Module: QC

Defined in:
lib/queue_classic.rb,
lib/queue_classic/conn.rb,
lib/queue_classic/queue.rb,
lib/queue_classic/setup.rb,
lib/queue_classic/worker.rb,
lib/queue_classic/queries.rb

Defined Under Namespace

Modules: Conn, Queries, Setup Classes: Queue, Worker

Constant Summary collapse

Root = 
File.expand_path("..", File.dirname(__FILE__))
SqlFunctions = 
File.join(QC::Root, "/sql/ddl.sql")
DropSqlFunctions = 
File.join(QC::Root, "/sql/drop_ddl.sql")
CreateTable = 
File.join(QC::Root, "/sql/create_table.sql")
APP_NAME =

You can use the APP_NAME to query for postgres related process information in the pg_stat_activity table.

ENV["QC_APP_NAME"] || "queue_classic"
TABLE_NAME =

Why do you want to change the table name? Just deal with the default OK? If you do want to change this, you will need to update the PL/pgSQL lock_head() function. Come on. Don’t do it.… Just stick with the default.

"queue_classic_jobs"
QUEUE =

Each row in the table will have a column that notes the queue. You can point your workers at different queues but only one at a time.

ENV["QUEUE"] || "default"
TOP_BOUND =

Set this to 1 for strict FIFO. There is nothing special about 9.…

(ENV["QC_TOP_BOUND"] || 9).to_i
LISTENING_WORKER =

If you are using PostgreSQL > 9 then you will have access to listen/notify with payload. Set this value if you wish to make your worker more efficient.

!ENV["QC_LISTENING_WORKER"].nil?
FORK_WORKER =

Set this variable if you wish for the worker to fork a UNIX process for each locked job. Remember to re-establish any database connections. See the worker for more details.

!ENV["QC_FORK_WORKER"].nil?
MAX_LOCK_ATTEMPTS =

The worker uses an exponential back-off algorithm to lock a job. This value will be used as the max exponent.

(ENV["QC_MAX_LOCK_ATTEMPTS"] || 5).to_i

Class Method Summary collapse

Class Method Details

.default_queue ⇒ Object 



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# File 'lib/queue_classic.rb', line 70

def self.default_queue
  @default_queue ||= begin
    Queue.new(QUEUE)
  end
end

.default_queue=(queue) ⇒ Object 



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# File 'lib/queue_classic.rb', line 66

def self.default_queue=(queue)
  @default_queue = queue
end

.log(data) ⇒ Object 



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# File 'lib/queue_classic.rb', line 89

def self.log(data)
  result = nil
  data = {:lib => "queue-classic"}.merge(data)
  if block_given?
    start = Time.now
    result = yield
    data.merge(:elapsed => Integer((Time.now - t0)*1000))
  end
  data.reduce(out=String.new) do |s, tup|
    s << [tup.first, tup.last].join("=") << " "
  end
  puts(out) if ENV["DEBUG"]
  return result
end

.log_yield(data) ⇒ Object 



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# File 'lib/queue_classic.rb', line 76

def self.log_yield(data)
  begin
    t0 = Time.now
    yield
  rescue => e
    log({:at => "error", :error => e.inspect}.merge(data))
    raise
  ensure
    t = Integer((Time.now - t0)*1000)
    log(data.merge(:elapsed => t)) unless e
  end
end

.method_missing(sym, *args, &block) ⇒ Object

Defer method calls on the QC module to the default queue. This facilitates QC.enqueue()



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# File 'lib/queue_classic.rb', line 57

def self.method_missing(sym, *args, &block)
  default_queue.send(sym, *args, &block)
end

.respond_to_missing?(method_name, include_private = false) ⇒ Boolean

Ensure QC.respond_to?(:enqueue) equals true (ruby 1.9 only)

Returns:

  • (Boolean) 


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# File 'lib/queue_classic.rb', line 62

def self.respond_to_missing?(method_name, include_private = false)
  default_queue.respond_to?(method_name)
end