Fixing bugs for sticky slot app settings by ShilpiRach · Pull Request #13693 · dotnet/aspire

ShilpiRach · 2025-12-23T04:57:28Z

Description

Current behavior

When an Aspire project is deployed, all the app service and slots are deployed with app settings that are not sticky to the deployment slots. When slot swap is done, the app settings also get swapped as expected.

This results in incorrect behavior for these cases:

Otel service name - The telemetry from production starts showing up for the slot it is swapped with.
App Service dependencies - The production slot of a service should continue to refer to the production slot of dependent services after the swap (similarly, all stage / dev slot app services should reference other stage / dev slot services, which get created together).

Description of the fix

We are making the slots for otel service name and app service dependencies as specific to deployment slots. These will not get swapped on slot swap operation.
Updated the Azure.Provizioning.AppService version to 1.3.1 which adds support for SlotConfigNames.
Fixes another issue with the creation of host names by correctly truncating web app and slot names in case they are longer than the allowed length. Host name creation logic.
- Without slot, the maximum length can be 60 characters. No change
- With slot, the web app name is truncated to 40 characters. It is then concatenated to "-{slot name}". The concatenated string is then truncated to 59 characters.

Fixes #13660

Checklist

Is this feature complete?
- Yes. Ready to ship.
- No. Follow-up changes expected.
Are you including unit tests for the changes and scenario tests if relevant?
- Yes
- No
Did you add public API?
- Yes
  - If yes, did you have an API Review for it?
    - Yes
    - No
  - Did you add <remarks /> and <code /> elements on your triple slash comments?
    - Yes
    - No
- No
Does the change make any security assumptions or guarantees?
- Yes
  - If yes, have you done a threat model and had a security review?
    - Yes
    - No
- No
Does the change require an update in our Aspire docs?
- Yes
  - Link to aspire-docs issue (consider using one of the following templates):
- No

github-actions · 2025-12-23T04:57:38Z

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 13693

Or

Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 13693"

src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebsiteContext.cs

…cky app settings for deployment slots.

Copilot

Pull request overview

This PR fixes a critical bug where Azure App Service deployment slot settings were not correctly configured as "sticky" (slot-specific), causing telemetry and app service dependencies to get mixed up after slot swaps. The fix ensures that OTEL_SERVICE_NAME and service dependency app settings remain specific to each deployment slot and do not swap during slot operations.

Key Changes

Updated Azure.Provisioning.AppService package from version 1.3.0 to 1.3.1 to support SlotConfigNames configuration
Added SlotConfigNames resource creation to mark specific app settings as sticky to deployment slots
Automatically marks OTEL_SERVICE_NAME and all app service endpoint reference settings as slot-sticky
Fixed hostname generation logic to properly truncate web app and slot names (max 40 chars for prefix when using slots, 59 chars total with slot suffix)
Refactored dashboard and Application Insights configuration methods to accept app settings lists directly instead of web site objects, reducing code duplication
Fixed typo: renamed computerEnv to computeEnv throughout the codebase

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 4 comments.

File	Description
`Directory.Packages.props`	Updates Azure.Provisioning.AppService package version from 1.3.0 to 1.3.1
`src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebsiteContext.cs`	Core implementation: adds SlotConfigNames resource, marks OTEL_SERVICE_NAME and endpoint references as sticky, refactors configuration methods
`src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebSiteResource.cs`	Fixes typo (computerEnv→computeEnv), improves hostname truncation logic with proper constants
`tests/Aspire.Hosting.Azure.Tests/Snapshots/*.verified.bicep` (17 files)	Updates test snapshots to include new slotConfigNames resource with appropriate sticky app settings

src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebsiteContext.cs

src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebSiteResource.cs

eerhardt

I just had some minor comments/feedback. This looks good.

src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebSiteResource.cs

src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebsiteContext.cs

eerhardt

LGTM. Nice work!

eerhardt · 2026-01-08T20:10:12Z

/backport to release/13.1

github-actions · 2026-01-08T20:10:21Z

Started backporting to release/13.1: https://github.com/dotnet/aspire/actions/runs/20830264615

Fixing bugs for sticky slot app settings

fb3105a

dotnet-policy-service bot added the community-contribution Indicates that the PR has been added by a community member label Dec 23, 2025

ShilpiR added 3 commits December 22, 2025 21:33

Fix max host prefix length

fb73a33

nit fix

84b46b3

Fixes

29da6e0

eerhardt mentioned this pull request Jan 5, 2026

Make OTEL_SERVICE_NAME sticky to deployment slots in Azure App Service #13665

Closed

11 tasks

eerhardt reviewed Jan 5, 2026

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src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebsiteContext.cs Outdated Show resolved Hide resolved

ShilpiR added 4 commits January 5, 2026 10:34

app service references

35fb098

Merge branch 'main' into deploymentslotfix

51907ca

Updated Azure.Provisioning.AppService to 1.3.1 to add support for sti…

1415659

…cky app settings for deployment slots.

Fxing unit tests

fd55d01

ShilpiRach marked this pull request as ready for review January 6, 2026 17:19

ShilpiRach requested a review from captainsafia as a code owner January 6, 2026 17:19

Copilot AI review requested due to automatic review settings January 6, 2026 17:19

Copilot started reviewing on behalf of ShilpiRach January 6, 2026 17:19 View session

nit fix

0944ec0

Copilot AI reviewed Jan 6, 2026

View reviewed changes

Added doc

64676b5

sarsharma approved these changes Jan 6, 2026

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sarsharma reviewed Jan 6, 2026

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src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebSiteResource.cs Show resolved Hide resolved

ShilpiR added 2 commits January 7, 2026 02:03

Added notes justifying the hostname constants

338319f

Reverting non-essential refactoring

dd8e668

eerhardt approved these changes Jan 8, 2026

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src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebSiteResource.cs Outdated Show resolved Hide resolved

src/Aspire.Hosting.Azure.AppService/AzureAppServiceWebsiteContext.cs Show resolved Hide resolved

ShilpiR added 2 commits January 8, 2026 01:27

minor fixes for PR comments

e93b114

nit fixes

e185ea0

eerhardt approved these changes Jan 8, 2026

View reviewed changes

eerhardt merged commit d85cba7 into dotnet:main Jan 8, 2026
286 checks passed

github-actions bot mentioned this pull request Jan 8, 2026

[release/13.1] [Testing] Fixing bugs for sticky slot app settings #13810

Merged

dotnet-policy-service bot added this to the 13.2 milestone Jan 8, 2026

ShilpiRach changed the title ~~[Testing] Fixing bugs for sticky slot app settings~~ Fixing bugs for sticky slot app settings Jan 9, 2026

github-actions bot locked and limited conversation to collaborators Feb 9, 2026

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Fixing bugs for sticky slot app settings#13693

Fixing bugs for sticky slot app settings#13693
eerhardt merged 14 commits intodotnet:mainfrom
ShilpiRach:deploymentslotfix

ShilpiRach commented Dec 23, 2025 •

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Description

Current behavior

Description of the fix

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Pull request overview

Key Changes

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ShilpiRach commented Dec 23, 2025 •

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