Backport CFS cargo registry config to hotfix/keyvault CI

eng/pipelines/templates/steps/use-rust.yml

@@ -15,8 +15,58 @@ parameters:
   - name: SetDefault
     type: boolean
     default: true
+  - name: ConfigureRegistry
+    type: boolean
+    default: true
 
 steps:
+# `variables/rust.yml` may relocate CARGO_HOME off the OS volume. Cargo finds its own
+# subcommands there, but tools invoked directly (taplo, cargo2junit) need it on PATH.
+- pwsh: |
+    $cargoBin = ([System.IO.Path]::Combine($env:CARGO_HOME, 'bin'))
+    New-Item -ItemType Directory -Force -Path $cargoBin | Out-Null
+
+    if (($env:PATH -split [System.IO.Path]::PathSeparator) -notcontains $cargoBin) {
+      Write-Host "##vso[task.prependpath]$cargoBin"
+    }
+  displayName: Add CARGO_HOME/bin to PATH
+  condition: and(succeeded(), ne(variables['CARGO_HOME'], ''))
+
+- ${{ if parameters.ConfigureRegistry }}:
+  # CI builds run under network isolation with no access to public crates.io. Route
+  # crates.io traffic through the azure-sdk-for-rust Azure Artifacts feed defined in
+  # eng/templates/config.toml.template, then authenticate cargo to it.
+  - pwsh: |
+      $cargoHome = $env:CARGO_HOME
+      if (-not $cargoHome) { $cargoHome = ([System.IO.Path]::Combine($HOME, '.cargo')) }
+      New-Item -ItemType Directory -Force -Path $cargoHome | Out-Null
+
+      $configPath = ([System.IO.Path]::Combine($cargoHome, 'config.toml'))
+      Copy-Item `
+        -Path '$(Build.SourcesDirectory)/eng/templates/config.toml.template' `
+        -Destination $configPath `
+        -Force
+
+      Write-Host "Wrote cargo config to $configPath"
+      Get-Content $configPath
+      Write-Host "##vso[task.setvariable variable=CargoConfigPath]$configPath"
+    displayName: Configure cargo to use the azure-sdk-for-rust feed
+
+  # Workaround issue in public pipelines. Revert when root cause issue is fixed:
+  # https://github.com/microsoft/azure-pipelines-tasks/issues/22421
+  # NuGetAuthenticate@1 uses the SYSTEMVSSCONNECTION endpoint token, which Azure
+  # DevOps does deliver to fork builds, and publishes it as VSS_NUGET_ACCESSTOKEN
+  # for later steps.
+  - task: NuGetAuthenticate@1
+    displayName: Acquire an Azure Artifacts token that fork builds can use
+
+  - task: CargoAuthenticate@0
+    displayName: Authenticate cargo to the azure-sdk-for-rust feed
+    inputs:
+      configFile: $(CargoConfigPath)
+    env:
+      SYSTEM_ACCESSTOKEN: $(VSS_NUGET_ACCESSTOKEN)
+
 - pwsh: |
     $Toolchain = '${{ parameters.Toolchain }}'
     $MaxAttempts = ${{ parameters.MaxAttempts }}  

eng/templates/config.toml.template

@@ -0,0 +1,36 @@
+# Cargo configuration used by CI builds to route crates.io traffic through the
+# Centralized Feed Service (CFS) instead of the public internet.
+#
+# This file should be copied to $CARGO_HOME/config.toml
+#
+# CargoAuthenticate@0 parses the [registries] table below and exports the
+# CARGO_REGISTRIES_AZURE_SDK_FOR_RUST_PUBLIC_TOKEN / _CREDENTIAL_PROVIDER variables that
+# cargo needs to authenticate against the feed.
+#
+# The `~force-auth` suffix on the feed name is required. See
+# https://learn.microsoft.com/azure/devops/artifacts/cargo/cargo-upstream-source.
+
+[registries]
+azure-sdk-for-rust-public = { index = "sparse+https://pkgs.dev.azure.com/azure-sdk/public/_packaging/azure-sdk-for-rust-public~force-auth/Cargo/index/" }
+
+[source.crates-io]
+replace-with = "azure-sdk-for-rust-public"
+
+# Both `cargo package` and `cargo publish` refuse to run while crates-io is replaced
+# unless the target registry is named, failing with:
+#
+#   error: crates-io is replaced with remote registry azure-sdk-for-rust-public;
+#   include `--registry azure-sdk-for-rust-public` or `--registry crates-io`
+#
+# The target registry must be the replacement, not crates-io. When packaging several
+# workspace members at once, cargo satisfies their unpublished inter-member versions
+# (for example typespec_client_core depending on typespec ^1.2.0-beta.1) from the crates
+# it just packaged. That overlay is only consulted when the target registry matches the
+# source deps resolve through, so `--registry crates-io` still fails to find them.
+#
+# Setting the default here keeps eng/scripts/Pack-Crates.ps1 free of CI-only flags, so
+# it behaves identically for local developers. Nothing publishes for real from cargo:
+# the only `cargo publish` in the repo is Pack-Crates.ps1's `--dry-run` validation, and
+# releases ship through ESRP.
+[registry]
+default = "azure-sdk-for-rust-public"