> A problem existed in midas for some time: when recording long data sets of time (or event) limited runs 
> with logger run auto restart set to "yes", the runs will automatically stop and restart as expected, but 
> sometimes the run will stop and never restart and beam will be lost until the experiment operator on shift 
> wakes up and restarts the run manually.
> 
> I have now traced this problem to a race condition inside the mlogger - when a run is being stopped from 
> the mlogger, the mlogger run transition handler (tr_stop) triggers an immediate attempt to start the next 
> run, without waiting for the run-stop transition to actually complete. If the run-stop transition does not 
> finish quickly enough, a safety check in start_the_run() will cause the run restart attempt to silently fail 
> without any error message.
> 
> This race condition is pretty rare but somehow I managed to replicate it while debugging the 
> multithreaded transitions. It is fixed by making mlogger wait until the run-stop transition completes.
> 
> https://bitbucket.org/tmidas/midas/commits/b2631fbed5f7b1ec80e8a6c8781ada0baed7702b
> 
> K.O.

More generally I kind of consider the mlogger auto restart facility as deprecated. It works in the background and the operator does not have a clue 
what is going on. We use now the sequencer to achieve exactly the same functionality. It just requires a few lines of sequencer code:

LOOP INFINITE 
  TRANSITION start 
  WAIT events, 5000 
  TRANSITION stop 
ENDLOOP 

So the run start is only executed after the runs has been successfully stopped. You can do things in the sequencer like "stop run and sequence 
immediately" or "stop after current run has finished" which are a bit hard to do with the old method. So people should move to the sequencer.

/Stefan

> 
> More generally I kind of consider the mlogger auto restart facility as deprecated. It works in the background and the operator does not have a clue 
> what is going on. We use now the sequencer to achieve exactly the same functionality.
>

Before subruns were available, most experiments at TRIUMF have used the "auto restart" function. Now, I think most of them use subruns,
with the notable exception of PIENU where the analysis framework could not handle subruns. (PIENU is now shutdown and disassembled).

>
> It just requires a few lines of sequencer code:
> 
> LOOP INFINITE 
>   TRANSITION start 
>   WAIT events, 5000 
>   TRANSITION stop 
> ENDLOOP 
> 

Mouse click "auto restart" to "yes" is a little bit simpler than setting up a sequencer file, and it survives a crash of mhttpd.

Does the sequencer survive a crash or a restart of mhttpd?

K.O.

> Does the sequencer survive a crash or a restart of mhttpd?

Yes. Of course runs will not be started/stopped when mhttpd is not running, but when you restart it gracefully continues where it stopped, since all variables such as event count or current line number of 
the sequence are store in the ODB.

/Stefan

A few months ago, definitions of SYNC and ASYNC in midas.h have been changed away from "0" and "1", 
and this caused problems with some event buffer management functions bm_xxx().

For example, when event buffers are getting full, bm_send_event(SYNC) unexpectedly started returning 
BM_ASYNC_RETURN instead of waiting for free space, causing unexpected crashes of frontend programs.

Part of the problem was confusion between SYNC/ASYNC used by buffer management (bm_xxx) and by run 
transition (cm_transition()) functions. Adding to confusion, documentation of bm_send_event() & co used 
FALSE/TRUE while most actual calls used SYNC/ASYNC.

To sort this out, an executive decision was made to abolish the SYNC/ASYNC defines:

For buffer management calls bm_send_event(), bm_receive_event(), etc, please use:
SYNC -> BM_WAIT
ASYNC -> BM_NO_WAIT

For run transitions, please use:
SYNC -> TR_SYNC
ASYNC -> TR_ASYNC
MTHREAD -> TR_MTHREAD
DETACH -> TR_DETACH

K.O.

In some experiments (i.e. DEAP), we see spurious symlinks to midas.log scattered just about everywhere. I 
now traced this to an uninitialized variable in cm_msg_log() and it should be fixed now. K.O.

The capability to generate doxygen documentation of MIDAS was restored.

Use "make dox" and "make cleandox",
find generated documentation in ./html,
look at it via "firefox html/index.html".

The documentation is not generated by default - it takes quite a long time to build all the call graphs.

And the call graphs is what makes this documentation useful - without some visual graphical 
representation it is quite difficult to understand some parts of MIDAS. Both caller and callee graphs are 
generated.

Note that doxygen documentation for the javascript functions in mhttpd.js is also generated, making a 
handy reference in addition to the full documentation on the MIDAS Wiki.

K.O.

> The capability to generate doxygen documentation of MIDAS was restored.
> 
> Use "make dox" and "make cleandox",
> find generated documentation in ./html,
> look at it via "firefox html/index.html".
> 
> The documentation is not generated by default - it takes quite a long time to build all the call graphs.
> 
> And the call graphs is what makes this documentation useful - without some visual graphical 
> representation it is quite difficult to understand some parts of MIDAS. Both caller and callee graphs are 
> generated.
> 
> Note that doxygen documentation for the javascript functions in mhttpd.js is also generated, making a 
> handy reference in addition to the full documentation on the MIDAS Wiki.
> 
> K.O.

To generate the files, you need doxygen installed which not everybody has. Is there a web site where one can see the generated graphs?

/Stefan

> > The capability to generate doxygen documentation of MIDAS was restored.
> > 
> > Use "make dox" and "make cleandox",
> > find generated documentation in ./html,
> > look at it via "firefox html/index.html".
> > 
> 
> To generate the files, you need doxygen installed which not everybody has.

On most Linux systems, doxygen is easy to install. Red Hat instructions are here: 
http://www.triumf.info/wiki/DAQwiki/index.php/SLinstall#Install_packages_needed_for_QUARTUS.2C_ROOT.2C_EPICS_and_MIDAS_DAQ

On MacOS, doxygen is easy to install via macports: sudo port install doxygen

> Is there a web site where one can see the generated graphs?

http://ladd00.triumf.ca/~olchansk/midas/index.html

there is no cron job to update this, but I may update it infrequently.

K.O.

> On most Linux systems, doxygen is easy to install. Red Hat instructions are here: 
> http://www.triumf.info/wiki/DAQwiki/index.php/SLinstall#Install_packages_needed_for_QUARTUS.2C_ROOT.2C_EPICS_and_MIDAS_DAQ
> 
> On MacOS, doxygen is easy to install via macports: sudo port install doxygen
> 
> > Is there a web site where one can see the generated graphs?
> 
> http://ladd00.triumf.ca/~olchansk/midas/index.html
> 
> there is no cron job to update this, but I may update it infrequently.
> 
> K.O.

Great, thanks a lot!

-Stefan

Latest C/C++ compilers (MacOS 10.10, GCC on RHEL7 and Ubuntu) generate a large number of new 
warnings about unused variables, unused functions, dead code, failure to check return values of system 
calls, etc.

Some of these warnings catch real bugs so we do not want to turn them off.

Most of these warnings have been cleaned out in the latest MIDAS code. On MacOS and RHEL6 Linux MIDA 
S compiles without any warnings. On RHEL7 and Ubuntu Linux there are some warnings from a few 
problematic files, history.c being the worst (it will be eventually cleaned out).

K.O.

I removed the example ssl certificate from the midas git repository (ssl_cert.pem). Now every midas 
installation must generate their own certificate - because to have any security at all each encryption 
private key has to be unique (and it has to be secret).

The command for generating a self-signed certificate is printed by mhttpd on startup:

openssl req -new -nodes -newkey rsa:2048 -sha256 -out ssl_cert.csr -keyout ssl_cert.key; openssl 
x509 -req -days 365 -sha256 -in ssl_cert.csr -signkey ssl_cert.key -out ssl_cert.pem; cat 
ssl_cert.key >> ssl_cert.pem

K.O.

I the agdaq system I see memory corruption in the mlogger. There were at least two bugs: one 
memory allocation error in mxml and one incorrect memset() in mlogger.cxx. The mxml bug is fixed 
in the mxml repository, mlogger.cxx bug is fixed in the midas-2017-10 branch.

I suggest that all update mxml to the latest version: (without waiting for the new midas release)
https://bitbucket.org/tmidas/mxml/commits/branch/master

K.O.

I wanted to try to summarize the current situation with regards to the handling of strings through the MIDAS web interface.

During the last year, we started the switch-over to using the new mjson-rpc functions in the MIDAS webpages.  As part of this work, changes were made that allowed for 
resizing strings through the MIDAS web interface (specifically through the MJSON-RPC calls). This reflected desires from some users that strings could be allowed to 
grow larger than the default 256 size that is usually used for MIDAS strings (for instance, see [1]).  In this first set of changes the ODB strings would always be resized to 
the exact size of the string that it was set to.

The problem with this change was that it breaks the behaviour of db_get_record(), which typically expects strings to be a fixed length of 32 or 256 (for instance, see 
[2,3]).  Konstantin notes that we can work around this problem by using db_get_record1() function, which automatically resizes strings to expected values; this method 
has already been used in the MIDAS core code.  But the problem would still remain for some user code that uses db_get_record.

As a short-term compromise solution, Stefan implemented a change where the MJSON-RPC string setting will now expand the size of strings, but not truncate them; ie a 
string that is size 256 will stay 256 bytes, unless you set it to something larger.  So this should fix most cases of user code that call db_get_record() and hence expects 
fixed string lengths. Users who call that db_get_record with strings that exceed the expected length will still have problems; but now you will at least get an explicit 
MIDAS error message, rather than just silent string truncation (as was the case before).

In the longer run we still want to develop a new set of ODB methods that more naturally support C++-style variable-length strings. But that's a discussion for the longer 
term.

[1] https://midas.triumf.ca/elog/Midas/1150
[2] https://bitbucket.org/tmidas/midas/issues/121/odb-inline-editor-truncates-stings
[3] https://midas.triumf.ca/elog/Midas/1343

Hi,

I realized that if I use 'rmlogger' to write events in ROOT format,
each event is counted twice;

to fix the problem I commented line 3446 of mlogger.cxx (inside root_write 
function):

 //log_chn->statistics.events_written++;

Regards,
Gennaro

> I realized that if I use 'rmlogger' to write events in ROOT format,
> each event is counted twice;
> 
> to fix the problem I commented line 3446 of mlogger.cxx (inside root_write 
> function):
> 
>  //log_chn->statistics.events_written++;
> 

I confirm this problem - event counter is incremented by root_write() and by log_write() after calling 
root_write() through the WriterRoot::wr_write().

I will try to fix this for the next release of midas, keep an eye on it here:
https://bitbucket.org/tmidas/midas/issues/177

BTW, I do not think the ROOT writer (and rmlogger) get much use these days, as most experiments we do 
today have data in binary formats that do not fit naturally for storage into ROOT TTree objects. We mostly 
record digitized waveforms and such and they are best stored in binary midas files. The ROOT analyzer 
would read them using the midasio.h classes from the ROOTANA package.

BTW2, for recording MIDAS data, ROOT I/O uses the wrong compression - they compress using gzip, 
which is too slow compared to LZ4 on one side and does not compress as well as BZIP2 on the other side.

K.O.

Hi,

> I confirm this problem - event counter is incremented by root_write() and by log_write() after calling 
> root_write() through the WriterRoot::wr_write().
> 
> I will try to fix this for the next release of midas, keep an eye on it here:
> https://bitbucket.org/tmidas/midas/issues/177

thanks !

> BTW, I do not think the ROOT writer (and rmlogger) get much use these days, as most experiments we do 
> today have data in binary formats that do not fit naturally for storage into ROOT TTree objects. We mostly 
> record digitized waveforms and such and they are best stored in binary midas files. The ROOT analyzer 
> would read them using the midasio.h classes from the ROOTANA package.

yes, I agree with you about this, but to have a "quick and dirty" plot on some ADC channels
can be a very nice "temporary" solution when you are developing your software DAQ...

Regards,
Gennaro

> BTW2, for recording MIDAS data, ROOT I/O uses the wrong compression - they compress using gzip, 
> which is too slow compared to LZ4 on one side and does not compress as well as BZIP2 on the other side.
> 
> K.O.

Hi,

> I confirm this problem - event counter is incremented by root_write() and by log_write() after calling 
> root_write() through the WriterRoot::wr_write().
> 
> I will try to fix this for the next release of midas, keep an eye on it here:
> https://bitbucket.org/tmidas/midas/issues/177

thanks !

> BTW, I do not think the ROOT writer (and rmlogger) get much use these days, as most experiments we do 
> today have data in binary formats that do not fit naturally for storage into ROOT TTree objects. We mostly 
> record digitized waveforms and such and they are best stored in binary midas files. The ROOT analyzer 
> would read them using the midasio.h classes from the ROOTANA package.

yes, I agree with you that ROOT files are not suitable to store "first level" data, but this is a very
useful solution when you are developing a software DAQ and you need some (quick) spectra in order
to verify some code...

Regards,
Gennaro

> 
> > BTW, I do not think the ROOT writer (and rmlogger) get much use these days ...
> 
> yes, I agree with you that ROOT files are not suitable to store "first level" data, but this is a very
> useful solution when you are developing a software DAQ and you need some (quick) spectra in order
> to verify some code...
> 


I confirm that we are keeping the ROOT writer, sometimes it is useful.

Also sorry about all the bugs in that code, it pretty much gets no testing this days, other than by people who try to use it.


K.O.

The modbset() function in mhttpd.js is not used anywhere in midas and it misleads midas users into thinking that it works like the old ODBSet() function, when 
it can not and it does not.

To explain the difference:

1) ODBSet() used synchronous RPC requests, which have been deprecated by the powers that be. Read more here:
https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Synchronous_and_Asynchronous_Requests
https://x443.wordpress.com/2012/12/01/why-you-should-use-xmlhttprequest-asynchronously/

2) in midas, we followed these instructions and developed an asynchronous RPC mechanism for calling midas functions from javascript. (we use the Promise 
construct, but the underlying JSON-RPC compatible communications can be used directly, without it).

3) using the asynchronous RPC is not as easy as the old ODBSet() & co - instead of just making a call "to write to ODB", one has to create a chain of nested 
event handler functions and one has to do at least some error handling.

4) this makes it impossible to program midas custom pages in javascript as if it were C/C++. (Please direct your complaints to the "web" and "javascript" 
powers that be).

5) to help writing midas custom pages, we have a good number of examples. For example, example.html has example
code for calling pretty much every midas json rpc function.

5a) to see the complete list of all rpc functions available in your copy of midas, follow the link to "json-rpc schema, text format" on the midas "help" page.

6) if you are writing a new custom page we suggest you start with one of the example templates in .../resources, a_example, a_template.

7) if you are updating an existing custom page, good luck. synchronous rpc seems to still work in most browsers, so the old OSBSet() & co should continue to 
work for now. For new code you should use the async rpc (with Promises, like we do for all midas pages). In practice this means a complete rewrite of each 
custom page (welcome to the 21st century).

Note that we have two separate js files in midas:

- midas.js is intended as a general purpose library for writing midas custom pages
- mhttpd.js is not intended for general use and contains javascript code used by mhttpd internally

The function itself is here, in case somebody needs it:

-function modbset(path, value)
-/* shortcut for mjsonrpc_db_paste() with standard error handling */
-{
-   if (Array.isArray(path)) {
-      mjsonrpc_db_paste(path,value).then(function(rpc) {}).catch(function(error) {
-         mjsonrpc_error_alert(error); });
-   } else {
-      mjsonrpc_db_paste([path],[value]).then(function(rpc) {}).catch(function(error) {
-         mjsonrpc_error_alert(error); });
-   }
-}
-

K.O.

I disagree. The modbset() function is used in many custom pages at PSI because people are tired of typing mjsonrpc_db_paste([path],[value]) vs. modbset(path, value). We need to keep 
modbset() which is well documented at 

https://midas.triumf.ca/MidasWiki/index.php/Custom_Page#modbset

Since modbset() does call the underlying mjsonrpc_db_paste(), it is as good or bad as that function. Plus it adds standard error handling to avoid the need of catching errors for each and 
every mjsonrpc_db_paste() call. If it is believed that modbset() has a problem, then this should be fixed in the source code of modbset(). Removing that function is not an option.

Stefan