wings/environment/docker/stream.go

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package docker
import (
"bufio"
"bytes"
"context"
"emperror.dev/errors"
"encoding/json"
"github.com/docker/docker/api/types"
"github.com/pterodactyl/wings/environment"
"strconv"
)
type dockerLogLine struct {
Log string `json:"log"`
}
var ErrNotAttached = errors.Sentinel("not attached to instance")
func (e *Environment) setStream(s *types.HijackedResponse) {
e.mu.Lock()
e.stream = s
e.mu.Unlock()
}
// Sends the specified command to the stdin of the running container instance. There is no
// confirmation that this data is sent successfully, only that it gets pushed into the stdin.
func (e *Environment) SendCommand(c string) error {
if !e.IsAttached() {
return ErrNotAttached
}
e.mu.RLock()
defer e.mu.RUnlock()
// If the command being processed is the same as the process stop command then we want to mark
// the server as entering the stopping state otherwise the process will stop and Wings will think
// it has crashed and attempt to restart it.
if e.meta.Stop.Type == "command" && c == e.meta.Stop.Value {
e.SetState(environment.ProcessStoppingState)
}
_, err := e.stream.Conn.Write([]byte(c + "\n"))
return errors.WithStackIf(err)
}
// Reads the log file for the server. This does not care if the server is running or not, it will
// simply try to read the last X bytes of the file and return them.
func (e *Environment) Readlog(lines int) ([]string, error) {
r, err := e.client.ContainerLogs(context.Background(), e.Id, types.ContainerLogsOptions{
ShowStdout: true,
ShowStderr: true,
Tail: strconv.Itoa(lines),
})
if err != nil {
return nil, errors.WithStackIf(err)
}
defer r.Close()
var out []string
scanner := bufio.NewScanner(r)
for scanner.Scan() {
out = append(out, scanner.Text())
}
return out, nil
}
// Docker stores the logs for server output in a JSON format. This function will iterate over the JSON
// that was read from the log file and parse it into a more human readable format.
func (e *Environment) parseLogToStrings(b []byte) ([]string, error) {
var hasError = false
var out []string
scanner := bufio.NewScanner(bytes.NewReader(b))
for scanner.Scan() {
var l dockerLogLine
// Unmarshal the contents and allow up to a single error before bailing out of the process. We
// do this because if you're arbitrarily reading a length of the file you'll likely end up
// with the first line in the output being improperly formatted JSON. In those cases we want to
// just skip over it. However if we see another error we're going to bail out because that is an
// abnormal situation.
if err := json.Unmarshal([]byte(scanner.Text()), &l); err != nil {
if hasError {
return nil, err
}
hasError = true
continue
}
out = append(out, l.Log)
}
return out, nil
}