zrepl/cmd/handler.go
Christian Schwarz 35dcfc234e Implement push support.
Pushing is achieved by inverting the roles on the established
connection, i.e. the client tells the server what data it should pull
from the client (PullMeRequest).

Role inversion is achieved by moving the server loop to the serverLoop
function of ByteStreamRPC, which can be called from both the Listen()
function (server-side) and the PullMeRequest() client-side function.

A donwside of this PullMe approach is that the replication policies
become part of the rpc, because the puller must follow the policy.
2017-05-20 18:17:08 +02:00

128 lines
3.3 KiB
Go

package main
import (
"fmt"
"github.com/zrepl/zrepl/rpc"
"github.com/zrepl/zrepl/zfs"
"io"
)
type Handler struct {
Logger Logger
PullACL zfs.DatasetMapping
SinkMappingFunc func(clientIdentity string) (mapping zfs.DatasetMapping, err error)
}
func (h Handler) HandleFilesystemRequest(r rpc.FilesystemRequest) (roots []zfs.DatasetPath, err error) {
h.Logger.Printf("handling fsr: %#v", r)
h.Logger.Printf("using PullACL: %#v", h.PullACL)
if roots, err = zfs.ZFSListMapping(h.PullACL); err != nil {
h.Logger.Printf("handle fsr err: %v\n", err)
return
}
h.Logger.Printf("returning: %#v", roots)
return
}
func (h Handler) HandleFilesystemVersionsRequest(r rpc.FilesystemVersionsRequest) (versions []zfs.FilesystemVersion, err error) {
// allowed to request that?
if _, err = h.PullACL.Map(r.Filesystem); err != nil {
h.Logger.Printf("filesystem: %#v\n", r.Filesystem)
h.Logger.Printf("pull mapping: %#v\n", h.PullACL)
h.Logger.Printf("allowed error: %#v\n", err)
return
}
h.Logger.Printf("allowed: %#v\n", r.Filesystem)
// find our versions
if versions, err = zfs.ZFSListFilesystemVersions(r.Filesystem); err != nil {
h.Logger.Printf("our versions error: %#v\n", err)
return
}
h.Logger.Printf("our versions: %#v\n", versions)
return
}
func (h Handler) HandleInitialTransferRequest(r rpc.InitialTransferRequest) (stream io.Reader, err error) {
h.Logger.Printf("handling initial transfer request: %#v", r)
// allowed to request that?
if _, err = h.PullACL.Map(r.Filesystem); err != nil {
h.Logger.Printf("initial transfer request acl errror: %#v", err)
return
}
h.Logger.Printf("invoking zfs send")
if stream, err = zfs.ZFSSend(r.Filesystem, &r.FilesystemVersion, nil); err != nil {
h.Logger.Printf("error sending filesystem: %#v", err)
}
h.Logger.Printf("finished zfs send")
return
}
func (h Handler) HandleIncrementalTransferRequest(r rpc.IncrementalTransferRequest) (stream io.Reader, err error) {
h.Logger.Printf("handling incremental transfer request: %#v", r)
// allowed to request that?
if _, err = h.PullACL.Map(r.Filesystem); err != nil {
h.Logger.Printf("incremental transfer request acl errror: %#v", err)
return
}
h.Logger.Printf("invoking zfs send")
if stream, err = zfs.ZFSSend(r.Filesystem, &r.From, &r.To); err != nil {
h.Logger.Printf("error sending filesystem: %#v", err)
}
h.Logger.Printf("finished zfs send")
return
}
func (h Handler) HandlePullMeRequest(r rpc.PullMeRequest, clientIdentity string, client rpc.RPCRequester) (err error) {
// Check if we have a sink for this request
// Use that mapping to do what happens in doPull
h.Logger.Printf("handling PullMeRequest: %#v", r)
var sinkMapping zfs.DatasetMapping
sinkMapping, err = h.SinkMappingFunc(clientIdentity)
if err != nil {
h.Logger.Printf("no sink mapping for client identity '%s', denying PullMeRequest", clientIdentity)
err = fmt.Errorf("no sink for client identity '%s'", clientIdentity)
return
}
h.Logger.Printf("doing pull...")
err = doPull(PullContext{
Remote: client,
Log: h.Logger,
Mapping: sinkMapping,
InitialReplPolicy: r.InitialReplPolicy,
})
if err != nil {
h.Logger.Printf("PullMeRequest failed with error: %s", err)
return
}
h.Logger.Printf("finished handling PullMeRequest: %#v", r)
return
}