{"record":{"id":"b820e74ee9f239aa","repo":"kubernetes/kops","slug":"s-is-not-a-valid-s3-url-no-bucket-defined","errorCode":null,"errorMessage":"%s is not a valid S3 URL. No bucket defined.","messagePattern":"(.+?) is not a valid S3 URL\\. No bucket defined\\.","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"util/pkg/vfs/s3context.go","lineNumber":379,"sourceCode":"\nfunc VFSPath(url string) (string, error) {\n\tif !s3UrlRegexp.MatchString(url) {\n\t\treturn \"\", fmt.Errorf(\"%s is not a valid S3 URL\", url)\n\t}\n\tgroupNames := s3UrlRegexp.SubexpNames()\n\tresult := s3UrlRegexp.FindAllStringSubmatch(url, -1)[0]\n\n\tcaptured := map[string]string{}\n\tfor i, value := range result {\n\t\tif value != \"\" {\n\t\t\tcaptured[groupNames[i]] = value\n\t\t}\n\t}\n\tbucket := captured[\"bucket\"]\n\tpath := captured[\"path\"]\n\tif bucket == \"\" {\n\t\tif path == \"\" {\n\t\t\treturn \"\", fmt.Errorf(\"%s is not a valid S3 URL. No bucket defined.\", url)\n\t\t}\n\t\treturn fmt.Sprintf(\"s3:/%s\", path), nil\n\t}\n\treturn fmt.Sprintf(\"s3://%s%s\", bucket, path), nil\n}\n","sourceCodeStart":361,"sourceCodeEnd":385,"githubUrl":"https://github.com/kubernetes/kops/blob/4c8573c808a73d578c5eadc86d410646ea0b0d73/util/pkg/vfs/s3context.go#L361-L385","documentation":"VFSPath matched the S3 URL regex but captured neither a bucket nor a path. The best-known case is the bare URL 's3://' or an equivalent like 's3:///' — the scheme is right but there is no bucket to operate on, so kOps throws this error instead of building a bucket-less path.","triggerScenarios":"VFSPath receives a URL whose regex capture groups for 'bucket' and 'path' are both empty — e.g. 's3://', 's3:///', or a URL consisting only of scheme+separators — while converting a state-store specification via buildVFSPath. (Note: 's3://<path-only>' intentionally succeeds, returning s3:/<path>.)","commonSituations":"KOPS_STATE_STORE set to a placeholder 's3://' in CI/CD or docs copy-paste; a variable expansion that lost the bucket name (unset $BUCKET leaving 's3://'); scripts concatenating 's3://' with an empty variable; templating tools rendering empty config values.","solutions":["Set the full store including the bucket: export KOPS_STATE_STORE=s3://<your-bucket> and re-run the command","Check the variable feeding the URL is actually populated (echo \"$BUCKET\") — an empty expansion yields s3://","In scripts, fail early: [ -n \"$BUCKET\" ] || { echo 'BUCKET not set'; exit 1; } before building the s3:// URL","Fix templating/CI config so the state-store field is not rendered empty; use a required-input check in your pipeline"],"exampleFix":"// before: empty variable collapses the URL\nkops create cluster --state \"s3://${BUCKET}\"\n// error: s3:// is not a valid S3 URL. No bucket defined.\n// after\n: \"${BUCKET:?BUCKET must be set}\"\nkops create cluster --state \"s3://${BUCKET}\"","handlingStrategy":"validation","validationCode":"// Require a non-empty bucket part in the S3 URL\nurl=\"${KOPS_STATE_STORE}\"\nrest=\"${url#s3://}\"\n[[ \"$url\" == s3://* && -n \"${rest%%/*}\" ]] \\\n  || { echo \"s3 URL missing bucket: $url\"; exit 1; }","typeGuard":"func hasBucketInS3URL(url string) bool {\n\tif !strings.HasPrefix(url, \"s3://\") {\n\t\treturn false\n\t}\n\trest := strings.TrimPrefix(url, \"s3://\")\n\tbucket := rest\n\tif i := strings.IndexByte(rest, '/'); i >= 0 {\n\t\tbucket = rest[:i]\n\t}\n\treturn bucket != \"\"\n}","tryCatchPattern":null,"preventionTips":["Guard variables used to build s3:// URLs: use ${BUCKET:?message} so empty values fail fast","Never hardcode placeholder 's3://' in CI templates for the state store; make the bucket a required input","Echo/inspect KOPS_STATE_STORE when it comes from templated config before kops runs","Keep bucket and prefix together in one validated variable instead of concatenating 's3://' at call sites"],"tags":["validation","s3","configuration","empty-value"],"backgroundTag":"invalid-s3-url","analyzedSha":"4c8573c808a73d578c5eadc86d410646ea0b0d73","analyzedAt":"2026-09-05T04:13:19.212Z","contentChangedAt":"2026-09-05T04:13:19.212Z","schemaVersion":2},"datasetVersion":"2026-09-12T12:17:11.808Z"}