// Restore takes the snapshot from the reader and attempts to apply it to the
// given Raft instance.
func Restore(logger *log.Logger, in io.Reader, r *raft.Raft) error {
// Wrap the reader in a gzip decompressor.
decomp, err := gzip.NewReader(in)
if err != nil {
return fmt.Errorf("failed to decompress snapshot: %v", err)
}
defer func() {
if err := decomp.Close(); err != nil {
logger.Printf("[ERR] snapshot: Failed to close snapshot decompressor: %v", err)
}
}()
// Make a scratch file to receive the contents of the snapshot data so
// we can avoid buffering in memory.
snap, err := ioutil.TempFile("", "snapshot")
if err != nil {
return fmt.Errorf("failed to create temp snapshot file: %v", err)
}
defer func() {
if err := snap.Close(); err != nil {
logger.Printf("[ERR] snapshot: Failed to close temp snapshot: %v", err)
}
if err := os.Remove(snap.Name()); err != nil {
logger.Printf("[ERR] snapshot: Failed to clean up temp snapshot: %v", err)
}
}()
// Read the archive.
var metadata raft.SnapshotMeta
if err := read(decomp, &metadata, snap); err != nil {
return fmt.Errorf("failed to read snapshot file: %v", err)
}
// Sync and rewind the file so it's ready to be read again.
if err := snap.Sync(); err != nil {
return fmt.Errorf("failed to sync temp snapshot: %v", err)
}
if _, err := snap.Seek(0, 0); err != nil {
return fmt.Errorf("failed to rewind temp snapshot: %v", err)
}
// Feed the snapshot into Raft.
if err := r.Restore(&metadata, snap, 60*time.Second); err != nil {
return fmt.Errorf("Raft error when restoring snapshot: %v", err)
}
return nil
}
// New takes a state snapshot of the given Raft instance into a temporary file
// and returns an object that gives access to the file as an io.Reader. You must
// arrange to call Close() on the returned object or else you will leak a
// temporary file.
func New(logger *log.Logger, r *raft.Raft) (*Snapshot, error) {
// Take the snapshot.
future := r.Snapshot()
if err := future.Error(); err != nil {
return nil, fmt.Errorf("Raft error when taking snapshot: %v", err)
}
// Open up the snapshot.
metadata, snap, err := future.Open()
if err != nil {
return nil, fmt.Errorf("failed to open snapshot: %v:", err)
}
defer func() {
if err := snap.Close(); err != nil {
logger.Printf("[ERR] snapshot: Failed to close Raft snapshot: %v", err)
}
}()
// Make a scratch file to receive the contents so that we don't buffer
// everything in memory. This gets deleted in Close() since we keep it
// around for re-reading.
archive, err := ioutil.TempFile("", "snapshot")
if err != nil {
return nil, fmt.Errorf("failed to create snapshot file: %v", err)
}
// If anything goes wrong after this point, we will attempt to clean up
// the temp file. The happy path will disarm this.
var keep bool
defer func() {
if keep {
return
}
if err := os.Remove(archive.Name()); err != nil {
logger.Printf("[ERR] snapshot: Failed to clean up temp snapshot: %v", err)
}
}()
// Wrap the file writer in a gzip compressor.
compressor := gzip.NewWriter(archive)
// Write the archive.
if err := write(compressor, metadata, snap); err != nil {
return nil, fmt.Errorf("failed to write snapshot file: %v", err)
}
// Finish the compressed stream.
if err := compressor.Close(); err != nil {
return nil, fmt.Errorf("failed to compress snapshot file: %v", err)
}
// Sync the compressed file and rewind it so it's ready to be streamed
// out by the caller.
if err := archive.Sync(); err != nil {
return nil, fmt.Errorf("failed to sync snapshot: %v", err)
}
if _, err := archive.Seek(0, 0); err != nil {
return nil, fmt.Errorf("failed to rewind snapshot: %v", err)
}
keep = true
return &Snapshot{archive, metadata.Index}, nil
}
var (
raftDir = flag.String("raftdir",
"/var/lib/robustirc",
"Directory in which raft state is stored. If this directory is empty, you need to specify -join.")
listen = flag.String("listen",
":443",
"[host]:port to listen on. Set to a port in the dynamic port range (49152 to 65535) and use DNS SRV records.")
version = flag.Bool("version",
false,
"Print version and exit")
singleNode = flag.Bool("singlenode",
false,
"Become a raft leader without any followers. Set to true if and only if starting the first node for the first time.")
join = flag.String("join",
"",
"host:port of an existing raft node in the network that should be joined. Will also be loaded from -raftdir.")
dumpCanaryState = flag.String("dump_canary_state",
"",
"If specified, initializes the raft node (from a snapshot), then dumps all message state to the specified file. To be used via robustirc-canary.")
dumpHeapProfile = flag.String("dump_heap_profile",
"",
"If specified, a heap profile will be dumped to the specified file. Only relevant when -dump_canary_state is set.")
canaryCompactionStart = flag.Int64("canary_compaction_start",
0,
"If > 0, a nanosecond precision UNIX timestamp of when the compaction was started (for deterministic results across runs).")
network = flag.String("network_name",
"",
`Name of the network (e.g. "robustirc.net") to use in IRC messages. Ideally also a DNS name pointing to one or more servers.`)
peerAddr = flag.String("peer_addr",
"",
`host:port of this raft node (e.g. "fastbox.robustirc.net:60667"). Must be publically reachable.`)
tlsCertPath = flag.String("tls_cert_path",
"",
"Path to a .pem file containing the TLS certificate.")
tlsKeyPath = flag.String("tls_key_path",
"",
"Path to a .pem file containing the TLS private key.")
networkPassword = flag.String("network_password",
"",
"A secure password to protect the communication between raft nodes. Use pwgen(1) or similar. If empty, the ROBUSTIRC_NETWORK_PASSWORD environment variable is used.")
node *raft.Raft
peerStore *raft.JSONPeers
ircStore *raft_store.LevelDBStore
ircServer *ircserver.IRCServer
executablehash = executableHash()
// Version is overwritten by Makefile.
Version = "unknown"
isLeaderGauge = prometheus.NewGaugeFunc(
prometheus.GaugeOpts{
Subsystem: "raft",
Name: "isleader",
Help: "1 if this node is the raft leader, 0 otherwise",
},
func() float64 {
if node.State() == raft.Leader {
return 1
}
return 0
},
)
sessionsGauge = prometheus.NewGaugeFunc(
prometheus.GaugeOpts{
Subsystem: "irc",
Name: "sessions",
Help: "Number of IRC sessions",
},
func() float64 {
return float64(ircServer.NumSessions())
},
)
appliedMessages = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "applied_messages",
Help: "How many raft messages were applied, partitioned by message type",
},
[]string{"type"},
)
secondsInState = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "seconds_in_state",
Help: "How many seconds the node was in each raft state",
},
[]string{"state"},
)
)
