Class: HostList

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

Instance Method Summary collapse

Constructor Details

#initialize(yaml: '/etc/hostlist.yaml', cache: '~/.hostlist.db') ⇒ HostList

Returns a new instance of HostList.



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# File 'lib/hostlist.rb', line 8

def initialize(yaml: '/etc/hostlist.yaml', cache: '~/.hostlist.db')
  @yaml = yaml
  @db_filename = cache
end

Instance Method Details

#export_ansible(filename = '/etc/ansible/hosts') ⇒ Object

Export the host list as an ansible hosts file.



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# File 'lib/hostlist.rb', line 97

def export_ansible(filename = '/etc/ansible/hosts')
  db = open_db
  output = []
  begin
    db.keys.each do |key|
      next if key == 'md5'
      output << "[#{key}]"
      db[key].each do |host|
        output << host
      end
    end
    output = output.join("\n")
    if filename and File.writable? filename
      File.open(filename, 'w') { |f| f.write(output) }
    else
      puts output
    end
  ensure
    db.close
  end
end

#generate_db(db) ⇒ Object

Read in yaml file and cache to database



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# File 'lib/hostlist.rb', line 76

def generate_db(db)
  db.clear
  db[:all] = []
  hosts = YAML.load_file(@yaml)
  hosts.each do |key, value|
    value['tags'].each do |tag|
      if db.has_key? tag
        db[tag] += key.expand
      else
        db[tag] = key.expand
      end
    end
    # Add servers to :all
    # TODO: Figure out why this isn't working. db[:all] is always an empty array.
    key.expand.each { |host| db[:all] += [host] unless db[:all].include?(host) }
  end
  db[:md5] = Digest::MD5.file(@yaml).to_s
  db.flush
end

#keys ⇒ Object

Return all the keys in the database.



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# File 'lib/hostlist.rb', line 41

def keys
  db = open_db
  begin
    keys = db.keys
  ensure
    db.close
  end
  return keys
end

#list(tags) ⇒ Object

Return array based on tags. Tags can be a string or array of strings.



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# File 'lib/hostlist.rb', line 14

def list(tags)
  tags = [tags] if tags.is_a? String
  # Verify we have the most recent data in our daybreak cache.
  db = open_db
  begin
    # Collect all the tags from the database
    hosts = []
    if tags.empty?
      hosts = db[:all]
    else
      tags.each do |tag|
        if db.has_key? tag
          if hosts == []
            hosts = db[tag]
          else
            hosts = hosts & db[tag]
          end
        end
      end
    end
  ensure
    db.close
  end
  return hosts
end

#open_db ⇒ Object

Open cache database



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# File 'lib/hostlist.rb', line 64

def open_db
  db = Daybreak::DB.new File.expand_path(@db_filename)
  if db.has_key? :md5
    file_md5 = Digest::MD5.file @yaml
    generate_db(db) unless file_md5 == db[:md5]
  else
    generate_db(db)
  end
  return db
end

#print_db ⇒ Object

Print the contents of the database for debugging purposes



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# File 'lib/hostlist.rb', line 52

def print_db
  db = open_db
  begin
    db.keys.each do |key|
      puts "db[#{key}] = #{db[key]}"
    end
  ensure
    db.close
  end
end