> > Hmm... for most experiments, we do not "install" midas. I should probably remove the "install" target from the Makefile.
> 
> 
> ... and change the documentation accordingly (Suzannah!?). Installing midas these days does not really make sense, since normally only one 
> users uses it on a given machine.
> 
> Stefan

I understand. Anyway, I preferred to install MIDAS in the /opt/midas folder to remain consistent with the other programs that we are using for 
our experiment (Pyrame and Calicoes from LLR). I am also using Linux systemd to enable mhttpd on startup (and other handy features like auto-
restart after a crash) and unfortunally CentOS doesn't support to enable systemd units as a non-root user.
So in my particular case, perhaps it made some sense to install MIDAS in a folder other than the source code folder
Giorgio

> > > Hmm... for most experiments, we do not "install" midas. I should probably remove the "install" target from the Makefile.
>
> install MIDAS in the /opt/midas folder to remain consistent with the other programs that we are using for 
> our experiment (Pyrame and Calicoes from LLR).

I see. Would this work as well? Instead of "make install" do this:
su - root
cd /opt
git pull midas
cd midas
make
add /opt/midas/linux/bin to your PATH. (is it time to get rid of the "linux" part from the default build path?!?)

> I am also using Linux systemd to enable mhttpd on startup

We use cron @reboot to start mhttpd.

But. CentOS7 systemd cron unit file has a bug and they run @reboot cron jobs before NIS and autofs is ready, see
http://www.triumf.info/wiki/DAQwiki/index.php/SLinstall#Enable_crontab_.40reboot_for_MIDAS_.28CentOS7.29

Can you post your systemd unit file to this elog, others may find it useful.

K.O.

> I see. Would this work as well? Instead of "make install" do this:
> su - root
> cd /opt
> git pull midas
> cd midas
> make
> add /opt/midas/linux/bin to your PATH. (is it time to get rid of the "linux" part from the default build path?!?)

Got it. I will do that in the future.

> Can you post your systemd unit file to this elog, others may find it useful.

[Unit]
Description=MIDAS data acquisition system
After=network.target
StartLimitIntervalSec=0

[Service]
Type=simple
Restart=always
RestartSec=3
User=neo
ExecStart=/opt/midas/bin/mhttpd -e WAGASCI --http 8081 --https 8444
Environment="MIDASSYS=/opt/midas" "MIDAS_EXPTAB=/home/neo/Code/WAGASCI/MIDAS/online/exptab" "MIDAS_EXPT_NAME=WAGASCI" 
"SVN_EDITOR=emacs -nw" "GIT_EDITOR=emacs -nw"
PassEnvironment=MIDASSYS MIDAS_EXPTAB MIDAS_EXPT_NAME SVN_EDITOR GIT_EDITOR

[Install]
WantedBy=multi-user.target

Dear all,
        I need to implement a DAQ sequence where a short run (100 events, which takes a couple of 
minutes) is taken every hour, with a long run in between two short runs. In the sequencer, I can do:

LOOP infinite

.... some ODB settings ....
     TRANSITION START
     WAIT events 100
     TRANSITION STOP

.... some ODB settings ....
     TRANSITION START
     WAIT seconds 3600
     TRANSITION STOP

ENDLOOP


I have two questions: 

- for the long run, I want to write on disk only a maximum number of events. I think I can suppress 
the event polling in the frontend, with an ODB query of the number of collected events. I'm 
wondering if there is a smarter way to do that. It is also ok if the run is stopped after a maximum 
number of events, but the subsequent short run should still start exactly after 1h from the previous 
short run. 

- with the script above, the real time lapse between the start of two short runs would depend on 
the duration of the short run itself. Is there a way to start the short run exactly 1 h after the starting 
of the previous short run?

Thank you in advance for your help,
              Francesco

Dear all,
         I'm running a DAQ frontend and it works well if one single run is
taken. If I try to take a second run right after, the run is performed but, when
stopping it, I get the error messages below. Any hint?

Thank you for your help,
      Francesco


11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:6022:cm_shutdown,ERROR] Killing
and Deleting client 'cygnus_daq' pid 12472

11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:6019:cm_shutdown,ERROR] Cannot
connect to client 'cygnus_daq' on host 'localhost', port 46341

11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:9539:rpc_client_connect,ERROR]
cannot connect to host "localhost", port 46341: connect() returned -1, errno 111
(Connection refused)

11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:10821:rpc_client_call,ERROR]
call to "cygnus_daq" on "localhost" RPC "rc_transition": error,
ss_recv_net_command() status 411

11:42:24.012 2019/03/12 [mhttpd,ERROR] [system.c:4715:ss_recv_net_command,ERROR]
error receiving network command header, see messages

11:42:24.011 2019/03/12 [mhttpd,ERROR] [system.c:4661:recv_tcp2,ERROR]
unexpected connection closure

11:42:23.994 2019/03/12 [cygnus_daq,ERROR] [midas.c:1951:,ERROR]
cm_disconnect_experiment not called at end of program

> Is there a way to start the short run exactly 1 h after the starting 
> of the previous short run?

This is not possible with the current sequencer.

> 
> .... some ODB settings ....
>      TRANSITION START
>      WAIT events 100
>      TRANSITION STOP
> I have two questions: 
> 
> - for the long run, I want to write on disk only a maximum number of events. I think I can suppress 
> the event polling in the frontend, with an ODB query of the number of collected events. I'm 
> wondering if there is a smarter way to do that. It is also ok if the run is stopped after a maximum 
> number of events, but the subsequent short run should still start exactly after 1h from the previous 
> short run. 

I don't know about a way to give you an exact number of events (maybe /Logger/Run duration). 

I personally use 
    WAIT ODBValue,"/Equipment/DTM/Statistics/Events sent",>,100

Where DTM is the frontend of my trigger. Because of the lag in the run stop, the run will always exceed by few
seconds*rates.

Hope it helps

> > Can you post your systemd unit file to this elog, others may find it useful.

Thank you very much!

Note: user name "neo" and home directory is hardwired into the unit file. Also
it runs after "network.target", this may be too early, it should run after nis and autofs
have started (and made home directories accessible). (not sure what systemd target
that is).

K.O.

> 
> [Unit]
> Description=MIDAS data acquisition system
> After=network.target
> StartLimitIntervalSec=0
> 
> [Service]
> Type=simple
> Restart=always
> RestartSec=3
> User=neo
> ExecStart=/opt/midas/bin/mhttpd -e WAGASCI --http 8081 --https 8444
> Environment="MIDASSYS=/opt/midas" "MIDAS_EXPTAB=/home/neo/Code/WAGASCI/MIDAS/online/exptab" 
"MIDAS_EXPT_NAME=WAGASCI" 
> "SVN_EDITOR=emacs -nw" "GIT_EDITOR=emacs -nw"
> PassEnvironment=MIDASSYS MIDAS_EXPTAB MIDAS_EXPT_NAME SVN_EDITOR GIT_EDITOR
> 
> [Install]
> WantedBy=multi-user.target

>          I'm running a DAQ frontend and it works well if one single run is
> taken. If I try to take a second run right after, the run is performed but, when
> stopping it, I get the error messages below. Any hint?

Sure. I will read the error messages for you: note that they come in reverse time order - oldest message is at the bottom. I 
will reverse them in my reading:

> 11:42:23.994 2019/03/12 [cygnus_daq,ERROR] [midas.c:1951:,ERROR]
> cm_disconnect_experiment not called at end of program

your frontend has exited (this error message is printed by the atexit() code, so you did not crash but called exit(), 
somehow).

> 11:42:24.011 2019/03/12 [mhttpd,ERROR] [system.c:4661:recv_tcp2,ERROR]
> unexpected connection closure

mhttpd reports that the socket connection to your frontend has closed (because the frontend stopped, closing all it's 
sockets)

> 11:42:24.012 2019/03/12 [mhttpd,ERROR] [system.c:4715:ss_recv_net_command,ERROR]
> error receiving network command header, see messages

mhttpd network code next layer reports this same error again

> 11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:10821:rpc_client_call,ERROR]
> call to "cygnus_daq" on "localhost" RPC "rc_transition": error,
> ss_recv_net_command() status 411

mhttpd network code next layer reports this same error again, now we see that it was trying
to execute a "run start" (or "stop") RPC call to your frontend. But your frontend unexpectedly
shutdown (instead of replying to the RPC).

Next messages after that is mhttpd decided that your frontend is faulty (does not respond to RPC correctly) and tried to 
shut it down, but failed (cannot connect, etc). Last message is mhttpd cleaning up your frontend from ODB (because the 
frontend did not cleanup after itself - it did not call cm_disconnect_experiment(), per the very first error message).


So this is what we see from the midas messages - your frontend unexpectedly exited during the run transition - if as you 
say the run was stopping at the time, it would be in your end_of_run() function.

To debug this, I would do:

a) put some printf() statements in end_of_run() and see what they say during the crash
b) run the frontend inside the debugger, you may need to set a breakpoint on exit() or something like that.


Good luck,
K.O.





> 
> Thank you for your help,
>       Francesco
> 
> 
> 11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:6022:cm_shutdown,ERROR] Killing
> and Deleting client 'cygnus_daq' pid 12472
> 
> 11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:6019:cm_shutdown,ERROR] Cannot
> connect to client 'cygnus_daq' on host 'localhost', port 46341
> 
> 11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:9539:rpc_client_connect,ERROR]
> cannot connect to host "localhost", port 46341: connect() returned -1, errno 111
> (Connection refused)
> 
> 11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:10821:rpc_client_call,ERROR]
> call to "cygnus_daq" on "localhost" RPC "rc_transition": error,
> ss_recv_net_command() status 411
> 
> 11:42:24.012 2019/03/12 [mhttpd,ERROR] [system.c:4715:ss_recv_net_command,ERROR]
> error receiving network command header, see messages
> 
> 11:42:24.011 2019/03/12 [mhttpd,ERROR] [system.c:4661:recv_tcp2,ERROR]
> unexpected connection closure
> 
> 11:42:23.994 2019/03/12 [cygnus_daq,ERROR] [midas.c:1951:,ERROR]
> cm_disconnect_experiment not called at end of program

I did not quite understand your desired sequence, is this what you want:

- at 1pm
- start a run
- record 100 events
- end the run
- (this will be, say, 1:15pm)
- start a run
- at 2pm
- end the run
- start a run
- record 100 events
- ad infinitum

There are 2 difficulties with this:

1) If you want your cycle to be exactly 1 hour, you need to use cron or something similar - if you just "start; sleep 3600; stop", 
your cycle will be slightly longer than 1 hour because starting and stopping runs takes some time to complete.

2) if you want your "100 event" run to start exactly precisely on the hour, you need to stop the previous run a few 
minutes/seconds before the hour to avoid the "run stop" delay.

Instead of using the sequencer, I would use a shell script (run it from crontab to avoid problem (1))

#/bin/sh
mtransition stop # stop the previous long run
odbedit set "/logger/channels/0/settings/event limit" 100
odbedit set "/logger/auto restart" "y"
mtransition start # start the short run
# end

In your frontend end_of_run() function, add this:
odb set "/logger/channels/0/settings/event limit" 0

This will produce the following sequence:

- script will stop previous long run
- set event limit to 100, start the "100 events" run
- logger will stop at 100 events, call your frontend end_of_run(), set event limit to 0
- logger auto restart will start a new run, event limit is now 0, this is your long run
- on the hour, cron runs your script, cycle repeats from the top.

Instead of cron, your can use a looper script. Note that you must run
the main script in the background (note the "&") to avoid problem (1).

#!/bin/foo
# looper script
while (true) {
   main_script &
   sleep 3600   
}
#end

To stop the sequence, kill the looper script.

K.O.


> Dear all,
>         I need to implement a DAQ sequence where a short run (100 events, which takes a couple of 
> minutes) is taken every hour, with a long run in between two short runs. In the sequencer, I can do:
> 
> LOOP infinite
> 
> .... some ODB settings ....
>      TRANSITION START
>      WAIT events 100
>      TRANSITION STOP
> 
> .... some ODB settings ....
>      TRANSITION START
>      WAIT seconds 3600
>      TRANSITION STOP
> 
> ENDLOOP
> 
> 
> I have two questions: 
> 
> - for the long run, I want to write on disk only a maximum number of events. I think I can suppress 
> the event polling in the frontend, with an ODB query of the number of collected events. I'm 
> wondering if there is a smarter way to do that. It is also ok if the run is stopped after a maximum 
> number of events, but the subsequent short run should still start exactly after 1h from the previous 
> short run. 
> 
> - with the script above, the real time lapse between the start of two short runs would depend on 
> the duration of the short run itself. Is there a way to start the short run exactly 1 h after the starting 
> of the previous short run?
> 
> Thank you in advance for your help,
>               Francesco

> Note: user name "neo" and home directory is hardwired into the unit file. Also
> it runs after "network.target", this may be too early, it should run after nis and autofs
> have started (and made home directories accessible). (not sure what systemd target
> that is).

Thank you very much for the comments!

My home directory is hardwired because it is not straightforward to add environment variables into 
systemd units. Actually, I install MIDAS through a bash shell script that automatically generates 
the unit file during installation. So, for another user who would use my script, the correct path 
in the unit file would be generated at installation time. Another option would be to create an 
environment file and then feed it to the unit file (EnvironmentFile directive) as explained here: 
https://coreos.com/os/docs/latest/using-environment-variables-in-systemd-units.html

For the autofs, thank you for the hint. I have modified the unit file accordingly.

As far as NIS is concerned, I am sorry but I don't know how it is used by MIDAS. Actually, I don't 
even have it installed on my machine. Anyway, I have modified the unit file accordingly (but I 
haven't tested with NIS installed).

The modified unit file is this:

[Unit]
Description=MIDAS data acquisition system
After=network.target rpcbind.target ypbind.target
StartLimitIntervalSec=0
RequiresMountsFor=%h

[Service]
Type=simple
Restart=always
RestartSec=3
User=neo
ExecStart=/opt/midas/bin/mhttpd -e <nameofyourexperiment> --http <yourhttpport> --https 
<yourhttpsport>
Environment="MIDASSYS=/opt/midas" "MIDAS_EXPTAB=<path/to/your/exptab>" "MIDAS_EXPT_NAME=
<nameofyourexperiment>" "SVN_EDITOR=emacs -nw" "GIT_EDITOR=emacs -nw"
PassEnvironment=MIDASSYS MIDAS_EXPTAB MIDAS_EXPT_NAME SVN_EDITOR GIT_EDITOR

[Install]
WantedBy=multi-user.target

> As far as NIS is concerned, I am sorry but I don't know how it is used by MIDAS.

NIS is traditionally used together with autofs to form clusters of UNIX/Linux machines. NIS is a database
of user names, passwords, home directories, NFS (autofs) mount points and NFS exports. autofs would
read all it's configuration from the NIS database.

So the correct boot sequence in most cases would be like this:
hardware init -> network init -> nis -> autofs -> users can login -> start midas (mhttpd) from cron @reboot or similar.

(In organizations that have a dedicated staff of IT sysadmins, you would see LDAP instead of NIS).

K.O.

Hi,
I'm developing a Slow Control equipment on a Linux board that send data on a remote server
running 'mserver'; the build goes fine, but  when I run the executable it seems that an assertion in 
midas.c failed:

[dfe01,INFO] Slow control equipment initialized
dfe: src/midas.c:838: cm_msg_flush_buffer: Assertion `rp[3]=='_'' failed.

if I remove line 838 from midas.c (fixing message length) the problem disappear...

Regards,
Gennaro

> [dfe01,INFO] Slow control equipment initialized
> dfe: src/midas.c:838: cm_msg_flush_buffer: Assertion `rp[3]=='_'' failed.
> if I remove line 838 from midas.c (fixing message length) the problem disappear...

Thank you for reporting this problem.

It is very strange, the check is for message start "MSG_", why "M", "S" and "G" are there
but "_" is missing? And you remove the check for "_" and the rest of the message is also okey?
Very odd.

I look at the code in midas.c and I also see is that the ring buffer has no protection against
overflow, it is created for max message length of around 1000 bytes, but I look at the code 
that feeds messages into it (cm_msg_format()) and it also has a buffer overrun
possibility (sprintf() instead snprintf()). Actually I just ran into this buffer overrun
myself when adding memory leak debugging code into mhttpd.

Anyhow, before this message that causes the crash, maybe perchance you have a long
message before it? Of length 1000 bytes of longer? (1000 bytes is 12 lines of 80 chars).

Or this is the very first message you generate? (other than the normal messages generated by mfe.c?)

Is there anything in midas.log around the time of the crash? (post it here or email it to me?) Also I would
like to see everything printed by your frontend from the start time all the way to the crash.

You can also add this code "assert(4+3*sizeof(int)+len < 1020)" in cm_msg_buffer() right before
rb_increment_wp() - it this assert fails, we definitely determine that we have a buffer overflow.

Thank in advance,
K.O.

> > [dfe01,INFO] Slow control equipment initialized
> > dfe: src/midas.c:838: cm_msg_flush_buffer: Assertion `rp[3]=='_'' failed.
> > if I remove line 838 from midas.c (fixing message length) the problem disappear...
> 
> Thank you for reporting this problem.
> 
> It is very strange, the check is for message start "MSG_", why "M", "S" and "G" are there
> but "_" is missing? And you remove the check for "_" and the rest of the message is also okey?
> Very odd.

if I remove the check for "_" then the first message is empty and next messages are ok...
If I don't remove the check the frontend fails at start and I find these lines in midas.log:

14:46:29.719 2019/03/19 [dfe01,INFO] Program dfe01 on host lxaria02 started
14:46:29.731 2019/03/19 [dfe01,INFO] Dome FE initialized
14:46:29.737 2019/03/19 [dfe01,ERROR] [system.c:4709:recv_tcp2,ERROR] unexpected connection closure
14:46:29.737 2019/03/19 [dfe01,ERROR] [midas.c:12814:recv_event_server,ERROR] recv_tcp2(header) returned -1
14:46:29.737 2019/03/19 [dfe01,ERROR] [midas.c:14699:rpc_server_receive,ERROR] recv_event_server() returned -1, abort
14:46:29.737 2019/03/19 [dfe01,TALK] Program 'dfe01' on host 'lxaria02' aborted
 
> You can also add this code "assert(4+3*sizeof(int)+len < 1020)" in cm_msg_buffer() right before
> rb_increment_wp() - it this assert fails, we definitely determine that we have a buffer overflow.

I added assert you suggested in cm_msg_buffer() function before rp_increment_wp() and 
result is always the same at same line:

[dfe01,INFO] Dome FE initialized
Dome0001-rc:
[dfe01,INFO] Slow control equipment initialized
dfe: src/midas.c:839: cm_msg_flush_buffer: Assertion `rp[3]=='_'' failed.
Aborted

Regards,
Gennaro

For the record, I am stumped by this problem. We have definitely ruled out any data overflow inside the midas message code (there are no 
long messages sent). My only guess is that the frontend itself is corrupting the midas message buffer, but this corruption
must be unlikely lucky to corrupt just the "_" character (and maybe what follows it) from the "MSG_" header inside the buffer.

If indeed this is memory corruption inside the frontend, to find and fix it, one would have to roll out valgrind and other malloc() debugging 
tools and good luck...

K.O.



> > > [dfe01,INFO] Slow control equipment initialized
> > > dfe: src/midas.c:838: cm_msg_flush_buffer: Assertion `rp[3]=='_'' failed.
> > > if I remove line 838 from midas.c (fixing message length) the problem disappear...
> > 
> > Thank you for reporting this problem.
> > 
> > It is very strange, the check is for message start "MSG_", why "M", "S" and "G" are there
> > but "_" is missing? And you remove the check for "_" and the rest of the message is also okey?
> > Very odd.
> 
> if I remove the check for "_" then the first message is empty and next messages are ok...
> If I don't remove the check the frontend fails at start and I find these lines in midas.log:
> 
> 14:46:29.719 2019/03/19 [dfe01,INFO] Program dfe01 on host lxaria02 started
> 14:46:29.731 2019/03/19 [dfe01,INFO] Dome FE initialized
> 14:46:29.737 2019/03/19 [dfe01,ERROR] [system.c:4709:recv_tcp2,ERROR] unexpected connection closure
> 14:46:29.737 2019/03/19 [dfe01,ERROR] [midas.c:12814:recv_event_server,ERROR] recv_tcp2(header) returned -1
> 14:46:29.737 2019/03/19 [dfe01,ERROR] [midas.c:14699:rpc_server_receive,ERROR] recv_event_server() returned -1, abort
> 14:46:29.737 2019/03/19 [dfe01,TALK] Program 'dfe01' on host 'lxaria02' aborted
>  
> > You can also add this code "assert(4+3*sizeof(int)+len < 1020)" in cm_msg_buffer() right before
> > rb_increment_wp() - it this assert fails, we definitely determine that we have a buffer overflow.
> 
> I added assert you suggested in cm_msg_buffer() function before rp_increment_wp() and 
> result is always the same at same line:
> 
> [dfe01,INFO] Dome FE initialized
> Dome0001-rc:
> [dfe01,INFO] Slow control equipment initialized
> dfe: src/midas.c:839: cm_msg_flush_buffer: Assertion `rp[3]=='_'' failed.
> Aborted
> 
> Regards,
> Gennaro

Dear MIDAS users,

We would like to announce a third MIDAS workshop at TRIUMF on Aug 7, 2019.
Stefan Ritt will again be visiting TRIUMF at this time.

The overall goal of the workshop is to present new features in MIDAS, to discuss
future changes and to hear experiences from different experiments.

We expect that some participants will connect remotely to the workshop; we will
setup a video-conferencing option.  The exact time of the workshop will be
decided later and will be optimized based on the geographic distribution of
remote attendees. So please let us know if you want to attend remotely.  We are
also happy for people to come in person to TRIUMF.  

A (very) preliminary agenda includes

- New default mhttpd pages and new APIs for custom pages
- Conversion of MIDAS to C++
- new C++ based frontend framework (tmfe and mvodb from ALPHA-g)
- MySQL/Postgres database for storing ODB configurations
- Plans for updating history plotting
- Using MIDAS with an online trigger farm
- new C++ multithreaded flow analyzer (manalyzer from ALPHA-g)

But please suggest other topics; we also hope to hear reports from particular
experiments.

Sincerely,
Thomas (on behalf of MIDAS developers)

the midas wiki was updated to the latest LTS point release 1.27.5.

Also, an installation error was fixed that prevented confirmation of new accounts (git checkout 
REL1_28 instead of REL1_27, resulting in a version mismatch).

Support for MediaWiki LTS release 1.27 ends this Summer.

Next LTS release series is 1.31, see https://en.wikipedia.org/wiki/MediaWiki_version_history

This version requires php version 7 or newer which comes standard with ubuntu LTS 18.04 
and el8 (RHEL8), but not with el6 (SL6) and el7 (CentOS-7).

I guess we shall start planning this upgrade and the move of the wiki to a new host machine.

K.O.

the midas wiki was updated to the latest LTS point release 1.27.7, the latest (last?) security update.

mediawiki series 1.27 is now officially EOL, see
https://lists.wikimedia.org/pipermail/mediawiki-announce/2019-June/000231.html

they recommend that all users upgrade to the current LTS series 1.31.

for us it means moving the wiki from the present el6 (SL6) computer to
a more up-to-date platform (el8 or ubuntu LTS 18.04).

K.O.

Hello everybody,

I have a strange JS behavior. In one of my frontends I create a key in the ODB with:

db_create_key(hDB, 0, "Equipment/Switching/Variables/DATA_WRITE", TID_INT);

In my custom page I have a JS function which loops over an array and sets the
value of this key with:

for (i = 0; i < lines.length; i++) {
        modbset("/Equipment/Switching/Variables/DATA_WRITE[" + String(i) + "]",
parseInt(lines[i]));
}

After calling this function I have an array in the ODB now. For my understanding
calling an INT like an array shouldn't be possible. So is this dangerous to do?

Best regards,
Marius