overwrite multislogger.Logger memory rather than reassigning pointer

cmd/launcher/launcher.go

@@ -185,8 +185,6 @@ func runLauncher(ctx context.Context, cancel func(), multiSlogger, systemMultiSl
 	fcOpts := []flags.Option{flags.WithCmdLineOpts(opts)}
 	flagController := flags.NewFlagController(logger, stores[storage.AgentFlagsStore], fcOpts...)
 	k := knapsack.New(stores, flagController, db, multiSlogger, systemMultiSlogger)
-	// reassign slogger to knapsack slogger to get launcher run id added to slogger
-	slogger = k.Slogger()
 
 	go runOsqueryVersionCheck(ctx, slogger, k.LatestOsquerydPath(ctx))
 	go timemachine.AddExclusions(ctx, k)
@@ -221,6 +219,7 @@ func runLauncher(ctx context.Context, cancel func(), multiSlogger, systemMultiSl
 		logger = teelogger.New(logger, logShipper)
 		logger = log.With(logger, "caller", log.Caller(5))
 		k.AddSlogHandler(logShipper.SlogHandler())
+
 		ctx = ctxlog.NewContext(ctx, logger) // Set the logger back in the ctx
 
 		k.SetTraceSamplingRateOverride(1.0, initialDebugDuration)

ee/agent/knapsack/knapsack.go

@@ -6,7 +6,6 @@ import (
 	"log/slog"
 
 	"github.com/go-kit/kit/log"
-	"github.com/kolide/kit/ulid"
 	"github.com/kolide/launcher/ee/agent/storage"
 	"github.com/kolide/launcher/ee/agent/types"
 	"github.com/kolide/launcher/ee/tuf"
@@ -33,7 +32,6 @@ type knapsack struct {
 	db *bbolt.DB
 
 	slogger, systemSlogger *multislogger.MultiSlogger
-	launcherRunId          string
 
 	// This struct is a work in progress, and will be iteratively added to as needs arise.
 	// Some potential future additions include:
@@ -47,11 +45,6 @@ func New(stores map[storage.Store]types.KVStore, flags types.Flags, db *bbolt.DB
 		stores:        stores,
 		slogger:       slogger,
 		systemSlogger: systemSlogger,
-		launcherRunId: ulid.New(),
-	}
-
-	if k.slogger != nil {
-		k.slogger.Logger = k.slogger.Logger.With("launcher_run_id", k.launcherRunId)
 	}
 
 	return k
@@ -68,9 +61,6 @@ func (k *knapsack) SystemSlogger() *slog.Logger {
 
 func (k *knapsack) AddSlogHandler(handler ...slog.Handler) {
 	k.slogger.AddHandler(handler...)
-	k.slogger.Logger = k.slogger.Logger.With("launcher_run_id", k.launcherRunId)
-
-	// also send system logs to the same handlers
 	k.systemSlogger.AddHandler(handler...)
 }
 

pkg/log/multislogger/multislogger.go

@@ -2,9 +2,9 @@ package multislogger
 
 import (
 	"context"
-	"io"
 	"log/slog"
 
+	"github.com/kolide/kit/ulid"
 	slogmulti "github.com/samber/slog-multi"
 )
 
@@ -33,40 +33,37 @@ var ctxValueKeysToAdd = []contextKey{
 
 type MultiSlogger struct {
 	*slog.Logger
-	handlers []slog.Handler
+	handlers      []slog.Handler
+	launcherRunId string
 }
 
 // New creates a new multislogger if no handlers are passed in, it will
 // create a logger that discards all logs
 func New(h ...slog.Handler) *MultiSlogger {
-	ms := new(MultiSlogger)
-
-	if len(h) == 0 {
-		// if we don't have any handlers passed in, we'll just discard the logs
-		// do not add the discard handler to the handlers so it will not be
-		// included when a handler is added
-		ms.Logger = slog.New(slog.NewTextHandler(io.Discard, nil))
-		return ms
+	ms := &MultiSlogger{
+		// setting to fanout with no handlers is noop
+		Logger:        slog.New(slogmulti.Fanout()),
+		launcherRunId: ulid.New(),
 	}
 
 	ms.AddHandler(h...)
 	return ms
 }
 
 // AddHandler adds a handler to the multislogger, this creates a branch new
-// slog.Logger under the the hood, mean any attributes added with
-// Logger.With will be lost
+// slog.Logger under the the hood, and overwrites old Logger memory address,
+// this means any attributes added with Logger.With will be lost
 func (m *MultiSlogger) AddHandler(handler ...slog.Handler) {
 	m.handlers = append(m.handlers, handler...)
 
 	// we have to rebuild the handler everytime because the slogmulti package we're
 	// using doesn't support adding handlers after the Fanout handler has been created
-	m.Logger = slog.New(
+	*m.Logger = *slog.New(
 		slogmulti.
 			Pipe(slogmulti.NewHandleInlineMiddleware(utcTimeMiddleware)).
 			Pipe(slogmulti.NewHandleInlineMiddleware(ctxValuesMiddleWare)).
 			Handler(slogmulti.Fanout(m.handlers...)),
-	)
+	).With("launcher_run_id", m.launcherRunId)
 }
 
 func utcTimeMiddleware(ctx context.Context, record slog.Record, next func(context.Context, slog.Record) error) error {