feat: Support OTel and JSON for logs (via log/slog) (#760)

Co-authored-by: Kyle Mendell <kmendell@ofkm.us>

backend/internal/service/app_config_service.go

@@ -14,7 +14,6 @@ import (
 	"time"
 
 	"github.com/hashicorp/go-uuid"
-
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
 

backend/internal/service/audit_log_service.go

@@ -3,7 +3,6 @@ package service
 import (
 	"context"
 	"fmt"
-	"log"
 	"log/slog"
 
 	userAgentParser "github.com/mileusna/useragent"
@@ -11,6 +10,7 @@ import (
 	"github.com/pocket-id/pocket-id/backend/internal/model"
 	"github.com/pocket-id/pocket-id/backend/internal/utils"
 	"github.com/pocket-id/pocket-id/backend/internal/utils/email"
+	"go.opentelemetry.io/otel/trace"
 	"gorm.io/gorm"
 )
 
@@ -82,7 +82,7 @@ func (s *AuditLogService) CreateNewSignInWithEmail(ctx context.Context, ipAddres
 	}
 	err := stmt.Count(&count).Error
 	if err != nil {
-		log.Printf("Failed to count audit logs: %v", err)
+		slog.ErrorContext(ctx, "Failed to count audit logs", slog.Any("error", err))
 		return createdAuditLog
 	}
 
@@ -91,7 +91,8 @@ func (s *AuditLogService) CreateNewSignInWithEmail(ctx context.Context, ipAddres
 		// We use a background context here as this is running in a goroutine
 		//nolint:contextcheck
 		go func() {
-			innerCtx := context.Background()
+			span := trace.SpanFromContext(ctx)
+			innerCtx := trace.ContextWithSpan(context.Background(), span)
 
 			// Note we don't use the transaction here because this is running in background
 			var user model.User
@@ -101,7 +102,8 @@ func (s *AuditLogService) CreateNewSignInWithEmail(ctx context.Context, ipAddres
 				First(&user).
 				Error
 			if innerErr != nil {
-				log.Printf("Failed to load user: %v", innerErr)
+				slog.ErrorContext(innerCtx, "Failed to load user from database to send notification email", slog.Any("error", innerErr))
+				return
 			}
 
 			innerErr = SendEmail(innerCtx, s.emailService, email.Address{
@@ -115,7 +117,8 @@ func (s *AuditLogService) CreateNewSignInWithEmail(ctx context.Context, ipAddres
 				DateTime:  createdAuditLog.CreatedAt.UTC(),
 			})
 			if innerErr != nil {
-				log.Printf("Failed to send email to '%s': %v", user.Email, innerErr)
+				slog.ErrorContext(innerCtx, "Failed to send notification email", slog.Any("error", innerErr), slog.String("address", user.Email))
+				return
 			}
 		}()
 	}

backend/internal/service/geolite_service.go

@@ -7,7 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"log"
+	"log/slog"
 	"net"
 	"net/http"
 	"net/netip"
@@ -52,13 +52,13 @@ func NewGeoLiteService(httpClient *http.Client) *GeoLiteService {
 
 	if common.EnvConfig.MaxMindLicenseKey == "" && common.EnvConfig.GeoLiteDBUrl == common.MaxMindGeoLiteCityUrl {
 		// Warn the user, and disable the periodic updater
-		log.Println("MAXMIND_LICENSE_KEY environment variable is empty. The GeoLite2 City database won't be updated.")
+		slog.Warn("MAXMIND_LICENSE_KEY environment variable is empty: the GeoLite2 City database won't be updated")
 		service.disableUpdater = true
 	}
 
 	// Initialize IPv6 local ranges
 	if err := service.initializeIPv6LocalRanges(); err != nil {
-		log.Printf("Warning: Failed to initialize IPv6 local ranges: %v", err)
+		slog.Warn("Failed to initialize IPv6 local ranges", slog.Any("error", err))
 	}
 
 	return service
@@ -96,7 +96,7 @@ func (s *GeoLiteService) initializeIPv6LocalRanges() error {
 	s.localIPv6Ranges = localRanges
 
 	if len(localRanges) > 0 {
-		log.Printf("Initialized %d IPv6 local ranges", len(localRanges))
+		slog.Info("Initialized IPv6 local ranges", slog.Int("count", len(localRanges)))
 	}
 	return nil
 }
@@ -186,11 +186,11 @@ func (s *GeoLiteService) GetLocationByIP(ipAddress string) (country, city string
 // UpdateDatabase checks the age of the database and updates it if it's older than 14 days.
 func (s *GeoLiteService) UpdateDatabase(parentCtx context.Context) error {
 	if s.isDatabaseUpToDate() {
-		log.Println("GeoLite2 City database is up-to-date")
+		slog.Info("GeoLite2 City database is up-to-date")
 		return nil
 	}
 
-	log.Println("Updating GeoLite2 City database")
+	slog.Info("Updating GeoLite2 City database")
 	downloadUrl := fmt.Sprintf(common.EnvConfig.GeoLiteDBUrl, common.EnvConfig.MaxMindLicenseKey)
 
 	ctx, cancel := context.WithTimeout(parentCtx, 10*time.Minute)
@@ -217,7 +217,7 @@ func (s *GeoLiteService) UpdateDatabase(parentCtx context.Context) error {
 		return fmt.Errorf("failed to extract database: %w", err)
 	}
 
-	log.Println("GeoLite2 City database successfully updated.")
+	slog.Info("GeoLite2 City database successfully updated.")
 	return nil
 }
 

backend/internal/service/jwt_service.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"log"
 	"time"
 
 	"github.com/lestrrat-go/jwx/v3/jwa"
@@ -64,16 +63,16 @@ type JwtService struct {
 	jwksEncoded      []byte
 }
 
-func NewJwtService(db *gorm.DB, appConfigService *AppConfigService) *JwtService {
+func NewJwtService(db *gorm.DB, appConfigService *AppConfigService) (*JwtService, error) {
 	service := &JwtService{}
 
 	// Ensure keys are generated or loaded
 	err := service.init(db, appConfigService, &common.EnvConfig)
 	if err != nil {
-		log.Fatalf("Failed to initialize jwt service: %v", err)
+		return nil, err
 	}
 
-	return service
+	return service, nil
 }
 
 func (s *JwtService) init(db *gorm.DB, appConfigService *AppConfigService, envConfig *common.EnvConfigSchema) (err error) {

backend/internal/service/ldap_service.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"strings"
@@ -130,7 +131,7 @@ func (s *LdapService) SyncGroups(ctx context.Context, tx *gorm.DB, client *ldap.
 
 		// Skip groups without a valid LDAP ID
 		if ldapId == "" {
-			log.Printf("Skipping LDAP group without a valid unique identifier (attribute: %s)", dbConfig.LdapAttributeGroupUniqueIdentifier.Value)
+			slog.Warn("Skipping LDAP group without a valid unique identifier", slog.String("attribute", dbConfig.LdapAttributeGroupUniqueIdentifier.Value))
 			continue
 		}
 
@@ -250,7 +251,7 @@ func (s *LdapService) SyncGroups(ctx context.Context, tx *gorm.DB, client *ldap.
 			return fmt.Errorf("failed to delete group '%s': %w", group.Name, err)
 		}
 
-		log.Printf("Deleted group '%s'", group.Name)
+		slog.Info("Deleted group", slog.String("group", group.Name))
 	}
 
 	return nil
@@ -295,7 +296,7 @@ func (s *LdapService) SyncUsers(ctx context.Context, tx *gorm.DB, client *ldap.C
 
 		// Skip users without a valid LDAP ID
 		if ldapId == "" {
-			log.Printf("Skipping LDAP user without a valid unique identifier (attribute: %s)", dbConfig.LdapAttributeUserUniqueIdentifier.Value)
+			slog.Warn("Skipping LDAP user without a valid unique identifier", slog.String("attribute", dbConfig.LdapAttributeUserUniqueIdentifier.Value))
 			continue
 		}
 
@@ -350,7 +351,7 @@ func (s *LdapService) SyncUsers(ctx context.Context, tx *gorm.DB, client *ldap.C
 		if databaseUser.ID == "" {
 			_, err = s.userService.createUserInternal(ctx, newUser, true, tx)
 			if errors.Is(err, &common.AlreadyInUseError{}) {
-				log.Printf("Skipping creating LDAP user '%s': %v", newUser.Username, err)
+				slog.Warn("Skipping creating LDAP user", slog.String("username", newUser.Username), slog.Any("error", err))
 				continue
 			} else if err != nil {
 				return fmt.Errorf("error creating user '%s': %w", newUser.Username, err)
@@ -358,7 +359,7 @@ func (s *LdapService) SyncUsers(ctx context.Context, tx *gorm.DB, client *ldap.C
 		} else {
 			_, err = s.userService.updateUserInternal(ctx, databaseUser.ID, newUser, false, true, tx)
 			if errors.Is(err, &common.AlreadyInUseError{}) {
-				log.Printf("Skipping updating LDAP user '%s': %v", newUser.Username, err)
+				slog.Warn("Skipping updating LDAP user", slog.String("username", newUser.Username), slog.Any("error", err))
 				continue
 			} else if err != nil {
 				return fmt.Errorf("error updating user '%s': %w", newUser.Username, err)
@@ -371,7 +372,7 @@ func (s *LdapService) SyncUsers(ctx context.Context, tx *gorm.DB, client *ldap.C
 			err = s.saveProfilePicture(ctx, databaseUser.ID, pictureString)
 			if err != nil {
 				// This is not a fatal error
-				log.Printf("Error saving profile picture for user %s: %v", newUser.Username, err)
+				slog.Warn("Error saving profile picture for user", slog.String("username", newUser.Username), slog.Any("error", err))
 			}
 		}
 	}
@@ -400,7 +401,7 @@ func (s *LdapService) SyncUsers(ctx context.Context, tx *gorm.DB, client *ldap.C
 				return fmt.Errorf("failed to disable user %s: %w", user.Username, err)
 			}
 
-			log.Printf("Disabled user '%s'", user.Username)
+			slog.Info("Disabled user", slog.String("username", user.Username))
 		} else {
 			err = s.userService.deleteUserInternal(ctx, user.ID, true, tx)
 			target := &common.LdapUserUpdateError{}
@@ -410,7 +411,7 @@ func (s *LdapService) SyncUsers(ctx context.Context, tx *gorm.DB, client *ldap.C
 				return fmt.Errorf("failed to delete user %s: %w", user.Username, err)
 			}
 
-			log.Printf("Deleted user '%s'", user.Username)
+			slog.Info("Deleted user", slog.String("username", user.Username))
 		}
 	}
 

backend/internal/service/user_service.go

@@ -7,12 +7,14 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"log/slog"
 	"net/url"
 	"os"
 	"strings"
 	"time"
 
 	"github.com/google/uuid"
+	"go.opentelemetry.io/otel/trace"
 	"gorm.io/gorm"
 
 	"github.com/pocket-id/pocket-id/backend/internal/common"
@@ -393,7 +395,8 @@ func (s *UserService) requestOneTimeAccessEmailInternal(ctx context.Context, use
 	// We use a background context here as this is running in a goroutine
 	//nolint:contextcheck
 	go func() {
-		innerCtx := context.Background()
+		span := trace.SpanFromContext(ctx)
+		innerCtx := trace.ContextWithSpan(context.Background(), span)
 
 		link := common.EnvConfig.AppURL + "/lc"
 		linkWithCode := link + "/" + oneTimeAccessToken
@@ -414,7 +417,8 @@ func (s *UserService) requestOneTimeAccessEmailInternal(ctx context.Context, use
 			ExpirationString:  utils.DurationToString(time.Until(expiration).Round(time.Second)),
 		})
 		if errInternal != nil {
-			log.Printf("Failed to send email to '%s': %v\n", user.Email, errInternal)
+			slog.ErrorContext(innerCtx, "Failed to send one-time access token email", slog.Any("error", errInternal), slog.String("address", user.Email))
+			return
 		}
 	}()