compose/pkg/utils/writer.go
Nicolas De loof 6204fb1c94
logs: fix for missing output on container exit (#10925)
We can't assume we receive container logs line by line. Some framework won't buffer output and will send char by char, and we also can receive looong lines which get buffered to 32kb and then cut into multiple logs.

This assumes we will catch container streams being closed before we receive a die event for container, which could be subject to race condition, but at least the impact here is minimal and the fix works for reproduction examples provided in linked issues.

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>
2023-08-23 08:57:18 -04:00

63 lines
1.5 KiB
Go

/*
Copyright 2020 Docker Compose CLI authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package utils
import (
"bytes"
"io"
)
// GetWriter creates a io.Writer that will actually split by line and format by LogConsumer
func GetWriter(consumer func(string)) io.WriteCloser {
return &splitWriter{
buffer: bytes.Buffer{},
consumer: consumer,
}
}
type splitWriter struct {
buffer bytes.Buffer
consumer func(string)
}
// Write implements io.Writer. joins all input, splits on the separator and yields each chunk
func (s *splitWriter) Write(b []byte) (int, error) {
n, err := s.buffer.Write(b)
if err != nil {
return n, err
}
for {
b = s.buffer.Bytes()
index := bytes.Index(b, []byte{'\n'})
if index < 0 {
break
}
line := s.buffer.Next(index + 1)
s.consumer(string(line[:len(line)-1]))
}
return n, nil
}
func (s *splitWriter) Close() error {
b := s.buffer.Bytes()
if len(b) == 0 {
return nil
}
s.consumer(string(b))
return nil
}