fix: avoid instantiating a logger if provided /dev/null (#24027)

- Adds some additional context to workspace traffic logging
- Fails traffic tests if 0 bytes read from connection

cli/clilog/clilog.go

@@ -104,7 +104,7 @@ func (b *Builder) Build(inv *serpent.Invocation) (log slog.Logger, closeLog func
 
 	addSinkIfProvided := func(sinkFn func(io.Writer) slog.Sink, loc string) error {
 		switch loc {
-		case "":
+		case "", "/dev/null":
 		case "/dev/stdout":
 			sinks = append(sinks, sinkFn(inv.Stdout))
 

cli/exp_scaletest.go

@@ -1401,6 +1401,9 @@ func (r *RootCmd) scaletestWorkspaceTraffic() *serpent.Command {
 				// Setup our workspace agent connection.
 				config := workspacetraffic.Config{
 					AgentID:       agent.ID,
+					WorkspaceID:   ws.ID,
+					WorkspaceName: ws.Name,
+					AgentName:     agent.Name,
 					BytesPerTick:  bytesPerTick,
 					Duration:      strategy.timeout,
 					TickInterval:  tickInterval,