19 Commits

Author SHA1 Message Date
Nick Elser
b9d3f1b7a1 Bump version and update changelog. 2019-09-04 14:36:40 -07:00
Nick Elser
270c05b80e Merge pull request #10 from levkk/levkk/support-pooled-clients
Add support for pooled memcached clients by using #with
2019-09-04 14:33:26 -07:00
Lev Kokotov
60e167e146 relax bundler dependency version 2019-08-22 16:16:57 -07:00
Lev Kokotov
ad08c8b5ea bump Bundler to 2 2019-08-22 16:14:01 -07:00
Lev Kokotov
9b8ef6c244 Add support for pooled memcached clients by using #with 2019-08-22 16:04:14 -07:00
Nick Elser
b8a1d7d9ac Merge pull request #8 from nickelser/update_changelog
Update changelog
2018-10-05 14:06:42 -07:00
Nick Elser
c58a247156 Run on more modern rubies, as well. 2018-10-05 16:40:25 -04:00
Nick Elser
8c37c24ee6 Merge branch 'master' into update_changelog 2018-10-05 16:31:49 -04:00
Nick Elser
29da8cf090 Add changelog entry, remove spurious gemspec entry. 2018-10-05 16:31:33 -04:00
Nick Elser
8ed488f071 Merge pull request #5 from keylimetoolbox/double-initial-set
Fix #initial_set which is causing a double attempt and delay on lock acquisition and incorrect drop on short acquisition_timeout
2018-10-05 13:28:16 -07:00
Nick Elser
152b6acf9c Merge pull request #7 from nickelser/update_rubocop
Update Rubocop, and bump the version.
2018-10-05 13:25:44 -07:00
Nick Elser
5e10afe534 Update Rubocop, and bump the version. 2018-10-05 16:14:49 -04:00
Nick Elser
0423eb9e12 Merge pull request #6 from GandalftheGUI/ian_remillard/remove_keys_after_last_lock_released
Add 'Time To Live' to mitigate potential memory leak
2018-10-05 13:06:29 -07:00
Ian Remillard
ca46f5f369 add default for expire on set 2018-10-01 10:48:50 -07:00
Ian Remillard
1022a6f9d3 move to expire only when all locks are released 2018-10-01 10:35:30 -07:00
Ian Remillard
6be3a5bdda edits to docs 2018-09-28 16:43:44 -07:00
Ian Remillard
aa4da5d739 update docs for new options 2018-09-28 13:19:01 -07:00
Ian Remillard
fdb0b7f9d5 adds lock ttl and lock_release_removes_key 2018-09-28 12:43:52 -07:00
Jeremy Wadsack
a13edcf7d1 Fix #initial_set which is causing a double attempt and delay on lock acquisition
The call to `#initial_set` in `#retry` and `#acquire_lock` is followed by `next` which leads to a second pass through the `#retry_with_timeout` loop and a sleep call for up to `:acquisition_delay`. This delay isn't necessary if the value can be set without a race condition.

Removing the `next` call causes the client to continue to retry because the transaction has been changed outside the transaction boundary:

In Redis, calling `SET` within a `WATCH`/`UNWATCH` block but not inside a `MULTI`/`EXEC` block will [cause the EXEC to fail the transaction](https://github.com/antirez/redis-doc/issues/734), so the first `#set` call fails and it requires a second pass. To resolve this I changed `#initial_set` to call `#set` within a `MULTI` block so that it would be inside the transaction.

In Memcache the call to `SET` without the `CAS` during `#initial_set` is going to cause the `SET` with `CAS` to fail (return `EXISTS`), and resulting in a second pass. To resolve this I changed `#initial_set` to use `SET` with `CAS` and return the CAS value to be used in the subsequent `#set` call that stores the lock token.
2018-08-30 13:06:16 -07:00
8 changed files with 52 additions and 25 deletions

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@@ -1,7 +1,9 @@
language: ruby
rvm:
- 2.2.0
- 2.3.1
- 2.2.6
- 2.3.7
- 2.4.4
- 2.5.1
services:
- memcached
- redis-server

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@@ -1,3 +1,12 @@
## 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).

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@@ -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

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@@ -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?
initial_set
next
end
cas = initial_set if val.nil?
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?
initial_set
next
end
cas = initial_set if val.nil?
cleared_locks = deserialize_and_clear_locks(val)

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@@ -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)
@client.set_cas(@key, newval, cas)
def set(newval, cas, expire: false)
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

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@@ -18,10 +18,14 @@ module Suo
[@client.get(@key), nil]
end
def set(newval, _)
def set(newval, _, expire: false)
ret = @client.multi do |multi|
if expire
multi.setex(@key, @options[:ttl], newval)
else
multi.set(@key, newval)
end
end
ret && ret[0] == OK_STR
end
@@ -35,7 +39,8 @@ module Suo
end
def initial_set(val = BLANK_STR)
@client.set(@key, val)
set(val, nil)
nil
end
end
end

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@@ -1,3 +1,3 @@
module Suo
VERSION = "0.3.2".freeze
VERSION = "0.3.4".freeze
end

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@@ -16,7 +16,6 @@ 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"]
@@ -26,9 +25,9 @@ Gem::Specification.new do |spec|
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 "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