ipfs-cluster/consensus/raft/log_op.go
Hector Sanjuan 3d49ac26a5 Feat: Split components into RPC Services
I had thought of this for a very long time but there were no compelling
reasons to do it. Specifying RPC endpoint permissions becomes however
significantly nicer if each Component is a different RPC Service. This also
fixes some naming issues like having to prefix methods with the component name
to separate them from methods named in the same way in some other component
(Pin and IPFSPin).
2019-05-04 21:36:10 +01:00

111 lines
2.6 KiB
Go

package raft
import (
"context"
"errors"
"go.opencensus.io/tag"
"go.opencensus.io/trace"
"github.com/ipfs/ipfs-cluster/api"
"github.com/ipfs/ipfs-cluster/state"
consensus "github.com/libp2p/go-libp2p-consensus"
)
// Type of consensus operation
const (
LogOpPin = iota + 1
LogOpUnpin
)
// LogOpType expresses the type of a consensus Operation
type LogOpType int
// LogOp represents an operation for the OpLogConsensus system.
// It implements the consensus.Op interface and it is used by the
// Consensus component.
type LogOp struct {
SpanCtx trace.SpanContext `codec:"s,omitempty"`
TagCtx []byte `codec:"t,omitempty"`
Cid *api.Pin `codec:"c,omitempty"`
Type LogOpType `codec:"p,omitempty"`
consensus *Consensus `codec:"-"`
tracing bool `codec:"-"`
}
// ApplyTo applies the operation to the State
func (op *LogOp) ApplyTo(cstate consensus.State) (consensus.State, error) {
var err error
ctx := context.Background()
if op.tracing {
tagmap, err := tag.Decode(op.TagCtx)
if err != nil {
logger.Error(err)
}
ctx = tag.NewContext(ctx, tagmap)
var span *trace.Span
ctx, span = trace.StartSpanWithRemoteParent(ctx, "consensus/raft/logop/ApplyTo", op.SpanCtx)
defer span.End()
}
state, ok := cstate.(state.State)
if !ok {
// Should never be here
panic("received unexpected state type")
}
pin := op.Cid
// We are about to pass "pin" it to go-routines that will make things
// with it (read its fields). However, as soon as ApplyTo is done, the
// next operation will be deserealized on top of "op". We nullify it
// to make sure no data races occur.
op.Cid = nil
switch op.Type {
case LogOpPin:
err = state.Add(ctx, pin)
if err != nil {
logger.Error(err)
goto ROLLBACK
}
// Async, we let the PinTracker take care of any problems
op.consensus.rpcClient.GoContext(
ctx,
"",
"PinTracker",
"Track",
pin,
&struct{}{},
nil,
)
case LogOpUnpin:
err = state.Rm(ctx, pin.Cid)
if err != nil {
logger.Error(err)
goto ROLLBACK
}
// Async, we let the PinTracker take care of any problems
op.consensus.rpcClient.GoContext(
ctx,
"",
"PinTracker",
"Untrack",
pin,
&struct{}{},
nil,
)
default:
logger.Error("unknown LogOp type. Ignoring")
}
return state, nil
ROLLBACK:
// We failed to apply the operation to the state
// and therefore we need to request a rollback to the
// cluster to the previous state. This operation can only be performed
// by the cluster leader.
logger.Error("Rollbacks are not implemented")
return nil, errors.New("a rollback may be necessary. Reason: " + err.Error())
}