workflow

Documentation

Overview

Package workflow defines types and functions for working with Vitess workflows.

This is still a very rough sketch, far from a final API, but I want to document some things here as I go:

(1) The lines between package workflow and package workflow/vexec are, uh,

blurry at best, and definitely need serious thinking and refinement. Maybe
there shouldn't even be two separate packages at all. The reason I have the
two packages right now is because I'm operating under the assumption that
there are workflows that are vexec, and then there are other workflows. If
it's true that all workflows are vexec workflows, then probably one single
package could make more sense. For now, two packages seems the way to go,
but like I said, the boundaries are blurry, and things that belong in one
package are in the other, because I haven't gone back and moved things
around.

(2) I'm aiming for this to be a drop-in replacement (more or less) for the

function calls in go/vt/wrangler. However, I'd rather define a better
abstraction if it means having to rewrite even significant portions of the
existing wrangler code to adapt to it, than make a subpar API in the name of
backwards compatibility. I'm not sure if that's a tradeoff I'll even need to
consider in the future, but I'm putting a stake in the ground on which side
of that tradeoff I intend to fall, should it come to it.

(3) Eventually we'll need to consider how the online schema migration workflows

fit into this. I'm trying to at least be somewhat abstract in the
vexec / queryplanner APIs to fit with the QueryParams thing that wrangler
uses, which _should_ work, but who knows?? Time will tell.

Index

• Variables
• type Server
  • func NewServer(ts *topo.Server, tmc tmclient.TabletManagerClient) *Server
  • func (s *Server) GetWorkflows(ctx context.Context, req *vtctldatapb.GetWorkflowsRequest) (*vtctldatapb.GetWorkflowsResponse, error)

Variables

var (
	// ErrInvalidWorkflow is a catchall error type for conditions that should be
	// impossible when operating on a workflow.
	ErrInvalidWorkflow = errors.New("invalid workflow")
	// ErrMultipleSourceKeyspaces occurs when a workflow somehow has multiple
	// source keyspaces across different shard primaries. This should be
	// impossible.
	ErrMultipleSourceKeyspaces = errors.New("multiple source keyspaces for a single workflow")
	// ErrMultipleTargetKeyspaces occurs when a workflow somehow has multiple
	// target keyspaces across different shard primaries. This should be
	// impossible.
	ErrMultipleTargetKeyspaces = errors.New("multiple target keyspaces for a single workflow")
)

Types

type Server

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

Server provides an API to work with Vitess workflows, like vreplication workflows (MoveTables, Reshard, etc) and schema migration workflows.

NB: This is in alpha, and you probably don't want to depend on it (yet!). Currently, it provides only a read-only API to vreplication workflows. Write actions on vreplication workflows, and schema migration workflows entirely, are not yet supported, but planned.

func NewServer

func NewServer(ts *topo.Server, tmc tmclient.TabletManagerClient) *Server

NewServer returns a new server instance with the given topo.Server and TabletManagerClient.

func (*Server) GetWorkflows

func (s *Server) GetWorkflows(ctx context.Context, req *vtctldatapb.GetWorkflowsRequest) (*vtctldatapb.GetWorkflowsResponse, error)

GetWorkflows returns a list of all workflows that exist in a given keyspace, with some additional filtering depending on the request parameters (for example, ActiveOnly=true restricts the search to only workflows that are currently running).

It has the same signature as the vtctlservicepb.VtctldServer's GetWorkflows rpc, and grpcvtctldserver delegates to this function.