auxiliary tenant IDs in the authentication process

[ianjensenisme]

This pull request focuses on adding support for auxiliary tenant IDs in the authentication process and updating related configurations. The most important changes include modifications to authentication methods, configuration structures, and provider setup.

Resolves #566

Authentication Enhancements:

• Modified AuthenticateClientCertificate, AuthenticateClientSecret, AuthenticateUsingCli, AuthenticateOIDC, and AuthenticateAzDOWorkloadIdentityFederation methods to include AdditionallyAllowedTenants from client.config.AuxiliaryTenantIDs. (internal/api/auth.go) [1] [2] [3] [4] [5]

Configuration Updates:

• Added AuxiliaryTenantIDs field to ProviderConfig and ProviderConfigModel structs. (internal/config/config.go) [1] [2]
• Introduced environment variables ENV_VAR_POWER_PLATFORM_AUXILIARY_TENANT_IDS and ENV_VAR_ARM_AUXILIARY_TENANT_IDS. (internal/constants/constants.go) [1] [2]

Provider Configuration:

• Added handling for auxiliary_tenant_ids in the provider schema and configuration setup. (internal/provider/provider.go) [1] [2] [3] [4]

Helper Functions:

• Added GetListStringValues function to handle list values from configuration or environment variables. (internal/helpers/config.go)

Testing:

• Added a unit test TestUnitApiClient_AuxTenants_GetConfig to verify the auxiliary tenant IDs configuration. (internal/api/client_test.go)

PR Overview

This PR adds support for auxiliary tenant IDs to enhance the authentication process and updates the provider configuration accordingly.

• Added a function to extract list string values from configuration and environment variables.
• Updated authentication methods to pass auxiliary tenant IDs to underlying credential providers.
• Enhanced provider schema and configuration to incorporate auxiliary tenant IDs.

Reviewed Changes

File	Description
internal/helpers/config.go	Added GetListStringValues function for extracting list values from config or env vars.
internal/api/client_test.go	Introduced a new unit test to verify auxiliary tenant IDs configuration.
internal/api/auth.go	Updated authentication methods to include auxiliary tenant IDs in credential options.
internal/provider/provider.go	Added "auxiliary_tenant_ids" to the provider schema and adjusted configuration for MSI.
internal/constants/constants.go	Introduced new environment variable constants for auxiliary tenant IDs.
internal/config/config.go	Extended configuration structs with the auxiliary tenant IDs field.
internal/services/environment/resource_environment.go	Removed an extra empty line.

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

internal/helpers/config.go:51

• [nitpick] Avoid shadowing the 'value' parameter by renaming the local variable (e.g., 'envVal') to improve clarity.

if value, ok := os.LookupEnv(k); ok && value != "" {

internal/provider/provider.go:312

• [nitpick] Consider refactoring the conversion of types.List to []string for clarity and efficiency; using a dedicated helper or built-in conversion (if available) might improve maintainability.

// TODO there has to be a better way than starting with the slice and converting it..

[ianjensenisme]

Would love reviewer input on the types.List-to-[]string debacle, as well as whether I can set up any more robust tests with our current test tenant resources.

[mattdot]

You are missing changie record

[ianjensenisme]

@mawasile and @mattdot : I manually tested aux tenant functionality tonight and it seems fine. Let me know if you have any preferences on automated tests. I'm limited in what I can do with the project's single tenant.