Class: Hedgerow

Inherits:
Object
  • Object
show all
Defined in:
lib/hedgerow.rb,
lib/hedgerow/version.rb

Defined Under Namespace

Classes: LockFailure

Constant Summary collapse

VERSION = 
"0.1.4"

Class Method Summary collapse

Class Method Details

.connection ⇒ Object 



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# File 'lib/hedgerow.rb', line 40

def connection
  @@connection ||= begin
    if defined?(ActiveRecord)
      ActiveRecord::Base.connection.raw_connection
    else
      raise "Could not find connection for hedgerow."
    end
  end
end

.connection=(connection) ⇒ Object 



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# File 'lib/hedgerow.rb', line 36

def connection=(connection)
  @@connection = connection
end

.lock(name, timeout) ⇒ Object 



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# File 'lib/hedgerow.rb', line 15

def lock(name, timeout)
  validate_name!(name)
  parse_response connection.prepare("SELECT GET_LOCK(?, ?)").execute(name, timeout)
end

.parse_response(r) ⇒ Object 



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# File 'lib/hedgerow.rb', line 31

def parse_response(r)
  val = r.to_a.flatten.first rescue 0
  val == 1 ? true : false
end

.release(name) ⇒ Object 



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# File 'lib/hedgerow.rb', line 20

def release(name)
  validate_name!(name)
  parse_response connection.prepare("SELECT RELEASE_LOCK(?)").execute(name)
end

.validate_name!(name) ⇒ Object 



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# File 'lib/hedgerow.rb', line 25

def validate_name!(name)
  if name.length > 64
    raise LockFailure.new("MySQL enforces a maximum length on lock names of 64 characters.")
  end
end

.with(name, opts = {}) ⇒ Object 



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# File 'lib/hedgerow.rb', line 5

def with(name, opts = {})
  if status = lock(name, opts[:timeout] || 10)
    yield
  else
    raise LockFailure.new("Could not acquire lock.")
  end
ensure
  release(name) if status
end