blob: ab8120dd44d420b9c391aec14322dadffe03b4d6 [file] [log] [blame]
package engine
import (
// A job is the fundamental unit of work in the docker engine.
// Everything docker can do should eventually be exposed as a job.
// For example: execute a process in a container, create a new container,
// download an archive from the internet, serve the http api, etc.
// The job API is designed after unix processes: a job has a name, arguments,
// environment variables, standard streams for input, output and error, and
// an exit status which can indicate success (0) or error (anything else).
// One slight variation is that jobs report their status as a string. The
// string "0" indicates success, and any other strings indicates an error.
// This allows for richer error reporting.
type Job struct {
Eng *Engine
Name string
Args []string
env *Env
Stdout *Output
Stderr *Output
Stdin *Input
handler Handler
status Status
end time.Time
onExit []func()
type Status int
const (
StatusOK Status = 0
StatusErr Status = 1
StatusNotFound Status = 127
// Run executes the job and blocks until the job completes.
// If the job returns a failure status, an error is returned
// which includes the status.
func (job *Job) Run() error {
// FIXME: make this thread-safe
// FIXME: implement wait
if !job.end.IsZero() {
return fmt.Errorf("%s: job has already completed", job.Name)
// Log beginning and end of the job
job.Eng.Logf("+job %s", job.CallString())
defer func() {
job.Eng.Logf("-job %s%s", job.CallString(), job.StatusString())
var errorMessage = bytes.NewBuffer(nil)
if job.handler == nil {
job.Errorf("%s: command not found", job.Name)
job.status = 127
} else {
job.status = job.handler(job)
job.end = time.Now()
// Wait for all background tasks to complete
if err := job.Stdout.Close(); err != nil {
return err
if err := job.Stderr.Close(); err != nil {
return err
if err := job.Stdin.Close(); err != nil {
return err
if job.status != 0 {
return fmt.Errorf("%s", Tail(errorMessage, 1))
return nil
func (job *Job) CallString() string {
return fmt.Sprintf("%s(%s)", job.Name, strings.Join(job.Args, ", "))
func (job *Job) StatusString() string {
// If the job hasn't completed, status string is empty
if job.end.IsZero() {
return ""
var okerr string
if job.status == StatusOK {
okerr = "OK"
} else {
okerr = "ERR"
return fmt.Sprintf(" = %s (%d)", okerr, job.status)
// String returns a human-readable description of `job`
func (job *Job) String() string {
return fmt.Sprintf("%s.%s%s", job.Eng, job.CallString(), job.StatusString())
func (job *Job) Env() *Env {
return job.env
func (job *Job) EnvExists(key string) (value bool) {
return job.env.Exists(key)
func (job *Job) Getenv(key string) (value string) {
return job.env.Get(key)
func (job *Job) GetenvBool(key string) (value bool) {
return job.env.GetBool(key)
func (job *Job) SetenvBool(key string, value bool) {
job.env.SetBool(key, value)
func (job *Job) GetenvSubEnv(key string) *Env {
return job.env.GetSubEnv(key)
func (job *Job) SetenvSubEnv(key string, value *Env) error {
return job.env.SetSubEnv(key, value)
func (job *Job) GetenvInt64(key string) int64 {
return job.env.GetInt64(key)
func (job *Job) GetenvInt(key string) int {
return job.env.GetInt(key)
func (job *Job) SetenvInt64(key string, value int64) {
job.env.SetInt64(key, value)
func (job *Job) SetenvInt(key string, value int) {
job.env.SetInt(key, value)
// Returns nil if key not found
func (job *Job) GetenvList(key string) []string {
return job.env.GetList(key)
func (job *Job) GetenvJson(key string, iface interface{}) error {
return job.env.GetJson(key, iface)
func (job *Job) SetenvJson(key string, value interface{}) error {
return job.env.SetJson(key, value)
func (job *Job) SetenvList(key string, value []string) error {
return job.env.SetJson(key, value)
func (job *Job) Setenv(key, value string) {
job.env.Set(key, value)
// DecodeEnv decodes `src` as a json dictionary, and adds
// each decoded key-value pair to the environment.
// If `src` cannot be decoded as a json dictionary, an error
// is returned.
func (job *Job) DecodeEnv(src io.Reader) error {
return job.env.Decode(src)
func (job *Job) EncodeEnv(dst io.Writer) error {
return job.env.Encode(dst)
func (job *Job) ImportEnv(src interface{}) (err error) {
return job.env.Import(src)
func (job *Job) Environ() map[string]string {
return job.env.Map()
func (job *Job) Logf(format string, args ...interface{}) (n int, err error) {
prefixedFormat := fmt.Sprintf("[%s] %s\n", job, strings.TrimRight(format, "\n"))
return fmt.Fprintf(job.Stderr, prefixedFormat, args...)
func (job *Job) Printf(format string, args ...interface{}) (n int, err error) {
return fmt.Fprintf(job.Stdout, format, args...)
func (job *Job) Errorf(format string, args ...interface{}) Status {
if format[len(format)-1] != '\n' {
format = format + "\n"
fmt.Fprintf(job.Stderr, format, args...)
return StatusErr
func (job *Job) Error(err error) Status {
fmt.Fprintf(job.Stderr, "%s\n", err)
return StatusErr
func (job *Job) StatusCode() int {
return int(job.status)