archiver function fails on first execution - making it not compatible with flow control

[ambarb]

For the code below, Shift+Enter is needed twice for the cell containing the last line of the input code below. This is also the case if PVs are changed or Kernel is restarted.

input code

from databroker.eventsource.archiver import ArchiverEventSource
from databroker import Broker
db = Broker.named('six',auto_register =  False)
labels = ['m6pit', 'm7pit', 'grpit']

pv_dict={labels[0]:'XF:02IDD-ES{Mir:6-Ax:Pch}Mtr.RBV', 
         labels[1]:'XF:02IDD-ES{Mono:2-Ax:MP}Mtr.RBV', 
         labels[2]:'XF:02IDD-ES{Mono:2-Ax:GP}Mtr.RBV'}


ARCHIVER_URL = 'http://xf02id1-ca1.cs.nsls2.local:17668'
arc = ArchiverEventSource(ARCHIVER_URL, 'US/Eastern', pv_dict)

scans =[66861,]
h = db[scans[0]]

data = arc.table_given_header(h)

Last line returns exception for the first execution (new PVs or reset kernel)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-7-2ab349fe4ecc> in <module>()
----> 1 data = arc.table_given_header(h)
      2 print(data.shape)
      3 print('\nlines returned from archive: ', data.shape[0])
      4 print('\nlines per PV (avg): ', data.shape[0]/len(labels))
      5 print('\nkeys of data:',data.keys() )

/opt/conda_envs/analysis-2018-3.2/lib/python3.6/site-packages/databroker/eventsource/archiver.py in table_given_header(self, header, fields)
    113         fields = set(fields)
    114         docs = list(self.docs_given_header(header=header,
--> 115                                     fill=False, fields=fields))
    116         return pd.DataFrame.from_records(data=docs, index='seq_num')
    117 

/opt/conda_envs/analysis-2018-3.2/lib/python3.6/site-packages/databroker/eventsource/archiver.py in docs_given_header(self, header, fill, fields, **kwargs)
     83         for d in self.descriptors_given_header(header):
     84             # Stash the desc uids in a local var so we can use them in events.
---> 85             pv = list(d['data_keys'].values())[0]['source']
     86             desc_uids[pv] = d['uid']
     87             yield d

TypeError: string indices must be integers

[ambarb]

Note that this is probably some version of data broker 0.9.x or 0.11.x.