Class: DynamodbModel::Erb

Inherits:
Object
  • Object
show all
Includes:
Log
Defined in:
lib/dynamodb_model/erb.rb

Overview

Renders Erb and provide better backtrace where there’s an error

Usage:

result = DynamodbModel::Erb.result(path, key1: "val1", key2: "val2")

Class Method Summary collapse

Methods included from Log

included, #log

Class Method Details

.result(path, variables = {}) ⇒ Object 



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# File 'lib/dynamodb_model/erb.rb', line 13

def result(path, variables={})
  set_template_variables(variables)
  template = IO.read(path)
  begin
    ERB.new(template, nil, "-").result(binding)
  rescue Exception => e
    log(e)
    log(e.backtrace) if ENV['DEBUG']

    # how to know where ERB stopped? - https://www.ruby-forum.com/topic/182051
    # syntax errors have the (erb):xxx info in e.message
    # undefined variables have (erb):xxx info in e.backtrac
    error_info = e.message.split("\n").grep(/\(erb\)/)[0]
    error_info ||= e.backtrace.grep(/\(erb\)/)[0]
    raise unless error_info # unable to find the (erb):xxx: error line
    line = error_info.split(':')[1].to_i
    log "Error evaluating ERB template on line #{line.to_s.colorize(:red)} of: #{path.sub(/^\.\//, '').colorize(:green)}"

    template_lines = template.split("\n")
    context = 5 # lines of context
    top, bottom = [line-context-1, 0].max, line+context-1
    spacing = template_lines.size.to_s.size
    template_lines[top..bottom].each_with_index do |line_content, index|
      line_number = top+index+1
      if line_number == line
        printf("%#{spacing}d %s\n".colorize(:red), line_number, line_content)
      else
        printf("%#{spacing}d %s\n", line_number, line_content)
      end
    end
    exit 1 unless ENV['TEST']
  end
end

.set_template_variables(variables) ⇒ Object 



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# File 'lib/dynamodb_model/erb.rb', line 47

def set_template_variables(variables)
  variables.each do |key, value|
    instance_variable_set(:"@#{key}", value)
  end
end