{"record":{"id":"44746b0680d29b53","repo":"vxcontrol/pentagi","slug":"failed-to-attach-list-exec-for-s-w","errorCode":null,"errorMessage":"failed to attach list exec for '%s': %w","messagePattern":"failed to attach list exec for '(.+?)': %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"backend/pkg/docker/client.go","lineNumber":998,"sourceCode":"\t// TTY GNU coreutils shell-quotes names and busybox wraps them in ANSI escapes,\n\t// so a readable file with a space / quote / non-ASCII byte would be mis-stat'd\n\t// and reported unreadable. `find -print0` emits literal bytes and is portable\n\t// (GNU + busybox); the NUL delimiter also survives names containing newlines.\n\t// No TTY: a TTY's onlcr would rewrite every \\n in the stream to \\r\\n —\n\t// including a \\n that is part of a filename — corrupting the name. Without a\n\t// TTY the exec stream is multiplexed and demuxed below.\n\tcreateResp, err := dc.ContainerExecCreate(ctx, containerID, client.ExecCreateOptions{\n\t\tCmd:          []string{\"find\", dirPath, \"-maxdepth\", \"1\", \"-mindepth\", \"1\", \"!\", \"-name\", \".*\", \"-print0\"},\n\t\tAttachStdout: true,\n\t\tAttachStderr: true,\n\t})\n\tif err != nil {\n\t\treturn ContainerDirListing{}, fmt.Errorf(\"failed to create list exec for '%s': %w\", dirPath, err)\n\t}\n\n\tresp, err := dc.ContainerExecAttach(ctx, createResp.ID, client.ExecAttachOptions{})\n\tif err != nil {\n\t\treturn ContainerDirListing{}, fmt.Errorf(\"failed to attach list exec for '%s': %w\", dirPath, err)\n\t}\n\toutput, readErr := demuxExecStdout(resp.Reader, maxListStdoutBytes)\n\tresp.Close()\n\tif readErr != nil {\n\t\treturn ContainerDirListing{}, fmt.Errorf(\"failed to read list output for '%s': %w\", dirPath, readErr)\n\t}\n\n\tinspect, err := dc.ContainerExecInspect(ctx, createResp.ID)\n\tif err != nil {\n\t\treturn ContainerDirListing{}, fmt.Errorf(\"failed to inspect list exec for '%s': %w\", dirPath, err)\n\t}\n\tif inspect.ExitCode != 0 {\n\t\treturn ContainerDirListing{}, fmt.Errorf(\"list command failed for '%s' with exit code %d: %s\", dirPath, inspect.ExitCode, string(output))\n\t}\n\n\tentryPaths, truncated := parseFindEntries(output)\n\n\tstats, failures := statContainerEntries(ctx, entryPaths, containerListWorkers, func(ctx context.Context, entryPath string) (container.PathStat, error) {","sourceCodeStart":980,"sourceCodeEnd":1016,"githubUrl":"https://github.com/vxcontrol/pentagi/blob/ea665308baaff015b226f308438a68d929d0f29b/backend/pkg/docker/client.go#L980-L1016","documentation":"After the list exec is created, ListContainerDir attaches to its stdio stream via ContainerExecAttach. This error wraps a failure of that attach call — the exec's output stream could not be connected. The exec may have been created but already finished, been removed, or the daemon connection dropped.","triggerScenarios":"ContainerExecAttach(ctx, createResp.ID, ...) fails because the exec instance no longer exists (container stopped between create and attach), the Docker daemon connection broke, or the API returned 404/500 for the exec ID.","commonSituations":"Race where the container is killed right after exec creation; Docker daemon restart or socket drop; network instability against a remote Docker (tcp://) endpoint; long-lived clients hitting an idle-connection timeout.","solutions":["Retry the whole ListContainerDir call once — the exec may have raced a container shutdown","Confirm the container was still running at the time of the call and re-run on a live container","Check Docker daemon health/socket connectivity (`docker ps`, DOCKER_HOST config)","If using a remote daemon, verify network stability and keep-alive settings"],"exampleFix":null,"handlingStrategy":"retry","validationCode":"state, err := dc.ContainerInspect(ctx, containerID)\nif err != nil || !state.State.Running {\n    return fmt.Errorf(\"container gone before attach\")\n}","typeGuard":null,"tryCatchPattern":"listing, err := client.ListContainerDir(ctx, containerID, dir)\nif err != nil && strings.Contains(err.Error(), \"failed to attach list exec\") {\n    // transient: retry once with a fresh exec\n    listing, err = client.ListContainerDir(ctx, containerID, dir)\n}","preventionTips":["Avoid stopping/removing containers while introspection runs","Keep Docker daemon connections healthy; reconnect on idle timeouts","For remote daemons, use stable low-latency links","Wrap docker calls with bounded retry + backoff"],"tags":["docker","exec","stream"],"backgroundTag":"docker-exec-attach-failed","analyzedSha":"ea665308baaff015b226f308438a68d929d0f29b","analyzedAt":"2026-09-01T14:16:31.421Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}