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moby--moby/engine/job.go

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package engine
import (
"io"
"strings"
"fmt"
"encoding/json"
"github.com/dotcloud/docker/utils"
)
// 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 []string
Stdin io.ReadCloser
Stdout io.WriteCloser
Stderr io.WriteCloser
handler func(*Job) string
status string
}
// 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 {
randId := utils.RandomString()[:4]
fmt.Printf("Job #%s: %s\n", randId, job)
defer fmt.Printf("Job #%s: %s = '%s'", randId, job, job.status)
if job.handler == nil {
job.status = "command not found"
} else {
job.status = job.handler(job)
}
if job.status != "0" {
return fmt.Errorf("%s: %s", job.Name, job.status)
}
return nil
}
// String returns a human-readable description of `job`
func (job *Job) String() string {
return strings.Join(append([]string{job.Name}, job.Args...), " ")
}
func (job *Job) Getenv(key string) (value string) {
for _, kv := range job.env {
if strings.Index(kv, "=") == -1 {
continue
}
parts := strings.SplitN(kv, "=", 2)
if parts[0] != key {
continue
}
if len(parts) < 2 {
value = ""
} else {
value = parts[1]
}
}
return
}
func (job *Job) GetenvBool(key string) (value bool) {
s := strings.ToLower(strings.Trim(job.Getenv(key), " \t"))
if s == "" || s == "0" || s == "no" || s == "false" || s == "none" {
return false
}
return true
}
func (job *Job) SetenvBool(key string, value bool) {
if value {
job.Setenv(key, "1")
} else {
job.Setenv(key, "0")
}
}
func (job *Job) GetenvList(key string) []string {
sval := job.Getenv(key)
l := make([]string, 0, 1)
if err := json.Unmarshal([]byte(sval), &l); err != nil {
l = append(l, sval)
}
return l
}
func (job *Job) SetenvList(key string, value []string) error {
sval, err := json.Marshal(value)
if err != nil {
return err
}
job.Setenv(key, string(sval))
return nil
}
func (job *Job) Setenv(key, value string) {
job.env = append(job.env, key + "=" + value)
}