// Package fluentd provides the log driver for forwarding server logs // to fluentd endpoints. package fluentd import ( "fmt" "math" "net" "strconv" "strings" "time" "github.com/Sirupsen/logrus" "github.com/docker/docker/daemon/logger" "github.com/docker/docker/daemon/logger/loggerutils" "github.com/docker/go-units" "github.com/fluent/fluent-logger-golang/fluent" ) type fluentd struct { tag string containerID string containerName string writer *fluent.Fluent extra map[string]string } const ( name = "fluentd" defaultHost = "127.0.0.1" defaultPort = 24224 defaultBufferLimit = 1024 * 1024 defaultTagPrefix = "docker" // logger tries to reconnect 2**32 - 1 times // failed (and panic) after 204 years [ 1.5 ** (2**32 - 1) - 1 seconds] defaultRetryWait = 1000 defaultTimeout = 3 * time.Second defaultMaxRetries = math.MaxInt32 defaultReconnectWaitIncreRate = 1.5 addressKey = "fluentd-address" bufferLimitKey = "fluentd-buffer-limit" retryWaitKey = "fluentd-retry-wait" maxRetriesKey = "fluentd-max-retries" asyncConnectKey = "fluentd-async-connect" ) func init() { if err := logger.RegisterLogDriver(name, New); err != nil { logrus.Fatal(err) } if err := logger.RegisterLogOptValidator(name, ValidateLogOpt); err != nil { logrus.Fatal(err) } } // New creates a fluentd logger using the configuration passed in on // the context. The supported context configuration variable is // fluentd-address. func New(ctx logger.Context) (logger.Logger, error) { host, port, err := parseAddress(ctx.Config[addressKey]) if err != nil { return nil, err } tag, err := loggerutils.ParseLogTag(ctx, "{{.DaemonName}}.{{.ID}}") if err != nil { return nil, err } extra := ctx.ExtraAttributes(nil) bufferLimit := defaultBufferLimit if ctx.Config[bufferLimitKey] != "" { bl64, err := units.RAMInBytes(ctx.Config[bufferLimitKey]) if err != nil { return nil, err } bufferLimit = int(bl64) } retryWait := defaultRetryWait if ctx.Config[retryWaitKey] != "" { rwd, err := time.ParseDuration(ctx.Config[retryWaitKey]) if err != nil { return nil, err } retryWait = int(rwd.Seconds() * 1000) } maxRetries := defaultMaxRetries if ctx.Config[maxRetriesKey] != "" { mr64, err := strconv.ParseUint(ctx.Config[maxRetriesKey], 10, strconv.IntSize) if err != nil { return nil, err } maxRetries = int(mr64) } asyncConnect := false if ctx.Config[asyncConnectKey] != "" { if asyncConnect, err = strconv.ParseBool(ctx.Config[asyncConnectKey]); err != nil { return nil, err } } fluentConfig := fluent.Config{ FluentPort: port, FluentHost: host, BufferLimit: bufferLimit, RetryWait: retryWait, MaxRetry: maxRetries, AsyncConnect: asyncConnect, } logrus.WithField("container", ctx.ContainerID).WithField("config", fluentConfig). Debug("logging driver fluentd configured") log, err := fluent.New(fluentConfig) if err != nil { return nil, err } return &fluentd{ tag: tag, containerID: ctx.ContainerID, containerName: ctx.ContainerName, writer: log, extra: extra, }, nil } func (f *fluentd) Log(msg *logger.Message) error { data := map[string]string{ "container_id": f.containerID, "container_name": f.containerName, "source": msg.Source, "log": string(msg.Line), } for k, v := range f.extra { data[k] = v } // fluent-logger-golang buffers logs from failures and disconnections, // and these are transferred again automatically. return f.writer.PostWithTime(f.tag, msg.Timestamp, data) } func (f *fluentd) Close() error { return f.writer.Close() } func (f *fluentd) Name() string { return name } // ValidateLogOpt looks for fluentd specific log option fluentd-address. func ValidateLogOpt(cfg map[string]string) error { for key := range cfg { switch key { case "env": case "labels": case "tag": case addressKey: case bufferLimitKey: case retryWaitKey: case maxRetriesKey: case asyncConnectKey: // Accepted default: return fmt.Errorf("unknown log opt '%s' for fluentd log driver", key) } } if _, _, err := parseAddress(cfg["fluentd-address"]); err != nil { return err } return nil } func parseAddress(address string) (string, int, error) { if address == "" { return defaultHost, defaultPort, nil } host, port, err := net.SplitHostPort(address) if err != nil { if !strings.Contains(err.Error(), "missing port in address") { return "", 0, fmt.Errorf("invalid fluentd-address %s: %s", address, err) } return host, defaultPort, nil } portnum, err := strconv.Atoi(port) if err != nil { return "", 0, fmt.Errorf("invalid fluentd-address %s: %s", address, err) } return host, portnum, nil }