channel

Documentation

Overview

Package channel contains protocol details of two-way communication channel between pmm-managed and pmm-agent.

Index

• type AgentResponse
• type Channel
  • func New(stream agentpb.Agent_ConnectClient) *Channel
  • func (c *Channel) Collect(ch chan<- prometheus.Metric)
  • func (c *Channel) Describe(ch chan<- *prometheus.Desc)
  • func (c *Channel) Requests() <-chan *ServerRequest
  • func (c *Channel) SendRequest(payload agentpb.AgentRequestPayload) agentpb.ServerResponsePayload
  • func (c *Channel) SendResponse(resp *AgentResponse)
  • func (c *Channel) Wait() error
• type ServerRequest

Types

type AgentResponse

type AgentResponse struct {
	ID      uint32
	Payload agentpb.AgentResponsePayload
}

AgentResponse represents agent's response. It is similar to agentpb.AgentMessage except it can contain only responses, and the payload is already unwrapped (XXX instead of AgentMessage_XXX).

type Channel

type Channel struct {
	// contains filtered or unexported fields
}

Channel encapsulates two-way communication channel between pmm-managed and pmm-agent.

All exported methods are thread-safe.

func New

func New(stream agentpb.Agent_ConnectClient) *Channel

New creates new two-way communication channel with given stream.

Stream should not be used by the caller after channel is created.

func (*Channel) Collect

func (c *Channel) Collect(ch chan<- prometheus.Metric)

Collect implement prometheus.Collector.

func (*Channel) Describe

func (c *Channel) Describe(ch chan<- *prometheus.Desc)

Describe implements prometheus.Collector.

func (*Channel) Requests

func (c *Channel) Requests() <-chan *ServerRequest

Requests returns a channel for incoming requests. It must be read. It is closed on any error (see Wait).

func (*Channel) SendRequest

func (c *Channel) SendRequest(payload agentpb.AgentRequestPayload) agentpb.ServerResponsePayload

SendRequest sends request to pmm-managed, blocks until response is available, and returns it. Response will be nil if channel is closed. It is no-op once channel is closed (see Wait).

func (*Channel) SendResponse

func (c *Channel) SendResponse(resp *AgentResponse)

SendResponse sends message to pmm-managed. It is no-op once channel is closed (see Wait).

func (*Channel) Wait

func (c *Channel) Wait() error

Wait blocks until channel is closed and returns the reason why it was closed.

When Wait returns, underlying gRPC connection should be terminated to prevent goroutine leak.

type ServerRequest

type ServerRequest struct {
	ID      uint32
	Payload agentpb.ServerRequestPayload
}

ServerRequest represents an request from server. It is similar to agentpb.ServerMessage except it can contain only requests, and the payload is already unwrapped (XXX instead of ServerMessage_XXX).