github.com/bigzoro/my_simplechain@v0.0.0-20240315012955-8ad0a2a29bb9/consensus/raft/backend/wal.go (about)

     1  package backend
     2  
     3  import (
     4  	"os"
     5  
     6  	"github.com/bigzoro/my_simplechain/consensus/raft"
     7  	"github.com/bigzoro/my_simplechain/log"
     8  
     9  	"github.com/coreos/etcd/raft/raftpb"
    10  	"github.com/coreos/etcd/wal"
    11  	"github.com/coreos/etcd/wal/walpb"
    12  )
    13  
    14  func (pm *ProtocolManager) openWAL(maybeRaftSnapshot *raftpb.Snapshot) *wal.WAL {
    15  	if !wal.Exist(pm.waldir) {
    16  		if err := os.Mkdir(pm.waldir, 0750); err != nil {
    17  			raft.Fatalf("cannot create waldir: %s", err)
    18  		}
    19  
    20  		wal, err := wal.Create(pm.waldir, nil)
    21  		if err != nil {
    22  			raft.Fatalf("failed to create waldir: %s", err)
    23  		}
    24  		wal.Close()
    25  	}
    26  
    27  	walsnap := walpb.Snapshot{}
    28  
    29  	log.Info("loading WAL", "term", walsnap.Term, "index", walsnap.Index)
    30  
    31  	if maybeRaftSnapshot != nil {
    32  		walsnap.Index, walsnap.Term = maybeRaftSnapshot.Metadata.Index, maybeRaftSnapshot.Metadata.Term
    33  	}
    34  
    35  	wal, err := wal.Open(pm.waldir, walsnap)
    36  	if err != nil {
    37  		raft.Fatalf("error loading WAL: %s", err)
    38  	}
    39  
    40  	return wal
    41  }
    42  
    43  func (pm *ProtocolManager) replayWAL(maybeRaftSnapshot *raftpb.Snapshot) *wal.WAL {
    44  	log.Info("replaying WAL")
    45  	wal := pm.openWAL(maybeRaftSnapshot)
    46  
    47  	_, hardState, entries, err := wal.ReadAll()
    48  	if err != nil {
    49  		raft.Fatalf("failed to read WAL: %s", err)
    50  	}
    51  
    52  	pm.raftStorage.SetHardState(hardState)
    53  	pm.raftStorage.Append(entries)
    54  
    55  	return wal
    56  }