{"record":{"id":"b08b881af86d2be3","repo":"vitessio/vitess","slug":"no-route-variable-found-with-name-s","errorCode":null,"errorMessage":"no route variable found with name %s","messagePattern":"no route variable found with name (.+?)","errorType":"http","errorClass":"errors.Internal","httpStatus":500,"severity":"error","filePath":"go/vt/vtadmin/http/request.go","lineNumber":132,"sourceCode":"\n\treturn defaultVal, nil\n}\n\n// Vars is a mapping of the route variable values in a given request.\n//\n// See (gorilla/mux).Vars for details. We define a type here to add some\n// additional behavior for extracting non-string values.\ntype Vars map[string]string\n\n// GetTabletAlias returns the route named `key` as a TabletAlias.\n//\n// It returns an error if the route has no variable with that name, or if it\n// cannot be parsed as a TabletAlias.\nfunc (v Vars) GetTabletAlias(key string) (*topodatapb.TabletAlias, error) {\n\taliasStr, ok := v[key]\n\tif !ok {\n\t\treturn nil, &errors.Internal{\n\t\t\tErr: fmt.Errorf(\"no route variable found with name %s\", key),\n\t\t}\n\t}\n\n\talias, err := topoproto.ParseTabletAlias(aliasStr)\n\tif err != nil {\n\t\treturn nil, &errors.BadRequest{\n\t\t\tErr:        err,\n\t\t\tErrDetails: fmt.Sprintf(\"could not parse route variable %s (= %v) as tablet alias\", key, aliasStr),\n\t\t}\n\t}\n\n\treturn alias, nil\n}\n","sourceCodeStart":114,"sourceCodeEnd":146,"githubUrl":"https://github.com/vitessio/vitess/blob/01a25a7d176f94613b8d59d799f438380a8760e4/go/vt/vtadmin/http/request.go#L114-L146","documentation":"VVars.GetTabletAlias in vtadmin's HTTP layer looks up a route variable by name and parses it as a TabletAlias. If the named route variable is absent from the request (wrong path template or missing parameter), it returns an errors.Internal indicating the variable was not found. This signals a routing/registration mismatch rather than bad user input.","triggerScenarios":"Calling GetTabletAlias(key) from an HTTP handler whose route does not define a `{key}` variable — e.g., handler registered for /tablet/{cluster_id} but code reads \"alias\"; typo between route template and key name.","commonSituations":"Developer adds a new handler but forgets the variable in the path pattern; copies a handler from another route with a differently named variable; client hits the wrong endpoint so no vars are populated.","solutions":["Ensure the route pattern declares the variable, e.g. /tablets/{cluster_id}/{alias}.","Fix the key string passed to GetTabletAlias to match the route variable name exactly (case-sensitive).","If the value is user-supplied and optional, use vars[key] directly and return a 400 instead of relying on GetTabletAlias.","Check that the client is calling the intended endpoint that carries the alias."],"exampleFix":"// before (route: /tablets/{cluster_id})\nalias, err := vars.GetTabletAlias(\"alias\")\n// after (route: /tablets/{cluster_id}/{alias})\napi.router.HandleFunc(\"/tablets/{cluster_id}/{alias}\", api.getTablet)\nalias, err := vars.GetTabletAlias(\"alias\")","handlingStrategy":"validation","validationCode":"if val, ok := mux.Vars(r)[\"alias\"]; !ok || val == \"\" {\n\thttp.Error(w, \"missing alias path parameter\", http.StatusBadRequest)\n\treturn\n}","typeGuard":"func hasVar(v httprouter.Params, key string) bool {\n\treturn v.ByName(key) != \"\"\n}","tryCatchPattern":"alias, err := vars.GetTabletAlias(\"alias\")\nif err != nil {\n\tvar e *errors.Internal\n\tif stderrors.As(err, &e) {\n\t\t// route/template mismatch — fix registration, not the request\n\t}\n\tNewErrorResponse(w, err)\n\treturn\n}","preventionTips":["Keep route variable names and GetTabletAlias keys in sync; define them as constants.","Add a startup test that hits each route with sample paths to verify vars resolve.","Review handler registrations when copying handlers between routes."],"tags":["http","routing","vtadmin","request-parsing"],"backgroundTag":"missing-route-variable","analyzedSha":"01a25a7d176f94613b8d59d799f438380a8760e4","analyzedAt":"2026-09-01T17:28:30.605Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}