Module: DWH::Factory

Includes:
Logger
Included in:
DWH
Defined in:
lib/dwh/factory.rb

Overview

Manages adapters. This should be the means by which adapters are created, loaded, and pooled.

Instance Method Summary collapse

Methods included from Logger

#logger, logger

Instance Method Details

#adapter?(adapter_name) ⇒ Boolean

Check if the given adapter is registered

Parameters:

  • adapter_name (String, Symbol)

Returns:

  • (Boolean) 


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# File 'lib/dwh/factory.rb', line 35

def adapter?(adapter_name)
  adapters.key?(adapter_name.to_sym)
end

#adapters ⇒ Object

Get the list of registed adapters



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# File 'lib/dwh/factory.rb', line 40

def adapters
  @adapters ||= {}
end

#create(adapter_name, config) ⇒ Object

The canonical way of creating an adapter instance in DWH.

Examples:

connect to MySQL

DWH.create(:mysql, { host: '127.0.0.1', databse: 'mydb', username: 'me', password: 'mypwd', client_name: 'Strata CLI'})

connect Trino

DWH.create(:trino, {host: 'localhost', catalog: 'native', username: 'Ajo'})

connect to Druid

DWH.create(:druid, {host: 'localhost',port: 8080, protocol: 'http'})

Parameters:

  • adapter_name (String, Symbol)
  • config (Hash) —

    options hash for the target database



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# File 'lib/dwh/factory.rb', line 65

def create(adapter_name, config)
  get_adapter(adapter_name).new(config)
end

#get_adapter(adapter_name) ⇒ Object

Get the adapter.

Parameters:

  • adapter_name (String, Symbol) 


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# File 'lib/dwh/factory.rb', line 27

def get_adapter(adapter_name)
  raise "Adapter '#{adapter_name}' not found. Did you forget to register it: DWH.register(MyAdapterClass)" unless adapter?(adapter_name)

  adapters[adapter_name.to_sym]
end

#pool(name, adapter_name, config, timeout: 5, size: 10) ⇒ Object

Create a pool of connections for a given name and adapter. Returns existing pool if it was already created.

Parameters:

  • name (String, Symbol) —

    custom name for your pool (stored as String)

  • adapter_name (String, Symbol)
  • config (Hash) —

    connection options

  • timeout (Integer) (defaults to: 5) —

    pool checkout time out

  • size (Integer) (defaults to: 10) —

    size of the pool



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# File 'lib/dwh/factory.rb', line 77

def pool(name, adapter_name, config, timeout: 5, size: 10)
  name = name.to_s
  pool_mutex.synchronize do
    if pools.key?(name)
      pools[name]
    else
      pools[name] = ConnectionPool.new(size: size, timeout: timeout) do
        create(adapter_name, config)
      end
    end
  end
end

#pool_mutex ⇒ Object

Mutex guarding pool creation / map mutation.



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# File 'lib/dwh/factory.rb', line 50

def pool_mutex
  @pool_mutex ||= Mutex.new
end

#pools ⇒ Object

Current active pools



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# File 'lib/dwh/factory.rb', line 45

def pools
  @pools ||= {}
end

#reaper_tick(frequency = 300) ⇒ Object

One reaper cycle: log pool stats (without checking out) and reap idle connections. Safe to call from tests; rescues per-pool so a shut-down pool cannot kill the loop.

Parameters:

  • frequency (Integer) (defaults to: 300) —

    idle threshold passed to ConnectionPool#reap



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# File 'lib/dwh/factory.rb', line 133

def reaper_tick(frequency = 300)
  # Snapshot so concurrent shutdown deletions do not mutate while we iterate.
  pools.to_a.each do |name, pool|
    logger.info "DB POOL FOR #{name} STATS:"
    logger.info "\tSize:      #{pool.size}"
    logger.info "\tIdle:      #{pool.idle}"
    logger.info "\tAvailable: #{pool.available}"
    pool.reap(frequency) { it.close }
  rescue ConnectionPool::PoolShuttingDownError => e
    logger.info "Skipping reaper for pool #{name}: #{e.class}"
  rescue StandardError => e
    logger.error "Reaper error for pool #{name}: #{e.class}: #{e.message}"
  end
end

#register(adapter_name, adapter_class) ⇒ Object

Register your new adapter.

Parameters:

  • adapter_name (String, Symbol) —

    your adapter name. Could be different from the class name.

  • adapter_class (Class) —

    actual class of the adapter.

Raises:



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# File 'lib/dwh/factory.rb', line 13

def register(adapter_name, adapter_class)
  raise ConfigError, 'adapter_class should be a class' unless adapter_class.is_a?(Class)

  adapter_class.load_settings
  adapters[adapter_name.to_sym] = adapter_class
end

#shutdown(pool = nil) ⇒ Object

Shutdown a specific pool or all pools

Parameters:

  • pool (String, Symbol, ConnectionPool, nil) (defaults to: nil) —

    pool or name of pool or nil to shut everything down



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# File 'lib/dwh/factory.rb', line 93

def shutdown(pool = nil)
  # Mutate the map under the same mutex as pool creation so a concurrent
  # create cannot be orphaned by @pools = {} / delete racing it.
  # Close outside the lock — ConnectionPool#shutdown can wait on check-in.
  to_close = pool_mutex.synchronize do
    case pool
    when String, Symbol
      # Delete first so a raising close cannot leave a dead pool in the map.
      removed = pools.delete(pool.to_s)
      removed ? [removed] : []
    when ConnectionPool
      key = pools.key(pool)
      pools.delete(key) if key
      [pool]
    else
      closing = pools.values
      @pools = {}
      closing
    end
  end
  to_close.each { |p| p.shutdown { it.close } }
end

#start_reaper(frequency = 300) ⇒ Thread

Start reaper that will periodically clean up unused or idle connections.

Parameters:

  • frequency (Integer) (defaults to: 300) —

    defaults to 300 seconds

Returns:

  • (Thread) —

    the reaper thread



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# File 'lib/dwh/factory.rb', line 120

def start_reaper(frequency = 300)
  logger.info 'Starting DB Adapter reaper process'
  Thread.new do
    loop do
      reaper_tick(frequency)
      sleep frequency
    end
  end
end

#unregister(adapter_name) ⇒ Object

Remove the given adapter from the registry.



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# File 'lib/dwh/factory.rb', line 21

def unregister(adapter_name)
  adapters.delete adapter_name.to_sym
end