Add a helper warmup function for hdf5 plugins of AD

[mrakitin]

This was originally implemented at NSLS-II TES, porting the function to here to be available to other beamlines.

[prjemian]

Since this method is needed for other file area detector writing plugins, perhaps it should be more general? Here is code from apstools that checks if warmup (aka prime) is needed:

def AD_plugin_primed(plugin):
    """
    Has area detector pushed an NDarray to the file writer plugin?  True or False

    PARAMETERS

    plugin
        *obj* :
        area detector plugin to be *primed* (such as ``detector.hdf1``)

    EXAMPLE::

        AD_plugin_primed(detector.hdf1)

    Works around an observed issue: #598
    https://github.com/NSLS-II/ophyd/issues/598#issuecomment-414311372

    If detector IOC has just been started and has not yet taken an image
    with the file writer plugin, then a TimeoutError will occur as the
    file writer plugin "Capture" is set to 1 (Start).  In such case,
    first acquire at least one image with the file writer plugin enabled.

    Also issue in apstools (needs a robust method to detect if primed):
    https://github.com/BCDA-APS/apstools/issues/464

    Since Area Detector release 2.1 (2014-10-14).

    The *prime* process is not needed if you select the
    *LazyOpen* feature with *Stream* mode for the file plugin.
    *LazyOpen* defers file creation until the first frame arrives
    in the plugin. This removes the need to initialize the plugin
    with a dummy frame before starting capture.
    """
    cam = plugin.parent.cam
    tests = []

    for obj in (cam, plugin):
        test = np.array(obj.array_size.get()).sum() != 0
        tests.append(test)
        if not test:
            logger.debug("'%s' image size is zero", obj.name)

    checks = dict(
        array_size=False,
        color_mode=True,
        data_type=True,
    )
    for key, as_string in checks.items():
        c = getattr(cam, key).get(as_string=as_string)
        p = getattr(plugin, key).get(as_string=as_string)
        test = c == p
        tests.append(test)
        if not test:
            logger.debug("%s does not match", key)

    return False not in tests

[prjemian]

Here's the code that primes the plugin:

def AD_prime_plugin2(plugin):
    """
    Prime this area detector's file writer plugin.

    Collect and push an NDarray to the file writer plugin.
    Works with all file writer plugins.

    Based on ``ophyd.areadetector.plugins.HDF5Plugin.warmup()``.

    PARAMETERS

    plugin
        *obj* :
        area detector plugin to be *primed* (such as ``detector.hdf1``)

    EXAMPLE::

        AD_prime_plugin2(detector.hdf1)

    """
    if AD_plugin_primed(plugin):
        logger.debug("'%s' plugin is already primed", plugin.name)
        return

    sigs = OrderedDict(
        [
            (plugin.enable, 1),
            (plugin.parent.cam.array_callbacks, 1),  # set by number
            (plugin.parent.cam.image_mode, 0),  # Single, set by number
            # Trigger mode names are not identical for every camera.
            # Assume here that the first item in the list is
            # the best default choice to prime the plugin.
            (plugin.parent.cam.trigger_mode, 0),  # set by number
            # just in case the acquisition time is set very long...
            (plugin.parent.cam.acquire_time, 1),
            (plugin.parent.cam.acquire_period, 1),
            (plugin.parent.cam.acquire, 1),  # set by number
        ]
    )

    original_vals = {sig: sig.get() for sig in sigs}

    for sig, val in sigs.items():
        time.sleep(0.1)  # abundance of caution
        sig.set(val).wait()

    time.sleep(2)  # wait for acquisition

    for sig, val in reversed(list(original_vals.items())):
        time.sleep(0.1)
        sig.set(val).wait()

[tacaswell]

Can we please do this as a plan so it will compose nicely?

def AD_prime_plugin2(plugin):
    """
    Prime this area detector's file writer plugin.

    Collect and push an NDarray to the file writer plugin.
    Works with all file writer plugins.

    Based on ``ophyd.areadetector.plugins.HDF5Plugin.warmup()``.

    PARAMETERS

    plugin
        *obj* :
        area detector plugin to be *primed* (such as ``detector.hdf1``)

    EXAMPLE::

        AD_prime_plugin2(detector.hdf1)

    """
    if AD_plugin_primed(plugin):
        logger.debug("'%s' plugin is already primed", plugin.name)
        return

    sigs = OrderedDict(
        [
            (plugin.enable, 1),
            (plugin.parent.cam.array_callbacks, 1),  # set by number
            (plugin.parent.cam.image_mode, 0),  # Single, set by number
            # Trigger mode names are not identical for every camera.
            # Assume here that the first item in the list is
            # the best default choice to prime the plugin.
            (plugin.parent.cam.trigger_mode, 0),  # set by number
            # just in case the acquisition time is set very long...
            (plugin.parent.cam.acquire_time, 1),
            (plugin.parent.cam.acquire_period, 1),
            (plugin.parent.cam.acquire, 1),  # set by number
        ]
    )

    original_vals = {}
    for sig in sigs:
        original_vals[sig] = yield from bps.rd(sig)

    for sig, val in sigs.items():
        yield from bps.sleep(.1)
        yield from bps.abs_set(sig, val)

    yield from bps.sleep(2)  # wait for acquisition

    for sig, val in reversed(original_vals.items()):
        yield from bps.sleep(.1)
        yield from bps.abs_set(sig, val)        

[prjemian]

I'd be happier seeing both AD_plugin_primed() and AD_prime_plugin2() (plan version) become part of ophyd.

[mrakitin]

We should revive it. Should it go to ophyd?