github.com/kaisenlinux/docker.io@v0.0.0-20230510090727-ea55db55fac7/engine/daemon/logger/journald/journald.go (about)

     1  //go:build linux
     2  // +build linux
     3  
     4  // Package journald provides the log driver for forwarding server logs
     5  // to endpoints that receive the systemd format.
     6  package journald // import "github.com/docker/docker/daemon/logger/journald"
     7  
     8  import (
     9  	"fmt"
    10  	"strconv"
    11  	"sync"
    12  	"unicode"
    13  
    14  	"github.com/coreos/go-systemd/v22/journal"
    15  	"github.com/docker/docker/daemon/logger"
    16  	"github.com/docker/docker/daemon/logger/loggerutils"
    17  	"github.com/sirupsen/logrus"
    18  )
    19  
    20  const name = "journald"
    21  
    22  type journald struct {
    23  	mu      sync.Mutex        //nolint:structcheck,unused
    24  	vars    map[string]string // additional variables and values to send to the journal along with the log message
    25  	readers map[*logger.LogWatcher]struct{}
    26  }
    27  
    28  func init() {
    29  	if err := logger.RegisterLogDriver(name, New); err != nil {
    30  		logrus.Fatal(err)
    31  	}
    32  	if err := logger.RegisterLogOptValidator(name, validateLogOpt); err != nil {
    33  		logrus.Fatal(err)
    34  	}
    35  }
    36  
    37  // sanitizeKeyMode returns the sanitized string so that it could be used in journald.
    38  // In journald log, there are special requirements for fields.
    39  // Fields must be composed of uppercase letters, numbers, and underscores, but must
    40  // not start with an underscore.
    41  func sanitizeKeyMod(s string) string {
    42  	n := ""
    43  	for _, v := range s {
    44  		if 'a' <= v && v <= 'z' {
    45  			v = unicode.ToUpper(v)
    46  		} else if ('Z' < v || v < 'A') && ('9' < v || v < '0') {
    47  			v = '_'
    48  		}
    49  		// If (n == "" && v == '_'), then we will skip as this is the beginning with '_'
    50  		if !(n == "" && v == '_') {
    51  			n += string(v)
    52  		}
    53  	}
    54  	return n
    55  }
    56  
    57  // New creates a journald logger using the configuration passed in on
    58  // the context.
    59  func New(info logger.Info) (logger.Logger, error) {
    60  	if !journal.Enabled() {
    61  		return nil, fmt.Errorf("journald is not enabled on this host")
    62  	}
    63  
    64  	// parse log tag
    65  	tag, err := loggerutils.ParseLogTag(info, loggerutils.DefaultTemplate)
    66  	if err != nil {
    67  		return nil, err
    68  	}
    69  
    70  	vars := map[string]string{
    71  		"CONTAINER_ID":      info.ContainerID[:12],
    72  		"CONTAINER_ID_FULL": info.ContainerID,
    73  		"CONTAINER_NAME":    info.Name(),
    74  		"CONTAINER_TAG":     tag,
    75  		"IMAGE_NAME":        info.ImageName(),
    76  		"SYSLOG_IDENTIFIER": tag,
    77  	}
    78  	extraAttrs, err := info.ExtraAttributes(sanitizeKeyMod)
    79  	if err != nil {
    80  		return nil, err
    81  	}
    82  	for k, v := range extraAttrs {
    83  		vars[k] = v
    84  	}
    85  	return &journald{vars: vars, readers: make(map[*logger.LogWatcher]struct{})}, nil
    86  }
    87  
    88  // We don't actually accept any options, but we have to supply a callback for
    89  // the factory to pass the (probably empty) configuration map to.
    90  func validateLogOpt(cfg map[string]string) error {
    91  	for key := range cfg {
    92  		switch key {
    93  		case "labels":
    94  		case "labels-regex":
    95  		case "env":
    96  		case "env-regex":
    97  		case "tag":
    98  		default:
    99  			return fmt.Errorf("unknown log opt '%s' for journald log driver", key)
   100  		}
   101  	}
   102  	return nil
   103  }
   104  
   105  func (s *journald) Log(msg *logger.Message) error {
   106  	vars := map[string]string{}
   107  	for k, v := range s.vars {
   108  		vars[k] = v
   109  	}
   110  	if msg.PLogMetaData != nil {
   111  		vars["CONTAINER_PARTIAL_ID"] = msg.PLogMetaData.ID
   112  		vars["CONTAINER_PARTIAL_ORDINAL"] = strconv.Itoa(msg.PLogMetaData.Ordinal)
   113  		vars["CONTAINER_PARTIAL_LAST"] = strconv.FormatBool(msg.PLogMetaData.Last)
   114  		if !msg.PLogMetaData.Last {
   115  			vars["CONTAINER_PARTIAL_MESSAGE"] = "true"
   116  		}
   117  	}
   118  
   119  	line := string(msg.Line)
   120  	source := msg.Source
   121  	logger.PutMessage(msg)
   122  
   123  	if source == "stderr" {
   124  		return journal.Send(line, journal.PriErr, vars)
   125  	}
   126  	return journal.Send(line, journal.PriInfo, vars)
   127  }
   128  
   129  func (s *journald) Name() string {
   130  	return name
   131  }