func emitLogRecord(lr *logRecord, sr *serveRecord, target *logplexc.Client,
isAudit bool, exit exitFn) {
// Buffer to format the complete log message in.
msgFmtBuf := bytes.Buffer{}
// Helps with formatting a series of nullable strings.
catOptionalField := func(prefix string, maybePresent *string) {
if maybePresent != nil {
if prefix != "" {
msgFmtBuf.WriteString(prefix)
msgFmtBuf.WriteString(": ")
}
msgFmtBuf.WriteString(*maybePresent)
msgFmtBuf.WriteByte('\n')
}
}
if sr.Prefix != "" {
msgFmtBuf.WriteString(sr.Prefix)
msgFmtBuf.WriteString(" ")
}
if isAudit {
// The audit endpoint may be multiplexed, so add the
// identity to help tell log records apart.
msgFmtBuf.WriteString("instance_type=shogun identity=" +
sr.I + " ")
}
catOptionalField("", lr.ErrMessage)
catOptionalField("Detail", lr.ErrDetail)
catOptionalField("Hint", lr.ErrHint)
catOptionalField("Query", lr.UserQuery)
err := target.BufferMessage(134, time.Now(),
"postgres",
"postgres."+strconv.Itoa(int(lr.Pid)),
msgFmtBuf.Bytes())
if err != nil {
exit(err)
}
}
func logWorker(die dieCh, l net.Listener, cfg logplexc.Config, sr *serveRecord) {
// Make world-writable so anything can connect and send logs.
// This may be be worth locking down more, but as-is unless
// pg_logplexcollector and the Postgres server share the same
// running user common umasks will be useless.
fi, err := os.Stat(sr.P)
if err != nil {
log.Fatalf(
"exiting, cannot stat just created socket %q: %v",
sr.P, err)
}
err = os.Chmod(sr.P, fi.Mode().Perm()|0222)
if err != nil {
log.Fatalf(
"exiting, cannot make just created socket "+
"world-writable %q: %v",
sr.P, err)
}
for {
select {
case <-die:
log.Print("listener exits normally from die request")
return
default:
break
}
conn, err := l.Accept()
if err != nil {
log.Printf("accept error: %v", err)
}
if err != nil {
log.Fatalf("serve database suffers unrecoverable "+
"error: %v", err)
}
go func() {
stream := core.NewBackendStream(conn)
var exit exitFn
exit = func(args ...interface{}) {
if len(args) == 1 {
log.Printf("Disconnect client: %v", args[0])
} else if len(args) > 1 {
if s, ok := args[0].(string); ok {
log.Printf(s, args[1:]...)
} else {
// Not an intended use case, but do
// one's best to print something.
log.Printf("Got a malformed exit: %v", args)
}
}
panic(&exit)
}
// Recovers from panic and exits in an orderly manner if (and
// only if) exit() is called; otherwise propagate the panic
// normally.
defer func() {
conn.Close()
// &exit is used as a sentinel value.
if r := recover(); r != nil && r != &exit {
panic(r)
}
}()
var msgInit msgInit
msgInit = func(m *core.Message, exit exitFn) {
err = stream.Next(m)
if err == io.EOF {
exit("postgres client disconnects")
} else if err != nil {
exit("could not read next message: %v", err)
}
}
// Protocol start-up; packets that are only received once.
processVerMsg(msgInit, exit)
ident := processIdentMsg(msgInit, exit)
log.Printf("client connects with identifier %q", ident)
// Resolve the identifier to a serve
if sr.I != ident {
exit("got unexpected identifier for socket: "+
"path %s, expected %s, got %s", sr.P, sr.I, ident)
}
// Set up client with serve
client := func(cfg logplexc.Config, url *url.URL) *logplexc.Client {
cfg.Logplex = *url
client, err := logplexc.NewClient(&cfg)
if err != nil {
exit(err)
}
return client
}
primary := client(cfg, &sr.u)
var audit *logplexc.Client
if sr.audit != nil {
audit = client(cfg, sr.audit)
}
defer func() {
primary.Close()
if audit != nil {
audit.Close()
}
}()
processLogMsg(die, primary, audit, msgInit, sr, exit)
}()
}
}