refactor: Migrate Machine InstanceType API handlers to WithTx

[chet]

Description

Continues the WithTx migration, covering both BeginTx sites in machineinstancetype.go (for Create and Delete).

Both handlers trigger a workflow and wait on we.Get, so they're also adopting our little timeoutResp pattern that has evolved over a few of these PRs.

Callouts are:

• Create and Delete both use WithTx + timeoutResp (not good fits for WithTxResult here).
• Moved MatchInstanceTypeCapabilitiesForMachines out of the tx (it was only using the session anyway) as well as scp.GetClientByID.
• Errors switched to NewAPIError.

Signed-off-by: Chet Nichols III chetn@nvidia.com

Type of Change

• Feature - New feature or functionality (feat:)
• Fix - Bug fixes (fix:)
• Chore - Modification or removal of existing functionality (chore:)
• Refactor - Refactoring of existing functionality (refactor:)
• Docs - Changes in documentation or OpenAPI schema (docs:)
• CI - Changes in GitHub workflows. Requires additional scrutiny (ci:)
• Version - Issuing a new release version (version:)

Services Affected

• API - API models or endpoints updated
• Workflow - Workflow service updated
• DB - DB DAOs or migrations updated
• Site Manager - Site Manager updated
• Cert Manager - Cert Manager updated
• Site Agent - Site Agent updated
• Flow - Flow service updated
• Powershelf Manager - Powershelf Manager updated
• NVSwitch Manager - NVSwitch Manager updated

Related Issues (Optional)

Breaking Changes

• This PR contains breaking changes

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• No testing required (docs, internal refactor, etc.)

Additional Notes

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📥 Commits

Reviewing files that changed from the base of the PR and between f813f8d and e72546a.

📒 Files selected for processing (1)

• api/pkg/api/handler/machineinstancetype.go

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Summary by CodeRabbit

• Refactor
  • Improved transaction handling and timeout management in Machine/InstanceType operations for better reliability and error handling.

Walkthrough

This PR refactors the Machine/InstanceType association handlers to use cdb.WithTx() for transaction management. Manual sql.Tx management is replaced with a closure-based pattern, Temporal client resolution is moved outside transactions, and timeout handling is deferred to post-transaction callbacks. Error handling is centralized through common.HandleTxError().

Changes

Machine Instance Type Handler Transaction Management

Layer / File(s)	Summary
Import removal and validation positioning api/pkg/api/handler/machineinstancetype.go	The database/sql import is removed to eliminate manual transaction option management. Capability-matching validation is positioned as a pure pre-transaction read-only check.
Create handler transaction refactoring api/pkg/api/handler/machineinstancetype.go	CreateMachineInstanceTypeHandler.Handle resolves the Temporal client before the transaction, moves association creation and workflow execution into cdb.WithTx(), defers timeout handling via timeoutResp callback, and populates response data outside the closure.
Delete handler transaction refactoring api/pkg/api/handler/machineinstancetype.go	DeleteMachineInstanceTypeHandler.Handle keeps Temporal resolution external, moves advisory locking, deletion, validation, and workflow execution into WithTx(), preserves skippable "object not found" error handling, and delegates final error reporting to common.HandleTxError().

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the primary change: migrating Machine InstanceType API handlers from BeginTx to WithTx pattern, reflecting the core refactoring objective.
Description check	✅ Passed	The description comprehensively explains the refactoring scope, implementation details (WithTx + timeoutResp pattern), code movements for optimization, and error handling changes, all directly aligned with the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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_{🕐 Last updated: 2026-05-21 19:39:25 UTC | Commit: e72546a}

[github-actions]

🔍 Container Scan Summary

Service	Total	Critical	High	Medium	Low	Other
nico-flow	66	4	34	18	2	8
nico-nsm	82	2	28	43	9	0
nico-psm	67	4	35	18	2	8
nico-rest-api	100	6	53	30	3	8
nico-rest-cert-manager	65	4	34	18	1	8
nico-rest-db	66	4	34	18	2	8
nico-rest-site-agent	65	4	34	18	1	8
nico-rest-site-manager	65	4	34	18	1	8
nico-rest-workflow	67	4	35	18	2	8
TOTAL	643	36	321	199	23	64

Per-CVE detail lives in the per-service grype-* artifacts (JSON + SARIF). Severity counts only — no CVE IDs published here.