Class: GraphQL::Dataloader::AsyncDataloader

Inherits:
Dataloader
  • Object
show all
Defined in:
lib/graphql/dataloader/async_dataloader.rb

Defined Under Namespace

Classes: Run

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ AsyncDataloader

Returns a new instance of AsyncDataloader.



21
22
23
24
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 21

def initialize(...)
  super
  create_pending_run
end

Instance Attribute Details

#pending_sources ⇒ Object (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



27
28
29
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 27

def pending_sources
  @pending_sources
end

Class Method Details

.install_graphql_methods ⇒ Object 



11
12
13
14
15
16
17
18
19
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 11

def self.install_graphql_methods
  if !Async::Task.method_defined?(:cancel)
    Async::Task.alias_method(:cancel, :stop)
  end
  if !Async::Task.method_defined?(:graphql_async_dataloader_run)
    Async::Task.attr_accessor(:graphql_async_dataloader_run)
    Async::Task.attr_accessor(:graphql_async_dataloader_condition)
  end
end

.use ⇒ Object 



6
7
8
9
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 6

def self.use(...)
  install_graphql_methods
  super
end

Instance Method Details

#active_run ⇒ Object 



195
196
197
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 195

def active_run
  @pending_run || current_task_run || raise(GraphQL::Error, "No available Run to append to, GraphQL-Ruby bug")
end

#append_job(callable = nil, &block) ⇒ Object 



186
187
188
189
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 186

def append_job(callable = nil, &block)
  active_run.jobs.push(callable || block)
  nil
end

#create_pending_run ⇒ Object 



29
30
31
32
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 29

def create_pending_run
  jobs_fiber_limit, total_fiber_limit = calculate_fiber_limit
  @pending_run = Run.new(self, total_fiber_limit, jobs_fiber_limit)
end

#current_task_run ⇒ Object

The current task's run, but only if it belongs to this dataloader. A different dataloader may be running inside one of our tasks (or vice versa), e.g. a query executed from a resolver or a subscription trigger; its run must not be reused.



202
203
204
205
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 202

def current_task_run
  run = Async::Task.current?&.graphql_async_dataloader_run
  run if run&.dataloader.equal?(self)
end

#lazy_at_depth(depth, lazy) ⇒ Object 



191
192
193
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 191

def lazy_at_depth(depth, lazy)
  active_run.lazies_at_depth[depth] << lazy
end

#run(trace_query_lazy: nil) ⇒ Object 



242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 242

def run(trace_query_lazy: nil)
  trace = Fiber[:__graphql_current_multiplex]&.current_trace
  run = @pending_run || current_task_run || raise(GraphQL::Error, "No available Run, GraphQL-Ruby internal bug")
  @pending_run = nil
  run.trace = trace
  first_pass = true
  trace&.begin_dataloader(self)
  fiber_vars = get_fiber_variables
  raised_error = nil
  jobs = run.jobs
  Sync do |_maybe_new_task|
    # Make sure there's a new task instance to hold `.graphql_...` state:
    task = Async::Task.new do |root_task|
      run.root_task = root_task
      root_task.graphql_async_dataloader_run = run
      set_fiber_variables(fiber_vars)

      while first_pass || run.running? || !jobs.empty?
        first_pass = false
        run_queue(run, run.snoozed_jobs_condition, :jobs)
        run_queue(run, run.snoozed_sources_condition, :sources)

        if !run.lazies_at_depth.empty?
          with_trace_query_lazy(trace_query_lazy) do
            if enqueue_next_pending_lazies(run.lazies_at_depth)
              run_queue(run, run.snoozed_jobs_condition, :jobs)
            end
          end
        end
      end
    rescue StandardError => err
      raised_error = err
      root_task.cancel
    end

    task.run
    task.wait
  end
  create_pending_run
  if raised_error
    raise raised_error
  end
  trace&.end_dataloader(self)
rescue UncaughtThrowError => e
  throw e.tag, e.value
end

#run_isolated ⇒ Object 



207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 207

def run_isolated
  previous_run = current_task_run
  prev_pending_keys = {}
  # Clear pending loads but keep already-cached records
  # in case they are useful to the given block.
  @source_cache.each do |source_class, batched_sources|
    batched_sources.each do |batch_args, batched_source_instance|
      if batched_source_instance.pending?
        prev_pending_keys[batched_source_instance] = batched_source_instance.pending.dup
        batched_source_instance.pending.clear
      end
    end
  end

  res = nil
  create_pending_run
  @pending_run.jobs << -> { res = yield }
  run
  res
ensure
  if previous_run
    Async::Task.current.graphql_async_dataloader_run = previous_run
    # clear the one created in #run:
    @pending_run = nil
  end
  prev_pending_keys.each do |source_instance, pending|
    pending.each do |key, value|
      next if source_instance.results.key?(key)

      queue_pending_source(source_instance) if source_instance.pending.empty?
      source_instance.pending[key] = value
    end
  end
end

#yield(source = Fiber[:__graphql_current_dataloader_source]) ⇒ Object 



34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
 
# File 'lib/graphql/dataloader/async_dataloader.rb', line 34

def yield(source = Fiber[:__graphql_current_dataloader_source])
  task = Async::Task.current
  run = task.graphql_async_dataloader_run
  trace = run.trace
  trace&.dataloader_fiber_yield(source)
  if !run.push_task_message(:paused_task, task)
    task.stop
  end
  condition = task.graphql_async_dataloader_condition
  condition.wait
  if !run.push_task_message(:resumed_task, task)
    task.stop
  end
  trace&.dataloader_fiber_resume(source)
  nil
end