{"record":{"id":"84d55f0c32ebd99a","repo":"abiosoft/colima","slug":"error-running-v-output-s-err-s","errorCode":null,"errorMessage":"error running %v, output: %s, err: %s","messagePattern":"error running (.+?), output: (.+?), err: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"environment/host/host.go","lineNumber":129,"sourceCode":"\tcmd.Stdout = &buf\n\tcmd.Stderr = &errBuf\n\n\terr := cmd.Run()\n\tif err != nil {\n\t\treturn \"\", errCmd(cmd.Args, errBuf, err)\n\t}\n\n\treturn strings.TrimSpace(buf.String()), nil\n}\n\nfunc errCmd(args []string, stderr bytes.Buffer, err error) error {\n\t// this is going to be part of a log output,\n\t// reading the first line of the error should suffice\n\toutput, _ := stderr.ReadString('\\n')\n\tif len(output) > 0 {\n\t\toutput = output[:len(output)-1]\n\t}\n\treturn fmt.Errorf(\"error running %v, output: %s, err: %s\", args, strconv.Quote(output), strconv.Quote(err.Error()))\n}\n\nfunc (h hostEnv) RunInteractive(args ...string) error {\n\tif len(args) == 0 {\n\t\treturn errors.New(\"args not specified\")\n\t}\n\tcmd := cli.CommandInteractive(args[0], args[1:]...)\n\tcmd.Env = append(os.Environ(), h.env...)\n\tif h.dir != \"\" {\n\t\tcmd.Dir = h.dir\n\t}\n\treturn cmd.Run()\n}\n\nfunc (h hostEnv) RunWith(stdin io.Reader, stdout io.Writer, args ...string) error {\n\tif len(args) == 0 {\n\t\treturn errors.New(\"args not specified\")\n\t}","sourceCodeStart":111,"sourceCodeEnd":147,"githubUrl":"https://github.com/abiosoft/colima/blob/c3a5f9184d83a197184f897a9f07eb3c01b3bc88/environment/host/host.go#L111-L147","documentation":"This is errCmd, the universal wrapper for any failed host command executed via hostEnv.Run/RunOutput: it formats the argv slice, the first line of captured stderr, and the underlying exec error. It is the single most common error surface in colima — every failed limactl/kubectl/docker/cp invocation on the host funnels through here, so the wrapped cause (err) and first stderr line are the real diagnostic payload.","triggerScenarios":"Any (h.host).Run/RunOutput/RunInteractive on the host exiting non-zero: 'limactl start' failing (VM boot errors), 'cp' failing in kubeconfig steps, 'kubectl config use-context' failing when kubectl is missing or the context is absent, brew-installed binaries removed mid-run, exec.ErrNotFound (binary not in PATH) surfaces here as err.","commonSituations":"brew upgrade removed/relinked lima or kubectl between colima runs; xcode CLT/license dialogs making helper binaries fail; PATH differences when colima runs from GUI launchers vs terminal; VM in a bad state making limactl error out; disk full making every write command fail.","solutions":["Read the message fully — 'output:' carries the command's first stderr line (e.g. limactl's actual complaint) and 'err:' the Go exec status; fix that root cause first.","Re-verify host dependencies: 'colima version', 'limactl --version', 'kubectl version --client' and reinstall missing pieces (brew install/reinstall lima kubectl).","If the failing command is limactl, inspect instance state: 'limactl list' and ~/.lima/<profile>/*.log for the underlying VM error; a wedged VM usually needs 'colima delete -f'.","Run the exact argv shown in the error manually in the same shell to reproduce interactively, e.g. copy the 'error running [...]' list verbatim.","Ensure PATH is sane in the launching context (GUI launchers, cron, CI inherit a minimal PATH — prefix /opt/homebrew/bin or /usr/local/bin)."],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":"// preflight the binary before invoking it via Run\nfunc runChecked(h environment.Host, args ...string) error {\n    if _, err := exec.LookPath(args[0]); err != nil {\n        return fmt.Errorf(\"%s not found in PATH\", args[0])\n    }\n    return h.Run(args...)\n}","typeGuard":null,"tryCatchPattern":"out, err := c.host.RunOutput(\"kubectl\", \"config\", \"use-context\", profile)\nif err != nil {\n    // errCmd embeds first stderr line; branch on known causes\n    if strings.Contains(err.Error(), exec.ErrNotFound.Error()) {\n        return fmt.Errorf(\"kubectl missing from PATH: %w\", err)\n    }\n    return fmt.Errorf(\"error updating kubeconfig: %w\", err)\n}","preventionTips":["Read the whole message — output: (first stderr line) and err: (exec status) carry the real cause.","Pin PATH in non-interactive launchers: export PATH=/opt/homebrew/bin:/usr/local/bin:$PATH.","Reproduce the exact argv printed in the error manually before guessing.","Keep lima/kubectl/docker CLIs in lockstep with your colima version."],"tags":["host","exec","command-failure","wrapper","cli"],"backgroundTag":null,"analyzedSha":"c3a5f9184d83a197184f897a9f07eb3c01b3bc88","analyzedAt":"2026-08-15T18:58:08.334Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}