rename instance var with method

Signed-off-by: Sathish <sbabu@progress.com>

libraries/backend/azure_connection.rb

@@ -36,9 +36,6 @@ class AzureConnection
   # @return [String] the graph api endpoint api version, e.g. v1.0
   attr_reader :graph_api_endpoint_api_version
 
-  # @return [Hash] tenant_id, client_id, client_secret, subscription_id
-  attr_reader :credentials
-
   # Creates a HTTP client.
   def initialize(client_args)
     # Validate parameter's type.
@@ -62,13 +59,6 @@ def initialize(client_args)
     @key_vault_dns_suffix = @client_args[:endpoint].key_vault_dns_suffix
     @graph_api_endpoint_api_version = @client_args[:endpoint].graph_api_endpoint_api_version
 
-    @credentials = {
-      tenant_id: ENV['AZURE_TENANT_ID'],
-      client_id: ENV['AZURE_CLIENT_ID'],
-      client_secret: ENV['AZURE_CLIENT_SECRET'],
-      subscription_id: ENV['AZURE_SUBSCRIPTION_ID'],
-    }
-
     @connection ||= Faraday.new do |conn|
       # Implement user provided HTTP client params for handling TimeOut exceptions.
       # https://www.rubydoc.info/gems/faraday/Faraday/Request/Retry
@@ -161,17 +151,17 @@ def rest_api_call(opts)
   #
   def authenticate(resource)
     # Validate the presence of credentials.
-    unless @credentials.values.compact.delete_if(&:empty?).size == 4
+    unless credentials.values.compact.delete_if(&:empty?).size == 4
       raise HTTPClientError::MissingCredentials, 'The following must be set in the Environment:'\
-        " #{@credentials.keys}.\n"\
-        "Missing: #{@credentials.keys.select { |key| @credentials[key].nil? }}"
+        " #{credentials.keys}.\n"\
+        "Missing: #{credentials.keys.select { |key| credentials[key].nil? }}"
     end
     # Build up the url that is required to authenticate with Azure REST API
-    auth_url = "#{@client_args[:endpoint].active_directory_endpoint_url}#{@credentials[:tenant_id]}/oauth2/token"
+    auth_url = "#{@client_args[:endpoint].active_directory_endpoint_url}#{credentials[:tenant_id]}/oauth2/token"
     body = {
       grant_type: 'client_credentials',
-      client_id: @credentials[:client_id],
-      client_secret: @credentials[:client_secret],
+      client_id: credentials[:client_id],
+      client_secret: credentials[:client_secret],
       resource: resource,
     }
     headers = {