class GraphQL::Schema::TimeoutMiddleware

This middleware will stop resolving new fields after `max_seconds` have elapsed. After the time has passed, any remaining fields will be `nil`, with errors added to the `errors` key. Any already-resolved fields will be in the `data` key, so you'll get a partial response.

You can provide a block which will be called with any timeout errors that occur.

Note that this will stop a query _in between_ field resolutions, but it doesn't interrupt long-running `resolve` functions. Be sure to use timeout options for external connections. For more info, see www.mikeperham.com/2015/05/08/timeout-rubys-most-dangerous-api/

@example Stop resolving fields after 2 seconds

MySchema.middleware << GraphQL::Schema::TimeoutMiddleware.new(max_seconds: 2)

@example Notifying Bugsnag on a timeout

MySchema.middleware << GraphQL::Schema::TimeoutMiddleware(max_seconds: 1.5) do |timeout_error, query|
 Bugsnag.notify(timeout_error, {query_string: query_ctx.query.query_string})
end

Public Class Methods

new(max_seconds:, context_key: nil, &block) click to toggle source

@param max_seconds [Numeric] how many seconds the query should be allowed to resolve new fields

# File lib/graphql/schema/timeout_middleware.rb, line 27
def initialize(max_seconds,, context_key: nil, &block)
  @max_seconds = max_seconds
  if context_key
    warn("TimeoutMiddleware's `context_key` is ignored, timeout data is now stored in isolated storage")
  end
  @error_handler = block
end

Public Instance Methods

call(parent_type, parent_object, field_definition, field_args, query_context) { || ... } click to toggle source
# File lib/graphql/schema/timeout_middleware.rb, line 35
def call(parent_type, parent_object, field_definition, field_args, query_context)
  ns = query_context.namespace(self.class)
  timeout_at = ns[:timeout_at] ||= Time.now + @max_seconds

  if timeout_at < Time.now
    on_timeout(parent_type, parent_object, field_definition, field_args, query_context)
  else
    yield
  end
end
on_timeout(parent_type, parent_object, field_definition, field_args, field_context) click to toggle source

This is called when a field would be resolved, except that we're over the time limit. @return [GraphQL::Schema::TimeoutMiddleware::TimeoutError] An error whose message will be added to the `errors` key

# File lib/graphql/schema/timeout_middleware.rb, line 48
def on_timeout(parent_type, parent_object, field_definition, field_args, field_context)
  err = GraphQL::Schema::TimeoutMiddleware::TimeoutError.new(parent_type, field_definition)
  if @error_handler
    query_proxy = TimeoutQueryProxy.new(field_context.query, field_context)
    @error_handler.call(err, query_proxy)
  end
  err
end