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moby--moby/api/server/httputils/write_log_stream.go
Aaron Lehmann b642b3f21f Avoid using a map for log attributes
Having a map per log entry seemed heavier than necessary. These
attributes end up being sorted and serialized, so storing them in a map
doesn't add anything (there's no random access element). In SwarmKit,
they originate as a slice, so there's an unnecessary conversion to a map
and back.

This also fixes the sort comparator, which used to inefficiently split
the string on each comparison.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2017-07-18 19:01:20 -07:00

96 lines
2.8 KiB
Go

package httputils
import (
"fmt"
"io"
"net/url"
"sort"
"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(attrsByteSlice(msg.Attrs), ' ')
logLine = append(logLine, msg.Line...)
}
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 []backend.LogAttr
func (b byKey) Len() int { return len(b) }
func (b byKey) Less(i, j int) bool { return b[i].Key < b[j].Key }
func (b byKey) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
func attrsByteSlice(a []backend.LogAttr) []byte {
// Note this sorts "a" in-place. That is fine here - nothing else is
// going to use Attrs or care about the order.
sort.Sort(byKey(a))
var ret []byte
for i, pair := range a {
k, v := url.QueryEscape(pair.Key), url.QueryEscape(pair.Value)
ret = append(ret, []byte(k)...)
ret = append(ret, '=')
ret = append(ret, []byte(v)...)
if i != len(a)-1 {
ret = append(ret, ',')
}
}
return ret
}