{"record":{"id":"686a1aea412038da","repo":"chenhg5/cc-connect","slug":"codex-app-server-stderr-pipe-w","errorCode":null,"errorMessage":"codex app-server stderr pipe: %w","messagePattern":"codex app-server stderr pipe: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"agent/codex/appserver_session.go","lineNumber":274,"sourceCode":"\tenv := append([]string(nil), s.extraEnv...)\n\tif s.codexHome != \"\" {\n\t\tenv = append(env, \"CODEX_HOME=\"+s.codexHome)\n\t}\n\tif len(env) > 0 {\n\t\tcmd.Env = core.MergeEnv(os.Environ(), env)\n\t}\n\n\tstdin, err := cmd.StdinPipe()\n\tif err != nil {\n\t\treturn fmt.Errorf(\"codex app-server stdin pipe: %w\", err)\n\t}\n\tstdout, err := cmd.StdoutPipe()\n\tif err != nil {\n\t\treturn fmt.Errorf(\"codex app-server stdout pipe: %w\", err)\n\t}\n\tstderr, err := cmd.StderrPipe()\n\tif err != nil {\n\t\treturn fmt.Errorf(\"codex app-server stderr pipe: %w\", err)\n\t}\n\tif err := cmd.Start(); err != nil {\n\t\treturn fmt.Errorf(\"codex app-server start: %w\", err)\n\t}\n\n\ts.procMu.Lock()\n\ts.cmd = cmd\n\ts.stdin = stdin\n\ts.procMu.Unlock()\n\n\tslog.Info(\"codex app-server session started\", \"transport\", \"stdio\", \"pid\", cmd.Process.Pid, \"work_dir\", s.workDir)\n\n\ts.wg.Add(3)\n\tgo s.readLoop(stdout)\n\tgo s.stderrLoop(stderr)\n\tgo s.waitLoop()\n\treturn nil\n}","sourceCodeStart":256,"sourceCodeEnd":292,"githubUrl":"https://github.com/chenhg5/cc-connect/blob/4000b2338aa6e850c99df54f8b0ed6ed7460b401/agent/codex/appserver_session.go#L256-L292","documentation":"This error wraps a failure from cmd.StderrPipe() while starting the codex app-server child process. The stderr pipe is required to capture app-server diagnostics; failing to allocate it aborts startup. The cause is OS-level, most commonly file-descriptor exhaustion.","triggerScenarios":"Calling StartSession on the codex agent; the third pipe acquisition (cmd.StderrPipe()) in the startup sequence returns an error — nearly always EMFILE/ENFILE after stdin/stdout pipes succeeded.","commonSituations":"See trigger scenarios.","solutions":["Raise the file-descriptor limit (ulimit -n 8192 or systemd LimitNOFILE=8192).","Check for fd leaks with lsof and ensure sessions close all three pipes.","Restart the daemon as an immediate mitigation."],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":"var lim syscall.Rlimit\nsyscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)\nif fdCount() > int(lim.Cur)-64 {\n    return errors.New(\"fd limit nearly exhausted\")\n}","typeGuard":null,"tryCatchPattern":"if err := session.Start(ctx); err != nil {\n    if errors.Is(err, syscall.EMFILE) || errors.Is(err, syscall.ENFILE) {\n        // environment problem, not a codex bug: surface actionable message\n        return fmt.Errorf(\"fd exhaustion (raise RLIMIT_NOFILE): %w\", err)\n    }\n    return err\n}","preventionTips":["Raise fd limits in deployment manifests (systemd, Docker default-ulimits).","Pair every process start with guaranteed teardown (defer Close).","Alert on fd-count growth trends."],"tags":["go","process","file-descriptors","pipe"],"backgroundTag":"file-descriptor-exhausted","analyzedSha":"4000b2338aa6e850c99df54f8b0ed6ed7460b401","analyzedAt":"2026-09-06T11:45:09.575Z","contentChangedAt":"2026-09-06T11:45:09.575Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}