{"record":{"id":"f4226ef4b1ba998e","repo":"hashicorp/nomad","slug":"received-an-error-from-stdout-log-stream-v","errorCode":null,"errorMessage":"received an error from stdout log stream: %v","messagePattern":"received an error from stdout log stream: (.+?)","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"command/alloc_logs.go","lineNumber":409,"sourceCode":"\n\t// Generate our logging UI that doesn't add any additional formatting to\n\t// output strings.\n\tlogUI, err := ui.NewLogUI(l.Ui)\n\tif err != nil {\n\t\treturn err\n\t}\n\n\t// Enter the main loop where we listen for log frames, errors, and a cancel\n\t// signal. Any error at this point will result in the stream being ended,\n\t// therefore should result in this command exiting. Otherwise, we would\n\t// just be printing a single stream, which might be hard to notice for the\n\t// user.\n\tfor {\n\t\tselect {\n\t\tcase <-signalCh:\n\t\t\treturn nil\n\t\tcase stdoutErr := <-stdoutErrCh:\n\t\t\treturn fmt.Errorf(\"received an error from stdout log stream: %v\", stdoutErr)\n\t\tcase stdoutFrame := <-stdoutFrames:\n\t\t\tif stdoutFrame != nil {\n\t\t\t\tlogUI.Output(string(stdoutFrame.Data))\n\t\t\t}\n\t\tcase stderrErr := <-stderrErrCh:\n\t\t\treturn fmt.Errorf(\"received an error from stderr log stream: %v\", stderrErr)\n\t\tcase stderrFrame := <-stderrFrames:\n\t\t\tif stderrFrame != nil {\n\t\t\t\tlogUI.Warn(string(stderrFrame.Data))\n\t\t\t}\n\t\t}\n\t}\n}\n\nfunc lookupAllocTask(alloc *api.Allocation) (string, error) {\n\ttg := alloc.Job.LookupTaskGroup(alloc.TaskGroup)\n\tif tg == nil {\n\t\treturn \"\", fmt.Errorf(\"Could not find allocation task group: %s\", alloc.TaskGroup)","sourceCodeStart":391,"sourceCodeEnd":427,"githubUrl":"https://github.com/hashicorp/nomad/blob/482b49bf1aec006f089bcfc7e632d8f6ac303e5e/command/alloc_logs.go#L391-L427","documentation":"nomad alloc logs tails an allocation's stdout log via the Nomad API's streaming Logs() call. When the background stream goroutine delivers an error on its error channel mid-stream, tailMultipleFiles aborts and wraps it in this message. It means the stdout log streaming connection failed after setup succeeded (server disconnect, allocation exit, network drop, etc.).","triggerScenarios":"Running `nomad alloc logs -f <alloc>` (tailMultipleFiles via Run) and the AllocFS().Logs(... FSLogNameStdout ...) stream errors while tailing: the allocation terminates and the server closes the stream, the Nomad client node restarts, or the HTTP streaming connection is dropped (proxy timeout, network interruption).","commonSituations":"Tailing logs of a short-lived/batch job whose allocation completes mid-tail; unstable VPN or network to the Nomad server; a load balancer killing long-lived streaming connections; Nomad client node failure or rescheduling of the allocation.","solutions":["Re-run `nomad alloc logs -f <alloc-id>`; if the allocation was rescheduled, tail the new allocation ID (`nomad status <job>` to find it).","Check connectivity to the Nomad server/agent and any proxy/LB idle timeouts in the streaming path; raise keepalive/idle timeouts.","Verify the allocation is still running with `nomad alloc status <alloc-id>` before tailing; if it exited, read the logs without -f or check with `nomad alloc logs -job`.","If errors recur, check server logs (`nomad monitor`) and client node health for the node hosting the allocation."],"exampleFix":"// before: one-shot tail that dies on stream error\nerr := c.tailMultipleFiles(client, alloc)\n\n// after: retry with backoff on transient stream errors\nfor attempt := 0; attempt < 3; attempt++ {\n    err := c.tailMultipleFiles(client, alloc)\n    if err == nil || !isRetryableStreamErr(err) {\n        return err\n    }\n    time.Sleep(time.Duration(attempt+1) * time.Second)\n}","handlingStrategy":"retry","validationCode":"alloc, _, err := client.Allocations().Info(allocID, nil)\nif err != nil { return err }\nif alloc.ClientStatus != \"running\" {\n    // allocation may exit mid-tail; fetch logs without -f instead\n    return client.AllocFS().Logs(alloc, false, task, api.FSLogNameStdout,\n        api.OffsetStart, 0, nil, nil) // handle err\n}\nreturn nil","typeGuard":"func streamAlive(errCh <-chan error) bool {\n    select {\n    case err, ok := <-errCh:\n        return ok && err == nil\n    default:\n        return true\n    }\n}","tryCatchPattern":"err := c.tailMultipleFiles(client, alloc)\nif err != nil && strings.Contains(err.Error(), \"received an error from stdout log stream\") {\n    // transient stream drop: check alloc status, then retry with backoff\n    alloc, _, _ := client.Allocations().Info(allocID, nil)\n    if alloc != nil && alloc.ClientStatus == \"running\" {\n        return retryTail(client, alloc) // bounded retries\n    }\n}","preventionTips":["Check `nomad alloc status` (ClientStatus == running) before starting a follow/tail session.","Avoid tailing allocations of batch jobs likely to exit; fetch non-followed logs instead.","Configure proxy/LB idle timeouts longer than your expected tail duration or add keepalives.","Wrap tail sessions in a retry loop with backoff for transient network drops."],"tags":["nomad","streaming","logs","network"],"backgroundTag":"log-stream-disconnected","analyzedSha":"482b49bf1aec006f089bcfc7e632d8f6ac303e5e","analyzedAt":"2026-09-04T07:54:14.808Z","contentChangedAt":"2026-09-04T07:54:14.808Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}