[ES] logging for indexer

CHANGELOG-EE

 Please view this file on the master branch, on stable branches it's out of date.
+v 8.11.3
+  - [ES] Add logging to indexer
 
 v 8.11.0 (unreleased)
   - Allow projects to be moved between repository storages

bin/elastic_repo_indexer

@@ -6,6 +6,10 @@ require 'json'
 require 'elasticsearch/git'
 require 'active_support'
 require 'active_support/core_ext'
+require 'benchmark'
+
+path_to_log_file = File.expand_path('../../log/es-indexer.log', __FILE__)
+LOGGER = Logger.new(path_to_log_file)
 
 PROJECT_ID = ARGV.shift
 REPO_PATH = ARGV.shift
@@ -13,6 +17,8 @@ FROM_SHA = ENV['FROM_SHA']
 TO_SHA = ENV['TO_SHA']
 RAILS_ENV = ENV['RAILS_ENV']
 
+LOGGER.info("[ES indexer]: Has been scheduled for project #{REPO_PATH} with SHA range #{FROM_SHA}:#{TO_SHA}")
+
 elastic_connection_info = JSON.parse ENV['ELASTIC_CONNECTION_INFO']
 ELASTIC_HOST = elastic_connection_info['host']
 ELASTIC_PORT = elastic_connection_info['port']
@@ -45,9 +51,21 @@ repo = Repository.new
 params = { from_rev: FROM_SHA, to_rev: TO_SHA }.compact
 
 print "Indexing commits..."
-repo.index_commits(params)
+
+timings = Benchmark.measure do
+  repo.index_commits(params)
+end
+
 puts "Done"
 
+LOGGER.info("[ES indexer]: Commits for #{REPO_PATH} are indexed. Time elapsed: #{timings.real}")
+
 print "Indexing blobs..."
-repo.index_blobs(params)
+
+timings = Benchmark.measure do
+  repo.index_blobs(params)
+end
+
 puts "Done"
+
+LOGGER.info("[ES indexer]: Blobs for #{REPO_PATH} are indexed. Time elapsed: #{timings.real}")