Class: Pgtk::Pool

Inherits:
Object
  • Object
show all
Defined in:
lib/pgtk/pool.rb

Overview

Pool.

Author

Yegor Bugayenko ([email protected])

Copyright

Copyright © 2019 Yegor Bugayenko

License

MIT

Instance Method Summary collapse

Constructor Details

#initialize(host: 'localhost', port:, dbname:, user:, password:) ⇒ Pool

Constructor.



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# File 'lib/pgtk/pool.rb', line 32

def initialize(host: 'localhost', port:, dbname:, user:, password:)
  @host = host
  @port = port
  @port = port
  @dbname = dbname
  @user = user
  @password = password
  @pool = Queue.new
end

Instance Method Details

#connect ⇒ Object

Get a connection from the pool and let us work with it. The block has to be provided, for example:

pgsql.connect do |c|
  c.transaction do |conn|
    conn.exec_params('DELETE FROM user WHERE id = $1', [id])
    conn.exec_params('INSERT INTO user (name) VALUES ($1)', [name])
  end
end



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# File 'lib/pgtk/pool.rb', line 77

def connect
  conn = @pool.pop
  begin
    yield conn
  ensure
    @pool << conn
  end
end

#exec(query, args = [], result = 0) ⇒ Object

Make a query and return the result as an array of hashes.



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# File 'lib/pgtk/pool.rb', line 54

def exec(query, args = [], result = 0)
  connect do |c|
    c.exec_params(query, args, result) do |res|
      if block_given?
        yield res
      else
        rows = []
        res.each { |r| rows << r }
        rows
      end
    end
  end
end

#start(max = 1) ⇒ Object

Start it with a fixed number of connections.



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# File 'lib/pgtk/pool.rb', line 43

def start(max = 1)
  max.times do
    @pool << PG.connect(
      dbname: @dbname, host: @host, port: @port,
      user: @user, password: @password
    )
  end
  self
end