Remove path config option from Azure service

The Active Storage service for Azure Storage has an option called `path`
that is ambiguous in meaning. It needs to be set to the primary blob
storage endpoint but that can be determined from the blobs client anyway.

To simplify the configuration this commit removes the `path` option and
gets the endpoint from the blobs client instead.

Closes #32225.

activestorage/lib/active_storage/service/azure_storage_service.rb

@@ -8,14 +8,13 @@ module ActiveStorage
   # Wraps the Microsoft Azure Storage Blob Service as an Active Storage service.
   # See ActiveStorage::Service for the generic API documentation that applies to all services.
   class Service::AzureStorageService < Service
-    attr_reader :client, :path, :blobs, :container, :signer
+    attr_reader :client, :blobs, :container, :signer
 
-    def initialize(path:, storage_account_name:, storage_access_key:, container:)
+    def initialize(storage_account_name:, storage_access_key:, container:)
       @client = Azure::Storage::Client.create(storage_account_name: storage_account_name, storage_access_key: storage_access_key)
       @signer = Azure::Storage::Core::Auth::SharedAccessSignature.new(storage_account_name, storage_access_key)
       @blobs = client.blob_client
       @container = container
-      @path = path
     end
 
     def upload(key, io, checksum: nil)
@@ -87,6 +86,7 @@ module ActiveStorage
         base_url = url_for(key)
         generated_url = signer.signed_uri(
           URI(base_url), false,
+          service: "b",
           permissions: "r",
           expiry: format_expiry(expires_in),
           content_disposition: content_disposition_with(type: disposition, filename: filename),
@@ -102,8 +102,12 @@ module ActiveStorage
     def url_for_direct_upload(key, expires_in:, content_type:, content_length:, checksum:)
       instrument :url, key: key do |payload|
         base_url = url_for(key)
-        generated_url = signer.signed_uri(URI(base_url), false, permissions: "rw",
-          expiry: format_expiry(expires_in)).to_s
+        generated_url = signer.signed_uri(
+          URI(base_url), false,
+          service: "b",
+          permissions: "rw",
+          expiry: format_expiry(expires_in)
+        ).to_s
 
         payload[:url] = generated_url
 
@@ -117,7 +121,7 @@ module ActiveStorage
 
     private
       def url_for(key)
-        "#{path}/#{container}/#{key}"
+        "#{blobs.host}/#{container}/#{key}"
       end
 
       def blob_for(key)

activestorage/test/service/configurations.example.yml

@@ -24,7 +24,6 @@
 #
 # azure:
 #   service: AzureStorage
-#   path: ""
 #   storage_account_name: ""
 #   storage_access_key: ""
 #   container: ""

guides/source/active_storage_overview.md

@@ -121,7 +121,6 @@ Declare an Azure Storage service in `config/storage.yml`:
 ```yaml
 azure:
   service: AzureStorage
-  path: ""
   storage_account_name: ""
   storage_access_key: ""
   container: ""