Azure Logic Apps Standard designer cannot launch locally, design-time API enters PID restart loop and keeps incrementing localhost port

[Nitin5acc]

Severity

P2 - High (Major functionality broken)

Describe the Bug with repro steps

Summary
In a local Logic Apps Standard workspace on Windows, Open Designer repeatedly fails with Unknown Error and ECONNREFUSED. The design-time API keeps restarting, reports Invalid func child process PID, and increments ports on each retry (8000, 8001, 8004, 8051, 9001). This makes the designer unusable.

Environment

OS: Windows
VS Code: current desktop build
Azure Logic Apps (Standard) extension: 5.230.15
Azure Functions extension: 1.20.3
Azure Functions Core Tools: 4.9.0+29aeab590e6c229a1a6631f6653df70f150f9f0e (64-bit)
Function Runtime Version: 4.1047.100.26071
Workspace: local Logic Apps Standard workspace containing one logic app project with host.json and local.settings.json
Repro Steps

Open Logic Apps Standard workspace.
Ensure local settings include AzureWebJobsStorage and Azurite is running.
Click Open Designer.
Wait for design-time API startup and retry behavior.
Actual Result

Designer fails with Unknown Error.
Output shows repeated ECONNREFUSED to localhost with changing ports.
Output also shows Invalid func child process PID and automatic design-time API restart.
In the same session, one startup sequence logs:
NodeJs Binaries path
DotNetSDK Binaries path
Error: Invalid Version: undefined
then Unknown Error and ECONNREFUSED
Expected Result

Design-time API starts once and remains attached to a stable local port.
Open Designer loads successfully.
No PID mismatch loop, no repeated port hopping, no Invalid Version: undefined.
Relevant Log Snippets

Starting Design Time Api for project: c:\cws\Auth0\localWsAuth0\localWs\Auth0LogStreamLocal
Error: Invalid Version: undefined
Invalid func child process PID set for project ... Restarting workflow design-time API.
Stopping Design Time Api for project ...
Starting Design Time Api for project ...
Error: connect ECONNREFUSED 127.0.0.1:8000
Error: connect ECONNREFUSED 127.0.0.1:8001
Error: connect ECONNREFUSED 127.0.0.1:8004
Error: connect ECONNREFUSED 127.0.0.1:8051
Error: connect ECONNREFUSED 127.0.0.1:9001
What I already tried

Verified AzureWebJobsStorage in both project and workflow-designtime local.settings.
Verified Azurite ports 10000/10001/10002 listening.
Verified manual func host can start on 8000 in some runs.
Reloaded window, reopened workspace, restarted VS Code.
Disabled and reset binaries dependency settings.
Pinned dependency paths for dotnet, node, and func binaries.
Killed stale func processes and retried with clean startup.
Impact
Designer is blocked for local development; workflow can only be edited manually in JSON.

If you want, I can also generate a shorter version optimized for GitHub issue form fields (Description, Repro, Logs, Impact) in one compact block.

GPT-5.3-Codex • 0.9x

What type of Logic App Is this happening in?

Consumption (Portal)

Are you experiencing a regression?

No response

Which operating system are you using?

Windows

Did you refer to the TSG before filing this issue? https://aka.ms/lauxtsg

Yes

Workflow JSON

Screenshots or Videos

No response

Environment

Summary
In a local Logic Apps Standard workspace on Windows, Open Designer repeatedly fails with Unknown Error and ECONNREFUSED. The design-time API keeps restarting, reports Invalid func child process PID, and increments ports on each retry (8000, 8001, 8004, 8051, 9001). This makes the designer unusable.

Environment

OS: Windows
VS Code: current desktop build
Azure Logic Apps (Standard) extension: 5.230.15
Azure Functions extension: 1.20.3
Azure Functions Core Tools: 4.9.0+29aeab590e6c229a1a6631f6653df70f150f9f0e (64-bit)
Function Runtime Version: 4.1047.100.26071
Workspace: local Logic Apps Standard workspace containing one logic app project with host.json and local.settings.json
Repro Steps

Open Logic Apps Standard workspace.
Ensure local settings include AzureWebJobsStorage and Azurite is running.
Click Open Designer.
Wait for design-time API startup and retry behavior.
Actual Result

Designer fails with Unknown Error.
Output shows repeated ECONNREFUSED to localhost with changing ports.
Output also shows Invalid func child process PID and automatic design-time API restart.
In the same session, one startup sequence logs:
NodeJs Binaries path
DotNetSDK Binaries path
Error: Invalid Version: undefined
then Unknown Error and ECONNREFUSED
Expected Result

Design-time API starts once and remains attached to a stable local port.
Open Designer loads successfully.
No PID mismatch loop, no repeated port hopping, no Invalid Version: undefined.
Relevant Log Snippets

Starting Design Time Api for project: c:\cws\Auth0\localWsAuth0\localWs\Auth0LogStreamLocal
Error: Invalid Version: undefined
Invalid func child process PID set for project ... Restarting workflow design-time API.
Stopping Design Time Api for project ...
Starting Design Time Api for project ...
Error: connect ECONNREFUSED 127.0.0.1:8000
Error: connect ECONNREFUSED 127.0.0.1:8001
Error: connect ECONNREFUSED 127.0.0.1:8004
Error: connect ECONNREFUSED 127.0.0.1:8051
Error: connect ECONNREFUSED 127.0.0.1:9001
What I already tried

Verified AzureWebJobsStorage in both project and workflow-designtime local.settings.
Verified Azurite ports 10000/10001/10002 listening.
Verified manual func host can start on 8000 in some runs.
Reloaded window, reopened workspace, restarted VS Code.
Disabled and reset binaries dependency settings.
Pinned dependency paths for dotnet, node, and func binaries.
Killed stale func processes and retried with clean startup.
Impact
Designer is blocked for local development; workflow can only be edited manually in JSON.

If you want, I can also generate a shorter version optimized for GitHub issue form fields (Description, Repro, Logs, Impact) in one compact block.

GPT-5.3-Codex • 0.9x

Additional context

No response

[github-actions]

AI Triage Analysis

Component: VS Code Extension — Design-Time API (apps/vs-code-designer/) | Priority: P2 | SKU: Standard (Local Development / VS Code)

⚠️ Note on SKU field: The issue form shows "Consumption (Portal)" but the entire description, environment, and logs clearly describe a Standard (Local Development) / VS Code scenario. This appears to be an accidental form selection.

Relevant Code

• apps/vs-code-designer/src/app/utils/codeless/startDesignTimeApi.ts:167-180 — validateRunningFuncProcess / checkFuncProcessId: verified source of the "Invalid func child process PID" message and the restart-then-reallocate-port loop
• apps/vs-code-designer/src/app/utils/codeless/startDesignTimeApi.ts:57-62 — portfinder.getPortPromise() called on each new designTimeInstance creation, explaining port hopping (8000→8001→8004→8051→9001)
• apps/vs-code-designer/src/app/utils/codeless/startDesignTimeApi.ts:182-208 — checkFuncProcessId: on Windows, waits 3 × 1s for childFuncPid to be set, then checks getChildProcessesWithScript for a child named func.exe; if func never fully starts, PID is never set → returns false → triggers restart
• apps/vs-code-designer/src/app/utils/binaries.ts:374-376 — checkMajorVersion calls semver.major(version) which throws "Invalid Version: undefined" if version is null/undefined — likely origin of the observed semver error

Probable Root Cause

The sequence appears to be: (1) Binary validation during startup calls semver.major() with an undefined version string (from a failed getLatestFuncCoreToolsVersion or similar lookup), throwing "Error: Invalid Version: undefined". (2) This failure prevents func from launching cleanly, so childFuncPid is never populated. (3) checkFuncProcessId times out after 3 retries with no PID → validateRunningFuncProcess calls stopDesignTimeApi + startDesignTimeApi. (4) Each new call to startDesignTimeApi invokes portfinder.getPortPromise() creating a fresh instance with a new port, causing the observed port hopping. The semver call path with an unguarded null return from version resolution is the likely trigger — cannot confirm the exact caller without more logs.

Suggested Investigation

1. Add a null/undefined guard before all semver.major() calls in binaries.ts (especially checkMajorVersion at line 374-376) to prevent the "Invalid Version: undefined" throw
2. Check whether getLatestFuncCoreToolsVersion or getLatestDotNetVersion returns null when GitHub/npm is unreachable, and ensure the caller handles null gracefully before passing to semver
3. On Windows, trace why func.exe is not appearing as a child process — possible AV/security software blocking func subprocess creation

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Automated analysis by issue triage agent. May contain inaccuracies — verify before acting.
Calibration: reviewed 0 past triages (no prior triage comments found), 0 corrections applied.

Generated by Issue Triage Agent for Azure Logic Apps UX for issue #9042 · ◷