Merged PR 749185: Add npmrc for internal buildxl package feed

- Adds two new npmrc files:
  - .internal-npmrc can be used with cloudbuild or vsts-npm-auth to generate a token locally
  - .ci-npmrc is  used for ADO builds using an environment variable to store the token
- vsts-npm-auth does not support non-Windows platforms, so we need to manually do what it does on bxl.sh
- TODO: once merged, enable npm authentication on CloudBuild for bxl PR and rolling queues.

Related work items: #2115724

.ci-npmrc

@@ -0,0 +1,10 @@
+; this npmrc is only meant to be used on ADO builds
+; before starting the build, we must set CLOUDBUILD_BUILDXL_SELFHOST_FEED_PAT_B64 to be a base64 encoded vso_packaging PAT for the BuildXL.Selfhost feed
+; begin auth token
+//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry/:username=cloudbuild
+//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry/:_password=${CLOUDBUILD_BUILDXL_SELFHOST_FEED_PAT_B64}
+//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry/:email=npm requires email to be set but doesn't use the value
+//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/:username=cloudbuild
+//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/:_password=${CLOUDBUILD_BUILDXL_SELFHOST_FEED_PAT_B64}
+//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/:email=npm requires email to be set but doesn't use the value
+; end auth token

.internal-npmrc

@@ -0,0 +1,4 @@
+; default npmrc for microsoft internal builds on local machines and CloudBuild
+; for CI builds on ADO use .ci-npmrc
+registry=https://cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry/
+always-auth=true

RunBxlWithPAT.ps1

@@ -53,6 +53,11 @@ Param(
 [Environment]::SetEnvironmentVariable("VSTSPERSONALACCESSTOKEN", $VstsPat, "Process")
 [Environment]::SetEnvironmentVariable("ARTIFACT_CREDENTIALPROVIDERS_PATH", $VstsCredProviderPath, "Process")
 
+# NPM authentication requires the PAT to be base64 encoded first
+$cbPatBytes = [System.Text.Encoding]::UTF8.GetBytes($CbPat)
+$b64CloudbuildPat = [Convert]::ToBase64String($cbPatBytes)
+[Environment]::SetEnvironmentVariable("CLOUDBUILD_BUILDXL_SELFHOST_FEED_PAT_B64", $b64CloudbuildPat, "Process")
+
 if ($NcPath)
 {
     [Environment]::SetEnvironmentVariable("NUGET_CREDENTIALPROVIDERS_PATH", $NcPath, "Process")

bxl.sh

@@ -238,6 +238,45 @@ function launchCredProvider() {
     $credProviderPath -U https://pkgs.dev.azure.com/cloudbuild/_packaging/BuildXL.Selfhost/nuget/v3/index.json -V Information -C -R
 }
 
+function setAuthenticationTokenInNpmrc() {
+    # This function is responsible for setting the PAT generated for our internal selfhost feed to be used by npm
+    # first parse the local npmrc to see if there already exists a valid PAT
+    if ! [ -f "$HOME/.npmrc" ]; then
+        # npmrc doesn't exist, lets create one one now
+        touch "$HOME/.npmrc"
+    else
+        # delete any existing lines in the npmrc that might contain a stale token
+        # existing token may be valid, but we don't need to check that here because the credential provider has already generated/cached one
+        # we can just replace the existing one and save the trouble of having to verify whether it is valid by making a web request
+        mv "$HOME/.npmrc" "$HOME/.npmrc.bak"
+        touch "$HOME/.npmrc"
+
+        while read line; do
+            if [[ "$line" == *"//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry"* ]]; then
+                continue
+            fi
+
+            echo "$line" >> "$HOME/.npmrc"
+        done < "$HOME/.npmrc.bak"
+
+        rm "$HOME/.npmrc.bak"
+    fi
+
+    # get a cached token from credential provider (it should already be cached from when we called it earlier for nuget)
+    # we use the nuget uri here, but all this does is return a token with vso_packaging which is what we need for npm
+    credProviderOutput=$($credProviderPath -U https://pkgs.dev.azure.com/cloudbuild/_packaging/BuildXL.Selfhost/nuget/v3/index.json -C -F Json)
+
+    # output is in the format '{"Username":"VssSessionToken","Password":"token"}'
+    token=$(echo $credProviderOutput | sed -E -e 's/.*\{"Username":"[a-zA-Z0-9]*","Password":"([a-zA-Z0-9]*)"\}.*/\1/')
+    b64token=$(echo -ne "$token" | base64)
+
+    # write new token to file
+    echo "" >> "$HOME/.npmrc"
+    echo "//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry/:username=VssSessionToken" >> "$HOME/.npmrc"
+    echo "//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry/:_password=$b64token" >> "$HOME/.npmrc"
+    echo "//cloudbuild.pkgs.visualstudio.com/_packaging/BuildXL.Selfhost/npm/registry/:email=not-used@example.com" >> "$HOME/.npmrc"
+}
+
 # allow this script to be sourced, in which case we shouldn't execute anything
 if [[ "$0" != "${BASH_SOURCE[0]}" ]]; then 
     return 0
@@ -274,10 +313,13 @@ fi
 # to prompt for credentials as a way to guarantee the auth token will be cached for the subsequent build.
 # This may prompt an interactive pop-up/console. ADO pipelines already configure the corresponding env vars 
 # so there is no need to do this on that case. Once the token is cached, launching the provider shouldn't need
-# any user interaction
+# any user interaction.
+# For npm authentication, we write the PAT to the npmrc file under $HOME/.npmrc.
+# On ADO builds, the CLOUDBUILD_BUILDXL_SELFHOST_FEED_PAT_B64 variable is set instead.
 # TF_BUILD is an environment variable that is always present on ADO builds. So we use it to detect that case.
 if [[ -n "$arg_Internal" &&  ! -n "$TF_BUILD" ]];then
     launchCredProvider
+    setAuthenticationTokenInNpmrc
 fi
 
 # Make sure we pass the credential provider as an env var to bxl invocation
@@ -301,6 +343,7 @@ if [[ -n "$arg_Internal" && -n "$ADOBuild" && (! -n $VSS_NUGET_EXTERNAL_FEED_END
     fi
 
     export VSS_NUGET_EXTERNAL_FEED_ENDPOINTS="{\"endpointCredentials\":[{\"endpoint\":\"https://pkgs.dev.azure.com/1essharedassets/_packaging/BuildXL/nuget/v3/index.json\",\"password\":\"$PAT1esSharedAssets\"},{\"endpoint\":\"https://pkgs.dev.azure.com/cloudbuild/_packaging/BuildXL.Selfhost/nuget/v3/index.json\",\"password\":\"$PATCloudBuild\"}]}" 
+    export CLOUDBUILD_BUILDXL_SELFHOST_FEED_PAT_B64=$(echo -ne "$PATCloudBuild" | base64)
 fi
 
 # For local builds we want to use the in-build Linux runtime (as opposed to the runtime.linux-x64.BuildXL package)