package io.axoniq.axonserver.grpc.command

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The CommandService defines the gRPC requests necessary for subscribing command handlers, and dispatching commands.

• rpc Dispatch (Command, CommandResponse)

  command.proto:14

  Dispatches the given command, returning the result of command execution

• rpc OpenStream (stream CommandProviderOutbound, stream CommandProviderInbound)

  command.proto:10

  Opens a stream allowing clients to register command handlers and receive commands.

  message CommandProviderOutbound

  command.proto:19

  An instruction from the components that provides the Command Handler towards AxonServer.

  • oneof request

    The instruction for AxonServer

    • CommandSubscription subscribe = 1

      Instruction to subscribe this component as handler of a specific type of command

    • CommandSubscription unsubscribe = 2

      Instruction to unsubscribe this component as handler of a specific type of command

    • FlowControl flow_control = 3

      Instruction to increase the number of instructions AxonServer may send to this component

    • CommandResponse command_response = 4

      Sends a result of Command processing

    • InstructionAck ack = 5

      Acknowledgement of previously sent instruction via inbound stream

  • string instruction_id = 6

    Instruction identifier. If this identifier is set, this instruction will be acknowledged via inbound stream

  message CommandProviderInbound

  command.proto:45

  An instruction or confirmation from AxonServer towards the component that provides the Command Handler

  • oneof request

    The instruction from AxonServer for this component

    • InstructionAck ack = 1

      Acknowledgement of previously sent instruction via outbound stream

    • Command command = 2

      A command for this component to process

  • string instruction_id = 3

    Instruction identifier. If this identifier is set, this instruction will be acknowledged via outbound stream

A message representing a Command that needs to be routed to a component capable of handling it

Used as request type in: CommandService.Dispatch

Used as field type in: CommandProviderInbound

• string message_identifier = 1

  The unique identifier of the Command Message

• string name = 2

  The name of the command, used for routing it to a destination capable of handling it

• int64 timestamp = 3

  The time at which the command was dispatched

• optional SerializedObject payload = 4

  The payload of the Command, providing details on the instructions for the recipient

• map<string, MetaDataValue> meta_data = 5

  Meta Data entries of the Command Message, providing contextual information to the recipient

• repeated ProcessingInstruction processing_instructions = 6

  Instructions for AxonServer when routing this Command Message

• string client_id = 7

  The unique identifier of the component dispatching this message

• string component_name = 8

  The name/type of the component dispatching this message

Message representing the result of Command Handler execution

Used as response type in: CommandService.Dispatch

Used as field type in: CommandProviderOutbound

• string message_identifier = 1

  The unique identifier of the response message

• string error_code = 2

  An error code describing the error, if any

• optional ErrorMessage error_message = 3

  A detailed description of the error

• optional SerializedObject payload = 4

  The payload to provide as a result to the dispatcher

• map<string, MetaDataValue> meta_data = 5

  Any meta data entries providing contextual information back to the dispatcher

• repeated ProcessingInstruction processing_instructions = 6

  Instructions for AxonServer when routing this Command Response Message

• string request_identifier = 7

  The unique identifier of the Command Message for which this is the response

Message describing a component's capability of handling a command type

Used in: CommandProviderOutbound

• string message_id = 1

  A unique identifier for this subscription. This identifier is returned in Acknowledgements to allow pipelining of subscription messages

• string command = 2

  The name of the command the component can handle

• string component_name = 3

  The name/type of the component handling the command

• string client_id = 4

  The unique identifier of the component instance subscribing

• int32 load_factor = 5

  A number that represents the client's relative load capacity compared to other clients. This information is interpreted by Axon Server in relation to the other connected nodes' values. Used to balance the dispatching of commands. If set to 0, Axon Server consider 100 as default value.