Which to use

This page is the field-level struct reference for Command/Query/CommandReply/QueryReply. For the task-oriented walkthroughs of handling incoming requests, see Handle Command and Handle Query.

RPC (Remote Procedure Call) provides synchronous request/response messaging through Commands (fire-and-wait, no data return) and Queries (request data with optional server-side caching).

Command Structs

KubeMQ.Command

Sent by the caller.

Field	Type	Description
`id`	`String.t()`	Auto-generated request ID
`channel`	`String.t()`	Target channel
`metadata`	`String.t()`	Optional metadata
`body`	`String.t() \| binary()`	Request payload
`timeout`	`pos_integer()`	Response timeout in milliseconds
`client_id`	`String.t()`	Sender client ID
`tags`	`map()`	Optional key-value tags

KubeMQ.CommandReceive

Received by the handler.

Field	Type	Description
`id`	`String.t()`	Request ID
`channel`	`String.t()`	Source channel
`metadata`	`String.t()`	Metadata
`body`	`String.t() \| binary()`	Request payload
`reply_channel`	`String.t()`	Channel for sending the reply
`tags`	`map()`	Key-value tags

KubeMQ.CommandReply

Returned by the handler callback.

Field	Type	Description
`request_id`	`String.t()`	Matches the received command ID
`response_to`	`String.t()`	Matches the reply channel
`executed`	`boolean()`	Whether the command succeeded
`error`	`String.t()`	Error message if failed
`metadata`	`String.t()`	Optional response metadata

KubeMQ.CommandResponse

Returned to the caller from send_command/2.

Field	Type	Description
`command_id`	`String.t()`	Command ID
`executed`	`boolean()`	Success flag
`executed_at`	`integer()`	Execution timestamp
`error`	`String.t()`	Error if failed

Query Structs

KubeMQ.Query

Sent by the caller. Supports server-side caching.

Field	Type	Description
`id`	`String.t()`	Auto-generated request ID
`channel`	`String.t()`	Target channel
`metadata`	`String.t()`	Optional metadata
`body`	`String.t() \| binary()`	Request payload
`timeout`	`pos_integer()`	Response timeout in milliseconds
`cache_key`	`String.t()`	Cache key for server-side caching
`cache_ttl`	`pos_integer()`	Cache TTL in milliseconds
`client_id`	`String.t()`	Sender client ID
`tags`	`map()`	Optional key-value tags

KubeMQ.QueryReply

Returned by the handler callback.

Field	Type	Description
`request_id`	`String.t()`	Matches the received query ID
`response_to`	`String.t()`	Matches the reply channel
`executed`	`boolean()`	Whether the query succeeded
`body`	`String.t() \| binary()`	Response data
`metadata`	`String.t()`	Response metadata
`cache_hit`	`boolean()`	Whether the response came from cache

KubeMQ.QueryResponse

Returned to the caller from send_query/2.

Field	Type	Description
`query_id`	`String.t()`	Query ID
`executed`	`boolean()`	Success flag
`body`	`String.t() \| binary()`	Response data
`metadata`	`String.t()`	Response metadata
`cache_hit`	`boolean()`	Cache hit flag
`error`	`String.t()`	Error if failed

Command Example

{:ok, sub} = KubeMQ.Client.subscribe_to_commands(client, "orders",
  on_command: fn cmd ->
    KubeMQ.CommandReply.new(
      request_id: cmd.id,
      response_to: cmd.reply_channel,
      executed: true
    )
  end
)

cmd = KubeMQ.Command.new(channel: "orders", body: "process", timeout: 10_000)
{:ok, resp} = KubeMQ.Client.send_command(client, cmd)

Query with Caching

query = KubeMQ.Query.new(
  channel: "products",
  body: "sku-123",
  timeout: 10_000,
  cache_key: "product-sku-123",
  cache_ttl: 60_000
)

{:ok, resp} = KubeMQ.Client.send_query(client, query)
IO.puts("Cache hit: #{resp.cache_hit}")

RPC