DockerCLI/cli/command/service/logs.go

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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/cli/service/logs"
"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 := logs.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
}