Add version control for ArrayNode eventing

[hamersaw]

Tracking issue

NA

Describe your changes

Add a version control flag for ArrayNode eventing. 0 means use the existing approach (ie. populating ExternalResourceInfo field on the TaskExecutionEvent) as a drop-in replacement for maptask. 1 means to write separate NodeExecutionEvents for each subNode execution (linked by parent node ID) for full metadata.

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Screenshots

NA

Note to reviewers

NA

[codecov]

Codecov Report

Attention: 43 lines in your changes are missing coverage. Please review.

Comparison is base (a903dc0) 59.00% compared to head (5f6c80a) 59.91%.

❗ Current head 5f6c80a differs from pull request most recent head fc3b0d7. Consider uploading reports for the commit fc3b0d7 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4165      +/-   ##
==========================================
+ Coverage   59.00%   59.91%   +0.90%     
==========================================
  Files         619      569      -50     
  Lines       52827    40999   -11828     
==========================================
- Hits        31170    24563    -6607     
+ Misses      19173    14053    -5120     
+ Partials     2484     2383     -101     

Flag	Coverage Δ
unittests	?

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Files	Coverage Δ
flytepropeller/pkg/controller/config/config.go	0.00% <ø> (ø)
...ytepropeller/pkg/controller/config/config_flags.go	76.25% <100.00%> (+2.17%)	⬆️
...g/controller/nodes/array/node_execution_context.go	61.53% <100.00%> (-6.03%)	⬇️
...ller/nodes/array/node_execution_context_builder.go	88.23% <100.00%> (+0.73%)	⬆️
flytepropeller/pkg/controller/nodes/array/utils.go	81.25% <100.00%> (+2.08%)	⬆️
...in/pkg/repositories/transformers/node_execution.go	74.69% <33.33%> (+2.14%)	⬆️
...lytepropeller/pkg/controller/nodes/transformers.go	51.59% <0.00%> (-1.53%)	⬇️
...ytepropeller/pkg/controller/nodes/array/handler.go	70.58% <68.75%> (+1.22%)	⬆️
...eller/pkg/controller/nodes/array/event_recorder.go	74.77% <74.77%> (ø)

... and 567 files with indirect coverage changes

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[eapolinario]

just curious, why are we changing this?

[hamersaw]

This test case is the scenario where the ArrayNode has not yet started. We write an single node and task event for each subnode to alert admin of it's existence - mainly so the UI can display undefined x20 to indicate that there are 20 subtasks. We previously initially reported these with the Queued phase, because that skips input resolution downstream allowing us to just use a mocked in-memory input value from the array rather than copy each individual subnode input to a separate blobstore location. However, we can still use Queued as the initial phase during downstream evaluations and use Undefined here to more accurately report that these tasks have not yet started.