Class: EY::Snaplock
- Inherits:
-
Object
- Object
- EY::Snaplock
- Defined in:
- lib/ey_snaplock.rb,
lib/ey_snaplock/timer.rb,
lib/ey_snaplock/version.rb,
lib/ey_snaplock/database.rb,
lib/ey_snaplock/database/mysql.rb,
lib/ey_snaplock/database/postgresql9.rb
Defined Under Namespace
Constant Summary collapse
- REQUEST_TIMEOUT =
15
- PER_DATABASE_TIMEOUT =
5
- LONG_RUNNING_QUERY_RETRIES =
3
- VERSION =
'0.1.1'
Class Method Summary collapse
Instance Method Summary collapse
- #call ⇒ Object
- #clean_up_old_log_files(logs_to_keep = 10) ⇒ Object
- #database_lock(database_uri, timeout, &block) ⇒ Object
-
#initialize(callback_uri = nil, *database_uris) ⇒ Snaplock
constructor
A new instance of Snaplock.
- #request(uri) ⇒ Object
- #sync_filesystem(&block) ⇒ Object
- #timeout ⇒ Object
Constructor Details
#initialize(callback_uri = nil, *database_uris) ⇒ Snaplock
Returns a new instance of Snaplock.
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# File 'lib/ey_snaplock.rb', line 17 def initialize(callback_uri = nil, *database_uris) if callback_uri.nil? $stderr.puts "Usage: ey-snaplock CALLBACK_URI [DATABASE_URI] [DATABASE_URI] ..." abort "Error: CALLBACK_URI is required." end callback = request(callback_uri) callback = timeout(&callback) callback = sync_filesystem(&callback) database_uris.each do |database_uri| # it'd be nice to parallelize these database locks when we have more than one callback = database_lock(database_uri, PER_DATABASE_TIMEOUT, &callback) end @callback = callback end |
Class Method Details
.call(*argv) ⇒ Object
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# File 'lib/ey_snaplock.rb', line 12 def self.call(*argv) new(*argv).call exit 0 end |
Instance Method Details
#call ⇒ Object
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# File 'lib/ey_snaplock.rb', line 33 def call success, code, body = @callback.call if success exit else abort "Error: Received unsuccessful response #{code} from callback:\n#{body}" end end |
#clean_up_old_log_files(logs_to_keep = 10) ⇒ Object
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# File 'lib/ey_snaplock.rb', line 113 def clean_up_old_log_files(logs_to_keep = 10) ordinal = logs_to_keep.succ.to_s system("ls -r /var/log/ey-snaplock.*.log | tail -n +#{ordinal} | xargs -I@ rm @") end |
#database_lock(database_uri, timeout, &block) ⇒ Object
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# File 'lib/ey_snaplock.rb', line 71 def database_lock(database_uri, timeout, &block) database = Database.for(database_uri) with_locked_db = block if database.respond_to?(:has_long_running_queries?) log_file = '/var/log/ey-snaplock.' + Time.now.strftime("%Y-%m-%dT%H-%M-%S") + '.log' remaining_retries = LONG_RUNNING_QUERY_RETRIES while database.has_long_running_queries?(PER_DATABASE_TIMEOUT) && remaining_retries >= 0 if remaining_retries == 0 database.dump_process_list(log_file) clean_up_old_log_files $stderr.puts "Aborting Snaplock due to long running queries. Process list dumped to #{log_file}." exit 1 else remaining_retries -= 1 sleep PER_DATABASE_TIMEOUT end end end lambda do lock_filename = database.lock_filename file = File.open(lock_filename, File::RDWR|File::EXCL|File::CREAT) rescue nil if !file && File.mtime(lock_filename) < (Time.now - (20 * 60 * 60)) $stdout.puts "Cleared stale database lock: #{lock_filename}" file = File.open(lock_filename, File::RDWR|File::EXCL) elsif !file $stderr.puts "Failed to acquire database lock: #{lock_filename}" exit 1 end file.write(Process.pid.to_s) file.close begin database.with_lock(timeout, &with_locked_db) ensure File.delete(lock_filename) if File.exists?(lock_filename) end end end |
#request(uri) ⇒ Object
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# File 'lib/ey_snaplock.rb', line 42 def request(uri) uri = URI.parse(uri) http = Net::HTTP.new(uri.host, uri.port) http.use_ssl = true if uri.scheme == "https" lambda do response = http.request_post(post_path_for_uri(uri), "", "Content-Type" => "application/x-www-form-urlencoded") [(200...300).include?(response.code.to_i), response.code.to_i, response.body] end end |
#sync_filesystem(&block) ⇒ Object
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# File 'lib/ey_snaplock.rb', line 64 def sync_filesystem(&block) lambda do `sync && sync && sync` yield end end |
#timeout ⇒ Object
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# File 'lib/ey_snaplock.rb', line 53 def timeout lambda do begin EY::Snaplock::Timer.timeout(REQUEST_TIMEOUT) { yield } rescue Timeout::Error $stderr.puts "Timeout Exceeded: Callback request took longer than #{REQUEST_TIMEOUT} seconds." raise end end end |