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moby--moby/daemon/logger/journald/read.go
Akihiro Suda 9a82a9a8ea vendor containerd, BuildKit, protobuf, grpc, and golang.org/x
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
2020-03-03 10:25:20 +09:00

387 lines
11 KiB
Go

// +build linux,cgo,!static_build,journald
package journald // import "github.com/docker/docker/daemon/logger/journald"
// #include <sys/types.h>
// #include <sys/poll.h>
// #include <systemd/sd-journal.h>
// #include <errno.h>
// #include <stdio.h>
// #include <stdlib.h>
// #include <string.h>
// #include <time.h>
// #include <unistd.h>
//
//static int get_message(sd_journal *j, const char **msg, size_t *length, int *partial)
//{
// int rc;
// size_t plength;
// *msg = NULL;
// *length = 0;
// plength = strlen("CONTAINER_PARTIAL_MESSAGE=true");
// rc = sd_journal_get_data(j, "CONTAINER_PARTIAL_MESSAGE", (const void **) msg, length);
// *partial = ((rc == 0) && (*length == plength) && (memcmp(*msg, "CONTAINER_PARTIAL_MESSAGE=true", plength) == 0));
// rc = sd_journal_get_data(j, "MESSAGE", (const void **) msg, length);
// if (rc == 0) {
// if (*length > 8) {
// (*msg) += 8;
// *length -= 8;
// } else {
// *msg = NULL;
// *length = 0;
// rc = -ENOENT;
// }
// }
// return rc;
//}
//static int get_priority(sd_journal *j, int *priority)
//{
// const void *data;
// size_t i, length;
// int rc;
// *priority = -1;
// rc = sd_journal_get_data(j, "PRIORITY", &data, &length);
// if (rc == 0) {
// if ((length > 9) && (strncmp(data, "PRIORITY=", 9) == 0)) {
// *priority = 0;
// for (i = 9; i < length; i++) {
// *priority = *priority * 10 + ((const char *)data)[i] - '0';
// }
// if (length > 9) {
// rc = 0;
// }
// }
// }
// return rc;
//}
//static int is_attribute_field(const char *msg, size_t length)
//{
// static const struct known_field {
// const char *name;
// size_t length;
// } fields[] = {
// {"MESSAGE", sizeof("MESSAGE") - 1},
// {"MESSAGE_ID", sizeof("MESSAGE_ID") - 1},
// {"PRIORITY", sizeof("PRIORITY") - 1},
// {"CODE_FILE", sizeof("CODE_FILE") - 1},
// {"CODE_LINE", sizeof("CODE_LINE") - 1},
// {"CODE_FUNC", sizeof("CODE_FUNC") - 1},
// {"ERRNO", sizeof("ERRNO") - 1},
// {"SYSLOG_FACILITY", sizeof("SYSLOG_FACILITY") - 1},
// {"SYSLOG_IDENTIFIER", sizeof("SYSLOG_IDENTIFIER") - 1},
// {"SYSLOG_PID", sizeof("SYSLOG_PID") - 1},
// {"CONTAINER_NAME", sizeof("CONTAINER_NAME") - 1},
// {"CONTAINER_ID", sizeof("CONTAINER_ID") - 1},
// {"CONTAINER_ID_FULL", sizeof("CONTAINER_ID_FULL") - 1},
// {"CONTAINER_TAG", sizeof("CONTAINER_TAG") - 1},
// };
// unsigned int i;
// void *p;
// if ((length < 1) || (msg[0] == '_') || ((p = memchr(msg, '=', length)) == NULL)) {
// return -1;
// }
// length = ((const char *) p) - msg;
// for (i = 0; i < sizeof(fields) / sizeof(fields[0]); i++) {
// if ((fields[i].length == length) && (memcmp(fields[i].name, msg, length) == 0)) {
// return -1;
// }
// }
// return 0;
//}
//static int get_attribute_field(sd_journal *j, const char **msg, size_t *length)
//{
// int rc;
// *msg = NULL;
// *length = 0;
// while ((rc = sd_journal_enumerate_data(j, (const void **) msg, length)) > 0) {
// if (is_attribute_field(*msg, *length) == 0) {
// break;
// }
// rc = -ENOENT;
// }
// return rc;
//}
import "C"
import (
"errors"
"strings"
"time"
"unsafe"
"github.com/coreos/go-systemd/v22/journal"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/daemon/logger"
"github.com/sirupsen/logrus"
)
func (s *journald) Close() error {
s.mu.Lock()
for r := range s.readers {
r.ProducerGone()
delete(s.readers, r)
}
s.mu.Unlock()
return nil
}
// convert error code returned from a sd_journal_* function
// (which returns -errno) to a string
func CErr(ret C.int) string {
return C.GoString(C.strerror(C.int(-ret)))
}
func (s *journald) drainJournal(logWatcher *logger.LogWatcher, j *C.sd_journal, oldCursor *C.char, untilUnixMicro uint64) (*C.char, bool, int) {
var (
msg, data, cursor *C.char
length C.size_t
stamp C.uint64_t
priority, partial C.int
done bool
shown int
)
// Walk the journal from here forward until we run out of new entries
// or we reach the until value (if provided).
drain:
for {
// Try not to send a given entry twice.
if oldCursor != nil {
for C.sd_journal_test_cursor(j, oldCursor) > 0 {
if C.sd_journal_next(j) <= 0 {
break drain
}
}
}
// Read and send the logged message, if there is one to read.
i := C.get_message(j, &msg, &length, &partial)
if i != -C.ENOENT && i != -C.EADDRNOTAVAIL {
// Read the entry's timestamp.
if C.sd_journal_get_realtime_usec(j, &stamp) != 0 {
break
}
// Break if the timestamp exceeds any provided until flag.
if untilUnixMicro != 0 && untilUnixMicro < uint64(stamp) {
done = true
break
}
// Set up the time and text of the entry.
timestamp := time.Unix(int64(stamp)/1000000, (int64(stamp)%1000000)*1000)
line := C.GoBytes(unsafe.Pointer(msg), C.int(length))
if partial == 0 {
line = append(line, "\n"...)
}
// Recover the stream name by mapping
// from the journal priority back to
// the stream that we would have
// assigned that value.
source := ""
if C.get_priority(j, &priority) == 0 {
if priority == C.int(journal.PriErr) {
source = "stderr"
} else if priority == C.int(journal.PriInfo) {
source = "stdout"
}
}
// Retrieve the values of any variables we're adding to the journal.
var attrs []backend.LogAttr
C.sd_journal_restart_data(j)
for C.get_attribute_field(j, &data, &length) > C.int(0) {
kv := strings.SplitN(C.GoStringN(data, C.int(length)), "=", 2)
attrs = append(attrs, backend.LogAttr{Key: kv[0], Value: kv[1]})
}
// Send the log message, unless the consumer is gone
select {
case <-logWatcher.WatchConsumerGone():
done = true // we won't be able to write anything anymore
break drain
case logWatcher.Msg <- &logger.Message{
Line: line,
Source: source,
Timestamp: timestamp.In(time.UTC),
Attrs: attrs,
}:
shown++
}
// Call sd_journal_process() periodically during the processing loop
// to close any opened file descriptors for rotated (deleted) journal files.
if shown%1024 == 0 {
if ret := C.sd_journal_process(j); ret < 0 {
// log a warning but ignore it for now
logrus.WithField("container", s.vars["CONTAINER_ID_FULL"]).
WithField("error", CErr(ret)).
Warn("journald: error processing journal")
}
}
}
// If we're at the end of the journal, we're done (for now).
if C.sd_journal_next(j) <= 0 {
break
}
}
// free(NULL) is safe
C.free(unsafe.Pointer(oldCursor))
if C.sd_journal_get_cursor(j, &cursor) != 0 {
// ensure that we won't be freeing an address that's invalid
cursor = nil
}
return cursor, done, shown
}
func (s *journald) followJournal(logWatcher *logger.LogWatcher, j *C.sd_journal, cursor *C.char, untilUnixMicro uint64) *C.char {
s.mu.Lock()
s.readers[logWatcher] = struct{}{}
s.mu.Unlock()
waitTimeout := C.uint64_t(250000) // 0.25s
for {
status := C.sd_journal_wait(j, waitTimeout)
if status < 0 {
logWatcher.Err <- errors.New("error waiting for journal: " + CErr(status))
goto cleanup
}
select {
case <-logWatcher.WatchConsumerGone():
goto cleanup // won't be able to write anything anymore
case <-logWatcher.WatchProducerGone():
// container is gone, drain journal
default:
// container is still alive
if status == C.SD_JOURNAL_NOP {
// no new data -- keep waiting
continue
}
}
newCursor, done, recv := s.drainJournal(logWatcher, j, cursor, untilUnixMicro)
cursor = newCursor
if done || (status == C.SD_JOURNAL_NOP && recv == 0) {
break
}
}
cleanup:
s.mu.Lock()
delete(s.readers, logWatcher)
s.mu.Unlock()
close(logWatcher.Msg)
return cursor
}
func (s *journald) readLogs(logWatcher *logger.LogWatcher, config logger.ReadConfig) {
var (
j *C.sd_journal
cmatch, cursor *C.char
stamp C.uint64_t
sinceUnixMicro uint64
untilUnixMicro uint64
)
// Get a handle to the journal.
if rc := C.sd_journal_open(&j, C.int(0)); rc != 0 {
logWatcher.Err <- errors.New("error opening journal: " + CErr(rc))
close(logWatcher.Msg)
return
}
if config.Follow {
// Initialize library inotify watches early
if rc := C.sd_journal_get_fd(j); rc < 0 {
logWatcher.Err <- errors.New("error getting journald fd: " + CErr(rc))
close(logWatcher.Msg)
return
}
}
// If we end up following the log, we can set the journal context
// pointer and the channel pointer to nil so that we won't close them
// here, potentially while the goroutine that uses them is still
// running. Otherwise, close them when we return from this function.
following := false
defer func() {
if !following {
close(logWatcher.Msg)
}
C.sd_journal_close(j)
}()
// Remove limits on the size of data items that we'll retrieve.
if rc := C.sd_journal_set_data_threshold(j, C.size_t(0)); rc != 0 {
logWatcher.Err <- errors.New("error setting journal data threshold: " + CErr(rc))
return
}
// Add a match to have the library do the searching for us.
cmatch = C.CString("CONTAINER_ID_FULL=" + s.vars["CONTAINER_ID_FULL"])
defer C.free(unsafe.Pointer(cmatch))
if rc := C.sd_journal_add_match(j, unsafe.Pointer(cmatch), C.strlen(cmatch)); rc != 0 {
logWatcher.Err <- errors.New("error setting journal match: " + CErr(rc))
return
}
// If we have a cutoff time, convert it to Unix time once.
if !config.Since.IsZero() {
nano := config.Since.UnixNano()
sinceUnixMicro = uint64(nano / 1000)
}
// If we have an until value, convert it too
if !config.Until.IsZero() {
nano := config.Until.UnixNano()
untilUnixMicro = uint64(nano / 1000)
}
if config.Tail >= 0 {
// If until time provided, start from there.
// Otherwise start at the end of the journal.
if untilUnixMicro != 0 {
if rc := C.sd_journal_seek_realtime_usec(j, C.uint64_t(untilUnixMicro)); rc != 0 {
logWatcher.Err <- errors.New("error seeking provided until value: " + CErr(rc))
return
}
} else if rc := C.sd_journal_seek_tail(j); rc != 0 {
logWatcher.Err <- errors.New("error seeking to end of journal: " + CErr(rc))
return
}
// (Try to) skip backwards by the requested number of lines...
if C.sd_journal_previous_skip(j, C.uint64_t(config.Tail)) >= 0 {
// ...but not before "since"
if sinceUnixMicro != 0 &&
C.sd_journal_get_realtime_usec(j, &stamp) == 0 &&
uint64(stamp) < sinceUnixMicro {
C.sd_journal_seek_realtime_usec(j, C.uint64_t(sinceUnixMicro))
}
}
} else {
// Start at the beginning of the journal.
if rc := C.sd_journal_seek_head(j); rc != 0 {
logWatcher.Err <- errors.New("error seeking to start of journal: " + CErr(rc))
return
}
// If we have a cutoff date, fast-forward to it.
if sinceUnixMicro != 0 {
if rc := C.sd_journal_seek_realtime_usec(j, C.uint64_t(sinceUnixMicro)); rc != 0 {
logWatcher.Err <- errors.New("error seeking to start time in journal: " + CErr(rc))
return
}
}
if rc := C.sd_journal_next(j); rc < 0 {
logWatcher.Err <- errors.New("error skipping to next journal entry: " + CErr(rc))
return
}
}
if config.Tail != 0 { // special case for --tail 0
cursor, _, _ = s.drainJournal(logWatcher, j, nil, untilUnixMicro)
}
if config.Follow {
cursor = s.followJournal(logWatcher, j, cursor, untilUnixMicro)
// Let followJournal handle freeing the journal context
// object and closing the channel.
following = true
}
C.free(unsafe.Pointer(cursor))
return
}
func (s *journald) ReadLogs(config logger.ReadConfig) *logger.LogWatcher {
logWatcher := logger.NewLogWatcher()
go s.readLogs(logWatcher, config)
return logWatcher
}