Class: EventSource::Postgres::Get::SelectStatement

Inherits:
Object
  • Object
show all
Includes:
Log::Dependency
Defined in:
lib/event_source/postgres/get/select_statement.rb

Defined Under Namespace

Modules: Defaults

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.build(stream_name, position: nil, batch_size: nil) ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 25

def self.build(stream_name, position: nil, batch_size: nil)
  stream = Stream.new(stream_name)
  new(stream, position, batch_size)
end

Instance Method Details

#batch_size ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 13

def batch_size
  @batch_size ||= Defaults.batch_size
end

#position ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 9

def position
  @position ||= Defaults.position
end

#position_field ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 69

def position_field
  unless stream.category?
    'position'
  else
    'global_position'
  end
end

#sql ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 30

def sql
  logger.trace(tag: :sql) { "Composing select statement (Stream: #{stream_name}, Category: #{stream.category?}, Type: #{stream_type}, Position: #{position}, Batch Size: #{batch_size})" }

  statement = "    SELECT\n      id::varchar,\n      stream_name::varchar,\n      position::int,\n      type::varchar,\n      global_position::bigint,\n      data::varchar,\n      metadata::varchar,\n      time::timestamp\n    FROM\n      events\n    WHERE\n      \#{where_clause_field} = '\#{stream_name}' AND\n      \#{position_field} >= \#{position}\n    ORDER BY\n      \#{position_field} ASC\n    LIMIT\n      \#{batch_size}\n    ;\n  SQL\n\n  logger.debug(tag: :sql) { \"Composed select statement (Stream: \#{stream_name}, Category: \#{stream.category?}, Type: \#{stream_type}, Position: \#{position}, Batch Size: \#{batch_size})\" }\n  logger.debug(tags: [:data, :sql]) { \"Statement: \#{statement}\" }\n\n  statement\nend\n"

#stream_name ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 17

def stream_name
  stream.name
end

#stream_type ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 21

def stream_type
  stream.type
end

#where_clause_field ⇒ Object 



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# File 'lib/event_source/postgres/get/select_statement.rb', line 61

def where_clause_field
  unless stream.category?
    'stream_name'
  else
    'category(stream_name)'
  end
end