github.com/boynux/docker@v1.11.0-rc4/daemon/logger/journald/journald.go (about)

     1  // +build linux
     2  
     3  // Package journald provides the log driver for forwarding server logs
     4  // to endpoints that receive the systemd format.
     5  package journald
     6  
     7  import (
     8  	"fmt"
     9  	"strings"
    10  	"sync"
    11  
    12  	"github.com/Sirupsen/logrus"
    13  	"github.com/coreos/go-systemd/journal"
    14  	"github.com/docker/docker/daemon/logger"
    15  	"github.com/docker/docker/daemon/logger/loggerutils"
    16  )
    17  
    18  const name = "journald"
    19  
    20  type journald struct {
    21  	vars    map[string]string // additional variables and values to send to the journal along with the log message
    22  	readers readerList
    23  }
    24  
    25  type readerList struct {
    26  	mu      sync.Mutex
    27  	readers map[*logger.LogWatcher]*logger.LogWatcher
    28  }
    29  
    30  func init() {
    31  	if err := logger.RegisterLogDriver(name, New); err != nil {
    32  		logrus.Fatal(err)
    33  	}
    34  	if err := logger.RegisterLogOptValidator(name, validateLogOpt); err != nil {
    35  		logrus.Fatal(err)
    36  	}
    37  }
    38  
    39  // New creates a journald logger using the configuration passed in on
    40  // the context.
    41  func New(ctx logger.Context) (logger.Logger, error) {
    42  	if !journal.Enabled() {
    43  		return nil, fmt.Errorf("journald is not enabled on this host")
    44  	}
    45  	// Strip a leading slash so that people can search for
    46  	// CONTAINER_NAME=foo rather than CONTAINER_NAME=/foo.
    47  	name := ctx.ContainerName
    48  	if name[0] == '/' {
    49  		name = name[1:]
    50  	}
    51  
    52  	// parse log tag
    53  	tag, err := loggerutils.ParseLogTag(ctx, "")
    54  	if err != nil {
    55  		return nil, err
    56  	}
    57  
    58  	vars := map[string]string{
    59  		"CONTAINER_ID":      ctx.ContainerID[:12],
    60  		"CONTAINER_ID_FULL": ctx.ContainerID,
    61  		"CONTAINER_NAME":    name,
    62  		"CONTAINER_TAG":     tag,
    63  	}
    64  	extraAttrs := ctx.ExtraAttributes(strings.ToTitle)
    65  	for k, v := range extraAttrs {
    66  		vars[k] = v
    67  	}
    68  	return &journald{vars: vars, readers: readerList{readers: make(map[*logger.LogWatcher]*logger.LogWatcher)}}, nil
    69  }
    70  
    71  // We don't actually accept any options, but we have to supply a callback for
    72  // the factory to pass the (probably empty) configuration map to.
    73  func validateLogOpt(cfg map[string]string) error {
    74  	for key := range cfg {
    75  		switch key {
    76  		case "labels":
    77  		case "env":
    78  		case "tag":
    79  		default:
    80  			return fmt.Errorf("unknown log opt '%s' for journald log driver", key)
    81  		}
    82  	}
    83  	return nil
    84  }
    85  
    86  func (s *journald) Log(msg *logger.Message) error {
    87  	if msg.Source == "stderr" {
    88  		return journal.Send(string(msg.Line), journal.PriErr, s.vars)
    89  	}
    90  	return journal.Send(string(msg.Line), journal.PriInfo, s.vars)
    91  }
    92  
    93  func (s *journald) Name() string {
    94  	return name
    95  }