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moby--moby/daemon/logger/journald/journald.go
Jim Minter 4fdb17c777 Prevent ContainerLogs from hanging if container doesn't run for long
Signed-off-by: Jim Minter <jminter@redhat.com>
2017-04-20 12:27:51 +01:00

125 lines
3 KiB
Go

// +build linux
// Package journald provides the log driver for forwarding server logs
// to endpoints that receive the systemd format.
package journald
import (
"fmt"
"sync"
"unicode"
"github.com/Sirupsen/logrus"
"github.com/coreos/go-systemd/journal"
"github.com/docker/docker/daemon/logger"
"github.com/docker/docker/daemon/logger/loggerutils"
)
const name = "journald"
type journald struct {
mu sync.Mutex
vars map[string]string // additional variables and values to send to the journal along with the log message
readers readerList
closed bool
}
type readerList struct {
readers map[*logger.LogWatcher]*logger.LogWatcher
}
func init() {
if err := logger.RegisterLogDriver(name, New); err != nil {
logrus.Fatal(err)
}
if err := logger.RegisterLogOptValidator(name, validateLogOpt); err != nil {
logrus.Fatal(err)
}
}
// sanitizeKeyMode returns the sanitized string so that it could be used in journald.
// In journald log, there are special requirements for fields.
// Fields must be composed of uppercase letters, numbers, and underscores, but must
// not start with an underscore.
func sanitizeKeyMod(s string) string {
n := ""
for _, v := range s {
if 'a' <= v && v <= 'z' {
v = unicode.ToUpper(v)
} else if ('Z' < v || v < 'A') && ('9' < v || v < '0') {
v = '_'
}
// If (n == "" && v == '_'), then we will skip as this is the beginning with '_'
if !(n == "" && v == '_') {
n += string(v)
}
}
return n
}
// New creates a journald logger using the configuration passed in on
// the context.
func New(info logger.Info) (logger.Logger, error) {
if !journal.Enabled() {
return nil, fmt.Errorf("journald is not enabled on this host")
}
// parse log tag
tag, err := loggerutils.ParseLogTag(info, loggerutils.DefaultTemplate)
if err != nil {
return nil, err
}
vars := map[string]string{
"CONTAINER_ID": info.ContainerID[:12],
"CONTAINER_ID_FULL": info.ContainerID,
"CONTAINER_NAME": info.Name(),
"CONTAINER_TAG": tag,
}
extraAttrs, err := info.ExtraAttributes(sanitizeKeyMod)
if err != nil {
return nil, err
}
for k, v := range extraAttrs {
vars[k] = v
}
return &journald{vars: vars, readers: readerList{readers: make(map[*logger.LogWatcher]*logger.LogWatcher)}}, nil
}
// We don't actually accept any options, but we have to supply a callback for
// the factory to pass the (probably empty) configuration map to.
func validateLogOpt(cfg map[string]string) error {
for key := range cfg {
switch key {
case "labels":
case "env":
case "env-regex":
case "tag":
default:
return fmt.Errorf("unknown log opt '%s' for journald log driver", key)
}
}
return nil
}
func (s *journald) Log(msg *logger.Message) error {
vars := map[string]string{}
for k, v := range s.vars {
vars[k] = v
}
if msg.Partial {
vars["CONTAINER_PARTIAL_MESSAGE"] = "true"
}
line := string(msg.Line)
logger.PutMessage(msg)
if msg.Source == "stderr" {
return journal.Send(line, journal.PriErr, vars)
}
return journal.Send(line, journal.PriInfo, vars)
}
func (s *journald) Name() string {
return name
}