feat(taps): Queue parent contexts and sync child streams only when the queue is full

[edgarrmondragon]

Summary by Sourcery

Introduce batching of child stream synchronization by queueing parent contexts and flushing them when the queue reaches a configurable maximum or at the end of a parent sync.

New Features:

• Enable delayed syncing of child streams by queuing parent contexts instead of immediate synchronization.

Enhancements:

• Add a configurable QUEUE_MAX_SIZE attribute (default 1000) to control batch size of queued contexts.
• Implement an internal _child_context_queue and a _flush_child_context_queue method to process queued contexts in bulk.
• Modify _sync_children and _sync_records to enqueue contexts and trigger flushes when the queue is full or after parent sync ends.

Tests:

• Adjust existing parent-child tests to override QUEUE_MAX_SIZE and verify batched flushing behavior.

[sourcery-ai]

Reviewer's Guide

Implements batched child-stream synchronizations by queuing parent contexts in a list and flushing them in bulk when a maximum queue size is reached or after the parent stream finishes syncing.

Sequence diagram for batched child stream synchronization

sequenceDiagram
    participant ParentStream
    participant ChildContextQueue
    participant ChildStream
    loop For each parent context
        ParentStream->>ChildContextQueue: Add context to queue
        alt Queue size >= QUEUE_MAX_SIZE
            ParentStream->>ChildContextQueue: Flush queue
            ChildContextQueue->>ChildStream: Sync all queued contexts
            ChildContextQueue->>ChildContextQueue: Clear queue
        end
    end
    ParentStream->>ChildContextQueue: Flush any remaining contexts (after parent sync)
    ChildContextQueue->>ChildStream: Sync all remaining contexts
    ChildContextQueue->>ChildContextQueue: Clear queue

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Class diagram for updated Stream batching logic

classDiagram
    class Stream {
        +int QUEUE_MAX_SIZE
        +list _child_context_queue
        +_sync_children(child_context)
        +_flush_child_context_queue()
    }
    Stream --> "*" Stream : child_streams

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File-Level Changes

Change	Details	Files
Introduce queue size limit and context queue for batching child syncs	Define a new QUEUE_MAX_SIZE class attribute Initialize a list-based _child_context_queue in Stream.init	singer_sdk/streams/core.py
Enqueue child contexts instead of syncing immediately	Replace direct child_sync loop in _sync_children Append child_context to queue and check against QUEUE_MAX_SIZE	singer_sdk/streams/core.py
Add a flush method to process queued contexts	Implement _flush_child_context_queue to log and sync batches Clear the queue after processing	singer_sdk/streams/core.py
Ensure final flush after parent sync	Invoke _flush_child_context_queue at the end of _sync_records	singer_sdk/streams/core.py
Adjust tests to reflect batched syncing	Override QUEUE_MAX_SIZE in test Parent class Regenerate snapshots for batched behavior	tests/core/test_parent_child.py tests/core/snapshots/test_parent_child/*

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.61%. Comparing base (006da34) to head (d01a550).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3058      +/-   ##
==========================================
+ Coverage   93.59%   93.61%   +0.01%     
==========================================
  Files          69       69              
  Lines        5665     5681      +16     
  Branches      700      703       +3     
==========================================
+ Hits         5302     5318      +16     
  Misses        258      258              
  Partials      105      105              

Flag	Coverage Δ
core	80.49% <100.00%> (+0.10%)	⬆️
end-to-end	76.62% <36.84%> (-0.10%)	⬇️
optional-components	43.24% <15.78%> (-0.07%)	⬇️

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[codspeed-hq]

CodSpeed Performance Report

Merging #3058 will not alter performance

_{Comparing queue-child-streams (d01a550) with main (006da34)}

Summary

✅ 8 untouched

[edgarrmondragon]

@sourcery-ai review

[edgarrmondragon]

@sourcery-ai review

[sourcery-ai]

Hey @edgarrmondragon - I've reviewed your changes and they look great!

Prompt for AI Agents

Please address the comments from this code review:
## Individual Comments

### Comment 1
<location> `singer_sdk/streams/core.py:1368` </location>
<code_context>
+            self.name,
+        )
+
+        for context in self._child_context_queue:
+            for child_stream in self.child_streams:
+                if child_stream.selected or child_stream.has_selected_descendents:
+                    child_stream.sync(context=context)
+
</code_context>

<issue_to_address>
Consider exception handling during child stream sync.

An exception in child_stream.sync may halt queue processing. Wrap sync in try/except and log errors to enhance robustness.
</issue_to_address>

<suggested_fix>
<<<<<<< SEARCH
        for context in self._child_context_queue:
            for child_stream in self.child_streams:
                if child_stream.selected or child_stream.has_selected_descendents:
                    child_stream.sync(context=context)
=======
        for context in self._child_context_queue:
            for child_stream in self.child_streams:
                if child_stream.selected or child_stream.has_selected_descendents:
                    try:
                        child_stream.sync(context=context)
                    except Exception as exc:
                        self.logger.error(
                            "Error syncing child stream '%s' with context '%s': %s",
                            getattr(child_stream, "name", repr(child_stream)),
                            context,
                            exc,
                            exc_info=True,
                        )
>>>>>>> REPLACE

</suggested_fix>

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[read-the-docs-community]

Documentation build overview

📚 Meltano SDK | 🛠️ Build #30116999 | 📁 Comparing d01a550 against latest (308671e)

🔍 Preview build

Show files changed (2 files in total): 📝 2 modified | ➕ 0 added | ➖ 0 deleted

File	Status
genindex.html	📝 modified
classes/singer_sdk.Stream.html	📝 modified