I am trying to write a simple Slack chatbot for my team using Ruby. It's a bit rough because Slack doesn't have official support for Ruby. Nevertheless, I've been able to open a websocket and listen to Slack events using this code I wrote:
# frozen_string_literal: true
require "async"
require "async/io/stream"
require "async/http/endpoint"
require "async/websocket/client"
require "excon"
require "json"
module Slack
class Client
Error = Class.new(StandardError)
AquisitionError = Class.new(Error)
ConnectionError = Class.new(Error)
CONNECTION_AQUISITION_ENDPOINT = "https://slack.com/api/apps.connections.open"
def initialize
#token = "my-app-token"
end
def connect
connection_info = Excon.post(CONNECTION_AQUISITION_ENDPOINT, headers: {
"Content-type": "application/x-www-form-urlencoded",
Authorization: "Bearer #{#token}",
})
result = JSON.parse(connection_info.body)
raise(AquisitionError) unless result["ok"] # better error later
websocket = Async::HTTP::Endpoint.parse(result["url"])
Async do |_task|
Async::WebSocket::Client.connect(websocket) do |connection|
payload = connection.read
raise(ConnectionError) unless connection_check(payload)
puts "Listening..."
handle(payload) while (payload = connection.read)
end
end
end
private
def connection_check(payload)
payload[:type] == "hello"
end
def handle(payload)
puts payload.inspect
end
end
end
The documentation leads me to believe that I can write JSON to this connection e.g.
connection.write({
# JSON to send a message in Slack here
# Probably need to specify the channel somehow
# Probably need to specify if I'm using markdown
# Have no idea what the form should be
})
But I haven't been able to figure out what form that JSON needs to take.
I was also running into this and trying to determine why the docs do not provide a clear answer. It appears that you do not infact send requests back over websockets, and instead use websockets only to accept requests.
Which would mean that you would use something like the webAPI to perform responsive actions, you can see this pattern in the PythonSDK with websockets example provided by Slack.
eg:
if req.type == "events_api":
# Acknowledge the request, this ack is sent back over websockets
# the format is: { 'envelope_id': req['envelope_id'] }
response = SocketModeResponse(envelope_id=req.envelope_id)
client.send_socket_mode_response(response)
# Add a reaction to the message if it's a new message
# notice that this request uses the web_client here and not the socket one
if req.payload["event"]["type"] == "message" \
and req.payload["event"].get("subtype") is None:
client.web_client.reactions_add(
name="eyes",
channel=req.payload["event"]["channel"],
timestamp=req.payload["event"]["ts"],
)
I have the following program structure.
client = Client.new
params = client.get_params
pool = client.pool(size: params.size)
futures = params.map do |p|
pool.future(:perform_work, p)
end
futures.map(&:value)
Client is Celluloid-enabled class using include Celluloid. This works great until I try to execute the program in a loop. I need to dynamically resize pool of workers based on number of parameters I receive from external data-feed.
client = Client.new
pool = client.pool(size: 1)
loop do
params = client.get_params
....
**? pool.resize(size: params.size) ?**
....
futures = params.map do |p|
pool.future(:perform_work, p)
end
futures.map(&:value)
sleep 1
end
I tried include pool creation into the loop with subsequent pool.terminate but it's spamming threads and leads to actor crash.
Setting pool.size explicitly did the trick it seems
client = Client.new
pool = client.pool(size: 1)
loop do
params = client.get_params
pool.size = params.size
futures = params.map do |p|
pool.future(:perform_work, p)
end
futures.map(&:value)
sleep 1
end
I've managed to send emails via Google API thanks to the google-api-client gem:
def send_message(from:, to:, subject:, body:)
message = RMail::Message.new
message.header['From'] = from
message.header['To'] = to
message.header['Subject'] = subject
message.body = body
#service.send_user_message(
'me',
upload_source: StringIO.new(message.to_s),
content_type: 'message/rfc822'
)
end
Now I'm trying to attach files to the emails, but I couldn't find examples on how to do it. The example included in the gem's repository doesn't explain the case. I've started doing reverse engineering, but after almost the whole day making attempts I've started doing crazy things.
My last attempt was the following:
upload = Google::Apis::Core::UploadIO.new('/path/to/image.png', 'image/png', 'image.png')
file_part = Google::Apis::Core::FilePart.new(nil, upload)
message_object = Google::Apis::GmailV1::Message.new(payload: file_part, raw: 'this is a test body')
service.send_user_message('me', message_object, content_type: 'message/rfc822')
The Email was bounced.
What's the proper way to attach files?
Turns out it was easier than I expected. Here is an example:
class Client
def initialize(service)
#service = service
end
def send_message(from:, to:, subject:, body:)
message = RMail::Message.new
message.header.set('From', from)
message.header.set('To', to)
message.header.set('Subject', subject)
message.body = [text_part(body), file_part]
#service.send_user_message(
'me',
upload_source: StringIO.new(message.to_s),
content_type: 'message/rfc822'
)
end
private
def text_part(body)
part = RMail::Message.new
part.body = body
part
end
def file_part
part = RMail::Message.new
part.header.set('Content-Disposition', 'attachment', 'filename' => File.basename('/path/to/image.png'))
part.body = File.read('/path/to/image.png')
part
end
end
I'll wait for further responses, maybe there's something I'm not taking into account.
I know that current timeouts are currently not supported with Http.rb and Celluloid[1], but is there an interim workaround?
Here's the code I'd like to run:
def fetch(url, options = {} )
puts "Request -> #{url}"
begin
options = options.merge({ socket_class: Celluloid::IO::TCPSocket,
timeout_class: HTTP::Timeout::Global,
timeout_options: {
connect_timeout: 1,
read_timeout: 1,
write_timeout: 1
}
})
HTTP.get(url, options)
rescue HTTP::TimeoutError => e
[do more stuff]
end
end
Its goal is to test a server as being live and healthy. I'd be open to alternatives (e.g. %x(ping <server>)) but these seem less efficient and actually able to get at what I'm looking for.
[1] https://github.com/httprb/http.rb#celluloidio-support
You can set timeout on future calls when you fetch for the request
Here is how to use timeout with Http.rb and Celluloid-io
require 'celluloid/io'
require 'http'
TIMEOUT = 10 # in sec
class HttpFetcher
include Celluloid::IO
def fetch(url)
HTTP.get(url, socket_class: Celluloid::IO::TCPSocket)
rescue Exception => e
# error
end
end
fetcher = HttpFetcher.new
urls = %w(http://www.ruby-lang.org/ http://www.rubygems.org/ http://celluloid.io/)
# Kick off a bunch of future calls to HttpFetcher to grab the URLs in parallel
futures = urls.map { |u| [u, fetcher.future.fetch(u)] }
# Consume the results as they come in
futures.each do |url, future|
# Wait for HttpFetcher#fetch to complete for this request
response = future.value(TIMEOUT)
puts "*** Got #{url}: #{response.inspect}\n\n"
end
I am using ruby-smpp and redis to achive a queue based background worker to send SMPP messages.
And i am wondering if I am using eventmachine in the right way. It works but it doesnt feel right.
#!/usr/bin/env ruby
# Sample SMS gateway that can receive MOs (mobile originated messages) and
# DRs (delivery reports), and send MTs (mobile terminated messages).
# MTs are, in the name of simplicity, entered on the command line in the format
# <sender> <receiver> <message body>
# MOs and DRs will be dumped to standard out.
require 'smpp'
require 'redis/connection/hiredis'
require 'redis'
require 'yajl'
require 'time'
LOGFILE = File.dirname(__FILE__) + "/sms_gateway.log"
PIDFILE = File.dirname(__FILE__) + '/worker_test.pid'
Smpp::Base.logger = Logger.new(LOGFILE)
#Smpp::Base.logger.level = Logger::WARN
REDIS = Redis.new
class MbloxGateway
# MT id counter.
##mt_id = 0
# expose SMPP transceiver's send_mt method
def self.send_mt(sender, receiver, body)
if sender =~ /[a-z]+/i
source_addr_ton = 5
else
source_addr_ton = 2
end
##mt_id += 1
##tx.send_mt(('smpp' + ##mt_id.to_s), sender, receiver, body, {
:source_addr_ton => source_addr_ton
# :service_type => 1,
# :source_addr_ton => 5,
# :source_addr_npi => 0 ,
# :dest_addr_ton => 2,
# :dest_addr_npi => 1,
# :esm_class => 3 ,
# :protocol_id => 0,
# :priority_flag => 0,
# :schedule_delivery_time => nil,
# :validity_period => nil,
# :registered_delivery=> 1,
# :replace_if_present_flag => 0,
# :data_coding => 0,
# :sm_default_msg_id => 0
#
})
end
def logger
Smpp::Base.logger
end
def start(config)
# Write this workers pid to a file
File.open(PIDFILE, 'w') { |f| f << Process.pid }
# The transceiver sends MT messages to the SMSC. It needs a storage with Hash-like
# semantics to map SMSC message IDs to your own message IDs.
pdr_storage = {}
# Run EventMachine in loop so we can reconnect when the SMSC drops our connection.
loop do
EventMachine::run do
##tx = EventMachine::connect(
config[:host],
config[:port],
Smpp::Transceiver,
config,
self # delegate that will receive callbacks on MOs and DRs and other events
)
# Let the connection start before we check for messages
EM.add_timer(3) do
# Maybe there is some better way to do this. IDK, But it works!
EM.defer do
loop do
# Pop a message
message = REDIS.lpop 'messages:send:queue'
if message # If there is a message. Process it and check the queue again
message = Yajl::Parser.parse(message, :check_utf8 => false) # Parse the message from Json to Ruby hash
if !message['send_after'] or (message['send_after'] and Time.parse(message['send_after']) < Time.now)
self.class.send_mt(message['sender'], message['receiver'], message['body']) # Send the message
REDIS.publish 'log:messages', "#{message['sender']} -> #{message['receiver']}: #{message['body']}" # Push the message to the redis queue so we can listen to the channel
else
REDIS.lpush 'messages:queue', Yajl::Encoder.encode(message)
end
else # If there is no message. Sleep for a second
sleep 1
end
end
end
end
end
sleep 2
end
end
# ruby-smpp delegate methods
def mo_received(transceiver, pdu)
logger.info "Delegate: mo_received: from #{pdu.source_addr} to #{pdu.destination_addr}: #{pdu.short_message}"
end
def delivery_report_received(transceiver, pdu)
logger.info "Delegate: delivery_report_received: ref #{pdu.msg_reference} stat #{pdu.stat}"
end
def message_accepted(transceiver, mt_message_id, pdu)
logger.info "Delegate: message_accepted: id #{mt_message_id} smsc ref id: #{pdu.message_id}"
end
def message_rejected(transceiver, mt_message_id, pdu)
logger.info "Delegate: message_rejected: id #{mt_message_id} smsc ref id: #{pdu.message_id}"
end
def bound(transceiver)
logger.info "Delegate: transceiver bound"
end
def unbound(transceiver)
logger.info "Delegate: transceiver unbound"
EventMachine::stop_event_loop
end
end
# Start the Gateway
begin
puts "Starting SMS Gateway. Please check the log at #{LOGFILE}"
# SMPP properties. These parameters work well with the Logica SMPP simulator.
# Consult the SMPP spec or your mobile operator for the correct settings of
# the other properties.
config = {
:host => 'server.com',
:port => 3217,
:system_id => 'user',
:password => 'password',
:system_type => 'type', # default given according to SMPP 3.4 Spec
:interface_version => 52,
:source_ton => 0,
:source_npi => 1,
:destination_ton => 1,
:destination_npi => 1,
:source_address_range => '',
:destination_address_range => '',
:enquire_link_delay_secs => 10
}
gw = MbloxGateway.new
gw.start(config)
rescue Exception => ex
puts "Exception in SMS Gateway: #{ex} at #{ex.backtrace.join("\n")}"
end
Some easy steps to make this code more EventMachine-ish:
Get rid of the blocking Redis driver, use em-hiredis
Stop using defer. Pushing work out to threads with the Redis driver will make things even worse as it relies on locks around the socket it's using.
Get rid of the add_timer(3)
Get rid of the inner loop, replace it by rescheduling a block for the next event loop using EM.next_tick. The outer one is somewhat unnecessary. You shouldn't loop around EM.run as well, it's cleaner to properly handle a disconnect by doing a reconnect in your unbound method instead of stopping and restarting the event loop, by calling the ##tx.reconnect.
Don't sleep, just wait. EventMachine will tell you when new things come in on a network socket.
Here's how the core code around EventMachine would look like with some of the improvements:
def start(config)
File.open(PIDFILE, 'w') { |f| f << Process.pid }
pdr_storage = {}
EventMachine::run do
##tx = EventMachine::connect(
config[:host],
config[:port],
Smpp::Transceiver,
config,
self
)
REDIS = EM::Hiredis.connect
pop_message = lambda do
REDIS.lpop 'messages:send:queue' do |message|
if message # If there is a message. Process it and check the queue again
message = Yajl::Parser.parse(message, :check_utf8 => false) # Parse the message from Json to Ruby hash
if !message['send_after'] or (message['send_after'] and Time.parse(message['send_after']) < Time.now)
self.class.send_mt(message['sender'], message['receiver'], message['body'])
REDIS.publish 'log:messages', "#{message['sender']} -> #{message['receiver']}: #{message['body']}"
else
REDIS.lpush 'messages:queue', Yajl::Encoder.encode(message)
end
end
EM.next_tick &pop_message
end
end
end
end
Not perfect and could use some cleaning up too, but this is more what it should be like in an EventMachine manner. No sleeps, avoid using defer if possible, and don't use network drivers that potentially block, implement traditional loop by rescheduling things on the next reactor loop. In terms of Redis, the difference is not that big, but it's more EventMachine-y this way imho.
Hope this helps. Happy to explain further if you still have questions.
You're doing blocking Redis calls in EM's reactor loop. It works, but isn't the way to go. You could take a look at em-hiredis to properly integrate Redis calls with EM.