A warning, in case others have the same problem I had.

In the past you could configure mhttpd so that the 'Elog' button would redirect to an external ELOG server; to do this you only needed to create and set the ODB variable '/Elog/URL' to the URL of your external ELOG server.

But with the newer MIDAS you need to set two ODB variables:

* "/Elog/URL" needs to be set to the URL of the external ELOG.
* "/Elog/External Elog" needs to be set to 'y'

I hadn't noticed this and was confused why my Elog button wasn't working after upgrading MIDAS.

MIDAS documentation was updated to reflect this change:

https://midas.triumf.ca/MidasWiki/index.php/Electronic_Logbook_(ELOG)

Hi everyone,

I am currently trying to access a ROOT file produced by manalyzer. By calling JSROOT.openFile("MIDAS_DOMAIN/outputRUN.root"). I can download the rootfile via MIDAS_DOMAIN/outputRUN.root. Using JSROOT.openFile results in an 501 error, 
since the request feature is not provided. Using a simple API and uploading outputRUN.root there worked fine (when the run finised). 

Is there a way to use JSROOT.openFile with the current analyzed root file in Midas (so during the run)? I know that one can access histograms of the THttpServer via JSON but I need to get the full root tree.

Cheers,
Marius

> 
> I am currently trying to access a ROOT file produced by manalyzer. By calling JSROOT.openFile("MIDAS_DOMAIN/outputRUN.root"). I can download the rootfile via MIDAS_DOMAIN/outputRUN.root. Using JSROOT.openFile results in an 501 error, 
> since the request feature is not provided. Using a simple API and uploading outputRUN.root there worked fine (when the run finised). 
> 
> Is there a way to use JSROOT.openFile with the current analyzed root file in Midas (so during the run)? I know that one can access histograms of the THttpServer via JSON but I need to get the full root tree.
> 

Good questions. Right now in manalyzer I do not do anything more than starting the ROOT web server (so whatever
they support should work) and providing two "standard" location: one in the output file for histograms
and other permanent output and one in memory for transient objects, such as waveform plots, etc.

At some point I would like to provide a function to "get" TAFlowEvent objects so you can do things
like event displays in javascript. But I need a c++ to json serializer and standard c++ does not have it.
So I will have to use the clang serializer (also used by ROOT) and it will take me a few days
to figure it out.

Back to "openFile".

If you figure out the missing bits that need to be added to our code,
please post them here or submit them as a pull request or a bug report in bitbucket.

Also it would be good if you can provide a code example of "openFile" working elsewhere
but not with manalyzer, if I can run it, maybe I can figure out what's missing. But lacking
some example code, there is nothing for me to hack at.

K.O.

Thank you for the answer :)

> At some point I would like to provide a function to "get" TAFlowEvent objects so you can do things
> like event displays in javascript. But I need a c++ to json serializer and standard c++ does not have it.
> So I will have to use the clang serializer (also used by ROOT) and it will take me a few days
> to figure it out.

That sounds exactly what I was searching for. Because I wanted to create an interface between rootana and 
an event display build in javascript. Since all I tried did not really worked with the current rootana
I have now a "solution". I use the MIDAS python client, read directly events from the MIDAS buffer and provided
the events in a JSON format with the python flask API. Since the rendering of the event display is the bottleneck 
and I only need a view events to display this solution worked really well for me. Maybe having such a JSON API of 
the event buffer in MIDAS directly would also work for most of the event display applications or other simple javescript 
applications (my opinion).

> If you figure out the missing bits that need to be added to our code,
> please post them here or submit them as a pull request or a bug report in bitbucket.

One of the problems I had was the CORS domain of the THttpServer. In manalyzer:1894 you do 
sprintf(str, "http:127.0.0.1:%d", httpPort); but there are additional options for the THttpServer (like "?cors=DOMAIN").
So maybe a flag while starting manalyzer passing such options would be nice. I will create a pull request passing them later.

> Also it would be good if you can provide a code example of "openFile" working elsewhere
> but not with manalyzer, if I can run it, maybe I can figure out what's missing. But lacking
> some example code, there is nothing for me to hack at.

The problem is that it was not even running on simple THttpServer using interactive root:

    serv = new THttpServer("http:8088?cors=*");
    TFile *_file0 = TFile::Open("example_root.root")
    serv->Register("File", _file0);

So I tried just saving the file in the $MIDAS_DIR and tried to use mserver with JSROOT.openFile. I attached the html file and 
a test root file.

Cheers,
Marius

well, if this is something in ROOT, perhaps you can pursue it with the ROOT crowd,
they are quite friendly.

on my side, if all you need is to pull event data banks, this is easy to add
in mhttpd.

the jsonrpc request will look something like this:

get_event {
"buffer":"system",
"get_type":"GET_LATEST", (or whatever bm_receive_event() can do)
"include_banks":["AAAA","BBBB"],
"exclude_banks":["CCCC","DDDD"]
}

and return something like this:

event {
"header":{"event_id":1,...},
"banks":{
"AAAA":[1,2,3,4],
"BBBB":NULL (you asked for it, so you always get it, but it is NULL if bank does not exist)
}
}

would this work for what you are doing?

(this is not good enough if data has to be pre-digested by c++ analysis in rootana)

K.O.

I also need midas events going back to the

I also need midas events going back to the browser for single event display, so put +1 for me.

Please also consider to use JavaScript typed arrays instead of JSON. For large midas banks, type 
arrays are 5-10 times faster than JSON encoding/decoding.

Best,
Stefan

> would this work for what you are doing?

Yes, having such a function would be perfect for the applications I have a the moment.

> (this is not good enough if data has to be pre-digested by c++ analysis in rootana)

Also agree, if one wants to have a more sophisticated applications it is definitely needed to preprocess the data.

Cheers,
Marius

By default, MIDAS creates shared memory event data buffers of default size
EVENT_BUFFER_SIZE defined in midas.h and until now making of large data buffers
for high data rate or large event size experiments was complicated.

Now, bm_open_buffer() will try to read the event buffer size from ODB. If
"/Experiment/Buffer Sizes/BUFFER_NAME" of type DWORD exists, it's value is used
as the buffer size, overriding the default value.

For example, to increase the size of the default MIDAS event buffer ("SYSTEM")
to 2000000 bytes, shutdown all MIDAS programs, delete the old .SYSTEM.SHM file
(and the shared memory segment, using ipcrm). Then run odbedit, cd /Experiment,
mkdir "Buffer Sizes", cd "Buffer Sizes", create DWORD SYSTEM, set SYSTEM
2000000. Then start the rest of the MIDAS programs. Check that the buffer has
the correct size by looking at the size of .SYSTEM.SHM and of the shared memory
segment (ipcs).

This method work for all MIDAS buffers, except for ODB, where the size has to be
specified at creation time using the odbedit command "-s" argument.

K.O.

Using normal RPC socket:

event size    speed [MB/sec] CPU usage front-end  CPU usage server
==================================================================
    40          3            22                   100                
  1000         44            25                   100
100000        101            14                    50

Using new event socket:

event size    speed [MB/sec] CPU usage front-end  CPU usage server
==================================================================
    40         12            100                   34                
  1000         99            58                    59
100000        101            14                    43

rpc_mode = 1

I updated the MIDAS javascript examples in examples/javascript1. All existing mhttpd.js functions are 
now exampled. (yes).

Here is the full list of functions, with notes:

ODBSet(path, value, pwdname);
ODBGet(path, format, defval, len, type);
ODBMGet(paths, callback, formats); --- doc incomplete - no example of callback() use
ODBGetRecord(path);
ODBExtractRecord(record, key);
new ODBKey(path); --- doc incomplete, wrong - one has to use "new ODBKey" - last_used was added.
ODBCopy(path, format); -- no doc
ODBRpc_rev0(name, rpc, args); --- doc refer to example
ODBRpc_rev1(name, rpc, max_reply_length, args); --- same
ODBGetMsg(n);
ODBGenerateMsg(m);
ODBGetAlarms(); --- no doc
ODBEdit(path); --- undoc - forces page reload

As annotated, the main documentation is partially incomplete and partially wrong (i.e. ODBKey() has to be 
invoked as "new ODBKey()"). I hope this will be corrected soon. In the mean time, I recommend that 
everybody uses this example as best documentation available.
http://ladd00.triumf.ca/~daqweb/doc/midas/html/RC_mhttpd_custom_js_lib.html

svn rev 5360
K.O.

> ODBCopy(path, format); -- no doc

Updated example of ODBCopy:

format="" returns data in traditional ODB save format
format="xml" returns data in XML encoding
format="json" returns data in JSON encoding.

K.O.

ss_thread_create now returns the thread ID on success, and zero on failure.
Previously returned SS_SUCCESS or SS_NO_THREAD. User must now test the
return value to determine result.

ss_thread_kill added to kill the passed thread ID. Returns SS_SUCCESS or
SS_NO_THREAD.

Any thread creation must be verified now, and old code must be examined to
ensure the return value is checked.

> ss_thread_create now returns the thread ID on success, and zero on failure.
> Previously returned SS_SUCCESS or SS_NO_THREAD. User must now test the
> return value to determine result.
> 
> ss_thread_kill added to kill the passed thread ID. Returns SS_SUCCESS or
> SS_NO_THREAD.
> 
> Any thread creation must be verified now, and old code must be examined to
> ensure the return value is checked.

Thank you for that post. Internally, threads are not use in midas, so there 
should be no problem. Only experiments using threads explicitly should take 
care.

Add installation commands. Please see the attachment.

I commited fixes for a few minor compilation errors in the VME drivers
(vmicvme.c, etc)
I also added new drivers for the v513 latch and v560 scaler that I wrote for
CERN-ALPHA.

(Maybe I should mention that we also have drivers for the SIS 3820 multiscaler,
the v895 VME discriminator and a few more modules. Will commit them as they mature).

K.O.

I’m trying to run MIDAS using a frontend code/client named “fetiglab”. Run stops 
after 2/3sec with an error saying “Unknown error 319 from client “fetiglab” on 
localhost.

Frontend code compiled without any errors and MIDAS reads the frontend 
successfully, this only comes when I start the new run on MIDAS, here are a few 
more details from the terminal-

11:46:32 [fetiglab,ERROR] [odb.cxx:11268:db_get_record,ERROR] struct size 
mismatch for "/" (expected size: 1, size in ODB: 41920)

11:46:32 [Logger,INFO] Deleting previous file 
"/home/rcmp/online3/run00621_000.root"

11:46:32 [ODBEdit,ERROR] [midas.cxx:5073:cm_transition,ERROR] transition START 
aborted: client "fetiglab" returned status 319

11:46:32 [ODBEdit,ERROR] [midas.cxx:5246:cm_transition,ERROR] Could not start a 
run: cm_transition() status 319, message 'Unknown error 319 from client 
'fetiglab' on host "localhost"'

TR_STARTABORT transition: cleanup after failure to start a run

‌

I’ve also enclosed a screenshot for the same, any suggestions would be highly 
appreciated. thanks

> I’m trying to run MIDAS using a frontend code/client named “fetiglab”. Run stops 
> after 2/3sec with an error saying “Unknown error 319 from client “fetiglab” on 
> localhost.

actually run never starts.

> 11:46:32 [fetiglab,ERROR] [odb.cxx:11268:db_get_record,ERROR] struct size 
> mismatch for "/" (expected size: 1, size in ODB: 41920)

this is the error that causes run start to fail. for reasons unknown
your frontend is trying to do a db_get_record() from "/" (ODB root top directory).

if this is an mfe.c frontend, I do not think I have ever seen it do something
like this.

so, a puzzle.

K.O.

Hello!
Sometimes when I mess around with the history plots I get the following error:

[mhttpd,ERROR] [history.cxx:97:xread,ERROR] Error: Unexpected end-of-file when 
reading file "/home/wagasci-ana/Data/online/210219.hst"

I have tried the following without success:

- Remove the MIDAS history files
- Restart mhttpd and mlogger

I do not know what triggers the error but when it triggers the above message is 
printed hundres of times a second, completely spamming the message log.

It happened again today after I set the label of a frontend too long making 
mlogger crash. After fixing the label length, the above message appeared and it 
does not seem to go away.