Force autonomous .bat files to run sequentially - windows

Question

I have a reasonably large number of .bat files that are launched by the Windows Task Scheduler. And, subsequently, or by an app that's called in the process. In the latter case, the app launches a .bat file to log that it has started and another .bat file to log that it has completed. They all trigger another single logging .bat file that writes to a log file. There a multiple situations that cause them to overlap:
all of the Task Scheduler tasks are manually Run at once
one of the app tasks is still running when another related Task
Scheduler runs on schedule.
So, we sometimes see:
the process cannot access the file because it is being used by another
process.
And, the result of this is that log entries are missed.
Just to be clear:
Task Scheduler tasks:
go1 >>> launches bat_name1.bat
go2 >>> launches bat_name2.bat
etc.
bat_name1.bat, bat_name2.bat,....
CALL log.bat %bat_nameN%
app.exe %bat_nameN%
EXIT
app.exe task:nameN
launches STARTnameN.bat
(runs the core of the app)
launches ENDnameN.bat
STARTnameN.bat and ENDnameN.bat
log.bat %nameN%
log.bat
#ECHO OFF
SET fileloc=C:\Users\Public\BackupLogs
echo %time% %date% %2 %3 %~1>%fileloc%\temp.txt
type %fileloc%\temp.txt>>%fileloc%\backuplog.txt
So the objective would be to allow all these programs to run autonomously but to sequentialize the result so the log files can be completely written without interference.
One thought would be to separate the temp.txt into tempN.txt,... and to append the result to the single backuplog.txt as a part of the ending process. That would likely make it better but doesn't appear to be a 100% solution as there could still be overlaps?

Answer 1

You could test if the append fails and retry via something like:
:try_append
copy /b %fileloc%\backuplog.txt+%fileloc%\temp.txt %fileloc%\backuplog.txt
if errorlevel 1 goto try_append
(copy must be used as internal commands such as echo and type won't set the error level.)
That would improve things, however you'd still have the problem of collision on the %fileloc%\temp.txt file. Perhaps you have a way to easily resolve this using unique temp names in your various .bat files.
If not, better random temp filenames can be created using %time::=% (millisecond randomness), but even that could conceivably collide.
When I want a truly random filename I involve the value of the RDTSC opcode which changes every processor clock cycle making collisions impossible. There are open source tools available to help with this, eg: capture RDTSC opcode. But perhaps that is a topic for another question.