Class: Elasticsearch::IndexStager

Inherits:
Object
  • Object
show all
Defined in:
lib/elasticsearch/index_stager.rb

Constant Summary collapse

VERSION = 
'1.0.0'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts) ⇒ IndexStager

Returns a new instance of IndexStager.



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# File 'lib/elasticsearch/index_stager.rb', line 7

def initialize(opts)
  @index_name = opts[:index_name] or fail ":index_name required"
  @es_client = opts[:es_client] or fail ":es_client required"
end

Instance Attribute Details

#es_client ⇒ Object (readonly)

Returns the value of attribute es_client.



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# File 'lib/elasticsearch/index_stager.rb', line 5

def es_client
  @es_client
end

#index_name ⇒ Object (readonly)

Returns the value of attribute index_name.



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# File 'lib/elasticsearch/index_stager.rb', line 5

def index_name
  @index_name
end

Instance Method Details

#alias_stage_to_tmp_index ⇒ Object 



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# File 'lib/elasticsearch/index_stager.rb', line 21

def alias_stage_to_tmp_index
  es_client.indices.delete index: stage_index_name rescue false
  es_client.indices.update_aliases body: {
    actions: [
      { add: { index: tmp_index_name, alias: stage_index_name } } 
    ]   
  }   
end

#promote(live_index_name = index_name) ⇒ Object 



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# File 'lib/elasticsearch/index_stager.rb', line 30

def promote(live_index_name=index_name)
  @live_index_name = live_index_name || index_name

  # the renaming actions (performed atomically by ES)
  rename_actions = [ 
    { remove: { index: stage_aliased_to, alias: stage_index_name } },
    {    add: { index: stage_index_name, alias: @live_index_name } } 
  ]   

  # zap any existing index known as index_name,
  # but do it conditionally since it is reasonable that it does not exist.
  to_delete = []
  existing_live_index = es_client.indices.get_aliases(index: @live_index_name)
  existing_live_index.each do |k,v|

    # if the index is merely aliased, remove its alias as part of the aliasing transaction.
    if k != @live_index_name
      rename_actions.unshift({ remove: { index: k, alias: @live_index_name } })

      # mark it for deletion when we've successfully updated aliases
      to_delete.push k

    else
      # this is a real, unaliased index with this name, so it must be deleted.
      # (This usually happens the first time we implement the aliasing scheme against
      # an existing installation.)
      es_client.indices.delete index: @live_index_name rescue false
    end
  end

  # re-alias
  es_client.indices.update_aliases body: { actions: rename_actions }

  # clean up
  to_delete.each do |idxname|
    es_client.indices.delete index: idxname rescue false
  end
end

#stage_index_name ⇒ Object 



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# File 'lib/elasticsearch/index_stager.rb', line 12

def stage_index_name
  index_name + "_staged"
end

#tmp_index_name ⇒ Object 



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# File 'lib/elasticsearch/index_stager.rb', line 16

def tmp_index_name
  @_suffix ||= Time.now.strftime('%Y%m%d%H%M%S') + '-' + SecureRandom.hex[0..7]
  "#{index_name}_#{@_suffix}"
end