forked from elastic/logstash-forwarder
/
registrar.go
53 lines (48 loc) · 1.41 KB
/
registrar.go
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package main
import (
"log"
"os"
"syscall"
"encoding/json"
)
func Registrar(input chan []*FileEvent) {
for events := range input {
state := make(map[string]*FileState)
log.Printf("Registrar received %d events\n", len(events))
// Take the last event found for each file source
for _, event := range events {
// skip stdin
if *event.Source == "-" {
continue
}
// have to dereference the FileInfo here because os.FileInfo is an
// interface, not a struct, so Go doesn't have smarts to call the Sys()
// method on a pointer to os.FileInfo. :(
fstat := (*(event.fileinfo)).Sys().(*syscall.Stat_t)
state[*event.Source] = &FileState{
Source: event.Source,
// take the offset + length of the line + newline char and
// save it as the new starting offset.
Offset: event.Offset + int64(len(*event.Text)) + 1,
Inode: fstat.Ino,
Device: fstat.Dev,
}
}
if len(state) > 0 {
write(state)
os.Rename(".lumberjack.new", ".lumberjack")
}
}
}
func write(state map[string]*FileState) {
log.Printf("Saving registrar state.\n")
// Open tmp file, write, flush, rename
file, err := os.Create(".lumberjack.new")
if err != nil {
log.Printf("Failed to open .lumberjack.new for writing: %s\n", err)
return
}
encoder := json.NewEncoder(file)
encoder.Encode(state)
file.Close()
}