Re: How to: IOC reading information from file?

["Cobb, Tom \(DLSLtd,RAL,LSCI\) via Tech-talk" <tech-talk at aps.anl.gov>]

An alternative approach if going down the Python route is to write the whole IOC in Python using pythonSoftIOC. Something like this:

import json

# Import the basic framework components.

from softioc import asyncio_dispatcher, builder, softioc

# Set the record prefix

builder.SetDeviceName("MY-DEVICE-PREFIX")

# Make some dummy data

with open("/tmp/mydata.json", "w") as f:

    f.write('{"my_var": 1.0}')

# Create some records

value = builder.aIn("VALUE", initial_value=0.0)

def set_value_from_json(path: str):

    with open(path) as f:

        text = f.read()

    value.set(json.loads(text)["my_var"])

path = builder.stringOut("PATH", always_update=True, on_update=set_value_from_json)

# Boilerplate get the IOC started

builder.LoadDatabase()

softioc.iocInit(asyncio_dispatcher.AsyncioDispatcher())

# Finally leave the IOC running with an interactive shell.

softioc.interactive_ioc(globals())

# On commandline:

# $ caget MY-DEVICE-PREFIX:VALUE

# MY-DEVICE-PREFIX:VALUE 0.0

# $ caput MY-DEVICE-PREFIX:PATH /tmp/mydata.json

# $ caget MY-DEVICE-PREFIX:VALUE

# MY-DEVICE-PREFIX:VALUE 1.0

Thanks,

Tom

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>
Sent: 28 November 2022 20:55
To: Marco A. Barra Montevechi Filho <marco.filho at lnls.br>
Cc: Nariyoshi, Pedro <nariyosh at frib.msu.edu>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: How to: IOC reading information from file?

 

On 11/28/22 12:37, Michael Davidsaver wrote:
> On 11/28/22 12:05, Marco A. Barra Montevechi Filho via Tech-talk wrote:
>> Thanks for the suggestion, Pedro!
>>
>> At the end of the day, i figured that maybe autosave fdbrestore function would do what i wanted. Unfortunately, the function was resulting in segmentation fault. Looking in tech-talk i found this thread: https://epics.anl.gov/tech-talk/2014/msg01851.php <https://epics.anl.gov/tech-talk/2014/msg01851.php> which suggested that for autosave versions before 5.4.1 it is a known bug which is fixed after that. Since im using autosave 5-10-2 and the PVs are not very long, i gave up using autosave for this.
>
> Could you provide any details which might go into a ticket?
> Specific arguments used?  ideally a stack trace?  etc...
>
> https://github.com/epics-modules/autosave/issues

I haven't tried fdbrestore() previously, so I'm not certain about the
caput() errors.  It certainly didn't crash on me.

Did you do full cleanup and rebuild when switching between autosave versions?
(eg. "make distclean", or just deleting and re-downloading the source)

Linking in old object code files is great way to experience some bizarre crashes.


> epics> var save_restoreDebug 5
> epics> fdbrestore "ioc_settings.sav"
> save_restore:fdbrestore:entry
> save_restore:request_manual_restore: entry
> save_restore task: calling do_manual_restore('ioc_settings.sav')
> save_restore:do_manual_restore: entry for file 'ioc_settings.sav'
> epics> do_manual_restore:ca_put() to 'TST:Speed-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:DM-Sel.VAL'failed.
> do_manual_restore:ca_put() to 'TST:SampT-Sel.VAL'failed.
> do_manual_restore:ca_put() to 'TST:SampT:N-Sel.VAL'failed.
> do_manual_restore:ca_put() to 'TST:SampDet-Sel.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Plt-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Samp-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Plt:N-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Samp:N-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Gn:X-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Gn:Y-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Gn:Z-SP.VAL'failed.
> do_manual_restore:ca_put() to 'TST:Tl-Sel.VAL'failed.
> save_restore: manual restore status=1 (0==success)

 

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