Support for invoking and processing queries

README.md

@@ -178,7 +178,7 @@ Besides calling activities workflows can:
 - Use timers
 - Receive signals
 - Execute other (child) workflows
-- Respond to queries [not yet implemented]
+- Respond to queries
 
 
 ## Activities

examples/bin/query

@@ -0,0 +1,14 @@
+#!/usr/bin/env ruby
+require_relative '../init'
+
+Dir[File.expand_path('../workflows/*.rb', __dir__)].each { |f| require f }
+
+workflow_class_name, workflow_id, run_id, query, args = ARGV
+workflow_class = Object.const_get(workflow_class_name)
+
+if ![workflow_class, workflow_id, run_id, query].all?
+  fail 'Wrong arguments, use `bin/query WORKFLOW WORKFLOW_ID RUN_ID QUERY [ARGS]`'
+end
+
+result = Temporal.query_workflow(workflow_class, query, workflow_id, run_id, args)
+puts result.inspect

examples/bin/worker

@@ -36,6 +36,7 @@ worker.register_workflow(MetadataWorkflow)
 worker.register_workflow(ParentCloseWorkflow)
 worker.register_workflow(ParentWorkflow)
 worker.register_workflow(ProcessFileWorkflow)
+worker.register_workflow(QueryWorkflow)
 worker.register_workflow(QuickTimeoutWorkflow)
 worker.register_workflow(RandomlyFailingWorkflow)
 worker.register_workflow(ReleaseWorkflow)

examples/spec/integration/query_workflow_spec.rb

@@ -0,0 +1,54 @@
+require 'workflows/query_workflow'
+require 'temporal/errors'
+
+describe QueryWorkflow, :integration do
+  subject { described_class }
+
+  it 'returns the correct result for the queries' do
+    workflow_id, run_id = run_workflow(described_class)
+
+    # Query with nil workflow class
+    expect(Temporal.query_workflow(nil, 'state', workflow_id, run_id))
+      .to eq 'started'
+
+    # Query with arbitrary args
+    expect(Temporal.query_workflow(described_class, 'state', workflow_id, run_id,
+      'upcase', 'ignored', 'reverse'))
+      .to eq 'DETRATS'
+
+    # Query with no args
+    expect(Temporal.query_workflow(described_class, 'signal_count', workflow_id, run_id))
+      .to eq 0
+
+    # Query with unregistered handler
+    expect { Temporal.query_workflow(described_class, 'unknown_query', workflow_id, run_id) }
+      .to raise_error(Temporal::QueryFailed, 'Workflow did not register a handler for unknown_query')
+
+    Temporal.signal_workflow(described_class, 'make_progress', workflow_id, run_id)
+
+    # Query for updated signal_count with an unsatisfied reject condition
+    expect(Temporal.query_workflow(described_class, 'signal_count', workflow_id, run_id, query_reject_condition: :not_open))
+      .to eq 1
+
+    Temporal.signal_workflow(described_class, 'finish', workflow_id, run_id)
+    wait_for_workflow_completion(workflow_id, run_id)
+
+    # Repeating original query scenarios above, expecting updated state and signal results
+    expect(Temporal.query_workflow(nil, 'state', workflow_id, run_id))
+      .to eq 'finished'
+
+    expect(Temporal.query_workflow(described_class, 'state', workflow_id, run_id,
+      'upcase', 'ignored', 'reverse'))
+      .to eq 'DEHSINIF'
+
+    expect(Temporal.query_workflow(described_class, 'signal_count', workflow_id, run_id))
+      .to eq 2
+
+    expect { Temporal.query_workflow(described_class, 'unknown_query', workflow_id, run_id) }
+      .to raise_error(Temporal::QueryFailed, 'Workflow did not register a handler for unknown_query')
+
+    # Now that the workflow is completed, test a query with a reject condition satisfied
+    expect { Temporal.query_workflow(described_class, 'state', workflow_id, run_id, query_reject_condition: :not_open) }
+      .to raise_error(Temporal::QueryFailed, 'Query rejected: status WORKFLOW_EXECUTION_STATUS_COMPLETED')
+  end
+end

examples/workflows/query_workflow.rb

@@ -0,0 +1,36 @@
+class QueryWorkflow < Temporal::Workflow
+  attr_reader :state, :signal_count, :last_signal_received
+
+  def execute
+    @state = "started"
+    @signal_count = 0
+    @last_signal_received = nil
+
+    workflow.on_query("state") { |*args| apply_transforms(state, args) }
+    workflow.on_query("signal_count") { signal_count }
+
+    workflow.on_signal do |signal|
+      @signal_count += 1
+      @last_signal_received = signal
+    end
+
+    workflow.wait_for { last_signal_received == "finish" }
+    @state = "finished"
+
+    {
+      signal_count: signal_count,
+      last_signal_received: last_signal_received,
+      final_state: state
+    }
+  end
+
+  private
+
+  def apply_transforms(value, transforms)
+    return value if value.nil? || transforms.empty?
+    transforms.inject(value) do |memo, input|
+      next memo unless memo.respond_to?(input)
+      memo.public_send(input)
+    end
+  end
+end

lib/temporal.rb

@@ -20,6 +20,7 @@ module Temporal
                  :describe_namespace,
                  :list_namespaces,
                  :signal_workflow,
+                 :query_workflow,
                  :await_workflow_result,
                  :reset_workflow,
                  :terminate_workflow,
@@ -48,11 +49,11 @@ def metrics
     end
 
     private
-    
+
     def default_client
       @default_client ||= Client.new(config)
     end
-    
+
     def config
       @config ||= Configuration.new
     end

lib/temporal/client.rb

@@ -176,6 +176,29 @@ def signal_workflow(workflow, signal, workflow_id, run_id, input = nil, namespac
       )
     end
 
+    # Issue a query against a running workflow
+    #
+    # @param workflow [Temporal::Workflow, nil] workflow class or nil
+    # @param query [String] name of the query to issue
+    # @param workflow_id [String]
+    # @param run_id [String]
+    # @param args [String, Array, nil] optional arguments for the query
+    # @param namespace [String, nil] if nil, choose the one declared on the workflow class or the
+    #   global default
+    # @param query_reject_condition [Symbol] check Temporal::Connection::GRPC::QUERY_REJECT_CONDITION
+    def query_workflow(workflow, query, workflow_id, run_id, *args, namespace: nil, query_reject_condition: nil)
+      execution_options = ExecutionOptions.new(workflow, {}, config.default_execution_options)
+
+      connection.query_workflow(
+        namespace: namespace || execution_options.namespace,
+        workflow_id: workflow_id,
+        run_id: run_id,
+        query: query,
+        args: args,
+        query_reject_condition: query_reject_condition
+      )
+    end
+
     # Long polls for a workflow to be completed and returns workflow's return value.
     #
     # @note This function times out after 30 seconds and throws Temporal::TimeoutError,
@@ -207,7 +230,7 @@ def await_workflow_result(workflow, workflow_id:, run_id: nil, timeout: nil, nam
           timeout: timeout || max_timeout,
         )
       rescue GRPC::DeadlineExceeded => e
-        message = if timeout 
+        message = if timeout
           "Timed out after your specified limit of timeout: #{timeout} seconds"
         else
           "Timed out after #{max_timeout} seconds, which is the maximum supported amount."

lib/temporal/concerns/payloads.rb

@@ -21,6 +21,10 @@ def from_signal_payloads(payloads)
         from_payloads(payloads)&.first
       end
 
+      def from_query_payloads(payloads)
+        from_payloads(payloads)&.first
+      end
+
       def from_payload_map(payload_map)
         payload_map.map { |key, value| [key, from_payload(value)] }.to_h
       end
@@ -45,6 +49,10 @@ def to_signal_payloads(data)
         to_payloads([data])
       end
 
+      def to_query_payloads(data)
+        to_payloads([data])
+      end
+
       def to_payload_map(data)
         data.transform_values(&method(:to_payload))
       end

lib/temporal/connection/grpc.rb

@@ -26,6 +26,12 @@ class GRPC
         close: Temporal::Api::Enums::V1::HistoryEventFilterType::HISTORY_EVENT_FILTER_TYPE_CLOSE_EVENT,
       }.freeze
 
+      QUERY_REJECT_CONDITION = {
+        none: Temporal::Api::Enums::V1::QueryRejectCondition::QUERY_REJECT_CONDITION_NONE,
+        not_open: Temporal::Api::Enums::V1::QueryRejectCondition::QUERY_REJECT_CONDITION_NOT_OPEN,
+        not_completed_cleanly: Temporal::Api::Enums::V1::QueryRejectCondition::QUERY_REJECT_CONDITION_NOT_COMPLETED_CLEANLY
+      }.freeze
+
       DEFAULT_OPTIONS = {
         max_page_size: 100
       }.freeze
@@ -142,7 +148,7 @@ def get_workflow_execution_history(
         event_type: :all,
         timeout: nil
       )
-        if wait_for_new_event 
+        if wait_for_new_event
           if timeout.nil?
             # This is an internal error.  Wrappers should enforce this.
             raise "You must specify a timeout when wait_for_new_event = true."
@@ -183,13 +189,28 @@ def poll_workflow_task_queue(namespace:, task_queue:)
         poll_request.execute
       end
 
-      def respond_workflow_task_completed(namespace:, task_token:, commands:)
+      def respond_query_task_completed(namespace:, task_token:, query_result:)
+        query_result_proto = Serializer.serialize(query_result)
+        request = Temporal::Api::WorkflowService::V1::RespondQueryTaskCompletedRequest.new(
+          task_token: task_token,
+          namespace: namespace,
+          completed_type: query_result_proto.result_type,
+          query_result: query_result_proto.answer,
+          error_message: query_result_proto.error_message,
+        )
+
+        client.respond_query_task_completed(request)
+      end
+
+      def respond_workflow_task_completed(namespace:, task_token:, commands:, query_results: {})
         request = Temporal::Api::WorkflowService::V1::RespondWorkflowTaskCompletedRequest.new(
           namespace: namespace,
           identity: identity,
           task_token: task_token,
-          commands: Array(commands).map { |(_, command)| Serializer.serialize(command) }
+          commands: Array(commands).map { |(_, command)| Serializer.serialize(command) },
+          query_results: query_results.transform_values { |value| Serializer.serialize(value) }
         )
+
         client.respond_workflow_task_completed(request)
       end
 
@@ -452,16 +473,43 @@ def get_search_attributes
         raise NotImplementedError
       end
 
-      def respond_query_task_completed
-        raise NotImplementedError
-      end
-
       def reset_sticky_task_queue
         raise NotImplementedError
       end
 
-      def query_workflow
-        raise NotImplementedError
+      def query_workflow(namespace:, workflow_id:, run_id:, query:, args: nil, query_reject_condition: nil)
+        request = Temporal::Api::WorkflowService::V1::QueryWorkflowRequest.new(
+          namespace: namespace,
+          execution: Temporal::Api::Common::V1::WorkflowExecution.new(
+            workflow_id: workflow_id,
+            run_id: run_id
+          ),
+          query: Temporal::Api::Query::V1::WorkflowQuery.new(
+            query_type: query,
+            query_args: to_query_payloads(args)
+          )
+        )
+        if query_reject_condition
+          condition = QUERY_REJECT_CONDITION[query_reject_condition]
+          raise Client::ArgumentError, 'Unknown query_reject_condition specified' unless condition
+
+          request.query_reject_condition = condition
+        end
+
+        begin
+          response = client.query_workflow(request)
+        rescue ::GRPC::InvalidArgument => e
+          raise Temporal::QueryFailed, e.details
+        end
+
+        if response.query_rejected
+          rejection_status = response.query_rejected.status || 'not specified by server'
+          raise Temporal::QueryFailed, "Query rejected: status #{rejection_status}"
+        elsif !response.query_result
+          raise Temporal::QueryFailed, 'Invalid response from server'
+        else
+          from_query_payloads(response.query_result)
+        end
       end
 
       def describe_workflow_execution(namespace:, workflow_id:, run_id:)
@@ -534,7 +582,7 @@ def serialize_status_filter(value)
 
         sym = Temporal::Workflow::Status::API_STATUS_MAP.invert[value]
         status = Temporal::Api::Enums::V1::WorkflowExecutionStatus.resolve(sym)
-        
+
         Temporal::Api::Filter::V1::StatusFilter.new(status: status)
       end
     end

lib/temporal/connection/serializer.rb

@@ -1,4 +1,5 @@
 require 'temporal/workflow/command'
+require 'temporal/workflow/query_result'
 require 'temporal/connection/serializer/schedule_activity'
 require 'temporal/connection/serializer/start_child_workflow'
 require 'temporal/connection/serializer/request_activity_cancellation'
@@ -10,6 +11,8 @@
 require 'temporal/connection/serializer/fail_workflow'
 require 'temporal/connection/serializer/signal_external_workflow'
 require 'temporal/connection/serializer/upsert_search_attributes'
+require 'temporal/connection/serializer/query_answer'
+require 'temporal/connection/serializer/query_failure'
 
 module Temporal
   module Connection
@@ -26,6 +29,8 @@ module Serializer
         Workflow::Command::FailWorkflow => Serializer::FailWorkflow,
         Workflow::Command::SignalExternalWorkflow => Serializer::SignalExternalWorkflow,
         Workflow::Command::UpsertSearchAttributes => Serializer::UpsertSearchAttributes,
+        Workflow::QueryResult::Answer => Serializer::QueryAnswer,
+        Workflow::QueryResult::Failure => Serializer::QueryFailure,
       }.freeze
 
       def self.serialize(object)

lib/temporal/connection/serializer/query_answer.rb

@@ -0,0 +1,19 @@
+require 'temporal/connection/serializer/base'
+require 'temporal/concerns/payloads'
+
+module Temporal
+  module Connection
+    module Serializer
+      class QueryAnswer < Base
+        include Concerns::Payloads
+
+        def to_proto
+          Temporal::Api::Query::V1::WorkflowQueryResult.new(
+            result_type: Temporal::Api::Enums::V1::QueryResultType::QUERY_RESULT_TYPE_ANSWERED,
+            answer: to_query_payloads(object.result)
+          )
+        end
+      end
+    end
+  end
+end

lib/temporal/connection/serializer/query_failure.rb

@@ -0,0 +1,16 @@
+require 'temporal/connection/serializer/base'
+
+module Temporal
+  module Connection
+    module Serializer
+      class QueryFailure < Base
+        def to_proto
+          Temporal::Api::Query::V1::WorkflowQueryResult.new(
+            result_type: Temporal::Api::Enums::V1::QueryResultType::QUERY_RESULT_TYPE_FAILED,
+            error_message: object.error.message
+          )
+        end
+      end
+    end
+  end
+end

lib/temporal/errors.rb

@@ -67,7 +67,7 @@ class ClientVersionNotSupportedFailure < ApiError; end
   class FeatureVersionNotSupportedFailure < ApiError; end
   class NamespaceAlreadyExistsFailure < ApiError; end
   class CancellationAlreadyRequestedFailure < ApiError; end
-  class QueryFailedFailure < ApiError; end
+  class QueryFailed < ApiError; end
   class UnexpectedResponse < ApiError; end
 
 end