feat: make log level configurable, use log/slog

cmd/knowledgebot/main.go

@@ -2,7 +2,8 @@ package main
 
 import (
 	"context"
-	"log"
+	"log/slog"
+	"os"
 	"os/signal"
 	"syscall"
 )
@@ -13,6 +14,7 @@ func main() {
 
 	err := rootCmd.ExecuteContext(ctx)
 	if err != nil {
-		log.Fatal("FATAL: ", err)
+		slog.Error(err.Error())
+		os.Exit(1)
 	}
 }

cmd/knowledgebot/root.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"log/slog"
 	"os"
 	"strings"
 
@@ -21,6 +22,7 @@ var (
 )
 
 func init() {
+	rootCmd.PersistentFlags().Var(logLevelFlag("INFO"), "log-level", "set the log level")
 	rootCmd.SetFlagErrorFunc(func(cmd *cobra.Command, err error) error {
 		_ = cmd.Help()
 		return err
@@ -32,10 +34,10 @@ func Execute() error {
 }
 
 func preRunEnvVars(cmd *cobra.Command, args []string) error {
-	return parseFlagsWithEnvVars(cmd.Flags(), "KLB_")
+	return applyEnvVarsToFlags(cmd.Flags(), "KLB_")
 }
 
-func parseFlagsWithEnvVars(fs *pflag.FlagSet, envVarPrefix string) error {
+func applyEnvVarsToFlags(fs *pflag.FlagSet, envVarPrefix string) error {
 	var err error
 
 	fs.VisitAll(func(f *pflag.Flag) {
@@ -50,3 +52,34 @@ func parseFlagsWithEnvVars(fs *pflag.FlagSet, envVarPrefix string) error {
 
 	return err
 }
+
+type logLevelFlag string
+
+func (logLevelFlag) Set(s string) error {
+	var level slog.Level
+
+	switch s {
+	case "DEBUG":
+		level = slog.LevelDebug
+	case "INFO":
+		level = slog.LevelInfo
+	case "WARN":
+		level = slog.LevelWarn
+	case "ERROR":
+		level = slog.LevelError
+	default:
+		return fmt.Errorf("unsupported log level %q provided. supported log levels are DEBUG, INFO, WARN, ERROR", s)
+	}
+
+	slog.SetLogLoggerLevel(level)
+
+	return nil
+}
+
+func (f logLevelFlag) String() string {
+	return string(f)
+}
+
+func (f logLevelFlag) Type() string {
+	return "LEVEL"
+}

cmd/knowledgebot/serve.go

@@ -2,7 +2,7 @@ package main
 
 import (
 	"context"
-	"log"
+	"log/slog"
 	"net"
 	"net/http"
 
@@ -101,11 +101,11 @@ func runServer(cmd *cobra.Command, args []string) error {
 		<-ctx.Done()
 		err := srv.Shutdown(ctx)
 		if err != nil {
-			log.Println("ERROR: failed to shutdown server:", err)
+			slog.Error("failed to shutdown server: " + err.Error())
 		}
 	}()
 
-	log.Println("listening on", srv.Addr)
+	slog.Info("listening on " + srv.Addr)
 
 	err := srv.ListenAndServe()
 	if err == http.ErrServerClosed {

internal/importer/crawler/crawler.go

@@ -5,7 +5,7 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"
-	"log"
+	"log/slog"
 	"net/url"
 	"regexp"
 	"strings"
@@ -32,7 +32,7 @@ type Crawler struct {
 }
 
 func (s *Crawler) Crawl(ctx context.Context, seedURL string) error {
-	log.Printf("crawling %s with maxDepth=%d, maxPages=%d and urlRegex=%s", seedURL, s.MaxDepth, s.MaxPages, s.URLRegex)
+	slog.Info("crawling "+seedURL, "maxDepth", s.MaxDepth, "maxPages", s.MaxPages, "urlRegex", s.URLRegex)
 
 	startTime := time.Now()
 
@@ -84,26 +84,26 @@ func (s *Crawler) crawl(ctx context.Context, seedURL *url.URL, ch chan<- []schem
 			}
 		}
 
-		log.Println("visiting", req.URL)
+		slog.Info("visiting " + req.URL.String())
 	})
 
 	c.OnResponse(func(f *colly.Response) {
 		err := s.processHTML(ctx, f.Request.URL, string(f.Body), ch)
 		if err != nil {
-			log.Println("WARNING:", err)
+			slog.Warn(err.Error())
 		}
 	})
 
 	c.OnHTML("a[href]", func(e *colly.HTMLElement) {
 		err := e.Request.Visit(e.Attr("href"))
 		if err != nil {
-			log.Println("ERROR: failed to visit page:", err)
+			slog.Debug("failed to visit page: " + err.Error())
 		}
 	})
 
 	err := c.Visit(seedURL.String())
 	if err != nil {
-		log.Println("ERROR: failed to crawl page:", err)
+		slog.Warn("failed to crawl page: " + err.Error())
 	}
 
 	c.Wait()
@@ -127,7 +127,7 @@ func (s *Crawler) processHTML(ctx context.Context, url *url.URL, html string, ch
 		return fmt.Errorf("split text: %w", err)
 	}
 
-	log.Printf("scraped %d chunks from %s", len(chunks), url)
+	slog.Info(fmt.Sprintf("scraped %d chunks from %s", len(chunks), url))
 
 	docs := make([]schema.Document, 0, len(chunks))
 
@@ -221,7 +221,7 @@ func (s *Crawler) indexDocumentChunks(ctx context.Context, cancel context.Cancel
 
 	elapsed := time.Since(startTime)
 
-	log.Printf("indexed %d chunks of %d document(s) in %s", chunkCount, docCount, elapsed)
+	slog.Info(fmt.Sprintf("indexed %d chunks of %d document(s) in %s", chunkCount, docCount, elapsed))
 
 	return ctx.Err()
 }

internal/qdrantutils/collection.go

@@ -5,7 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"log"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"time"
@@ -37,7 +37,7 @@ func CreateQdrantCollectionIfNotExist(ctx context.Context, qdrantURL, collection
 	}
 
 	if resp.StatusCode == http.StatusOK {
-		log.Printf("created qdrant collection %q", collection)
+		slog.Info("created qdrant collection " + collection)
 		return nil
 	}
 

internal/qna/qnaworkflow.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"log"
+	"log/slog"
 	"strings"
 
 	"github.com/tmc/langchaingo/llms"
@@ -82,7 +82,7 @@ func (w *QuestionAnswerWorkflow) Answer(ctx context.Context, question string) (<
 		return nil, err
 	}
 
-	log.Println("Requesting LLM answer for prompt:\n  ", strings.ReplaceAll(prompt, "\n", "\n  "))
+	slog.Info("Requesting LLM answer for prompt:" + strings.ReplaceAll("\n"+prompt, "\n", "\n  "))
 
 	go func() {
 		defer close(ch)
@@ -124,13 +124,13 @@ func searchResultsToSourceRefs(docs []schema.Document) []SourceReference {
 	for _, doc := range docs {
 		urlKey, ok := doc.Metadata["url"].(string)
 		if !ok {
-			log.Println("WARNING: vectordb search result doc does not specify 'url' metadata key")
+			slog.Warn("vectordb search result doc does not specify 'url' metadata key")
 			continue
 		}
 
 		title, ok := doc.Metadata["title"].(string)
 		if !ok {
-			log.Println("WARNING: vectordb search result doc does not specify 'title' metadata key")
+			slog.Warn("vectordb search result doc does not specify 'title' metadata key")
 			continue
 		}
 

internal/server/qnahandler.go

@@ -3,7 +3,7 @@ package server
 import (
 	"encoding/json"
 	"fmt"
-	"log"
+	"log/slog"
 	"net/http"
 
 	"github.com/mgoltzsche/knowledgebot/internal/qna"
@@ -15,7 +15,7 @@ func newQuestionAnswerHandler(ai *qna.QuestionAnswerWorkflow) http.Handler {
 		if question == "" {
 			err := req.ParseForm()
 			if err != nil {
-				log.Println("WARNING: parse form data:", err)
+				slog.Warn("parse form data: " + err.Error())
 			}
 
 			question = req.Form.Get("q")
@@ -40,7 +40,7 @@ func newQuestionAnswerHandler(ai *qna.QuestionAnswerWorkflow) http.Handler {
 
 			data, err := json.Marshal(chunk)
 			if err != nil {
-				log.Println("ERROR: failed to marshal chunk:", err)
+				slog.Error("failed to marshal chunk: " + err.Error())
 				continue
 			}