Class: CanvasSync::JobBatches::Batch

Inherits:
Object
  • Object
show all
Includes:
RedisModel
Defined in:
lib/canvas_sync/job_batches/batch.rb,
lib/canvas_sync/job_batches/status.rb,
lib/canvas_sync/job_batches/callback.rb

Defined Under Namespace

Modules: Callback Classes: NoBlockGivenError, RedisProxy, Status

Constant Summary collapse

BID_EXPIRE_TTL = 
90.days.to_i
INDEX_ALL_BATCHES = 
false
SCHEDULE_CALLBACK = 
RedisScript.new(Pathname.new(__FILE__) + "../schedule_callback.lua")
BID_HIERARCHY = 
RedisScript.new(Pathname.new(__FILE__) + "../hier_batch_ids.lua")

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from RedisModel

#persist_bid_attr, #read_bid_attr

Constructor Details

#initialize(existing_bid = nil) ⇒ Batch

Returns a new instance of Batch.



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# File 'lib/canvas_sync/job_batches/batch.rb', line 39

def initialize(existing_bid = nil)
  @bid = existing_bid || SecureRandom.urlsafe_base64(10)
  @existing = !(!existing_bid || existing_bid.empty?)  # Basically existing_bid.present?
  @initialized = false
  @bidkey = "BID-" + @bid.to_s
  self.created_at = Time.now.utc.to_f unless @existing
end

Instance Attribute Details

#bid ⇒ Object (readonly)

Returns the value of attribute bid.



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# File 'lib/canvas_sync/job_batches/batch.rb', line 29

def bid
  @bid
end

Class Method Details

.bid_hierarchy(bid, depth: 4, per_depth: 5, slice: nil) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 539

def bid_hierarchy(bid, depth: 4, per_depth: 5, slice: nil)
  args = [bid, depth, per_depth]
  args << slice if slice
  redis do |r|
    BID_HIERARCHY.call(r, [], args)
  end
end

.cleanup_redis(bid) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 447

def cleanup_redis(bid)
  logger.debug {"Cleaning redis of batch #{bid}"}
  redis do |r|
    r.zrem("batches", bid)
    r.zrem("BID-ROOT-bids", bid)
    r.unlink(
      "BID-#{bid}",
      "BID-#{bid}-callbacks-complete",
      "BID-#{bid}-callbacks-success",
      "BID-#{bid}-failed",
      "BID-#{bid}-dead",

      "BID-#{bid}-batches-success",
      "BID-#{bid}-batches-complete",
      "BID-#{bid}-batches-failed",
      "BID-#{bid}-bids",
      "BID-#{bid}-jids",
      "BID-#{bid}-pending_callbacks",
    )
  end
end

.cleanup_redis_index! ⇒ Object

Administrative/console method to cleanup expired batches from the WebUI



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# File 'lib/canvas_sync/job_batches/batch.rb', line 501

def cleanup_redis_index!
  suffixes = ["", "-callbacks-complete", "-callbacks-success", "-failed", "-dead", "-batches-success", "-batches-complete", "-batches-failed", "-bids", "-jids", "-pending_callbacks"]

  redis do |r|
    cleanup_index = ->(index) {
      r.zrangebyscore(index, "0", BID_EXPIRE_TTL.seconds.ago.to_i).each do |bid|
        r.zrem(index, bid) if cleanup_redis_index_for("BID-#{bid}", suffixes)
      end
    }

    cleanup_index.("BID-ROOT-bids")
    cleanup_index.("batches")
  end
end

.cleanup_redis_index_for(key, suffixes = [""]) ⇒ Object

Internal method to cleanup a Redis Hash and related keys



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# File 'lib/canvas_sync/job_batches/batch.rb', line 480

def cleanup_redis_index_for(key, suffixes = [""])
  redis do |r|
    if r.hget(k, "created_at").present?
      r.multi do |r|
        suffixes.each do |suffix|
          r.expire(key + suffix, BID_EXPIRE_TTL)
        end
      end
      false
    else
      r.multi do |r|
        suffixes.each do |suffix|
          r.unlink(key + suffix)
        end
      end
      true
    end
  end
end

.current ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 31

def self.current
  Thread.current[CURRENT_BATCH_THREAD_KEY]
end

.current_context ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 35

def self.current_context
  self.current&.context
end

.delete_prematurely!(bid) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 469

def delete_prematurely!(bid)
  child_bids = redis do |r|
    r.zrange("BID-#{bid}-bids", 0, -1)
  end
  child_bids.each do |cbid|
    delete_prematurely!(cbid)
  end
  cleanup_redis(bid)
end

.enqueue_callbacks(event, bid) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 376

def enqueue_callbacks(event, bid)
  batch_key = "BID-#{bid}"
  callback_key = "#{batch_key}-callbacks-#{event}"

  exists, callbacks, queue, parent_bid, callback_params = redis do |r|
    r.multi do |r|
      r.exists?(batch_key)

      r.smembers(callback_key)
      r.hget(batch_key, "callback_queue")
      r.hget(batch_key, "parent_bid")
      r.hget(batch_key, "callback_params")
    end
  end

  return unless exists

  queue ||= "default"
  parent_bid = !parent_bid || parent_bid.empty? ? nil : parent_bid # Basically parent_bid.blank?

  # Internal callback params. If this is present, we're trying to enqueue callbacks for a callback, which is a special case that
  # indicates that the callback completed and we need to close the triggering batch (which is in a done-but-not-cleaned state)
  callback_params = JSON.parse(callback_params) if callback_params.present?

  # User-configured parameters/arguments to pass to the callback
  callback_args = callbacks.reduce([]) do |memo, jcb|
    cb = JSON.load(jcb)
    memo << [cb['callback'], event.to_s, cb['opts'], bid, parent_bid]
  end

  opts = {"bid" => bid, "event" => event}
  should_schedule_batch = callback_args.present? && !callback_params.present?
  already_processed = redis do |r|
    SCHEDULE_CALLBACK.call(r, [batch_key], [event.to_s, should_schedule_batch.to_s, BID_EXPIRE_TTL])
  end

  return if already_processed == 'true'

  if should_schedule_batch
    logger.debug {"Enqueue callback bid: #{bid} event: #{event} args: #{callback_args.inspect}"}

    # Create a new Batch to handle the callbacks and add it to the _parent_ batch
    #   (this ensures that the parent's lifecycle status can't change until the child's callbacks are done)
    with_batch(parent_bid) do
      cb_batch = self.new
      cb_batch.callback_params = {
        for_bid: bid,
        event: event,
      }
      opts['callback_bid'] = cb_batch.bid

      logger.debug {"Adding callback batch: #{cb_batch.bid} for batch: #{bid}"}
      cb_batch.jobs do
        push_callbacks(callback_args, queue)
      end
    end
  end

  if callback_params.present?
    # This is a callback for a callback. Passing `origin` to the Finalizer allows it to also cleanup the original/callback-triggering batch
    opts['origin'] = callback_params
  end

  # The Finalizer marks this batch as complete, bumps any necessary counters, cleans up this Batch _if_ no callbacks were scheduled,
  #   and enqueues parent-Batch callbacks if needed.
  logger.debug {"Run batch finalizer bid: #{bid} event: #{event} args: #{callback_args.inspect}"}
  finalizer = Batch::Callback::Finalize.new
  status = Status.new bid
  finalizer.dispatch(status, opts)
end

.logger ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 531

def logger
  ::CanvasSync.logger
end

.process_dead_job(bid, jid) ⇒ Object

Dead jobs are a Sidekiq feature. If this is called for a job, process_failed_job was also called



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# File 'lib/canvas_sync/job_batches/batch.rb', line 358

def process_dead_job(bid, jid)
  enqueue_callbacks(:death, bid)

  with_callback_check(bid) do |r|
    r.sadd("BID-#{bid}-dead", jid)
    r.expire("BID-#{bid}-dead", BID_EXPIRE_TTL)
  end
end

.process_failed_job(bid, jid) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 349

def process_failed_job(bid, jid)
  with_callback_check(bid, except: [:success]) do |r|
    r.sadd("BID-#{bid}-failed", jid)
    r.expire("BID-#{bid}-failed", BID_EXPIRE_TTL)
  end
end

.process_successful_job(bid, jid) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 367

def process_successful_job(bid, jid)
  with_callback_check(bid) do |r|
    r.srem("BID-#{bid}-failed", jid)
    r.hincrby("BID-#{bid}", "pending", -1)
    r.hincrby("BID-#{bid}", "successful-jobs", 1)
    r.zrem("BID-#{bid}-jids", jid)
  end
end

.push_callbacks(args, queue) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 535

def push_callbacks(args, queue)
  Batch::Callback::worker_class.enqueue_all(args, queue)
end

.redis(&blk) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 516

def redis(&blk)
  return RedisProxy.new unless block_given?

  if Thread.current[:job_batches_redis]
    yield Thread.current[:job_batches_redis]
  else
    ::Bearcat.redis do |r|
      Thread.current[:job_batches_redis] = r
      yield r
    ensure
      Thread.current[:job_batches_redis] = nil
    end
  end
end

.with_batch(batch) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 180

def self.with_batch(batch)
  batch = self.new(batch) if batch.is_a?(String)
  parent = Thread.current[CURRENT_BATCH_THREAD_KEY]
  Thread.current[CURRENT_BATCH_THREAD_KEY] = batch
  yield
ensure
  Thread.current[CURRENT_BATCH_THREAD_KEY] = parent
end

.with_callback_check(bid, except: [], only: Callback::VALID_CALLBACKS, &blk) ⇒ Object

Perform a success/failure/complete/etc transaction against Redis, checking

if any callbacks should be triggered



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# File 'lib/canvas_sync/job_batches/batch.rb', line 264

def with_callback_check(bid, except: [], only: Callback::VALID_CALLBACKS, &blk)
  except = Array(except).map(&:to_sym)
  only = Array(only).map(&:to_sym)

  precount = 0

  all_results = redis do |r|
    return unless r.exists?("BID-#{bid}")

    r.multi do |r|
      # The block probably doesn't _have_ to be part of the same transaction, but it was easier than
      #   re-assessing possible race-conditions and is technically more performant
      blk.call(r)
      futures = r.instance_variable_get(:@futures) || r.instance_variable_get(:@pipeline)&.futures || r.instance_variable_get(:@client)&.futures
      precount = futures.size

      # Misc
      r.hget("BID-#{bid}", "parent_bid")
      r.hget("BID-#{bid}", "keep_open")
      r.scard("BID-#{bid}-holds")

      # Jobs
      r.hincrby("BID-#{bid}", "pending", 0)
      r.scard("BID-#{bid}-failed")
      r.scard("BID-#{bid}-dead")

      # Batches
      r.hincrby("BID-#{bid}", "children", 0)
      r.scard("BID-#{bid}-batches-complete")
      r.scard("BID-#{bid}-batches-success")
      r.scard("BID-#{bid}-batches-failed")
      r.scard("BID-#{bid}-batches-stagnated")

      # Touch Expirations
      r.expire("BID-#{bid}", BID_EXPIRE_TTL)
      r.expire("BID-#{bid}-batches-success", BID_EXPIRE_TTL)
    end
  end

  # Exclude return values from the passed block
  actual_results = all_results[precount..-1]

  # "pending" = not successful (yet)
  # "failed" = dead or retrying
  # "complete" = successful or failed

  parent_bid, keep_open, holds, \
    pending_jobs, failed_jobs, dead_jobs, \
    child_batches, complete_batches, success_batches, failed_batches, stagnated_batches \
    = actual_results

  pending_batches = child_batches - success_batches

  if keep_open == 'true' || (holds && holds > 0)
    except << :complete
    except << :success
  end

  trigger_callback = ->(callback) {
    next if except.include?(callback.to_sym)
    next unless only.include?(callback.to_sym)

    Batch.logger.debug {"Finalize #{callback} bid: #{parent_bid}"}
    enqueue_callbacks(callback, bid)
  }

  # Handling all of these cases in one method may be a little less performant than in more specialized methods, but
  #   I was dealing with duplicate Redis queries and checks being made in up to 4 places and it was getting out of
  #   hand - this combined method should be easier to maintain and reason about

  all_successful = pending_jobs.zero? && child_batches == success_batches

  if all_successful || (pending_jobs == failed_jobs && child_batches == complete_batches) # All Complete
    trigger_callback.call(:complete)
  end

  if all_successful # All Successfull
    trigger_callback.call(:success)
  elsif pending_jobs == dead_jobs && pending_batches == stagnated_batches # Stagnated
    trigger_callback.call(:stagnated)
  end

  all_results[0...precount]
end

.without_batch(&blk) ⇒ Object

Any Batches or Jobs created in the given block won’t be assocaiated to the current batch



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# File 'lib/canvas_sync/job_batches/batch.rb', line 190

def self.without_batch(&blk)
  with_batch(nil, &blk)
end

Instance Method Details

#append_jobs(jids) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 194

def append_jobs(jids)
  jids = Array(jids)
  jids = jids.uniq
  return unless jids.size > 0

  redis do |r|
    tme = Time.now.utc.to_f
    added = r.zadd(@bidkey + "-jids", jids.map{|jid| [tme, jid] }, nx: true)
    r.multi do |r|
      r.hincrby(@bidkey, "pending", added)
      r.hincrby(@bidkey, "job_count", added)
      r.expire(@bidkey, BID_EXPIRE_TTL)
      r.expire(@bidkey + "-jids", BID_EXPIRE_TTL)
    end
  end
end

#context ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 53

def context
  return @context if defined?(@context)

  if (@initialized || @existing)
    @context = ContextHash.new(bid)
  else
    @context = ContextHash.new(bid, {})
  end
end

#context=(value) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 63

def context=(value)
  raise "context is read-only once the batch has been started" if (@initialized || @existing) # && !allow_context_changes
  raise "context must be a Hash" unless value.is_a?(Hash) || value.nil?
  return nil if value.nil? && @context.nil?

  value = {} if value.nil?
  value = value.local if value.is_a?(ContextHash)

  @context ||= ContextHash.new(bid, {})
  @context.set_local(value)
  # persist_bid_attr('context', JSON.unparse(@context.local))
end

#invalidate_all ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 128

def invalidate_all
  redis.setex("invalidated-bid-#{bid}", BID_EXPIRE_TTL, 1)
end

#jobs ⇒ Object

Raises:



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# File 'lib/canvas_sync/job_batches/batch.rb', line 98

def jobs
  raise NoBlockGivenError unless block_given?

  persist!

  # TODO This keep_open! block is probably desired, but it has some caveats:
  #  - Old logic didn't auto-clean empty batches
  #  - Could be an issue if the Thread crashes at a bad moment (do we even need to plan for this?)
  #  - Technically there could be a race condition without it, but such hasn't been observed

  # keep_open! do
  begin
    parent = Thread.current[CURRENT_BATCH_THREAD_KEY]
    Thread.current[CURRENT_BATCH_THREAD_KEY] = self
    yield
  ensure
    Thread.current[CURRENT_BATCH_THREAD_KEY] = parent
  end
  # end

  nil
end

#keep_open!(token = SecureRandom.urlsafe_base64(10)) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 147

def keep_open!(token = SecureRandom.urlsafe_base64(10))
  if block_given?
    begin
      token = keep_open!(token)
      yield
    ensure
      let_close!(token)
    end
  else
    persist!

    redis.multi do |r|
      r.sadd("#{@bidkey}-holds", token)
      r.expire("#{@bidkey}-holds", BID_EXPIRE_TTL)
    end

    assert_batch_is_open

    token
  end
end

#let_close!(token = :unset) ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 169

def let_close!(token = :unset)
  self.class.with_callback_check(bid, only: %i[complete success]) do |r|
    if token == :unset # Legacy
      r.del("#{@bidkey}-holds")
      r.hset(@bidkey, 'keep_open', "false")
    else
      r.srem("#{@bidkey}-holds", token)
    end
  end
end

#on(event, callback, options = {}) ⇒ Object

Events: :complete - triggered once all jobs have been executed, regardless of success or failure. :success - triggered once all jobs haves successfully executed. :death - triggered after any job enters the dead state. :stagnated - triggered when a job dies and no other jobs/batches are active.



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# File 'lib/canvas_sync/job_batches/batch.rb', line 85

def on(event, callback, options = {})
  return unless Callback::VALID_CALLBACKS.include?(event.to_sym)

  callback_key = "#{@bidkey}-callbacks-#{event}"
  redis.multi do |r|
    r.sadd(callback_key, JSON.unparse({
      callback: callback,
      opts: options
    }))
    r.expire(callback_key, BID_EXPIRE_TTL)
  end
end

#parent ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 136

def parent
  if parent_bid
    Batch.new(parent_bid)
  end
end

#parent_bid ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 132

def parent_bid
  redis.hget(@bidkey, "parent_bid")
end

#placeholder! ⇒ Object

Mark this Batch as a placeholder. It will be persisted to Redis, but no jobs will be added. From here, you can either use ‘.jobs` on the batch to add jobs as usual, or call `.let_close!` to allow cleanup to occur.



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# File 'lib/canvas_sync/job_batches/batch.rb', line 123

def placeholder!
  # TODO Provide a stable `let_close!` token?
  persist!
end

#save_context_changes ⇒ Object 



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# File 'lib/canvas_sync/job_batches/batch.rb', line 76

def save_context_changes
  @context&.save!
end

#valid?(batch = self) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/canvas_sync/job_batches/batch.rb', line 142

def valid?(batch = self)
  valid = !redis.exists?("invalidated-bid-#{batch.bid}")
  batch.parent ? valid && valid?(batch.parent) : valid
end