| // Package streamformatter provides helper functions to format a stream. |
| package streamformatter // import "github.com/docker/docker/pkg/streamformatter" |
| |
| import ( |
| "encoding/json" |
| "fmt" |
| "io" |
| |
| "github.com/docker/docker/pkg/jsonmessage" |
| "github.com/docker/docker/pkg/progress" |
| ) |
| |
| const streamNewline = "\r\n" |
| |
| type jsonProgressFormatter struct{} |
| |
| func appendNewline(source []byte) []byte { |
| return append(source, []byte(streamNewline)...) |
| } |
| |
| // FormatStatus formats the specified objects according to the specified format (and id). |
| func FormatStatus(id, format string, a ...interface{}) []byte { |
| str := fmt.Sprintf(format, a...) |
| b, err := json.Marshal(&jsonmessage.JSONMessage{ID: id, Status: str}) |
| if err != nil { |
| return FormatError(err) |
| } |
| return appendNewline(b) |
| } |
| |
| // FormatError formats the error as a JSON object |
| func FormatError(err error) []byte { |
| jsonError, ok := err.(*jsonmessage.JSONError) |
| if !ok { |
| jsonError = &jsonmessage.JSONError{Message: err.Error()} |
| } |
| if b, err := json.Marshal(&jsonmessage.JSONMessage{Error: jsonError, ErrorMessage: err.Error()}); err == nil { |
| return appendNewline(b) |
| } |
| return []byte(`{"error":"format error"}` + streamNewline) |
| } |
| |
| func (sf *jsonProgressFormatter) formatStatus(id, format string, a ...interface{}) []byte { |
| return FormatStatus(id, format, a...) |
| } |
| |
| // formatProgress formats the progress information for a specified action. |
| func (sf *jsonProgressFormatter) formatProgress(id, action string, progress *jsonmessage.JSONProgress, aux interface{}) []byte { |
| if progress == nil { |
| progress = &jsonmessage.JSONProgress{} |
| } |
| var auxJSON *json.RawMessage |
| if aux != nil { |
| auxJSONBytes, err := json.Marshal(aux) |
| if err != nil { |
| return nil |
| } |
| auxJSON = new(json.RawMessage) |
| *auxJSON = auxJSONBytes |
| } |
| b, err := json.Marshal(&jsonmessage.JSONMessage{ |
| Status: action, |
| ProgressMessage: progress.String(), |
| Progress: progress, |
| ID: id, |
| Aux: auxJSON, |
| }) |
| if err != nil { |
| return nil |
| } |
| return appendNewline(b) |
| } |
| |
| type rawProgressFormatter struct{} |
| |
| func (sf *rawProgressFormatter) formatStatus(id, format string, a ...interface{}) []byte { |
| return []byte(fmt.Sprintf(format, a...) + streamNewline) |
| } |
| |
| func (sf *rawProgressFormatter) formatProgress(id, action string, progress *jsonmessage.JSONProgress, aux interface{}) []byte { |
| if progress == nil { |
| progress = &jsonmessage.JSONProgress{} |
| } |
| endl := "\r" |
| if progress.String() == "" { |
| endl += "\n" |
| } |
| return []byte(action + " " + progress.String() + endl) |
| } |
| |
| // NewProgressOutput returns a progress.Output object that can be passed to |
| // progress.NewProgressReader. |
| func NewProgressOutput(out io.Writer) progress.Output { |
| return &progressOutput{sf: &rawProgressFormatter{}, out: out, newLines: true} |
| } |
| |
| // NewJSONProgressOutput returns a progress.Output that formats output |
| // using JSON objects |
| func NewJSONProgressOutput(out io.Writer, newLines bool) progress.Output { |
| return &progressOutput{sf: &jsonProgressFormatter{}, out: out, newLines: newLines} |
| } |
| |
| type formatProgress interface { |
| formatStatus(id, format string, a ...interface{}) []byte |
| formatProgress(id, action string, progress *jsonmessage.JSONProgress, aux interface{}) []byte |
| } |
| |
| type progressOutput struct { |
| sf formatProgress |
| out io.Writer |
| newLines bool |
| } |
| |
| // WriteProgress formats progress information from a ProgressReader. |
| func (out *progressOutput) WriteProgress(prog progress.Progress) error { |
| var formatted []byte |
| if prog.Message != "" { |
| formatted = out.sf.formatStatus(prog.ID, prog.Message) |
| } else { |
| jsonProgress := jsonmessage.JSONProgress{Current: prog.Current, Total: prog.Total, HideCounts: prog.HideCounts, Units: prog.Units} |
| formatted = out.sf.formatProgress(prog.ID, prog.Action, &jsonProgress, prog.Aux) |
| } |
| _, err := out.out.Write(formatted) |
| if err != nil { |
| return err |
| } |
| |
| if out.newLines && prog.LastUpdate { |
| _, err = out.out.Write(out.sf.formatStatus("", "")) |
| return err |
| } |
| |
| return nil |
| } |
| |
| // AuxFormatter is a streamFormatter that writes aux progress messages |
| type AuxFormatter struct { |
| io.Writer |
| } |
| |
| // Emit emits the given interface as an aux progress message |
| func (sf *AuxFormatter) Emit(id string, aux interface{}) error { |
| auxJSONBytes, err := json.Marshal(aux) |
| if err != nil { |
| return err |
| } |
| auxJSON := new(json.RawMessage) |
| *auxJSON = auxJSONBytes |
| msgJSON, err := json.Marshal(&jsonmessage.JSONMessage{ID: id, Aux: auxJSON}) |
| if err != nil { |
| return err |
| } |
| msgJSON = appendNewline(msgJSON) |
| n, err := sf.Writer.Write(msgJSON) |
| if n != len(msgJSON) { |
| return io.ErrShortWrite |
| } |
| return err |
| } |