docker-logger/main.go

package main

import (
	"bufio"
	"context"
	"fmt"
	"io"
	"log"
	"log/slog"
	"time"

	"github.com/k0kubun/pp/v3"

	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/client"
	"github.com/docker/docker/pkg/stdcopy"

	"github.com/docker/docker/api/types/events"
	"github.com/docker/docker/api/types/filters"
)

var containers = make(map[string]int)

type LogType struct {
	Log           string
	Source        string
	ContainerName string
}

func main() {
	ctx := context.Background()
	pp.Println("Running1")
	ticker := time.NewTicker(1 * time.Second)
	defer ticker.Stop()
	logschan := make(chan LogType)
	go listContainersAndLogType(ctx, logschan)

	go func() {
		time.Sleep(3 * time.Second)
		slog.Info("Slept")
	}()
	for i := range logschan {
		slog.Info(i.ContainerName + ": " + i.Log)
	}
}

func eventListen(cli *client.Client, logschan chan<- LogType) {
	ctx := context.Background()

	options := events.ListOptions{
		Filters: filters.NewArgs(
			filters.Arg("type", "container"),
		),
	}

	eventChan, errChan := cli.Events(ctx, options)

	slog.Info("Waiting for events")
	for {
		select {
		case event := <-eventChan:
			switch event.Action {
			case "create":
				fmt.Println("Container created:", event.Actor.Attributes["image"])
			case "start":
				fmt.Println("Container started:", event.Actor.Attributes["image"])
				streamContainerLogs(ctx, cli, event.Actor.ID, logschan)
			case "die":
				fmt.Println("Container stopped:", event.Actor.Attributes["image"])
			case "destroy":
				fmt.Println("Container destroyed:", event.Actor.Attributes["image"])
			}
		case err := <-errChan:
			if err != nil {
				fmt.Println("Error listening to Docker events:", err)
				return
			}
		}
	}
}

func listContainersAndLogType(ctx context.Context, logschan chan<- LogType) {
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		log.Fatalf("Error creating Docker client: %v", err)
	}

	containers, err := cli.ContainerList(ctx, container.ListOptions{All: true})
	if err != nil {
		log.Fatalf("Error listing containers: %v", err)
	}

	pp.Println(len(containers))
	for _, curcont := range containers {
		go func() {
			defer streamContainerLogs(ctx, cli, curcont.ID, logschan)
		}()
	}

	fmt.Println("Ending")
	eventListen(cli, logschan)
}

func streamContainerLogs(ctx context.Context, cli *client.Client, containerID string, logschan chan<- LogType) {
	inspect, err := cli.ContainerInspect(ctx, containerID)
	if err != nil {
		log.Printf("Error inspecting container %s: %v", containerID, err)
		return
	}

	if len(inspect.Config.Cmd) == 0 {
		slog.Debug("Skipping container as cmd empty", "container-id", containerID, "container-image", inspect.Image)
		return
	}
	if inspect.Config.Cmd[0] == "/lilog" || inspect.Config.Cmd[0] == "sh" {
		slog.Debug("Skipping own container logs")
		return
	}

	logType := inspect.HostConfig.LogConfig.Type

	if inspect.State.Status != "running" {
		slog.Debug("Skipping container which isn't running", "container-id", containerID)
		return
	}

	fmt.Printf("Container: %s (%-20s) ID: %.12s LogDriver: %s\n",
		inspect.Config.Cmd[0], inspect.Image, inspect.ID, logType)
	reader, err := cli.ContainerLogs(ctx, containerID, container.LogsOptions{
		ShowStdout: true,
		ShowStderr: true,
		Follow:     true,
		Tail:       "0",
	})
	if err != nil {
		panic(err)
	}

	defer reader.Close()

	if inspect.Config.Tty {
		scanner := bufio.NewScanner(reader)
		for scanner.Scan() {
			logschan <- LogType{ContainerName: inspect.Name, Source: "tty", Log: scanner.Text()}
		}
	} else {
		stdoutPR, stdoutPW := io.Pipe()
		stderrPR, stderrPW := io.Pipe()

		defer stdoutPW.Close()
		defer stderrPW.Close()

		go func() {
			scanner := bufio.NewScanner(stdoutPR)
			for scanner.Scan() {
				logschan <- LogType{
					ContainerName: inspect.Name,
					Source:        "tty",
					Log:           scanner.Text(),
				}
			}
		}()

		go func() {
			scanner := bufio.NewScanner(stderrPR)
			for scanner.Scan() {
				logschan <- LogType{
					ContainerName: inspect.Name,
					Source:        "tty",
					Log:           scanner.Text(),
				}
			}
		}()

		_, err := stdcopy.StdCopy(stdoutPW, stderrPW, reader)
		if err != nil {
			panic(err)
		}
	}
}