error when using LiveTiffExporter

[ykchenwiegart]

We implemented LiveTiffExporter in 91-userscans.py, but it has problem related to 'db'.
It's unclear why db is None in the broker.py name space.

error trace-back:

In [7]: RE(xrfmap(xstart=49.0, xnumstep=3, xstepsize=0.1, ystart=51.0, ynumstep=3, ystepsize=0.1, rois=[sclr.channels.chan5.name]))
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
<ipython-input-7-92b9228ecf29> in <module>()
----> 1 RE(xrfmap(xstart=49.0, xnumstep=3, xstepsize=0.1, ystart=51.0, ynumstep=3, ystepsize=0.1, rois=[sclr.channels.chan5.name]))

/opt/conda_envs/collection-17Q2.0/lib/python3.6/site-packages/bluesky/run_engine.py in __call__(self, plan, subs, raise_if_interrupted, **metadata_kw)
    597                     # it (unless it is a canceled error)
    598                     if exc is not None:
--> 599                         raise exc
    600 
    601             if raise_if_interrupted and self._interrupted:

/opt/conda_envs/collection-17Q2.0/lib/python3.6/site-packages/bluesky/run_engine.py in _run(self)
   1021             self.log.error("Run aborted")
   1022             self.log.error("%r", err)
-> 1023             raise err
   1024         finally:
   1025             # Some done_callbacks may still be alive in other threads.

/opt/conda_envs/collection-17Q2.0/lib/python3.6/site-packages/bluesky/run_engine.py in _run(self)
    919                         resp = self._response_stack.pop()
    920                         try:
--> 921                             msg = self._plan_stack[-1].send(resp)
    922                         # We have exhausted the top generator
    923                         except StopIteration:

/home/xf08bm/.ipython/profile_collection/startup/91-userscans.py in xrfmap(xstart, xnumstep, xstepsize, ystart, ynumstep, ystepsize, rois)
     39         #setup LiveOutput
     40         xrfmapOutputTiffTemplate = xrfmapTiffOutputDir+"xrfmap_scan{start[scan_id]}" +roi+ ".tiff"
---> 41         xrfmapTiffexporter = LiveTiffExporter(roi, xrfmapOutputTiffTemplate)
     42         callbackToken = RE.subscribe('all', post_run(xrfmapTiffexporter))#check to see if this is the right way to have RE here...
     43         callbackTokenList.append(callbackToken)

/opt/conda_envs/collection-17Q2.0/lib/python3.6/site-packages/bluesky/callbacks/broker.py in __init__(self, field, template, dryrun, overwrite, db)
    208 
    209         if db is None:
--> 210             from databroker import DataBroker as db
    211 
    212         self.db = db

ImportError: cannot import name 'DataBroker'

91-userscnas code:

from bluesky.callbacks.broker import LiveTiffExporter

testevents = list(db.get_events(db[-1]))

xrfmapTiffOutputDir = '/home/xf08bm/DATA2017/Comissioning/20170616/'
#hard-coded for testing now; need to be set to automatically use SAF, today's date, etc.

def xrfmap(*, xstart, xnumstep, xstepsize,
            ystart, ynumstep, ystepsize,
            rois = []
            #shutter = True, align = False,
            #acqtime, numrois=1, i0map_show=True, itmap_show=False, record_cryo = False,
            #setenergy=None, u_detune=None, echange_waittime=10
            ):

    '''
    input:
         xstart, xnumstep, xstepsize (float)
         ystart, ynumstep, ystepsize (float)

    '''

    #define detector used for xrf mapping functions
    xrfdet = [sclr] #currently only the scalar; to-do: save full spectra

    xstop = xstart + xnumstep*xstepsize
    ystop = ystart + ynumstep*ystepsize

    #setup live callbacks:

    livetableitem = [xy_stage.x, xy_stage.y]
    livecallbacks = []
    callbackTokenList = []

    for roi in rois:
        livecallbacks.append(LiveGrid((ynumstep+1, xnumstep+1), roi, xlabel = 'x (mm)', ylabel = 'y (mm)', extent=[xstart, xstop, ystart, ystop]))
        livetableitem.append(roi)

        #setup LiveOutput
        xrfmapOutputTiffTemplate = xrfmapTiffOutputDir+"xrfmap_scan{start[scan_id]}" +roi+ ".tiff"
        xrfmapTiffexporter = LiveTiffExporter(roi, xrfmapOutputTiffTemplate)
        callbackToken = RE.subscribe('all', post_run(xrfmapTiffexporter))#check to see if this is the right way to have RE here...
        callbackTokenList.append(callbackToken)

    livecallbacks.append(LiveTable(livetableitem))

    xrfmap_scanplan = outer_product_scan(xrfdet, xy_stage.y, ystart, ystop, ynumstep+1, xy_stage.x, xstart, xstop, xnumstep+1, False)
    xrfmap_scanplan = bp.subs_wrapper(xrfmap_scanplan, livecallbacks)

    scaninfo = yield from xrfmap_scanplan

    for callbackToken in callbackTokenList:
        RE.unsubscribe(callbackToken)

    return xrfmap_scanplan