Class: Piggly::Installer

Inherits:
Object show all
Defined in:
lib/piggly/installer.rb

Instance Method Summary collapse

Constructor Details

#initialize(config, connection) ⇒ Installer

Returns a new instance of Installer.



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# File 'lib/piggly/installer.rb', line 4

def initialize(config, connection)
  @config, @connection = config, connection
end

Instance Method Details

#install(procedures, profile) ⇒ void

This method returns an undefined value.



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# File 'lib/piggly/installer.rb', line 9

def install(procedures, profile)
  @connection.exec("begin")

  install_support(profile)

  procedures.each do |p|
    begin
      trace(p, profile)
    rescue Parser::Failure
      $stdout.puts $!
    end
  end

  @connection.exec("commit")
rescue
  @connection.exec("rollback")
  raise
end

#install_support(profile) ⇒ Object

Installs necessary instrumentation support



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# File 'lib/piggly/installer.rb', line 65

def install_support(profile)
  @connection.set_notice_processor(&profile.notice_processor(@config))

# def connection.set_notice_processor
#   # do nothing: prevent the notice processor from being subverted
# end

  # install tracing functions
  @connection.exec <<-SQL
    -- Signals that a conditional expression was executed
    CREATE OR REPLACE FUNCTION piggly_cond(message varchar, value boolean)
      RETURNS boolean AS $$
    BEGIN
      IF value THEN
        RAISE WARNING '#{@config.trace_prefix} % t', message;
      ELSE
        RAISE WARNING '#{@config.trace_prefix} % f', message;
      END IF;
      RETURN value;
    END $$ LANGUAGE 'plpgsql' VOLATILE;
  SQL

  @connection.exec <<-SQL
    -- Generic signal
    CREATE OR REPLACE FUNCTION piggly_signal(message varchar, signal varchar)
      RETURNS void AS $$
    BEGIN
      RAISE WARNING '#{@config.trace_prefix} % %', message, signal;
    END $$ LANGUAGE 'plpgsql' VOLATILE;
  SQL

  @connection.exec <<-SQL
    -- Signals that a (sub)expression was executed. handles '' and NULL value
    CREATE OR REPLACE FUNCTION piggly_expr(message varchar, value varchar)
      RETURNS varchar AS $$
    BEGIN
      RAISE WARNING '#{@config.trace_prefix} %', message;
      RETURN value;
    END $$ LANGUAGE 'plpgsql' VOLATILE;
  SQL

  @connection.exec <<-SQL
    -- Signals that a (sub)expression was executed. handles all other types
    CREATE OR REPLACE FUNCTION piggly_expr(message varchar, value anyelement)
      RETURNS anyelement AS $$
    BEGIN
      RAISE WARNING '#{@config.trace_prefix} %', message;
      RETURN value;
    END $$ LANGUAGE 'plpgsql' VOLATILE;
  SQL

  @connection.exec <<-SQL
    -- Signals that a branch was taken
    CREATE OR REPLACE FUNCTION piggly_branch(message varchar)
      RETURNS void AS $$
    BEGIN
      RAISE WARNING '#{@config.trace_prefix} %', message;
    END $$ LANGUAGE 'plpgsql' VOLATILE;
  SQL
end

#trace(procedure, profile) ⇒ void

This method returns an undefined value.



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# File 'lib/piggly/installer.rb', line 42

def trace(procedure, profile)
  # recompile with instrumentation
  compiler = Compiler::TraceCompiler.new(@config)
  result   = compiler.compile(procedure)
    # result[:tree] - tagged and rewritten parse tree
    # result[:tags] - collection of Tag values in the tree
    # result[:code] - instrumented

  @connection.exec(procedure.definition(result[:code]))
  
  profile.add(procedure, result[:tags], result)
rescue
  $!.message << "\nError installing traced procedure #{procedure.name} "
  $!.message << "from #{procedure.source_path(@config)}"
  raise
end

#uninstall(procedures) ⇒ void

This method returns an undefined value.



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# File 'lib/piggly/installer.rb', line 29

def uninstall(procedures)
  @connection.exec("begin")

  procedures.each{|p| untrace(p) }
  uninstall_support

  @connection.exec("commit")
rescue
  @connection.exec("rollback")
  raise
end

#uninstall_support ⇒ Object

Uninstalls instrumentation support



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# File 'lib/piggly/installer.rb', line 127

def uninstall_support
  @connection.set_notice_processor{|x| $stderr.puts x }
  @connection.exec "DROP FUNCTION IF EXISTS piggly_cond(varchar, boolean)"
  @connection.exec "DROP FUNCTION IF EXISTS piggly_expr(varchar, varchar)"
  @connection.exec "DROP FUNCTION IF EXISTS piggly_expr(varchar, anyelement)"
  @connection.exec "DROP FUNCTION IF EXISTS piggly_branch(varchar)"
  @connection.exec "DROP FUNCTION IF EXISTS piggly_signal(varchar, varchar)"
end

#untrace(procedure) ⇒ void

This method returns an undefined value.



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# File 'lib/piggly/installer.rb', line 60

def untrace(procedure)
  @connection.exec(procedure.definition(procedure.source(@config)))
end