package service import ( "bytes" "fmt" "io" "sort" "strconv" "strings" "golang.org/x/net/context" "github.com/docker/cli/cli" "github.com/docker/cli/cli/command" "github.com/docker/cli/cli/command/idresolver" "github.com/docker/docker/api/types" "github.com/docker/docker/api/types/swarm" "github.com/docker/docker/client" "github.com/docker/docker/pkg/stdcopy" "github.com/docker/docker/pkg/stringid" "github.com/pkg/errors" "github.com/spf13/cobra" ) type logsOptions struct { noResolve bool noTrunc bool noTaskIDs bool follow bool since string timestamps bool tail string details bool raw bool target string } func newLogsCommand(dockerCli *command.DockerCli) *cobra.Command { var opts logsOptions cmd := &cobra.Command{ Use: "logs [OPTIONS] SERVICE|TASK", Short: "Fetch the logs of a service or task", Args: cli.ExactArgs(1), RunE: func(cmd *cobra.Command, args []string) error { opts.target = args[0] return runLogs(dockerCli, &opts) }, Tags: map[string]string{"version": "1.29"}, } flags := cmd.Flags() // options specific to service logs flags.BoolVar(&opts.noResolve, "no-resolve", false, "Do not map IDs to Names in output") flags.BoolVar(&opts.noTrunc, "no-trunc", false, "Do not truncate output") flags.BoolVar(&opts.raw, "raw", false, "Do not neatly format logs") flags.SetAnnotation("raw", "version", []string{"1.30"}) flags.BoolVar(&opts.noTaskIDs, "no-task-ids", false, "Do not include task IDs in output") // options identical to container logs flags.BoolVarP(&opts.follow, "follow", "f", false, "Follow log output") flags.StringVar(&opts.since, "since", "", "Show logs since timestamp (e.g. 2013-01-02T13:23:37) or relative (e.g. 42m for 42 minutes)") flags.BoolVarP(&opts.timestamps, "timestamps", "t", false, "Show timestamps") flags.BoolVar(&opts.details, "details", false, "Show extra details provided to logs") flags.SetAnnotation("details", "version", []string{"1.30"}) flags.StringVar(&opts.tail, "tail", "all", "Number of lines to show from the end of the logs") return cmd } func runLogs(dockerCli *command.DockerCli, opts *logsOptions) error { ctx := context.Background() options := types.ContainerLogsOptions{ ShowStdout: true, ShowStderr: true, Since: opts.since, Timestamps: opts.timestamps, Follow: opts.follow, Tail: opts.tail, // get the details if we request it OR if we're not doing raw mode // (we need them for the context to pretty print) Details: opts.details || !opts.raw, } cli := dockerCli.Client() var ( maxLength = 1 responseBody io.ReadCloser tty bool // logfunc is used to delay the call to logs so that we can do some // processing before we actually get the logs logfunc func(context.Context, string, types.ContainerLogsOptions) (io.ReadCloser, error) ) service, _, err := cli.ServiceInspectWithRaw(ctx, opts.target, types.ServiceInspectOptions{}) if err != nil { // if it's any error other than service not found, it's Real if !client.IsErrServiceNotFound(err) { return err } task, _, err := cli.TaskInspectWithRaw(ctx, opts.target) if err != nil { if client.IsErrTaskNotFound(err) { // if the task isn't found, rewrite the error to be clear // that we looked for services AND tasks and found none err = fmt.Errorf("no such task or service: %v", opts.target) } return err } tty = task.Spec.ContainerSpec.TTY maxLength = getMaxLength(task.Slot) // use the TaskLogs api function logfunc = cli.TaskLogs } else { // use ServiceLogs api function logfunc = cli.ServiceLogs tty = service.Spec.TaskTemplate.ContainerSpec.TTY if service.Spec.Mode.Replicated != nil && service.Spec.Mode.Replicated.Replicas != nil { // if replicas are initialized, figure out if we need to pad them replicas := *service.Spec.Mode.Replicated.Replicas maxLength = getMaxLength(int(replicas)) } } // we can't prettify tty logs. tell the user that this is the case. // this is why we assign the logs function to a variable and delay calling // it. we want to check this before we make the call and checking twice in // each branch is even sloppier than this CLI disaster already is if tty && !opts.raw { return errors.New("tty service logs only supported with --raw") } // now get the logs responseBody, err = logfunc(ctx, opts.target, options) if err != nil { return err } defer responseBody.Close() // tty logs get straight copied. they're not muxed with stdcopy if tty { _, err = io.Copy(dockerCli.Out(), responseBody) return err } // otherwise, logs are multiplexed. if we're doing pretty printing, also // create a task formatter. var stdout, stderr io.Writer stdout = dockerCli.Out() stderr = dockerCli.Err() if !opts.raw { taskFormatter := newTaskFormatter(cli, opts, maxLength) stdout = &logWriter{ctx: ctx, opts: opts, f: taskFormatter, w: stdout} stderr = &logWriter{ctx: ctx, opts: opts, f: taskFormatter, w: stderr} } _, err = stdcopy.StdCopy(stdout, stderr, responseBody) return err } // getMaxLength gets the maximum length of the number in base 10 func getMaxLength(i int) int { return len(strconv.Itoa(i)) } type taskFormatter struct { client client.APIClient opts *logsOptions padding int r *idresolver.IDResolver // cache saves a pre-cooked logContext formatted string based on a // logcontext object, so we don't have to resolve names every time cache map[logContext]string } func newTaskFormatter(client client.APIClient, opts *logsOptions, padding int) *taskFormatter { return &taskFormatter{ client: client, opts: opts, padding: padding, r: idresolver.New(client, opts.noResolve), cache: make(map[logContext]string), } } func (f *taskFormatter) format(ctx context.Context, logCtx logContext) (string, error) { if cached, ok := f.cache[logCtx]; ok { return cached, nil } nodeName, err := f.r.Resolve(ctx, swarm.Node{}, logCtx.nodeID) if err != nil { return "", err } serviceName, err := f.r.Resolve(ctx, swarm.Service{}, logCtx.serviceID) if err != nil { return "", err } task, _, err := f.client.TaskInspectWithRaw(ctx, logCtx.taskID) if err != nil { return "", err } taskName := fmt.Sprintf("%s.%d", serviceName, task.Slot) if !f.opts.noTaskIDs { if f.opts.noTrunc { taskName += fmt.Sprintf(".%s", task.ID) } else { taskName += fmt.Sprintf(".%s", stringid.TruncateID(task.ID)) } } paddingCount := f.padding - getMaxLength(task.Slot) padding := "" if paddingCount > 0 { padding = strings.Repeat(" ", paddingCount) } formatted := taskName + "@" + nodeName + padding f.cache[logCtx] = formatted return formatted, nil } type logWriter struct { ctx context.Context opts *logsOptions f *taskFormatter w io.Writer } func (lw *logWriter) Write(buf []byte) (int, error) { // this works but ONLY because stdcopy calls write a whole line at a time. // if this ends up horribly broken or panics, check to see if stdcopy has // reneged on that assumption. (@god forgive me) // also this only works because the logs format is, like, barely parsable. // if something changes in the logs format, this is gonna break // there should always be at least 2 parts: details and message. if there // is no timestamp, details will be first (index 0) when we split on // spaces. if there is a timestamp, details will be 2nd (`index 1) detailsIndex := 0 numParts := 2 if lw.opts.timestamps { detailsIndex++ numParts++ } // break up the log line into parts. parts := bytes.SplitN(buf, []byte(" "), numParts) if len(parts) != numParts { return 0, errors.Errorf("invalid context in log message: %v", string(buf)) } // parse the details out details, err := client.ParseLogDetails(string(parts[detailsIndex])) if err != nil { return 0, err } // and then create a context from the details // this removes the context-specific details from the details map, so we // can more easily print the details later logCtx, err := lw.parseContext(details) if err != nil { return 0, err } output := []byte{} // if we included timestamps, add them to the front if lw.opts.timestamps { output = append(output, parts[0]...) output = append(output, ' ') } // add the context, nice and formatted formatted, err := lw.f.format(lw.ctx, logCtx) if err != nil { return 0, err } output = append(output, []byte(formatted+" | ")...) // if the user asked for details, add them to be log message if lw.opts.details { // ugh i hate this it's basically a dupe of api/server/httputils/write_log_stream.go:stringAttrs() // ok but we're gonna do it a bit different // there are optimizations that can be made here. for starters, i'd // suggest caching the details keys. then, we can maybe draw maps and // slices from a pool to avoid alloc overhead on them. idk if it's // worth the time yet. // first we need a slice d := make([]string, 0, len(details)) // then let's add all the pairs for k := range details { d = append(d, k+"="+details[k]) } // then sort em sort.Strings(d) // then join and append output = append(output, []byte(strings.Join(d, ","))...) output = append(output, ' ') } // add the log message itself, finally output = append(output, parts[detailsIndex+1]...) _, err = lw.w.Write(output) if err != nil { return 0, err } return len(buf), nil } // parseContext returns a log context and REMOVES the context from the details map func (lw *logWriter) parseContext(details map[string]string) (logContext, error) { nodeID, ok := details["com.docker.swarm.node.id"] if !ok { return logContext{}, errors.Errorf("missing node id in details: %v", details) } delete(details, "com.docker.swarm.node.id") serviceID, ok := details["com.docker.swarm.service.id"] if !ok { return logContext{}, errors.Errorf("missing service id in details: %v", details) } delete(details, "com.docker.swarm.service.id") taskID, ok := details["com.docker.swarm.task.id"] if !ok { return logContext{}, errors.Errorf("missing task id in details: %s", details) } delete(details, "com.docker.swarm.task.id") return logContext{ nodeID: nodeID, serviceID: serviceID, taskID: taskID, }, nil } type logContext struct { nodeID string serviceID string taskID string }