Class: Heroku::ReadOnly

Inherits:
Object
  • Object
show all
Defined in:
lib/heroku/readonly.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ ReadOnly

Returns a new instance of ReadOnly.

Raises:

  • (ArgumentError) 


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# File 'lib/heroku/readonly.rb', line 5

def initialize(options={})
  raise ArgumentError unless options.is_a?(Hash)

  @enabled = false
  @have_polled = false
  @url = options[:url]
  @time_between_retries = options[:time_between_retries] || 2
  @write_cache = options[:write_cache]
  @read_cache = options[:read_cache]
end

Class Method Details

.disable(put_url) ⇒ Object 



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# File 'lib/heroku/readonly.rb', line 72

def self.disable(put_url)
  update(put_url, "ok")
end

.enable(put_url) ⇒ Object 



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# File 'lib/heroku/readonly.rb', line 68

def self.enable(put_url)
  update(put_url, "readonly")
end

.update(put_url, body) ⇒ Object 



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# File 'lib/heroku/readonly.rb', line 63

def self.update(put_url, body)
  out = `curl -s -m 3 -X PUT -H "Content-Type:" -d "#{body}" "#{put_url}"`
  raise(out) unless ($? == 0)
end

Instance Method Details

#check ⇒ Object 



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# File 'lib/heroku/readonly.rb', line 16

def check
  Timeout.timeout(1) do
    RestClient.get(@url) != 'ok'
  end
rescue StandardError, Timeout::Error => e
  true
end

#enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/heroku/readonly.rb', line 53

def enabled?
  if @read_cache
    read_from_cache
  elsif !@have_polled
    raise('never polled, no read_cache')
  else
    @enabled
  end
end

#poll(attempt = 1) ⇒ Object 



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# File 'lib/heroku/readonly.rb', line 24

def poll(attempt=1)
  result = check
  if (result == @enabled) || (attempt >= 3)
    @have_polled = true
    @enabled = result
    write_to_cache
    result
  elsif attempt < 3
    sleep(@time_between_retries)
    poll(attempt+1)
  end
end

#read_from_cache ⇒ Object 



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# File 'lib/heroku/readonly.rb', line 43

def read_from_cache
  if !File.exists?(@read_cache)
    true
  elsif File.mtime(@read_cache) < Time.now - 60*5
    true
  else
    File.read(@read_cache).strip != 'ok'
  end
end

#write_to_cache ⇒ Object 



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# File 'lib/heroku/readonly.rb', line 37

def write_to_cache
  if @write_cache
    File.open(@write_cache, 'w') { |f| f.write(@enabled ? 'readonly' : 'ok') }
  end
end