Hi,

I like the new eqtable, but stumbled over some issues.

1) In the attached snapshot you see that the values shown from our vacuum Pirani and Penning cells are all zero, which of course is not true.
It would be nice to have under the equipment settings some formatting options, like the possibility to add units.

2) If one of the number evaluates to Infinity, the table is not shown properly anymore.

Best,
  Andreas

Great! This is it.
Sorry that I missed it in the docu.

Best,
  Andreas

I have two more questions related to Units, Format for Equipment/Settings:

1) It looks as if I can have units per channel only for the Input/Output channels but not for Demand/Measured channels. 
For instance we do have HV FE which collect devices with kV and V demand settings. It looks like this is not possible (see attachment) to have per channel units.
Is this right, or do I miss something here?

2) This new functionality needs entries under /Equipment/<eq-name>/Settings. The class driver generates the necessary structures if they are missing at the startup
of the scfe. It would be nice that the new, additional entries would be generate as well: Editable, Unit Input, Unit Format, etc. Perhaps optionally, if a DD is providing it?

Best,
  Andreas 

Currently one has to set the required flag in the ODB (e.g., /Programs/Logger/Required) to "y" for the program 
to appear on the "Programs page" and being able to start and stop the program easily.

However, if one wants to run with the "Prevent start on required progs" in /Experiment enabled, all the 
programs in the "Programs page" need to be running and one cannot have one of them stopped while still 
taking a run.

It would be nice to separate these two functionalities: Have a flag that makes the program appear on the 
"Programs page" and have a flag that controls the "Prevent start on required frogs" functionality.

Hi,

I don't know if this actually fits the Bug Report category. I've been trying to install Midas on my Mac OS 
Mavericks and I keep getting errors like "conflicting types for '___builtin____strlcpy_chk' ..." and similarly for 
strlcat. I googled a bit and I think the problem might be that in Mavericks strlcat and strlcpy are already 
defined in string.h, and so there might be a redundant definition somewhere. I'm not sure what the best 
way to fix this would be though. Any help would be appreciated.

Thanks,

Andre

> > 
> > I don't know if this actually fits the Bug Report category. I've been trying to install Midas on my Mac OS 
> > Mavericks and I keep getting errors like "conflicting types for '___builtin____strlcpy_chk' ..." and similarly for 
> > strlcat. I googled a bit and I think the problem might be that in Mavericks strlcat and strlcpy are already 
> > defined in string.h, and so there might be a redundant definition somewhere. I'm not sure what the best 
> > way to fix this would be though. Any help would be appreciated.
> > 
> 
> We have run into this problem - MacOS 10.9 plays funny games with definitions of strlcpy() & co - and it has been fixed since last Summer.
> 
> For the record, current MIDAS builds just fine on MacOS 10.9.2.
> 
> For a pure test, try the instructions posted at midas.triumf.ca:
> 
> cd $HOME
> mkdir packages
> cd packages
> git clone https://bitbucket.org/tmidas/midas
> git clone https://bitbucket.org/tmidas/mscb
> git clone https://bitbucket.org/tmidas/mxml
> cd midas
> make
> 
> K.O.

Thanks, it works like a charm now! I must have obtained an outdated version of Midas.

Andre

Hello,

I'm wondering if it would be possible to add the ability to lock ODB variables as 
a sequencer command.

The "Lock when running" directory in the ODB /Experiment tree seems to apply only 
during a run - I'd like a way to lock a variable outside a run.

Is this possible within the sequencer?  Or have I overlooked existing 
functionality?

Thanks!

Amy

We're using the lazylogger to trigger a script that copies files, and the lag 
between a completed file appearing and the lazylogger trigger occasionally feels 
uncomfortably long.  It's not too bad - at most, around five or so minutes.  But 
of course it's tough to be patient when you're waiting to look at data.

The settings for our lazylogger specify a 'Stay behind' of zero and a 'Period' of 
zero.

Is there a way to make the lazylogger less lazy?  What determines the time 
between the appearance of a file and the lazylogger trigger?

We're using mhttpd for calls that end up working better with asynchronous requests, and we've built up sort of a parallel, asynchronous library using javascript Promises.

The Promises (which are in the ES6 spec) have worked incredibly well for building well-behaved, sequential calls to mhttpd.  Personally, I also find their syntax much easier to wrap my
head around, especially compared to callbacks.

I'd be happy to add these functions to midas.js if there's general interest. 

> If using a synchronous AJAX call, such as "foo=ODBGet("/runinfo/state");", google chrome will prints this to the javascript console:
> 
> "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check http://xhr.spec.whatwg.org/."
> 
> The referenced URL has this text:
> 
> "Synchronous XMLHttpRequest outside of workers is in the process of being removed from the web platform as it has detrimental effects to the end user's experience. (This is a long 
> process that takes many years.) Developers must not pass false for the async argument when the JavaScript global environment is a document environment. User agents are strongly 
> encouraged to warn about such usage in developer tools and may experiment with throwing an InvalidAccessError exception when it occurs."
> 
> Then jQuery say this: http://api.jquery.com/jquery.ajax/
> 
> "As of jQuery 1.8, the use of async: false with jqXHR ($.Deferred) is deprecated; you must use the success/error/complete callback options instead of the corresponding methods of the 
> jqXHR object such as jqXHR.done() or the deprecated jqXHR.success()."
> 
> This sounds rather severe but one must flow with the flow. Synchronous RPC is out, async is in.
> 
> Many of the old MIDAS AJAX functions are fully synchronous (i.e. "foo=ODBGet("/blah");"), some more recent ones support both sync and async use (i.e. ODBMCopy()).
> 
> All the newly added functions *must* by async-only. For example, all the new JSON-RPC functions are async-only and require the use of callbacks to get at the data.
> 
> Converting existing javascript custom pages from sync AJAX (hah! it's SJAX, not AJAX) will require some work, and one might as well start today.
> 
> Personally, I think this excessive use of callbacks for all javascript web page programming is an unnecessary PITA, but I also do understand the motivation
> of people who write web browsers and javascript engines - removal of support for synchronous RPC makes many things much simpler -
> and even small speedup of javascript execution and better browser efficiency is welcome improvements (but not free improvements - as old web pages need to be converted).
> 
> K.O.

When using the sequencer to start and stop runs which use a deferred transition,
the sequencer fails with a "Cannot stop run: ..." error.

Checking for the "CM_DEFERRED_TRANSITION" case in the first-pass block of the
'Stop' code in sequencer.cxx is one way to solve the problem - though there may
well be better solutions. 

My edited portion of sequencer.cxx is below.  Is this an acceptable solution
that could be introduced to the master branch?

} else if (equal_ustring(mxml_get_value(pn), "Stop")) {
    if (!seq.transition_request) {
       seq.transition_request = TRUE;
       size = sizeof(state);
       db_get_value(hDB, 0, "/Runinfo/State", &state, &size, TID_INT, FALSE);
       if (state != STATE_STOPPED) {
          status = cm_transition(TR_STOP, 0, str, sizeof(str), TR_MTHREAD |
TR_SYNC, TRUE);
          if (status == CM_DEFERRED_TRANSITION) {
             // do nothing
          } else if (status != CM_SUCCESS) {
             sprintf(str, "Cannot stop run: %s", str);
             seq_error(str);
          }
       }
    } else {
       // Wait until transition has finished
       size = sizeof(state);
       db_get_value(hDB, 0, "/Runinfo/State", &state, &size, TID_INT, FALSE);
       if (state == STATE_STOPPED) {
          seq.transition_request = FALSE;

          if (seq.stop_after_run) {
             seq.stop_after_run = FALSE;
             seq.running = FALSE;
             seq.finished = TRUE;
             cm_msg(MTALK, "sequencer", "Sequencer is finished.");
          } else
             seq.current_line_number++;

          db_set_record(hDB, hKeySeq, &seq, sizeof(seq), 0);
       } else {
         // do nothing
       }
    }
}

> Why don't you post the functions here so that we can have a look? 

Here is (1) my promisified HTTP request function and (2) a function that uses the returned promises to build an asynchronous, sequential chain of requests to Midas.

Note that if something seems ugly, it's likely because I didn't take the time to clean it up, and not because it particularly *needs* to be ugly.

###### promisified HTTP request ######
In addition to promisifying HTTP requests to Midas, I wanted the Promise.resolve from this function to always return valid JSON.  I also wanted the promise to reject if the response from mhttpd indicated
failure - so that we wouldn't have to rewrite this error checking throughout the code.  The function is so long becuase we make many different calls to mhttpd, and most of them need custom error checking
and, if successful, response packaging.

// begin cdms.daq.utilities.get()
cdms.daq.utilities.get = function(url) {
  return new Promise(function(resolve, reject) {
    // XHR request
    var req = new XMLHttpRequest();
    req.open('GET',url);
 
    req.onload = function() {
      //console.log('done with ', url);
      if(req.status == 200 || req.status == 302) {
        // 'http://dcrc01.triumf.ca:8081/?cmd=jcopy&odb=CustomScript/nonexistent&encoding=json'
        // 'http://dcrc01.triumf.ca:8081/?cmd=jkey&odb=CustomScript/nonexistent'
        // both return <DB_NO_KEY>
        if(/DB_NO_KEY/gi.test(req.response)) {
          reject(req.response);
      
        // 'http://dcrc01.triumf.ca:8081/?cmd=jkey&odb=CustomScript/nonexistent&encoding=json' 
        // returns {"/error": 312}
        } else if(/error.+:\s*\d+/.test(req.response)) {
          reject('<DB_NO_KEY>');
 
        // attempting to start (or stop) a run when a run is already started (or stopped) with
        // 'http://dcrc01.triumf.ca:8081/?cmd=stop' 
        // returns ...<title>MIDAS error</title></head><body><H1>Run is not running</H1>...
        } else if(/MIDAS error/i.test(req.response)) {
          var error_str = /<H1>(.*)<\/H1>/i.exec(req.response);
          reject(error_str[0]);
 
        // 'http://dcrc01.triumf.ca:8081/?cmd=jcreate&odb=/test/foo2&type=7&encoding=json'
        // returns either 1 (creation successful) or 311 (already exists)
        } else if(/jcreate/i.test(url) && (req.response=='1' || req.response=='311')) {
          resolve({'success': true});
 
        // 'http://dcrc01.triumf.ca:8081/?cmd=jset&odb=/test/foo2&val=9&encoding=json'
        // returns OK
        } else if(/jset/i.test(url) && (req.response=='OK')) {
          resolve({'success': true});
 
        // http://dcrc01.triumf.ca:8081/SEQ/?cmd=Load+Script
        // returns an html page showing all available sequencer files
        } else if(/SEQ.*cmd=Load.+Script/i.test(url)) {
          console.log('match Seq load script command url');
          fileList = req.response.match(/\w+.msl/gi);
          resolve({'success': true, 'files': fileList});
 
        // http://dcrc01.triumf.ca:8081/SEQ/?cmd=jmsg&n=10
        // returns 10 most recent messages
        } else if(/.*cmd=jmsg/i.test(url)) {
          console.log('match command url to get messages from mlogger');
          //console.log(req.response);
          resolve({'success': true, 'messages': req.response});
 
        // http://dcrc01.triumf.ca:8081/SEQ/?fs=testflash.msl&dir=&cmd=Load
        // returns <html>redir</html>
        } else if(/SEQ.+fs=\w+.msl&.*cmd=Load/i.test(url)) {
          resolve({'success': true});
 
        // http://dcrc01.triumf.ca:8081/SEQ/?cmd=Start+Script&params=1
        // returns a status of 302 but no response
        } else if(/SEQ.+\?cmd=Start.+Script/i.test(url)) {
          resolve({'success': true});
 
        // http://dcrc01.triumf.ca:8081/?customscript=XYZ&redir=.
        // returns a status of 302 but no response
        // although the redir causes a network call to
        // (in this case) the Midas home page,
        // and that seems to be the req.response
        } else if(/redir/i.test(url)) {
          resolve({'success': true});
 
        // all other responses should be valid JSON
        } else {
          try {
            var json_obj = JSON.parse(req.response);
 
            if(json_obj && typeof json_obj === "object" && json_obj !== null){
              resolve(json_obj);
            }
          } catch(err) {
            console.log('url is ',url);
            console.log('response is ',req.response);
 
            alert(err);
            reject(err);
          }
      }
    } 
    };
     
    req.onerror = function() {
      reject(Error("Network Error"));
    };
 
    req.send();
    //console.log('request to ', url);
  });
}; // end cdms.daq.utilities.get()


###### using promisified HTTP request ######
This is an excerpt that attempts to 
(1) run a script on the DAQ computer, producing a sequencer file
(2) check that the script is completed
(3) load the sequencer file
(4) run the sequencer

Failures on any step jump to the catch, which prints the error on screen.

These are HTTP calls, and given my buggy network should be asynchronous.  At the same time, each of these steps should happen only after its predecessor is completed.  To force sequential execution,
functions within a .then() clause return a Promise object. 

// set the argument string for {{scriptname}}
// then run {{scriptname}}
// check the message log until the success of the script is verified
// check that the sequencer sees the expected file (not implemented!)
// then load the resulting sequencer file
// then start the sequencer
cdms.daq.utilities.get(url).then(function() {
  // call customscript
  var cmd_str = '?customscript=' + scriptName_str + '&redir=.';
  return cdms.daq.utilities.get(baseURL_str + cmd_str);
}).then(function() {
  return checkScriptLoop(uid);
}).then(function() {
  var load_str = baseURL_str + '/SEQ/?cmd=Load+Script';
  console.log('execute promise for url ', load_str);
  return cdms.daq.utilities.get(load_str);
}).then(function() {
  var load_str = '/SEQ/?fs=' + seqFile_str + '&dir=&cmd=Load';
  console.log('execute promise for url ', load_str);
  return cdms.daq.utilities.get(baseURL_str + load_str);
}).then(function() {
  var startSeq_str = '/SEQ/?cmd=Start+Script&params=1';
  console.log('execute promise for url ', startSeq_str);
  return cdms.daq.utilities.get(baseURL_str + startSeq_str);
}).catch(function(error) {
  alert(error);
}).then(function() {
  window.frames['flash-frame'].location = baseURL_str + '/SEQ/';
});

> I checked again on browser compatibility:
> 
> el6: firefox 38 - ok, google-chrome 27 - no
> el7: firefox 38 - ok, google-chrome 46 - ok
> ubuntu: firefox 42 - ok
> 
> mac os, windows - we say "latest firefox or google-chrome is required", then - ok
> 
> So we are probably okey with using javascript Promises with MIDAS...

It looks like this does mean that people using RHEL6 won't have the option of chrome - can they update chrome?

One option is to include a polyfill library like Lie (https://github.com/calvinmetcalf/lie).

> Right now the JSON-RPC client library does not check the return status of MIDAS calls themselves, i.e. ODBGet("/nonexistant") will go to Promise.resolve() with
> the MIDAS db_find_key() status DB_NO_KEY instead of Promise.reject(). So some error handling in Promise.resolve() is still required.

> I am thinking how to make these calls go to the error handler automatically, but there is no obvious solution for ODBMGet(["/runinfo", "/nonexistant"]) - the first path
> is a success, the second is a failure, do I fail the entire transaction (i.e. with a JSON-RPC error)? Same for JSON-RPC batch transactions - if one transaction
> in the batch fails, do I Promise.reject() all of them?


Generally, I'd prefer a grouped-request like ODBMGet to return an array of
Promises.  This way, I get to decide how to handle the request responses.  While
I do have cases where I use Promise.all(...), most of my current code would want
to treat each response individually.

But as you point out, my approach differs from the Midas approach significantly.
While I've set up my queries to reject on responses like DB_NO_KEY, the function
mjsonrpc_send_request in mhttpd.js tests purely for a successful http
request.

Since ODBMGet makes a *single* http call, I'd naively lean toward having it
return a single Promise.  Presumably, one that resolves if the http request
"goes through" and rejects if the http request fails. 

My perspective may not be the useful one to consider, though.  If other users
expect an array of promises returned from ODBMGet, definitely feel free to
ignore my thoughts on the matter.

If people really want ODBMGet to return an array of promises, one way to do it
would be to have a 'get' function that only cares about the success of the http
request, and a separate 'response checking' function that validates the
response.  ODBMGet can use these two functions together to return an array of
Promises:

#########
mhttpd.js
#########
function get(url) { 
  // return a promise that resolves if the http request returns status=200
  // reject if the http request does anything else
}

function checkResponse(response) {
  // return a promise that resolves for "good" responses
  // and rejects for "bad response"
}

function ODBMGet(path_arr) {
  var url = // build url from path_arr
  
  // syntax get().then(A).catch(B) means
  // if the http request goes through, A is executed
  // if the http request fails, B is executed
  // ;
  // for get, failure means no successful reply at all
  // so ODBMGet should return an array of rejected Promises 
  get(url).then(function(response) {
    response_arr = // split the response
    return response_arr.map(checkResponse)
  }).catch(function(err) {
    return path_arr.forEach(function() {
      return Promise.reject(err)
    })
  })
}

#########
user code
#########
// here the Promises are treated individually
var response_arr = ODBMGet([path1, path2, path3])

response_arr.forEach(function(thisResponse) {
  thisResponse.then( /* do something */ )
              .catch( /* do something else */ )
})

// and here the failure of a single promise in the array
// determines the code that's executed next
var required_arr = ODBMGet([pathA, pathB, pathC])

Promise.all(required_arr).then( /* do something */ )
                         .catch( /* do something else */ )

Both the /Script and /CustomScript trees in the ODB allow users to trigger a 
script via Midas - which silently truncates command strings longer than 
256 characters.

I'd prefer that Midas place no limit on string length.  Failing that, it would be
helpful to have character limits called out in the documentation 
(https://midas.triumf.ca/MidasWiki/index.php//Script_ODB_tree#.3Cscript-name.3E_key_or_subtree,
https://midas.triumf.ca/MidasWiki/index.php//Customscript_ODB_tree).

As far as I can tell, odb.c allows arbitrarily large strings in the ODB data.  
(Although key *names* are restricted to 256 characters.)  I've submitted one 
possible version of an arbitrary-length exec_script() as a pull request 
(https://bitbucket.org/tmidas/midas/pull-requests/).

Am I misunderstanding any critical pieces?  Does Midas intentionally treat 
strings in the ODB as limited to 256 characters?

Using low-level memory allocation routines in higher-level programs like mhttpd makes me nervous.

We could use vector arrays to allow variable-sized allocation, and use the data() member function to access the char* needed for functions like strlcat,
db_get_data, and db_sprintf.

This conforms to the c++ standard, but doesn't require explicit freeing by the user - at least, not when you're allocating std::vector<char>.

Amy

> Thank you for reporting this problem:
> 
> a) ODB key *names* are restricted to 31 characters (32 bytes, last byte is a NUL), not 256 characters.
> b) ODB string length is unlimited (32-bit length field)
> c) ODB C API "db_get_value" & co require fixed length buffer and most users of this API provide a 256-byte fixed buffer for strings, some of them also do not 
> check the status code, resulting in silent truncation. (I think the ODB functions themselves report truncation to midas.log, so not completely silent).
> 
> We try to fix this where we must - but it is cumbersome with the current ODB API - as in your fix on has to:
> - get the ODB key, extract size
> - allocate buffer
> - call db_get_value() & co
> - use the data
> - remember to free the buffer on each and every return path
> 
> The first three steps could become one if we had an ODB "get_data" function that automatically allocated the data buffer.
> 
> But the main source of bugs will be the last step - remember to free the buffer, always.
> 
> P.S.
> 
> We are not alone in pondering how to do this best. If you want to see it "done right",
> read the fresh-off-the-presses book "Go Programming Language" by Alan Donovan and Brian Kernighan,
> http://www.gopl.io/
> 
> Brian Kernighan is the "K" in K&R "C programming language", still around and kicking, now at Google.
> Sadly the "R" passed away in 2011 - http://www.nytimes.com/2011/10/14/technology/dennis-ritchie-programming-trailblazer-dies-at-70.html
> 
> K.O.
> 
> > Both the /Script and /CustomScript trees in the ODB allow users to trigger a 
> > script via Midas - which silently truncates command strings longer than 
> > 256 characters.
> > 
> > I'd prefer that Midas place no limit on string length.  Failing that, it would be
> > helpful to have character limits called out in the documentation 
> > (https://midas.triumf.ca/MidasWiki/index.php//Script_ODB_tree#.3Cscript-name.3E_key_or_subtree,
> > https://midas.triumf.ca/MidasWiki/index.php//Customscript_ODB_tree).
> > 
> > As far as I can tell, odb.c allows arbitrarily large strings in the ODB data.  
> > (Although key *names* are restricted to 256 characters.)  I've submitted one 
> > possible version of an arbitrary-length exec_script() as a pull request 
> > (https://bitbucket.org/tmidas/midas/pull-requests/).
> > 
> > Am I misunderstanding any critical pieces?  Does Midas intentionally treat 
> > strings in the ODB as limited to 256 characters?

I've recently run into issues when using JSON.parse on ODB keys containing 
8-bit data.

For JSON.parse to successfully parse a string, (A) the string must be valid 
UTF-8, (B) several whitespace characters, control characters, and the 
characters " and \ must be escaped, and (C) you've got to follow the key-
value rules laid out in http://www.json.org/.

The web browser takes care of (A), and I verified that for this key Midas 
handled (C) correctly.  In principle, the function json_write in odb.c 
handles (B) - but json_write does not escape control characters.

To manage this problem, I modified json_write (in odb.c) to replace any 
control character with the more-inocuous character, 'C'.  My default case 
now looks like:

default:
         {
           // if a char is a control character,
           // print 'C' in its place
           // note that this loses data:
           // a more-correct method would be to print
           // \uXXXX, where XXXX is the character in hex
           if(iscntrl(*s)){
             (*buffer)[(*buffer_end)++] = 'C';
             s++;
           } else {
             (*buffer)[(*buffer_end)++] = *s++;
           }
         }
      
Where the call to iscntrl(*s) requires the addition of the ctype.h header 
file.

I'm guessing a blanket replacement of control characters with 'C' isn't 
something all Midas users would want to do.  Replacing the control character 
with its hex value seems like a good choice - but not without adding bounds 
checking!

An alternative to changing odb.c could be to add a regex to Midas response 
text which removes all control characters (U+0000 - U+001F): 

var resp_lint = req.response.replace(/[\u{0000}-\u{001F}]/gmu, '');
var json_obj = JSON.parse(resp_lint);

Unfortunately, the 'u' regex flax doesn't work on the Firefox version 
included in Scientific Linux 6.8.  

I recently needed to watch the Midas messages for a particular error - and 
thus needed a command to "get all the messages since a time t".

The documentation (https://midas.triumf.ca/MidasWiki/index.php/AJAX#jmsg) 
documents a way to "get the most recent n messages" - but when I dug into the 
code, I was delighted to find that the existing Midas code also supports the 
"get all messages since t" query.

For the "get all messages since t" query, the parameter t should be the unix 
timestamp in seconds, and the parameter n should be zero: curl -X GET 
"http://localhost:8081/?cmd=jmsg&n=0&t=1473437918".

Pretty useful!  Perhaps this should be added to the AJAX documentation?

I'd like to use the mjsonrpc db_get_values method, but (as indicated in the
documentation) it returns all ODB keys as lowercase.

This breaks quite a lot of my code - it was written with the old AJAX commands,
and these did respect the capitalization of the ODB keys.

Would it be possible to add a capitalization-preserve option to db_get_values? 

It appears I needed to read the documentation more closely - the method db_save
does respect key-name capitalization and solves my problem.

Is db_save considered a deprecated method?  If so, I'd reiterate my suggestion for
a capitalize-preserve option for db_get_values.

Otherwise, I'll plan on using db_save.

> I'd like to use the mjsonrpc db_get_values method, but (as indicated in the
> documentation) it returns all ODB keys as lowercase.
> 
> This breaks quite a lot of my code - it was written with the old AJAX commands,
> and these did respect the capitalization of the ODB keys.
> 
> Would it be possible to add a capitalization-preserve option to db_get_values? 

We're using the History Logger MIDAS feature and writing to mySQL tables, but 
in some cases have run into issues installing mySQL on centos7 systems.

Has anyone ever tried running this MIDAS feature with MariaDB rather than 
mySQL?