package docker_log import ( "bufio" "bytes" "context" "crypto/tls" "fmt" "io" "strings" "sync" "time" "unicode" "github.com/docker/docker/api/types" "github.com/docker/docker/api/types/filters" "github.com/docker/docker/pkg/stdcopy" "github.com/influxdata/telegraf" "github.com/influxdata/telegraf/filter" "github.com/influxdata/telegraf/internal" "github.com/influxdata/telegraf/internal/docker" tlsint "github.com/influxdata/telegraf/internal/tls" "github.com/influxdata/telegraf/plugins/inputs" ) var sampleConfig = ` ## Docker Endpoint ## To use TCP, set endpoint = "tcp://[ip]:[port]" ## To use environment variables (ie, docker-machine), set endpoint = "ENV" # endpoint = "unix:///var/run/docker.sock" ## When true, container logs are read from the beginning; otherwise ## reading begins at the end of the log. # from_beginning = false ## Timeout for Docker API calls. # timeout = "5s" ## Containers to include and exclude. Globs accepted. ## Note that an empty array for both will include all containers # container_name_include = [] # container_name_exclude = [] ## Container states to include and exclude. Globs accepted. ## When empty only containers in the "running" state will be captured. # container_state_include = [] # container_state_exclude = [] ## docker labels to include and exclude as tags. Globs accepted. ## Note that an empty array for both will include all labels as tags # docker_label_include = [] # docker_label_exclude = [] ## Set the source tag for the metrics to the container ID hostname, eg first 12 chars source_tag = false ## Optional TLS Config # tls_ca = "/etc/telegraf/ca.pem" # tls_cert = "/etc/telegraf/cert.pem" # tls_key = "/etc/telegraf/key.pem" ## Use TLS but skip chain & host verification # insecure_skip_verify = false ` const ( defaultEndpoint = "unix:///var/run/docker.sock" // Maximum bytes of a log line before it will be split, size is mirroring // docker code: // https://github.com/moby/moby/blob/master/daemon/logger/copier.go#L21 maxLineBytes = 16 * 1024 ) var ( containerStates = []string{"created", "restarting", "running", "removing", "paused", "exited", "dead"} // ensure *DockerLogs implements telegaf.ServiceInput _ telegraf.ServiceInput = (*DockerLogs)(nil) ) type DockerLogs struct { Endpoint string `toml:"endpoint"` FromBeginning bool `toml:"from_beginning"` Timeout internal.Duration `toml:"timeout"` LabelInclude []string `toml:"docker_label_include"` LabelExclude []string `toml:"docker_label_exclude"` ContainerInclude []string `toml:"container_name_include"` ContainerExclude []string `toml:"container_name_exclude"` ContainerStateInclude []string `toml:"container_state_include"` ContainerStateExclude []string `toml:"container_state_exclude"` IncludeSourceTag bool `toml:"source_tag"` tlsint.ClientConfig newEnvClient func() (Client, error) newClient func(string, *tls.Config) (Client, error) client Client labelFilter filter.Filter containerFilter filter.Filter stateFilter filter.Filter opts types.ContainerListOptions wg sync.WaitGroup mu sync.Mutex containerList map[string]context.CancelFunc } func (d *DockerLogs) Description() string { return "Read logging output from the Docker engine" } func (d *DockerLogs) SampleConfig() string { return sampleConfig } func (d *DockerLogs) Init() error { var err error if d.Endpoint == "ENV" { d.client, err = d.newEnvClient() if err != nil { return err } } else { tlsConfig, err := d.ClientConfig.TLSConfig() if err != nil { return err } d.client, err = d.newClient(d.Endpoint, tlsConfig) if err != nil { return err } } // Create filters err = d.createLabelFilters() if err != nil { return err } err = d.createContainerFilters() if err != nil { return err } err = d.createContainerStateFilters() if err != nil { return err } filterArgs := filters.NewArgs() for _, state := range containerStates { if d.stateFilter.Match(state) { filterArgs.Add("status", state) } } if filterArgs.Len() != 0 { d.opts = types.ContainerListOptions{ Filters: filterArgs, } } return nil } func (d *DockerLogs) addToContainerList(containerID string, cancel context.CancelFunc) error { d.mu.Lock() defer d.mu.Unlock() d.containerList[containerID] = cancel return nil } func (d *DockerLogs) removeFromContainerList(containerID string) error { d.mu.Lock() defer d.mu.Unlock() delete(d.containerList, containerID) return nil } func (d *DockerLogs) containerInContainerList(containerID string) bool { d.mu.Lock() defer d.mu.Unlock() _, ok := d.containerList[containerID] return ok } func (d *DockerLogs) cancelTails() error { d.mu.Lock() defer d.mu.Unlock() for _, cancel := range d.containerList { cancel() } return nil } func (d *DockerLogs) matchedContainerName(names []string) string { // Check if all container names are filtered; in practice I believe // this array is always of length 1. for _, name := range names { trimmedName := strings.TrimPrefix(name, "/") match := d.containerFilter.Match(trimmedName) if match { return trimmedName } } return "" } func (d *DockerLogs) Gather(acc telegraf.Accumulator) error { ctx := context.Background() acc.SetPrecision(time.Nanosecond) ctx, cancel := context.WithTimeout(ctx, d.Timeout.Duration) defer cancel() containers, err := d.client.ContainerList(ctx, d.opts) if err != nil { return err } for _, container := range containers { if d.containerInContainerList(container.ID) { continue } containerName := d.matchedContainerName(container.Names) if containerName == "" { continue } ctx, cancel := context.WithCancel(context.Background()) d.addToContainerList(container.ID, cancel) // Start a new goroutine for every new container that has logs to collect d.wg.Add(1) go func(container types.Container) { defer d.wg.Done() defer d.removeFromContainerList(container.ID) err = d.tailContainerLogs(ctx, acc, container, containerName) if err != nil && err != context.Canceled { acc.AddError(err) } }(container) } return nil } func (d *DockerLogs) hasTTY(ctx context.Context, container types.Container) (bool, error) { ctx, cancel := context.WithTimeout(ctx, d.Timeout.Duration) defer cancel() c, err := d.client.ContainerInspect(ctx, container.ID) if err != nil { return false, err } return c.Config.Tty, nil } func (d *DockerLogs) tailContainerLogs( ctx context.Context, acc telegraf.Accumulator, container types.Container, containerName string, ) error { imageName, imageVersion := docker.ParseImage(container.Image) tags := map[string]string{ "container_name": containerName, "container_image": imageName, "container_version": imageVersion, } if d.IncludeSourceTag { tags["source"] = hostnameFromID(container.ID) } // Add matching container labels as tags for k, label := range container.Labels { if d.labelFilter.Match(k) { tags[k] = label } } hasTTY, err := d.hasTTY(ctx, container) if err != nil { return err } tail := "0" if d.FromBeginning { tail = "all" } logOptions := types.ContainerLogsOptions{ ShowStdout: true, ShowStderr: true, Timestamps: true, Details: false, Follow: true, Tail: tail, } logReader, err := d.client.ContainerLogs(ctx, container.ID, logOptions) if err != nil { return err } // If the container is using a TTY, there is only a single stream // (stdout), and data is copied directly from the container output stream, // no extra multiplexing or headers. // // If the container is *not* using a TTY, streams for stdout and stderr are // multiplexed. if hasTTY { return tailStream(acc, tags, container.ID, logReader, "tty") } else { return tailMultiplexed(acc, tags, container.ID, logReader) } } func parseLine(line []byte) (time.Time, string, error) { parts := bytes.SplitN(line, []byte(" "), 2) switch len(parts) { case 1: parts = append(parts, []byte("")) } tsString := string(parts[0]) // Keep any leading space, but remove whitespace from end of line. // This preserves space in, for example, stacktraces, while removing // annoying end of line characters and is similar to how other logging // plugins such as syslog behave. message := bytes.TrimRightFunc(parts[1], unicode.IsSpace) ts, err := time.Parse(time.RFC3339Nano, tsString) if err != nil { return time.Time{}, "", fmt.Errorf("error parsing timestamp %q: %v", tsString, err) } return ts, string(message), nil } func tailStream( acc telegraf.Accumulator, baseTags map[string]string, containerID string, reader io.ReadCloser, stream string, ) error { defer reader.Close() tags := make(map[string]string, len(baseTags)+1) for k, v := range baseTags { tags[k] = v } tags["stream"] = stream r := bufio.NewReaderSize(reader, 64*1024) for { line, err := r.ReadBytes('\n') if len(line) != 0 { ts, message, err := parseLine(line) if err != nil { acc.AddError(err) } else { acc.AddFields("docker_log", map[string]interface{}{ "container_id": containerID, "message": message, }, tags, ts) } } if err != nil { if err == io.EOF { return nil } return err } } } func tailMultiplexed( acc telegraf.Accumulator, tags map[string]string, containerID string, src io.ReadCloser, ) error { outReader, outWriter := io.Pipe() errReader, errWriter := io.Pipe() var wg sync.WaitGroup wg.Add(1) go func() { defer wg.Done() err := tailStream(acc, tags, containerID, outReader, "stdout") if err != nil { acc.AddError(err) } }() wg.Add(1) go func() { defer wg.Done() err := tailStream(acc, tags, containerID, errReader, "stderr") if err != nil { acc.AddError(err) } }() _, err := stdcopy.StdCopy(outWriter, errWriter, src) outWriter.Close() errWriter.Close() src.Close() wg.Wait() return err } // Start is a noop which is required for a *DockerLogs to implement // the telegraf.ServiceInput interface func (d *DockerLogs) Start(telegraf.Accumulator) error { return nil } func (d *DockerLogs) Stop() { d.cancelTails() d.wg.Wait() } // Following few functions have been inherited from telegraf docker input plugin func (d *DockerLogs) createContainerFilters() error { filter, err := filter.NewIncludeExcludeFilter(d.ContainerInclude, d.ContainerExclude) if err != nil { return err } d.containerFilter = filter return nil } func (d *DockerLogs) createLabelFilters() error { filter, err := filter.NewIncludeExcludeFilter(d.LabelInclude, d.LabelExclude) if err != nil { return err } d.labelFilter = filter return nil } func (d *DockerLogs) createContainerStateFilters() error { if len(d.ContainerStateInclude) == 0 && len(d.ContainerStateExclude) == 0 { d.ContainerStateInclude = []string{"running"} } filter, err := filter.NewIncludeExcludeFilter(d.ContainerStateInclude, d.ContainerStateExclude) if err != nil { return err } d.stateFilter = filter return nil } func init() { inputs.Add("docker_log", func() telegraf.Input { return &DockerLogs{ Timeout: internal.Duration{Duration: time.Second * 5}, Endpoint: defaultEndpoint, newEnvClient: NewEnvClient, newClient: NewClient, containerList: make(map[string]context.CancelFunc), } }) } func hostnameFromID(id string) string { if len(id) > 12 { return id[0:12] } return id }