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https://issues.apache.org/jira/browse/BEAM-8425?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16954007#comment-16954007
]
Ning Kang commented on BEAM-8425:
---------------------------------
To get ipython kernel (without try-except for non-interactive scenario):
```
from IPython import get_ipython
_ipython = get_ipython()
```
To get prompt number of current PTransform applied:
```
len(vars(_ipython)['user_ns']['In'])-1
```
Bonus, to get all code executed by the user in this kernel:
_ipython.magic('%history')
> Notifying Interactive Beam user about Beam related cell deletion or
> re-execution
> --------------------------------------------------------------------------------
>
> Key: BEAM-8425
> URL: https://issues.apache.org/jira/browse/BEAM-8425
> Project: Beam
> Issue Type: New Feature
> Components: runner-py-interactive
> Reporter: Ning Kang
> Assignee: Ning Kang
> Priority: Major
>
> There is a general problem about Interactive Notebooks that when an end user
> deletes a cell that has been executed or re-executes a cell, those previous
> executions are hidden from the end user.
> However, hidden states will still have side effects in the notebook.
> This kind of problem bothers Beam even more because Beam's pipeline
> construction statements are note idempotent and pipeline execution is
> decoupled and deferred from pipeline construction.
> Re-executing a cell with Beam statements that build a pipeline would cause
> unexpected pipeline state and the user wouldn't notice it due to the problem
> of notebooks.
> We'll intercept each transform application invocation from the
> InteractiveRunner and record the ipython/notebook prompt number. Then each
> time a user executes a cell that applies PTransform, we'll compare the
> recorded list of prompt numbers with current notebook file's content and
> figure out if there is any missing number. If so, we know for sure that a
> re-execution happens and use display manager to notify the end user of
> potential side effects caused by hidden states of the notebook/ipython.
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