class Consul::Template::Generator::CTRunner

Attributes

session[RW]

Public Class Methods

new(consul_session_id = nil, do_create_session = true) click to toggle source
# File lib/consul/template/generator/init.rb, line 7
def initialize(consul_session_id = nil, do_create_session = true)
  @config = Consul::Template::Generator.config
  if (consul_session_id.nil? && do_create_session)
    create_session
  else
    @session = consul_session_id
  end
end

Public Instance Methods

acquire_lock(target_key) { || ... } click to toggle source
# File lib/consul/template/generator/key_value.rb, line 8
def acquire_lock(target_key)
  lock_key = @config.lock_key target_key
  @config.logger.debug "Attempting to acquire lock on key: #{lock_key}"
  Consul::Template::Generator.renew_session @session
  unless Diplomat::Lock.acquire(lock_key, @session)
    raise KeyNotLockedError, "Unable to acquire lock on key: #{lock_key}"
  end
  @config.logger.debug "Lock acquired on key: #{lock_key}"

  begin
    yield
  ensure
    Diplomat::Lock.release(lock_key, @session)
  end
end
acquire_session_lock() { || ... } click to toggle source
# File lib/consul/template/generator/key_value.rb, line 24
def acquire_session_lock
  acquire_lock(@config.session_lock_key) do
    yield
  end
end
create_session() click to toggle source
# File lib/consul/template/generator/init.rb, line 16
def create_session
  unless @session.nil?
    destroy_session
  end
  @session = Consul::Template::Generator.create_session @config.session_name, @config.session_ttl
end
destroy_session() click to toggle source
# File lib/consul/template/generator/init.rb, line 23
def destroy_session
  return if @session.nil?
  attempts = 0
  begin
    destroyed = Consul::Template::Generator.destroy_session @session
  rescue
    Consul::Template::Generator.config.logger.info "Failed to destroy session: #{@session}, attempt number #{attempts}"
  ensure
    @session = destroyed ? nil : @session
    unless @session.nil?
      attempts += 1
      sleep 0.25
    end
  end until (@session.nil? || attempts > 4)
end
post_graphite_event(path) click to toggle source
# File lib/consul/template/generator/graphite.rb, line 7
def post_graphite_event(path)
  @config.logger.debug "Posting event to graphite. Server: #{@config.graphite_host}, Path: #{path}"
  host, port = @config.graphite_host.split(':')
  begin
    s = TCPSocket.open(host, port)
    s.write("#{path} 1 #{Time.new.to_i}\n")
    s.close
  rescue Exception => e
    @config.logger.error "An unknown error occurred while posting data to graphite: #{e.message}"
  end
end
render_template(template) click to toggle source
# File lib/consul/template/generator/ct.rb, line 8
def render_template(template)
  body = nil
  cmd = %{#{@config.consul_template_binary} -dry -once -template #{template}}
  procs = ::Open4.popen4(*cmd) do |pid, stdin, stdout, stderr|
    body = stdout.read.strip
    # consul-template -dry inserts '> \n' at the top of stdout, remove it
    body.sub!(/^>\s+\n/, '')
  end
  status = procs.to_i
  hash = ::Digest::MD5.hexdigest(body)
  return status, body, hash
end
retrieve_template(template_key) click to toggle source
# File lib/consul/template/generator/key_value.rb, line 39
def retrieve_template(template_key)
  @config.logger.info "Downloading key: #{template_key}"
  begin
    Diplomat::Kv.get(template_key, nil, :return, :return)
  rescue Exception => e
    raise TemplateUploadError, "Encountered an unexpected error while uploading template: #{e.message}"
  end
end
run(template, template_key, comp_hash = nil, diff_changes = false) click to toggle source
# File lib/consul/template/generator/run.rb, line 8
def run(template, template_key, comp_hash = nil, diff_changes = false)
  status, body, hash, uploaded_hash = nil, nil, nil, nil
  acquire_lock template_key do
    @config.logger.debug "Attempting to render template: #{template}"
    status, body, hash = render_template template
    unless status == 0
      raise TemplateRenderError, "consul-template exited with on-zero exit status"
    end
    if body.nil? || body.empty?
      raise TemplateRenderError, "rendered template is nil or empty!"
    end
    @config.logger.debug "Template rendered..."
    if comp_hash.nil? || comp_hash != hash
      @config.logger.info "Change in template discovered, attempting to upload to key #{template_key}"
      @config.logger.debug "Existing hash: #{comp_hash || 'nil'}, new hash: #{hash}"

      if diff_changes
        @config.logger.info "Diffing templates..."
        curr_template = retrieve_template template_key
        diff = Diffy::Diff.new(curr_template, body, :include_diff_info => true, :context => 5).to_s(:text)
        @config.logger.info diff
      end

      uploaded = upload_template(template_key, body)
      if uploaded
        @config.logger.info "New template uploaded..."
        uploaded_hash = hash
      else
        raise TemplateUploadError, "Template not uploaded!"
      end
    else
      @config.logger.info "No change in template, skipping upload..."
    end
  end
  return uploaded_hash
end
upload_template(template_key, raw_template) click to toggle source
# File lib/consul/template/generator/key_value.rb, line 30
def upload_template(template_key, raw_template)
  @config.logger.info "Uploading key: #{template_key}"
  begin
    Diplomat::Kv.put(template_key, raw_template)
  rescue Exception => e
    raise TemplateUploadError, "Encountered an unexpected error while uploading template: #{e.message}"
  end
end