Remove code which generates a deprecation warning

use monotonic time for retry timeout check

.github/workflows/CI.yml

@@ -0,0 +1,38 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - '2.5'
+          - '2.6'
+          - '2.7'
+          - '3.0'
+          - ruby-head
+    continue-on-error: ${{ matrix.ruby == 'ruby-head' }}
+    services:
+      memcached:
+        image: memcached
+        ports:
+          - 11211:11211
+      redis:
+        image: redis
+        ports:
+          - 6379:6379
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+      - run: |
+          bundle exec rake

.travis.yml

@@ -1,7 +0,0 @@
-language: ruby
-rvm:
-  - 2.2.0
-  - 2.3.1
-services:
-  - memcached
-  - redis-server

CHANGELOG.md

@@ -1,3 +1,19 @@
+## 0.4.0
+
+- Monotonic clock for locks, avoiding issues with DST (thanks @doits)
+- Pooled connection support (thanks @mlarraz)
+- Switch to Github actions for tests (thanks @mlarraz)
+- Update supported Ruby versions (thanks @mlarraz & @pat)
+
+## 0.3.4
+
+- Support for connection pooling when using memcached locks, via `with` blocks using Dalli (thanks to Lev).
+
+## 0.3.3
+
+- Default TTL for keys to allow for short-lived locking keys (thanks to Ian Remillard) without leaking memory.
+- Vastly improve initial lock acquisition, especially on Redis (thanks to Jeremy Wadscak).
+
 ## 0.3.2
 
 - Custom lock tokens (thanks to avokhmin).

README.md

@@ -1,4 +1,4 @@
-# Suo [![Build Status](https://travis-ci.org/nickelser/suo.svg?branch=master)](https://travis-ci.org/nickelser/suo) [![Code Climate](https://codeclimate.com/github/nickelser/suo/badges/gpa.svg)](https://codeclimate.com/github/nickelser/suo) [![Test Coverage](https://codeclimate.com/github/nickelser/suo/badges/coverage.svg)](https://codeclimate.com/github/nickelser/suo) [![Gem Version](https://badge.fury.io/rb/suo.svg)](http://badge.fury.io/rb/suo)
+# Suo [![Build Status](https://github.com/nickelser/suo/workflows/CI/badge.svg)](https://github.com/nickelser/suo/actions?query=workflow%3ACI) [![Code Climate](https://codeclimate.com/github/nickelser/suo/badges/gpa.svg)](https://codeclimate.com/github/nickelser/suo) [![Gem Version](https://badge.fury.io/rb/suo.svg)](http://badge.fury.io/rb/suo)
 
 :lock: Distributed semaphores using Memcached or Redis in Ruby.
 
@@ -72,6 +72,15 @@ suo.lock do |token|
 end
 ```
 
+### Time To Live
+
+```ruby
+Suo::Client::Redis.new("bar_resource", ttl: 60) #ttl in seconds
+```
+
+A key representing a set of lockable resources is removed once the last resource lock is released and the `ttl` time runs out. When another lock is acquired and the key has been removed the key has to be recreated.
+
+
 ## TODO
  - more race condition tests
 

lib/suo.rb

@@ -2,7 +2,6 @@ require "securerandom"
 require "monitor"
 
 require "dalli"
-require "dalli/cas/client"
 
 require "redis"
 

lib/suo/client/base.rb

@@ -5,7 +5,8 @@ module Suo
         acquisition_timeout: 0.1,
         acquisition_delay: 0.01,
         stale_lock_expiration: 3600,
-        resources: 1
+        resources: 1,
+        ttl: 60,
       }.freeze
 
       BLANK_STR = "".freeze
@@ -55,16 +56,13 @@ module Suo
         retry_with_timeout do
           val, cas = get
 
-          if val.nil?
+          cas = initial_set if val.nil?
-            initial_set
-            next
-          end
 
           cleared_locks = deserialize_and_clear_locks(val)
 
           refresh_lock(cleared_locks, token)
 
-          break if set(serialize_locks(cleared_locks), cas)
+          break if set(serialize_locks(cleared_locks), cas, expire: cleared_locks.empty?)
         end
       end
 
@@ -81,7 +79,7 @@ module Suo
           acquisition_lock = remove_lock(cleared_locks, token)
 
           break unless acquisition_lock
-          break if set(serialize_locks(cleared_locks), cas)
+          break if set(serialize_locks(cleared_locks), cas, expire: cleared_locks.empty?)
         end
       rescue LockClientError => _ # rubocop:disable Lint/HandleExceptions
         # ignore - assume success due to optimistic locking
@@ -101,10 +99,7 @@ module Suo
         retry_with_timeout do
           val, cas = get
 
-          if val.nil?
+          cas = initial_set if val.nil?
-            initial_set
-            next
-          end
 
           cleared_locks = deserialize_and_clear_locks(val)
 
@@ -137,10 +132,10 @@ module Suo
       end
 
       def retry_with_timeout
-        start = Time.now.to_f
+        start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
 
         retry_count.times do
-          elapsed = Time.now.to_f - start
+          elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - start
           break if elapsed >= options[:acquisition_timeout]
 
           synchronize do

lib/suo/client/memcached.rb

@@ -7,21 +7,29 @@ module Suo
       end
 
       def clear
-        @client.delete(@key)
+        @client.with { |client| client.delete(@key) }
       end
 
       private
 
       def get
-        @client.get_cas(@key)
+        @client.with { |client| client.get_cas(@key) }
       end
 
-      def set(newval, cas)
+      def set(newval, cas, expire: false)
-        @client.set_cas(@key, newval, cas)
+        if expire
+          @client.with { |client| client.set_cas(@key, newval, cas, @options[:ttl]) }
+        else
+          @client.with { |client| client.set_cas(@key, newval, cas) }
+        end
       end
 
       def initial_set(val = BLANK_STR)
-        @client.set(@key, val)
+        @client.with do |client|
+          client.set(@key, val)
+          _val, cas = client.get_cas(@key)
+          cas
+        end
       end
     end
   end

lib/suo/client/redis.rb

@@ -9,33 +9,46 @@ module Suo
       end
 
       def clear
-        @client.del(@key)
+        with { |r| r.del(@key) }
       end
 
       private
 
-      def get
+      def with(&block)
-        [@client.get(@key), nil]
+        if @client.respond_to?(:with)
+          @client.with(&block)
+        else
+          yield @client
+        end
       end
 
-      def set(newval, _)
+      def get
-        ret = @client.multi do |multi|
+        [with { |r| r.get(@key) }, nil]
-          multi.set(@key, newval)
+      end
+
+      def set(newval, _, expire: false)
+        ret = with do |r|
+          r.multi do |rr|
+            if expire
+              rr.setex(@key, @options[:ttl], newval)
+            else
+              rr.set(@key, newval)
+            end
+          end
         end
 
         ret && ret[0] == OK_STR
       end
 
       def synchronize
-        @client.watch(@key) do
+        with { |r| r.watch(@key) { yield } }
-          yield
-        end
       ensure
-        @client.unwatch
+        with { |r| r.unwatch }
       end
 
       def initial_set(val = BLANK_STR)
-        @client.set(@key, val)
+        set(val, nil)
+        nil
       end
     end
   end

lib/suo/version.rb

@@ -1,3 +1,3 @@
 module Suo
-  VERSION = "0.3.2".freeze
+  VERSION = "0.4.0".freeze
 end

suo.gemspec

@@ -16,19 +16,18 @@ Gem::Specification.new do |spec|
 
   spec.files         = `git ls-files -z`.split("\x0")
   spec.bindir        = "bin"
-  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
-  spec.required_ruby_version = "~> 2.0"
+  spec.required_ruby_version = ">= 2.5"
 
   spec.add_dependency "dalli"
   spec.add_dependency "redis"
   spec.add_dependency "msgpack"
 
-  spec.add_development_dependency "bundler", "~> 1.5"
+  spec.add_development_dependency "bundler"
-  spec.add_development_dependency "rake", "~> 10.0"
+  spec.add_development_dependency "rake", "~> 13.0"
-  spec.add_development_dependency "rubocop", "~> 0.30.0"
+  spec.add_development_dependency "rubocop", "~> 0.49.0"
   spec.add_development_dependency "minitest", "~> 5.5.0"
   spec.add_development_dependency "codeclimate-test-reporter", "~> 0.4.7"
 end