docker-compose/ecs/logs.go

/*
   Copyright 2020 Docker, Inc.

   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 ecs

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"os"
	"os/signal"
	"strconv"
	"strings"

	"github.com/compose-spec/compose-go/cli"
)

func (b *ecsAPIService) Logs(ctx context.Context, options *cli.ProjectOptions, writer io.Writer) error {
	name := options.Name
	if name == "" {
		project, err := cli.ProjectFromOptions(options)
		if err != nil {
			return err
		}
		name = project.Name
	}

	consumer := logConsumer{
		colors: map[string]colorFunc{},
		width:  0,
		writer: writer,
	}
	err := b.SDK.GetLogs(ctx, name, consumer.Log)
	if err != nil {
		return err
	}

	signalChan := make(chan os.Signal, 1)
	signal.Notify(signalChan, os.Interrupt)
	<-signalChan
	return nil
}

func (l *logConsumer) Log(service, container, message string) {
	cf, ok := l.colors[service]
	if !ok {
		cf = <-loop
		l.colors[service] = cf
		l.computeWidth()
	}
	prefix := fmt.Sprintf("%-"+strconv.Itoa(l.width)+"s |", service)

	for _, line := range strings.Split(message, "\n") {
		buf := bytes.NewBufferString(fmt.Sprintf("%s %s\n", cf(prefix), line))
		l.writer.Write(buf.Bytes()) // nolint:errcheck
	}
}

func (l *logConsumer) computeWidth() {
	width := 0
	for n := range l.colors {
		if len(n) > width {
			width = len(n)
		}
	}
	l.width = width + 3
}

type logConsumer struct {
	colors map[string]colorFunc
	width  int
	writer io.Writer
}