{"record":{"id":"68d131a13731e0f4","repo":"hashicorp/nomad","slug":"error-at-index-d-err-w","errorCode":null,"errorMessage":"error at index: %d, Err: %w","messagePattern":"error at index: (.+?), Err: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"command/operator_debug.go","lineNumber":970,"sourceCode":"\t\t}\n\t\treturn fmt.Errorf(\"failed to stream events: %w\", err)\n\t}\n\n\teventCount := 0\n\terrCount := 0\n\theartbeatCount := 0\n\tchannelEventCount := 0\n\n\tvar mErrs *multierror.Error\n\n\tfor {\n\t\tselect {\n\t\tcase event := <-eventCh:\n\t\t\tchannelEventCount++\n\t\t\tif event.Err != nil {\n\t\t\t\terrCount++\n\t\t\t\tc.verboseOutf(\"error from event stream: index; %d err: %v\", event.Index, event.Err)\n\t\t\t\tmErrs = multierror.Append(mErrs, fmt.Errorf(\"error at index: %d, Err: %w\", event.Index, event.Err))\n\t\t\t\tbreak\n\t\t\t}\n\n\t\t\tif event.IsHeartbeat() {\n\t\t\t\theartbeatCount++\n\t\t\t\tcontinue\n\t\t\t}\n\n\t\t\tfor _, e := range event.Events {\n\t\t\t\teventCount++\n\t\t\t\tc.verboseOutf(\"Event: %4d, Index: %d, Topic: %-10s, Type: %s, FilterKeys: %s\", eventCount, e.Index, e.Topic, e.Type, e.FilterKeys)\n\n\t\t\t\tbytes, err := json.Marshal(e)\n\t\t\t\tif err != nil {\n\t\t\t\t\terrCount++\n\t\t\t\t\tmErrs = multierror.Append(mErrs, fmt.Errorf(\"failed to marshal json from Topic: %s, Type: %s, Err: %w\", e.Topic, e.Type, err))\n\t\t\t\t}\n","sourceCodeStart":952,"sourceCodeEnd":988,"githubUrl":"https://github.com/hashicorp/nomad/blob/482b49bf1aec006f089bcfc7e632d8f6ac303e5e/command/operator_debug.go#L952-L988","documentation":"While consuming the event channel, each received event carries its own Err field. When an individual streamed frame reports an error, captureEventStream counts it, logs it, and appends it to a multierror wrapped as 'error at index: N, Err: ...'. The capture loop keeps running; these errors surface at the end via mErrs.ErrorOrNil().","triggerScenarios":"The agent pushed an error frame onto the event channel — typically the blocking query timed out or was broken (agent restart, 5xx, RPC error) and the stream delivered an event whose Err is non-nil at a specific index.","commonSituations":"Long captures crossing the agent's blocking-query default timeout (10m) where the library re-blocks but surfaces an intermediate error; agent reload/restart during capture; transient network blips between client and agent.","solutions":["Inspect the wrapped Err for the specific index — it names the per-frame cause (timeout, EOF, 5xx)","Treat isolated occurrences as transient: rerun the capture to get a clean eventstream.json","If timeouts recur, keep the capture duration under the agent's blocking query limits or use an agent with higher query timeout settings","Verify agent health/stability (server/agent logs) if error frames appear repeatedly"],"exampleFix":null,"handlingStrategy":"fallback","validationCode":null,"typeGuard":"func isEventError(ev events.Event) bool { return ev.Err != nil }","tryCatchPattern":"for event := range eventCh {\n\tif event.Err != nil {\n\t\terrs = multierror.Append(errs, fmt.Errorf(\"error at index: %d, Err: %w\", event.Index, event.Err))\n\t\tcontinue // keep capturing later events\n\t}\n}","preventionTips":["Keep capture windows shorter than the agent's blocking-query timeout","Monitor agent logs for restarts/RPC errors during captures","Rerun the capture if per-frame errors are frequent"],"tags":["streaming","consul-api","partial-failure"],"backgroundTag":"stream-error-event","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"}