Region.FromRegionId() throws CultureNotFoundException when running in Docker (Alpine, .NET 9)

[RazvanGolan]

Summary

When using Region.FromRegionId() in the OCI .NET SDK, the runtime throws a CultureNotFoundException because the SDK internally calls:

new CultureInfo("en-US", useUserOverride: false)

In Docker (Alpine-based images), .NET defaults to Globalization Invariant Mode, where only the invariant culture is available. As a result, "en-US" cannot be created, and the OCI SDK fails to initialize the region registry, throwing this error:

System.TypeInitializationException: The type initializer for 'Oci.Common.Region' threw an exception.
 ---> System.Globalization.CultureNotFoundException: Only the invariant culture is supported in globalization-invariant mode.
en-US is an invalid culture identifier.
   at System.Globalization.CultureInfo..ctor(String name, Boolean useUserOverride)
   at Oci.Common.Region.Register(...)
   at Oci.Common.Region..cctor()
   --- End of inner exception stack trace ---
   at Oci.Common.Region.FromRegionId(String regionId)

Environment

• OCI .NET SDK: v85.0.0
• .NET Runtime: .NET 9
• OS: Linux (Alpine base image)
• Environment: Docker container
• Globalization mode: Invariant mode

Use Case

Creating an OCI Object Storage client using:

var provider = new SimpleAuthenticationDetailsProvider
{
    TenantId = credentials.Tenancy,
    UserId = credentials.UserId,
    Fingerprint = credentials.Fingerprint,
    Region = Region.FromRegionId(credentials.RegionEndpoint),
    PrivateKeySupplier = new StringBasedPrivateKeySupplier(credentials.PrivateKey)
};

var client = new ObjectStorageClient(provider);

Reproducible Example (Default Single-Project Setup)

Dockerfile

This Dockerfile represents a standard minimal C# project built and run in Docker

FROM mcr.microsoft.com/dotnet/sdk:9.0-alpine AS build

WORKDIR /src
COPY . .
RUN dotnet restore
RUN dotnet publish -c Release -o /app/publish

FROM mcr.microsoft.com/dotnet/aspnet:9.0-alpine

WORKDIR /app
COPY --from=build /app/publish .

ENTRYPOINT ["dotnet", "OciIntegrationTest.dll"]

Program.cs (Minimal Repro)

using Oci.Common;
using Oci.ObjectstorageService;

var region = Region.FromRegionId("eu-frankfurt-1"); // <-- exception here
Console.WriteLine(region.RegionId);

This reproduces the crash on every Alpine-based .NET image unless the user manually installs ICU and disables invariant mode.

Expected Behavior

• Should work in Docker without requiring ICU libraries
• Or fallback to CultureInfo.InvariantCulture when running under invariant mode

Suggested Fix

Consider replacing:

regionId.Trim().ToLower(new CultureInfo("en-US", useUserOverride: false));

with:

regionId.Trim().ToLower(CultureInfo.InvariantCulture);