telegraf/plugins/inputs/docker_log/docker_log.go

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package docker_log
import (
"bufio"
"context"
"crypto/tls"
"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 = []
## 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"`
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()
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 {
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,
}
// 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: false,
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 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)
var err error
var message string
for {
message, err = r.ReadString('\n')
// 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 = strings.TrimRightFunc(message, unicode.IsSpace)
if len(message) != 0 {
acc.AddFields("docker_log", map[string]interface{}{
"container_id": containerID,
"message": message,
}, tags)
}
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),
}
})
}