github.com/rsampaio/docker@v0.7.2-0.20150827203920-fdc73cc3fc31/daemon/logger/syslog/syslog.go (about)

     1  // +build linux
     2  
     3  // Package syslog provides the logdriver for forwarding server logs to syslog endpoints.
     4  package syslog
     5  
     6  import (
     7  	"errors"
     8  	"fmt"
     9  	"log/syslog"
    10  	"net"
    11  	"net/url"
    12  	"os"
    13  	"path"
    14  	"strconv"
    15  	"strings"
    16  
    17  	"github.com/Sirupsen/logrus"
    18  	"github.com/docker/docker/daemon/logger"
    19  	"github.com/docker/docker/pkg/urlutil"
    20  )
    21  
    22  const name = "syslog"
    23  
    24  var facilities = map[string]syslog.Priority{
    25  	"kern":     syslog.LOG_KERN,
    26  	"user":     syslog.LOG_USER,
    27  	"mail":     syslog.LOG_MAIL,
    28  	"daemon":   syslog.LOG_DAEMON,
    29  	"auth":     syslog.LOG_AUTH,
    30  	"syslog":   syslog.LOG_SYSLOG,
    31  	"lpr":      syslog.LOG_LPR,
    32  	"news":     syslog.LOG_NEWS,
    33  	"uucp":     syslog.LOG_UUCP,
    34  	"cron":     syslog.LOG_CRON,
    35  	"authpriv": syslog.LOG_AUTHPRIV,
    36  	"ftp":      syslog.LOG_FTP,
    37  	"local0":   syslog.LOG_LOCAL0,
    38  	"local1":   syslog.LOG_LOCAL1,
    39  	"local2":   syslog.LOG_LOCAL2,
    40  	"local3":   syslog.LOG_LOCAL3,
    41  	"local4":   syslog.LOG_LOCAL4,
    42  	"local5":   syslog.LOG_LOCAL5,
    43  	"local6":   syslog.LOG_LOCAL6,
    44  	"local7":   syslog.LOG_LOCAL7,
    45  }
    46  
    47  type syslogger struct {
    48  	writer *syslog.Writer
    49  }
    50  
    51  func init() {
    52  	if err := logger.RegisterLogDriver(name, New); err != nil {
    53  		logrus.Fatal(err)
    54  	}
    55  	if err := logger.RegisterLogOptValidator(name, ValidateLogOpt); err != nil {
    56  		logrus.Fatal(err)
    57  	}
    58  }
    59  
    60  // New creates a syslog logger using the configuration passed in on
    61  // the context. Supported context configuration variables are
    62  // syslog-address, syslog-facility, & syslog-tag.
    63  func New(ctx logger.Context) (logger.Logger, error) {
    64  	tag := ctx.Config["syslog-tag"]
    65  	if tag == "" {
    66  		tag = ctx.ContainerID[:12]
    67  	}
    68  
    69  	proto, address, err := parseAddress(ctx.Config["syslog-address"])
    70  	if err != nil {
    71  		return nil, err
    72  	}
    73  
    74  	facility, err := parseFacility(ctx.Config["syslog-facility"])
    75  	if err != nil {
    76  		return nil, err
    77  	}
    78  
    79  	log, err := syslog.Dial(
    80  		proto,
    81  		address,
    82  		facility,
    83  		path.Base(os.Args[0])+"/"+tag,
    84  	)
    85  	if err != nil {
    86  		return nil, err
    87  	}
    88  
    89  	return &syslogger{
    90  		writer: log,
    91  	}, nil
    92  }
    93  
    94  func (s *syslogger) Log(msg *logger.Message) error {
    95  	if msg.Source == "stderr" {
    96  		return s.writer.Err(string(msg.Line))
    97  	}
    98  	return s.writer.Info(string(msg.Line))
    99  }
   100  
   101  func (s *syslogger) Close() error {
   102  	return s.writer.Close()
   103  }
   104  
   105  func (s *syslogger) Name() string {
   106  	return name
   107  }
   108  
   109  func parseAddress(address string) (string, string, error) {
   110  	if address == "" {
   111  		return "", "", nil
   112  	}
   113  	if !urlutil.IsTransportURL(address) {
   114  		return "", "", fmt.Errorf("syslog-address should be in form proto://address, got %v", address)
   115  	}
   116  	url, err := url.Parse(address)
   117  	if err != nil {
   118  		return "", "", err
   119  	}
   120  
   121  	// unix socket validation
   122  	if url.Scheme == "unix" {
   123  		if _, err := os.Stat(url.Path); err != nil {
   124  			return "", "", err
   125  		}
   126  		return url.Scheme, url.Path, nil
   127  	}
   128  
   129  	// here we process tcp|udp
   130  	host := url.Host
   131  	if _, _, err := net.SplitHostPort(host); err != nil {
   132  		if !strings.Contains(err.Error(), "missing port in address") {
   133  			return "", "", err
   134  		}
   135  		host = host + ":514"
   136  	}
   137  
   138  	return url.Scheme, host, nil
   139  }
   140  
   141  // ValidateLogOpt looks for syslog specific log options
   142  // syslog-address, syslog-facility, & syslog-tag.
   143  func ValidateLogOpt(cfg map[string]string) error {
   144  	for key := range cfg {
   145  		switch key {
   146  		case "syslog-address":
   147  		case "syslog-facility":
   148  		case "syslog-tag":
   149  		default:
   150  			return fmt.Errorf("unknown log opt '%s' for syslog log driver", key)
   151  		}
   152  	}
   153  	if _, _, err := parseAddress(cfg["syslog-address"]); err != nil {
   154  		return err
   155  	}
   156  	if _, err := parseFacility(cfg["syslog-facility"]); err != nil {
   157  		return err
   158  	}
   159  	return nil
   160  }
   161  
   162  func parseFacility(facility string) (syslog.Priority, error) {
   163  	if facility == "" {
   164  		return syslog.LOG_DAEMON, nil
   165  	}
   166  
   167  	if syslogFacility, valid := facilities[facility]; valid {
   168  		return syslogFacility, nil
   169  	}
   170  
   171  	fInt, err := strconv.Atoi(facility)
   172  	if err == nil && 0 <= fInt && fInt <= 23 {
   173  		return syslog.Priority(fInt << 3), nil
   174  	}
   175  
   176  	return syslog.Priority(0), errors.New("invalid syslog facility")
   177  }