{"record":{"id":"8c8ae4dab0fd3ead","repo":"kubernetes/kops","slug":"failed-to-parse-template-error-s","errorCode":null,"errorMessage":"failed to parse template, error: %s","messagePattern":"failed to parse template, error: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/util/templater/templater.go","lineNumber":69,"sourceCode":"\tif failOnMissing {\n\t\ttm.Option(\"missingkey=error\")\n\t}\n\n\t// @step: add the snippits into the mix\n\tfor filename, snippet := range snippets {\n\t\tif filename == templateName {\n\t\t\treturn \"\", fmt.Errorf(\"snippet cannot have the same name as the template: %s\", filename)\n\t\t}\n\t\tif _, err = tm.New(filename).Parse(snippet); err != nil {\n\t\t\treturn rendered, fmt.Errorf(\"unable to parse snippet: %s, error: %s\", filename, err)\n\t\t}\n\t}\n\n\t// @step: render the actual template\n\twriter := new(bytes.Buffer)\n\tdefer func() {\n\t\tif r := recover(); r != nil {\n\t\t\terr = fmt.Errorf(\"failed to parse template, error: %s\", r)\n\t\t}\n\t}()\n\tif err = tm.ExecuteTemplate(writer, templateName, context); err != nil {\n\t\treturn\n\t}\n\n\treturn writer.String(), nil\n}\n\n// indentContent is responsible for indenting the string content\nfunc indentContent(indent int, content string) string {\n\tvar b bytes.Buffer\n\tlength := len(strings.Split(content, \"\\n\")) - 1\n\tfor i, x := range strings.Split(content, \"\\n\") {\n\t\t// @check if the length of the line is zero and set spacer\n\t\tspacer := indent\n\t\tif i == 0 || len(x) <= 0 {\n\t\t\tspacer = 0","sourceCodeStart":51,"sourceCodeEnd":87,"githubUrl":"https://github.com/kubernetes/kops/blob/4c8573c808a73d578c5eadc86d410646ea0b0d73/pkg/util/templater/templater.go#L51-L87","documentation":"The templater package recovers from a panic raised while executing a parsed Go text/template via ExecuteTemplate and converts the recovered value into this error. A panic here is not a template syntax problem (that fails at Parse time) but a runtime failure during rendering, most commonly a nil pointer dereference while accessing nested fields in the template context. The error wraps the raw recovered value rather than the template name, so it can be terse.","triggerScenarios":"tm.ExecuteTemplate panics while rendering the named template with the given context — e.g. a template expression dereferences a nil field of the context struct/map, indexes a nil slice, or calls a template func that panics.","commonSituations":"Rendering cloudconfig / nodeup templates with a partially populated Cluster or InstanceGroup context (nil pointers in the context struct), custom template functions that panic on unexpected input, or malformed context maps passed programmatically.","solutions":["Inspect the %s value in the error: a nil pointer dereference message points to which field the template touched; populate that field on the context object before rendering","Print/debug the rendered template and context (use the templater with a small test context) to find the expression that panics","Wrap risky template funcs so they return errors instead of panicking, and validate the context struct is fully initialized before calling Render","If the panic originates in kOps template assets, verify your kOps binary and channel/addon templates are at matching versions"],"exampleFix":"// before: context built by hand, missing required field\ncontext := map[string]interface{}{\"Cluster\": nil}\nout, err := templater.Execute(templater.CloudConfigTemplate, context)\n// panic -> \"failed to parse template, error: invalid memory address or nil pointer dereference\"\n// after: ensure required context is present\nif context[\"Cluster\"] == nil {\n    return fmt.Errorf(\"cluster context required for %s template\", templater.CloudConfigTemplate)\n}\nout, err := templater.Execute(templater.CloudConfigTemplate, context)","handlingStrategy":"try-catch","validationCode":"if ctx[\"Cluster\"] == nil {\n    return fmt.Errorf(\"template context missing Cluster\")\n}","typeGuard":"func hasRequiredFields(m map[string]interface{}, keys ...string) bool {\n    for _, k := range keys {\n        if _, ok := m[k]; !ok || m[k] == nil {\n            return false\n        }\n    }\n    return true\n}","tryCatchPattern":"out, err := tm.ExecuteTemplate(writer, templateName, context)\nif err != nil {\n    var rec interface{}\n    // recovered panic surfaces as err from Render via the deferred recover\n    return fmt.Errorf(\"template %s render failed: %w\", templateName, err)\n}\n_ = rec","preventionTips":["Fully initialize the template context struct before rendering","Avoid templates that index/deref possibly-nil nested fields; guard with `if` in templates","Wrap custom template funcs to return errors instead of panicking","Add a unit test rendering each template with a representative full context"],"tags":["go","templates","panic","kops"],"backgroundTag":"template-render-panic","analyzedSha":"4c8573c808a73d578c5eadc86d410646ea0b0d73","analyzedAt":"2026-09-05T04:13:19.212Z","contentChangedAt":"2026-09-05T04:13:19.212Z","schemaVersion":2},"datasetVersion":"2026-09-12T07:17:12.445Z"}