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require 'json_serialized_field'
require 'assignable_types'
require 'markdown_class_attributes'
require 'utils'
# Agent is the core class in Huginn, representing a configurable, schedulable, reactive system with memory that can
# be sub-classed for many different purposes. Agents can emit Events, as well as receive them and react in many different ways.
# The basic Agent API is detailed on the Huginn wiki: https://github.com/cantino/huginn/wiki/Creating-a-new-agent
class Agent < ActiveRecord::Base
include AssignableTypes
include MarkdownClassAttributes
include JSONSerializedField
markdown_class_attributes :description, :event_description
load_types_in "Agents"
SCHEDULES = %w[every_2m every_5m every_10m every_30m every_1h every_2h every_5h every_12h every_1d every_2d every_7d
midnight 1am 2am 3am 4am 5am 6am 7am 8am 9am 10am 11am noon 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm 9pm 10pm 11pm never]
EVENT_RETENTION_SCHEDULES = [["Forever", 0], ["1 day", 1], *([2, 3, 4, 5, 7, 14, 21, 30, 45, 90, 180, 365].map {|n| ["#{n} days", n] })]
attr_accessible :options, :memory, :name, :type, :schedule, :source_ids, :keep_events_for, :propagate_immediately
json_serialize :options, :memory
validates_presence_of :name, :user
validates_inclusion_of :keep_events_for, :in => EVENT_RETENTION_SCHEDULES.map(&:last)
validate :sources_are_owned
validate :validate_schedule
validate :validate_options
after_initialize :set_default_schedule
before_validation :set_default_schedule
before_validation :unschedule_if_cannot_schedule
before_save :unschedule_if_cannot_schedule
before_create :set_last_checked_event_id
after_save :possibly_update_event_expirations
belongs_to :user, :inverse_of => :agents
has_many :events, :dependent => :delete_all, :inverse_of => :agent, :order => "events.id desc"
has_one :most_recent_event, :inverse_of => :agent, :class_name => "Event", :order => "events.id desc"
has_many :logs, :dependent => :delete_all, :inverse_of => :agent, :class_name => "AgentLog", :order => "agent_logs.id desc"
has_many :received_events, :through => :sources, :class_name => "Event", :source => :events, :order => "events.id desc"
has_many :links_as_source, :dependent => :delete_all, :foreign_key => "source_id", :class_name => "Link", :inverse_of => :source
has_many :links_as_receiver, :dependent => :delete_all, :foreign_key => "receiver_id", :class_name => "Link", :inverse_of => :receiver
has_many :sources, :through => :links_as_receiver, :class_name => "Agent", :inverse_of => :receivers
has_many :receivers, :through => :links_as_source, :class_name => "Agent", :inverse_of => :sources
scope :of_type, lambda { |type|
type = case type
when String, Symbol, Class
type.to_s
when Agent
type.class.to_s
else
type.to_s
end
where(:type => type)
}
def check
# Implement me in your subclass of Agent.
end
def default_options
# Implement me in your subclass of Agent.
{}
end
def receive(events)
# Implement me in your subclass of Agent.
end
def receive_webhook(params)
# Implement me in your subclass of Agent.
["not implemented", 404]
end
# Implement me in your subclass to decide if your Agent is working.
def working?
raise "Implement me in your subclass"
end
def validate_options
# Implement me in your subclass to test for valid options.
end
def event_created_within?(days)
last_event_at && last_event_at > days.to_i.days.ago
end
def recent_error_logs?
last_event_at && last_error_log_at && last_error_log_at > (last_event_at - 2.minutes)
end
def create_event(attrs)
if can_create_events?
events.create!({
:user => user,
:expires_at => new_event_expiration_date
}.merge(attrs))
else
error "This Agent cannot create events!"
end
end
def credential(name)
@credential_cache ||= {}
if @credential_cache.has_key?(name)
@credential_cache[name]
else
@credential_cache[name] = user.user_credentials.where(:credential_name => name).first.try(:credential_value)
end
end
def reload
@credential_cache = {}
super
end
def new_event_expiration_date
keep_events_for > 0 ? keep_events_for.days.from_now : nil
end
def update_event_expirations!
if keep_events_for == 0
events.update_all :expires_at => nil
else
events.update_all "expires_at = DATE_ADD(`created_at`, INTERVAL #{keep_events_for.to_i} DAY)"
end
end
def make_message(payload, message = options[:message])
message.gsub(/<([^>]+)>/) { Utils.value_at(payload, $1) || "??" }
end
def trigger_webhook(params)
receive_webhook(params).tap do
self.last_webhook_at = Time.now
save!
end
end
def default_schedule
self.class.default_schedule
end
def cannot_be_scheduled?
self.class.cannot_be_scheduled?
end
def can_be_scheduled?
!cannot_be_scheduled?
end
def cannot_receive_events?
self.class.cannot_receive_events?
end
def can_receive_events?
!cannot_receive_events?
end
def cannot_create_events?
self.class.cannot_create_events?
end
def can_create_events?
!cannot_create_events?
end
def log(message, options = {})
puts "Agent##{id}: #{message}" unless Rails.env.test?
AgentLog.log_for_agent(self, message, options)
end
def error(message, options = {})
log(message, options.merge(:level => 4))
end
def delete_logs!
logs.delete_all
update_column :last_error_log_at, nil
end
# Validations and Callbacks
def sources_are_owned
errors.add(:sources, "must be owned by you") unless sources.all? {|s| s.user == user }
end
def validate_schedule
unless cannot_be_scheduled?
errors.add(:schedule, "is not a valid schedule") unless SCHEDULES.include?(schedule.to_s)
end
end
def set_default_schedule
self.schedule = default_schedule unless schedule.present? || cannot_be_scheduled?
end
def unschedule_if_cannot_schedule
self.schedule = nil if cannot_be_scheduled?
end
def set_last_checked_event_id
if newest_event_id = Event.order("id desc").limit(1).pluck(:id).first
self.last_checked_event_id = newest_event_id
end
end
def possibly_update_event_expirations
update_event_expirations! if keep_events_for_changed?
end
# Class Methods
class << self
def cannot_be_scheduled!
@cannot_be_scheduled = true
end
def cannot_be_scheduled?
!!@cannot_be_scheduled
end
def default_schedule(schedule = nil)
@default_schedule = schedule unless schedule.nil?
@default_schedule
end
def cannot_create_events!
@cannot_create_events = true
end
def cannot_create_events?
!!@cannot_create_events
end
def cannot_receive_events!
@cannot_receive_events = true
end
def cannot_receive_events?
!!@cannot_receive_events
end
# Find all Agents that have received Events since the last execution of this method. Update those Agents with
# their new `last_checked_event_id` and queue each of the Agents to be called with #receive using `async_receive`.
# This is called by bin/schedule.rb periodically.
def receive!(options={})
Agent.transaction do
scope = Agent.
select("agents.id AS receiver_agent_id, sources.id AS source_agent_id, events.id AS event_id").
joins("JOIN links ON (links.receiver_id = agents.id)").
joins("JOIN agents AS sources ON (links.source_id = sources.id)").
joins("JOIN events ON (events.agent_id = sources.id AND events.id > links.event_id_at_creation)").
where("agents.last_checked_event_id IS NULL OR events.id > agents.last_checked_event_id")
if options[:only_receivers].present?
scope = scope.where("agents.id in (?)", options[:only_receivers])
end
sql = scope.to_sql()
agents_to_events = {}
Agent.connection.select_rows(sql).each do |receiver_agent_id, source_agent_id, event_id|
agents_to_events[receiver_agent_id] ||= []
agents_to_events[receiver_agent_id] << event_id
end
event_ids = agents_to_events.values.flatten.uniq.compact
Agent.where(:id => agents_to_events.keys).each do |agent|
agent.update_attribute :last_checked_event_id, event_ids.max
Agent.async_receive(agent.id, agents_to_events[agent.id].uniq)
end
{
:agent_count => agents_to_events.keys.length,
:event_count => event_ids.length
}
end
end
# Given an Agent id and an array of Event ids, load the Agent, call #receive on it with the Event objects, and then
# save it with an updated `last_receive_at` timestamp.
#
# This method is tagged with `handle_asynchronously` and will be delayed and run with delayed_job. It accepts Agent
# and Event ids instead of a literal ActiveRecord models because it is preferable to serialize delayed_jobs with ids.
def async_receive(agent_id, event_ids)
agent = Agent.find(agent_id)
begin
agent.receive(Event.where(:id => event_ids))
agent.last_receive_at = Time.now
agent.save!
rescue => e
agent.error "Exception during receive: #{e.message} -- #{e.backtrace}"
raise
end
end
handle_asynchronously :async_receive
# Given a schedule name, run `check` via `bulk_check` on all Agents with that schedule.
# This is called by bin/schedule.rb for each schedule in `SCHEDULES`.
def run_schedule(schedule)
return if schedule == 'never'
types = where(:schedule => schedule).group(:type).pluck(:type)
types.each do |type|
type.constantize.bulk_check(schedule)
end
end
# Schedule `async_check`s for every Agent on the given schedule. This is normally called by `run_schedule` once
# per type of agent, so you can override this to define custom bulk check behavior for your custom Agent type.
def bulk_check(schedule)
raise "Call #bulk_check on the appropriate subclass of Agent" if self == Agent
where(:schedule => schedule).pluck("agents.id").each do |agent_id|
async_check(agent_id)
end
end
# Given an Agent id, load the Agent, call #check on it, and then save it with an updated `last_check_at` timestamp.
#
# This method is tagged with `handle_asynchronously` and will be delayed and run with delayed_job. It accepts an Agent
# id instead of a literal Agent because it is preferable to serialize delayed_jobs with ids, instead of with the full
# Agents.
def async_check(agent_id)
agent = Agent.find(agent_id)
begin
agent.check
agent.last_check_at = Time.now
agent.save!
rescue => e
agent.error "Exception during check: #{e.message} -- #{e.backtrace}"
raise
end
end
handle_asynchronously :async_check
end
end
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