d3m0k1d
90 lines
2.5 KiB
Go
90 lines
2.5 KiB
Go
package docker
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import (
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"bufio"
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"fmt"
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"io"
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"os/exec"
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"syscall"
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"gitea.d3m0k1d.ru/d3m0k1d/HellreigN/agent/internal/config"
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"gitea.d3m0k1d.ru/d3m0k1d/HellreigN/agent/internal/logsource"
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)
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var _ logsource.LogSource = new(DockerLogSource)
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// DockerLogSource reads logs from a Docker container via `docker logs -f`.
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type DockerLogSource struct {
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cmd *exec.Cmd
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stdout io.ReadCloser
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stdoutscanner *bufio.Scanner
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}
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// ReadLine implements logsource.LogSource.
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func (d *DockerLogSource) ReadLine() (string, error) {
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if d.stdoutscanner.Scan() {
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return d.stdoutscanner.Text(), nil
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} else {
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if d.stdoutscanner.Err() == nil {
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return "", fmt.Errorf("%w: %s", logsource.ErrDead, io.EOF)
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}
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return "", d.stdoutscanner.Err()
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}
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}
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// Close implements logsource.LogSource.
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func (d *DockerLogSource) Close() error {
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_ = d.cmd.Process.Signal(syscall.SIGTERM)
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return d.cmd.Wait()
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}
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// New creates a Docker log source for the given container.
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// The container name is taken from cfg.Path (if set) or cfg.Name.
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func New(cfg config.ServiceConfig) (*DockerLogSource, error) {
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containerName := cfg.Name
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if cfg.Path != nil && *cfg.Path != "" {
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containerName = *cfg.Path
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}
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// docker logs -f --tail=0 --no-color <container_name>
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// -f : follow new logs
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// --tail=0 : skip existing logs
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// --no-color: strip color codes for clean output
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cmd := exec.Command("docker", "logs", "-f", "--tail=0", "--no-color", containerName) //nolint:gosec
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stdout, err := cmd.StdoutPipe()
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if err != nil {
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return nil, fmt.Errorf("failed to create stdout pipe for docker logs: %w", err)
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}
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// Also capture stderr since docker logs merges stdout and stderr from the container
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stderr, err := cmd.StderrPipe()
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if err != nil {
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return nil, fmt.Errorf("failed to create stderr pipe for docker logs: %w", err)
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}
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err = cmd.Start()
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if err != nil {
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return nil, fmt.Errorf("failed to start docker logs for container %q: %w", containerName, err)
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}
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// Use MultiReader to merge stdout and stderr
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// Docker logs outputs container stdout+stderr to its own stdout, but we also
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// capture the docker CLI's stderr separately in case of errors (e.g. container not found)
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stdoutscanner := bufio.NewScanner(stdout)
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// Start a goroutine to consume stderr (we don't send docker CLI stderr as logs,
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// but we need to prevent the pipe from filling up)
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go func() {
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buf := make([]byte, 4096)
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for {
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_, err := stderr.Read(buf)
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if err != nil {
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return
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}
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}
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}()
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return &DockerLogSource{cmd, stdout, stdoutscanner}, nil
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}
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