Class: Etcd::Client

Inherits:
Object
  • Object
show all
Includes:
Helpers, Lockable
Defined in:
lib/etcd/client.rb

Overview

This is the central ruby class for Etcd. It provides methods for all Etcd api calls. It also provides few additional methods beyond the core Etcd api, like Etcd::Client#lock and Etcd::Client#eternal_watch, they are defined in separate modules and included in this class

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Lockable

#lock

Methods included from Helpers

#eternal_watch, #has_key?

Constructor Details

#initialize(opts = {}) ⇒ Client

Creates a new instance of Etcd::Client. It accepts a hash opts as argument

Parameters:

  • opts (Hash) (defaults to: {}) —

    The options for new Etcd::Client object



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# File 'lib/etcd/client.rb', line 29

def initialize(opts={})
  @host = opts[:host] || '127.0.0.1'
  @port = opts[:port] || 4001
  @read_timeout = opts[:read_timeout] || 60
  if opts.has_key?(:allow_redirect)
    @allow_redirect = opts[:allow_redirect]
  else
    @allow_redirect = true
  end
end

Instance Attribute Details

#allow_redirect ⇒ Object (readonly)

Returns the value of attribute allow_redirect.



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# File 'lib/etcd/client.rb', line 20

def allow_redirect
  @allow_redirect
end

#host ⇒ Object (readonly)

Returns the value of attribute host.



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# File 'lib/etcd/client.rb', line 20

def host
  @host
end

#http ⇒ Object (readonly)

Returns the value of attribute http.



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# File 'lib/etcd/client.rb', line 20

def http
  @http
end

#port ⇒ Object (readonly)

Returns the value of attribute port.



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# File 'lib/etcd/client.rb', line 20

def port
  @port
end

Instance Method Details

#api_execute(path, method, params = nil) ⇒ Object

This method sends api request to etcd server.

This method has following parameters as argument

  • path - etcd server path (etcd server end point)

  • method - the request method used

  • params - any additional parameters used by request method (optional)



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# File 'lib/etcd/client.rb', line 132

def api_execute(path, method, params=nil)

  http = if path=~/^http/
            uri = URI.parse(path)
            path =  uri.path
            Net::HTTP.new(uri.host, uri.port)
          else
            Net::HTTP.new(host, port)
          end
  http.read_timeout = @read_timeout

  case  method
  when :get
    unless params.nil?
      encoded_params = URI.encode_www_form(params)
      path+= "?" + encoded_params
    end
    req = Net::HTTP::Get.new(path)
  when :post
    encoded_params = URI.encode_www_form(params)
    req = Net::HTTP::Post.new(path)
    req.body= encoded_params
    Log.debug("Setting body for post '#{encoded_params}'")
  when :delete
    unless params.nil?
      encoded_params = URI.encode_www_form(params)
      path+= "?" + encoded_params
    end
    req = Net::HTTP::Delete.new(path)
  end

  Log.debug("Invoking: '#{req.class}' against '#{path}")
  res = http.request(req)
  Log.debug("Response code: #{res.code}")
  if res.is_a?(Net::HTTPSuccess)
    Log.debug("Http success")
    res.body
  elsif redirect?(res.code.to_i) and allow_redirect
    Log.debug("Http redirect, following")
    api_execute(res['location'], method, params)
  else
    Log.debug("Http error")
    Log.debug(res.body)
    res.error!
  end
end

#delete(key) ⇒ Object

Deletes a key along with all associated data

This method has following parameters as argument

  • key - key to be deleted



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# File 'lib/etcd/client.rb', line 98

def delete(key)
  response = api_execute(key_endpoint + key, :delete)
  json2obj(response)
end

#get(key) ⇒ Object

Retrives a key with its associated data, if key is not present it will return with message “Key Not Found”

This method has following parameters as argument

  • key - whose data to be retrive



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# File 'lib/etcd/client.rb', line 107

def get(key)
  response = api_execute(key_endpoint + key, :get)
  json2obj(response)
end

#key_endpoint ⇒ Object

Lists all the data (keys, dir etc) present in etcd store



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# File 'lib/etcd/client.rb', line 56

def key_endpoint
  version_prefix + '/keys'
end

#leader ⇒ Object

Get the current leader in a cluster



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# File 'lib/etcd/client.rb', line 51

def leader
  api_execute( version_prefix + '/leader', :get)
end

#machines ⇒ Object

Lists all machines in the cluster



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# File 'lib/etcd/client.rb', line 46

def machines
  api_execute( version_prefix + '/machines', :get).split(",").map(&:strip)
end

#set(key, value, ttl = nil) ⇒ Object

Adds a new key with specified value and ttl, overwrites old values if exists

This method has following parameters as argument

  • key - whose value to be set

  • value - value to be set for specified key

  • ttl - shelf life of a key (in secsonds) (optional)



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# File 'lib/etcd/client.rb', line 86

def set(key, value, ttl=nil)
  path  = key_endpoint + key
  payload = {'value' => value}
  payload['ttl'] = ttl unless ttl.nil?
  response = api_execute(path, :post, payload)
  json2obj(response)
end

#test_and_set(key, value, prevValue, ttl = nil) ⇒ Object

Set a new value for key if previous value of key is matched

This method takes following parameters as argument

  • key - whose value is going to change if previous value is matched

  • value - new value to be set for specified key

  • prevValue - value of a key to compare with existing value of key

  • ttl - shelf life of a key (in secsonds) (optional)



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# File 'lib/etcd/client.rb', line 72

def test_and_set(key, value, prevValue, ttl = nil)
  path  = key_endpoint + key
  payload = {'value' => value, 'prevValue' => prevValue }
  payload['ttl'] = ttl unless ttl.nil?
  response = api_execute(path, :post, payload)
  json2obj(response)
end

#version_prefix ⇒ Object

Currently use ‘v1’ as version for etcd store



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# File 'lib/etcd/client.rb', line 41

def version_prefix
  '/v1'
end

#watch(key, index = nil) ⇒ Object

Gives a notification when specified key changes

This method has following parameters as argument

  • key - key to be watched

  • index - etcd server index of specified key (optional)



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# File 'lib/etcd/client.rb', line 117

def watch(key, index=nil)
  response = if index.nil?
                api_execute(watch_endpoint + key, :get)
              else
                api_execute(watch_endpoint + key, :post, {'index' => index})
              end
  json2obj(response)
end

#watch_endpoint ⇒ Object

Watches all keys and notifies if anyone changes



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# File 'lib/etcd/client.rb', line 61

def watch_endpoint
  version_prefix + '/watch'
end