Feature to attempt consul get call to backup url if failure

During a choregraphie, consul could be down for various reasons.
In case of KV retrieval, introduce the option to retrieve data
from a backup url.
Option introduced is named consul_backup_url.

libraries/consul.rb

@@ -18,5 +18,23 @@ def self.setup_consul(options)
         options[:token] = options[:consul_token]
       end
     end
+
+    def self.update_backup_url(options)
+      require 'diplomat'
+      require 'diplomat/version'
+      return unless options[:consul_backup_url]
+
+      Diplomat.configure do |config|
+        config.url = @options[:consul_backup_url]
+      end
+    end
+
+    def self.reset_url
+      require 'diplomat'
+      require 'diplomat/version'
+      Diplomat.configure do |config|
+        config.url = 'http://localhost:8500'
+      end
+    end
   end
 end

libraries/primitive_consul_lock.rb

@@ -117,7 +117,9 @@ def self.get_or_create(path, concurrency:, **kwargs)
       dc = kwargs[:dc]
       token = kwargs[:token]
       require 'diplomat'
-      retry_left = 5
+      retry_total_attempts = 5
+      connection_failed_count = 0
+      retry_left = retry_total_attempts
       value = Mash.new({ version: 1, concurrency: concurrency, holders: {} })
       current_lock = begin
         Chef::Log.info "Fetch lock state for #{path}"
@@ -126,12 +128,15 @@ def self.get_or_create(path, concurrency:, **kwargs)
         retry_secs = 30
         Chef::Log.info "Consul did not respond, wait #{retry_secs} seconds and retry to let it (re)start: #{e}"
         sleep retry_secs
+        connection_failed_count += 1
+        ConsulCommon.update_backup_url(@options) if connection_failed_count == retry_total_attempts / 2
         (retry_left -= 1).positive? ? retry : raise
       rescue Diplomat::KeyNotFound
         Chef::Log.info "Lock for #{path} did not exist, creating with value #{value}"
         Diplomat::Kv.put(path, value.to_json, cas: 0, dc: dc, token: token) # we ignore success/failure of CaS
         (retry_left -= 1).positive? ? retry : raise
       end.first
+      ConsulCommon.reset_url
       desired_lock = bootstrap_lock(value, current_lock)
       new(path, new_lock: desired_lock, dc: dc, token: token)
     end