/
manifest_manager.go
87 lines (75 loc) · 2.04 KB
/
manifest_manager.go
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package main
import (
"encoding/json"
"os"
"path/filepath"
)
type manifestManager struct {
c chan manifestMsg
}
func newManifestManager(dir string) manifestManager {
return manifestManager{c: manifestLoop(dir)}
}
func (m manifestManager) set(name, reference string, manifest *DockerManifest) error {
c := make(chan *manifestMsg)
m.c <- manifestMsg{t: manifestMsgSet, name: name, reference: reference, manifest: manifest, c: c}
return (<-c).err
}
func (m manifestManager) get(name, reference string) (*DockerManifest, error) {
c := make(chan *manifestMsg)
m.c <- manifestMsg{t: manifestMsgGet, name: name, reference: reference, c: c}
res := <-c
return res.manifest, res.err
}
type manifestMsgType int
const (
manifestMsgGet manifestMsgType = iota
manifestMsgSet manifestMsgType = iota
)
type manifestMsg struct {
t manifestMsgType
c chan *manifestMsg
manifest *DockerManifest
name string
reference string
err error
}
func manifestLoop(dir string) chan manifestMsg {
ch := make(chan manifestMsg)
go func() {
for msg := range ch {
switch msg.t {
case manifestMsgGet:
subdir := filepath.Join(dir, msg.name)
if fd, err := os.Open(filepath.Join(subdir, msg.reference)); err != nil {
if err == os.ErrNotExist {
msg.c <- nil
} else {
msg.c <- &manifestMsg{err: err}
}
} else {
manifest := &DockerManifest{}
if err := json.NewDecoder(fd).Decode(manifest); err != nil {
msg.c <- &manifestMsg{err: err}
} else {
msg.c <- &manifestMsg{manifest: manifest}
}
}
case manifestMsgSet:
subdir := filepath.Join(dir, msg.name)
if err := os.MkdirAll(subdir, 0755); err != nil {
msg.c <- &manifestMsg{err: err}
} else if fd, err := os.Create(filepath.Join(subdir, msg.reference)); err != nil {
msg.c <- &manifestMsg{err: err}
} else if err := json.NewEncoder(fd).Encode(msg.manifest); err != nil {
msg.c <- &manifestMsg{err: err}
} else {
msg.c <- &manifestMsg{}
}
default:
panic(msg)
}
}
}()
return ch
}