Class: Blazer::DataSource

Inherits:
Object
  • Object
show all
Defined in:
lib/blazer/data_source.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(id, settings) ⇒ DataSource

Returns a new instance of DataSource.



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# File 'lib/blazer/data_source.rb', line 7

def initialize(id, settings)
  @id = id
  @settings = settings
  @connection_model =
    Class.new(Blazer::Connection) do
      def self.name
        "Blazer::Connection::#{object_id}"
      end
      establish_connection(settings["url"]) if settings["url"]
    end
end

Instance Attribute Details

#connection_model ⇒ Object (readonly)

Returns the value of attribute connection_model.



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# File 'lib/blazer/data_source.rb', line 5

def connection_model
  @connection_model
end

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/blazer/data_source.rb', line 5

def id
  @id
end

#settings ⇒ Object (readonly)

Returns the value of attribute settings.



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# File 'lib/blazer/data_source.rb', line 5

def settings
  @settings
end

Instance Method Details

#cache ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 39

def cache
  settings["cache"]
end

#cache_key(statement) ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 98

def cache_key(statement)
  ["blazer", "v2", id, Digest::MD5.hexdigest(statement)].join("/")
end

#clear_cache(statement) ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 94

def clear_cache(statement)
  Blazer.cache.delete(cache_key(statement))
end

#linked_columns ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 23

def linked_columns
  settings["linked_columns"] || {}
end

#name ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 19

def name
  settings["name"] || @id
end

#postgresql? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/blazer/data_source.rb', line 112

def postgresql?
  connection_model.connection.adapter_name == "PostgreSQL"
end

#redshift? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/blazer/data_source.rb', line 116

def redshift?
  connection_model.connection.adapter_name == "Redshift"
end

#run_statement(statement, options = {}) ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 47

def run_statement(statement, options = {})
  rows = nil
  error = nil
  cached_at = nil
  cache_key = self.cache_key(statement) if cache
  if cache && !options[:refresh_cache]
    value = Blazer.cache.read(cache_key)
    rows, cached_at = Marshal.load(value) if value
  end

  unless rows
    rows = []

    comment = "blazer"
    if options[:user].respond_to?(:id)
      comment << ",user_id:#{options[:user].id}"
    end
    if options[:user].respond_to?(Blazer.user_name)
      # only include letters, numbers, and spaces to prevent injection
      comment << ",user_name:#{options[:user].send(Blazer.user_name).to_s.gsub(/[^a-zA-Z0-9 ]/, "")}"
    end
    if options[:query].respond_to?(:id)
      comment << ",query_id:#{options[:query].id}"
    end

    in_transaction do
      begin
        connection_model.connection.execute("SET statement_timeout = #{timeout.to_i * 1000}") if timeout && (postgresql? || redshift?)
        result = connection_model.connection.select_all("#{statement} /*#{comment}*/")
        result.each do |untyped_row|
          row = {}
          untyped_row.each do |k, v|
            row[k] = result.column_types.empty? ? v : result.column_types[k].send(:type_cast, v)
          end
          rows << row
        end
      rescue ActiveRecord::StatementInvalid => e
        error = e.message.sub(/.+ERROR: /, "")
      end
    end

    Blazer.cache.write(cache_key, Marshal.dump([rows, Time.now]), expires_in: cache.to_f * 60) if !error && cache
  end

  [rows, error, cached_at]
end

#schemas ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 102

def schemas
  default_schema = (postgresql? || redshift?) ? "public" : connection_model.connection_config[:database]
  settings["schemas"] || [connection_model.connection_config[:schema] || default_schema]
end

#smart_columns ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 27

def smart_columns
  settings["smart_columns"] || {}
end

#smart_variables ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 31

def smart_variables
  settings["smart_variables"] || {}
end

#tables ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 107

def tables
  rows, error, cached_at = run_statement(connection_model.send(:sanitize_sql_array, ["SELECT table_name, column_name, ordinal_position, data_type FROM information_schema.columns WHERE table_schema IN (?)", schemas]))
  Hash[rows.group_by { |r| r["table_name"] }.map { |t, f| [t, f.sort_by { |f| f["ordinal_position"] }.map { |f| f.slice("column_name", "data_type") }] }.sort_by { |t, _f| t }]
end

#timeout ⇒ Object 



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# File 'lib/blazer/data_source.rb', line 35

def timeout
  settings["timeout"]
end

#use_transaction? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/blazer/data_source.rb', line 43

def use_transaction?
  settings.key?("use_transaction") ? settings["use_transaction"] : true
end