenAddress)
+	slog.Info("Server stopped", "reason", http.ListenAndServe(listenAddress, router))
 }
 
 type targetHandler func(*triax.Client, http.ResponseWriter, *http.Request, httprouter.Params)
diff --git a/main.go b/main.go
index 9531291..3ddada8 100644
--- a/main.go
+++ b/main.go
@@ -3,12 +3,12 @@ package main
 import (
 	"fmt"
 	"log"
+	"log/slog"
+	"os"
 	"runtime/debug"
 
-	"github.com/digineo/triax-eoc-exporter/exporter"
-	"github.com/digineo/triax-eoc-exporter/triax"
-
 	kingpin "github.com/alecthomas/kingpin/v2"
+	"github.com/digineo/triax-eoc-exporter/exporter"
 )
 
 // DefaultConfigPath points to the default config file location.
@@ -44,15 +44,38 @@ func main() {
 	kingpin.HelpFlag.Short('h')
 	kingpin.Parse()
 
+	initLogger(*verbose)
+
 	cfg, err := exporter.LoadConfig(*configFile)
 	if err != nil {
 		log.Fatal(err.Error())
 	}
 
-	triax.Verbose = *verbose
 	cfg.Start(*listenAddress, version)
 }
 
+func initLogger(verbose bool) {
+	opts := slog.HandlerOptions{
+		Level: slog.LevelInfo,
+		ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
+			// Remove time from the output
+			if a.Key == slog.TimeKey {
+				return slog.Attr{}
+			}
+
+			return a
+		},
+	}
+
+	if verbose {
+		opts.Level = slog.LevelDebug
+	}
+
+	logger := slog.New(slog.NewTextHandler(os.Stdout, &opts))
+	slog.SetDefault(logger)
+
+}
+
 func printVersion() {
 	info, ok := debug.ReadBuildInfo()
 	if !ok {
diff --git a/triax/client.go b/triax/client.go
index ae002a7..164dbaa 100644
--- a/triax/client.go
+++ b/triax/client.go
@@ -8,8 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
-	"log"
+	"log/slog"
 	"net/http"
 	"net/http/cookiejar"
 	"net/url"
@@ -23,14 +22,9 @@ type Client struct {
 	password string
 }
 
-var (
-	// Verbose increases verbosity.
-	Verbose bool
-
-	HTTPClient = http.Client{
-		Timeout: time.Second * 30,
-	}
-)
+var HTTPClient = http.Client{
+	Timeout: time.Second * 30,
+}
 
 func init() {
 	HTTPClient.Jar, _ = cookiejar.New(nil) // error is always nil
@@ -123,9 +117,7 @@ retry:
 func (c *Client) apiRequestRaw(ctx context.Context, method, path string, request, response interface{}) error {
 	url := fmt.Sprintf("%s://%s/api/%s", c.endpoint.Scheme, c.endpoint.Host, strings.TrimPrefix(path, "/"))
 
-	if Verbose {
-		log.Printf("%s %s", method, url)
-	}
+	slog.Info("HTTP Request", "method", method, "url", url)
 
 	var body io.Reader
 	if request != nil {
@@ -153,7 +145,7 @@ func (c *Client) apiRequestRaw(ctx context.Context, method, path string, request
 	defer res.Body.Close()
 
 	if res.StatusCode != http.StatusOK {
-		data, _ := ioutil.ReadAll(res.Body)
+		data, _ := io.ReadAll(res.Body)
 
 		return &ErrUnexpectedStatus{
 			Method: method,
@@ -163,19 +155,18 @@ func (c *Client) apiRequestRaw(ctx context.Context, method, path string, request
 		}
 	}
 
-	jsonData, err := ioutil.ReadAll(res.Body)
+	jsonData, err := io.ReadAll(res.Body)
 	if err != nil {
 		return err
 	}
 
 	if response != nil {
 		err = json.Unmarshal(jsonData, &response)
-		if Verbose || err != nil {
-			log.Println(string(jsonData))
-		}
 		if err != nil {
 			return fmt.Errorf("decoding response failed: %w", err)
 		}
+
+		slog.Debug("response received", "json", string(jsonData))
 	}
 
 	return nil