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moby--moby/api/server/httputils/write_log_stream.go
Drew Erny 1044093bb0 refactor logs and support service logs /w tty
Refactor container logs system to make communicating log messages
internally much simpler. Move responsibility for marshalling log
messages into the REST server. Support TTY logs. Pave the way for fixing
the ambiguous bytestream format. Pave the way for fixing details.

Signed-off-by: Drew Erny <drew.erny@docker.com>
2017-04-06 17:54:11 -07:00

92 lines
2.5 KiB
Go

package httputils
import (
"fmt"
"io"
"sort"
"strings"
"golang.org/x/net/context"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/pkg/ioutils"
"github.com/docker/docker/pkg/jsonlog"
"github.com/docker/docker/pkg/stdcopy"
)
// WriteLogStream writes an encoded byte stream of log messages from the
// messages channel, multiplexing them with a stdcopy.Writer if mux is true
func WriteLogStream(ctx context.Context, w io.Writer, msgs <-chan *backend.LogMessage, config *types.ContainerLogsOptions, mux bool) {
wf := ioutils.NewWriteFlusher(w)
defer wf.Close()
wf.Flush()
// this might seem like doing below is clear:
// var outStream io.Writer = wf
// however, this GREATLY DISPLEASES golint, and if you do that, it will
// fail CI. we need outstream to be type writer because if we mux streams,
// we will need to reassign all of the streams to be stdwriters, which only
// conforms to the io.Writer interface.
var outStream io.Writer
outStream = wf
errStream := outStream
sysErrStream := errStream
if mux {
sysErrStream = stdcopy.NewStdWriter(outStream, stdcopy.Systemerr)
errStream = stdcopy.NewStdWriter(outStream, stdcopy.Stderr)
outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout)
}
for {
msg, ok := <-msgs
if !ok {
return
}
// check if the message contains an error. if so, write that error
// and exit
if msg.Err != nil {
fmt.Fprintf(sysErrStream, "Error grabbing logs: %v\n", msg.Err)
continue
}
logLine := msg.Line
if config.Details {
logLine = append([]byte(stringAttrs(msg.Attrs)+" "), logLine...)
}
if config.Timestamps {
// TODO(dperny) the format is defined in
// daemon/logger/logger.go as logger.TimeFormat. importing
// logger is verboten (not part of backend) so idk if just
// importing the same thing from jsonlog is good enough
logLine = append([]byte(msg.Timestamp.Format(jsonlog.RFC3339NanoFixed)+" "), logLine...)
}
if msg.Source == "stdout" && config.ShowStdout {
outStream.Write(logLine)
}
if msg.Source == "stderr" && config.ShowStderr {
errStream.Write(logLine)
}
}
}
type byKey []string
func (s byKey) Len() int { return len(s) }
func (s byKey) Less(i, j int) bool {
keyI := strings.Split(s[i], "=")
keyJ := strings.Split(s[j], "=")
return keyI[0] < keyJ[0]
}
func (s byKey) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func stringAttrs(a backend.LogAttributes) string {
var ss byKey
for k, v := range a {
ss = append(ss, k+"="+v)
}
sort.Sort(ss)
return strings.Join(ss, ",")
}