{"record":{"id":"0e819f55feaf9cdd","repo":"apache/beam","slug":"unable-to-create-the-keytab-file-for-the-provided-secret","errorCode":null,"errorMessage":"Unable to create the keytab file for the provided secret.","messagePattern":"Unable to create the keytab file for the provided secret\\.","errorType":"exception","errorClass":"RuntimeException","httpStatus":null,"severity":"error","filePath":"sdks/java/extensions/kafka-factories/src/main/java/org/apache/beam/sdk/extensions/kafka/factories/KerberosConsumerFactoryFn.java","lineNumber":141,"sourceCode":"        // a keytab file and overwrite it.\n        continue;\n      }\n      String filename = \"kafka-client-\" + UUID.randomUUID().toString() + \".keytab\";\n\n      localFileString = super.getBaseDirectory() + \"/\" + LOCAL_FACTORY_TYPE + \"/\" + filename;\n      Path localFilePath = Paths.get(localFileString);\n      Path parentDir = localFilePath.getParent();\n      try {\n        if (parentDir != null) {\n          Files.createDirectories(parentDir);\n        }\n        Files.write(localFilePath, secretValue);\n        if (!new File(localFileString).canRead()) {\n          LOG.warn(\"The file is not readable\");\n        }\n        LOG.info(\"Successfully wrote file to path: {}\", localFilePath);\n      } catch (IOException e) {\n        throw new RuntimeException(\"Unable to create the keytab file for the provided secret.\");\n      }\n    }\n    // if no localFile was created, then we can assume that the secret is meant to be kept as a\n    // value.\n    return localFileString.isEmpty()\n        ? new String(secretValue, StandardCharsets.UTF_8)\n        : localFileString;\n  }\n}\n","sourceCodeStart":123,"sourceCodeEnd":151,"githubUrl":"https://github.com/apache/beam/blob/12126d8942aaf848030c478b4c6a28c6af861c66/sdks/java/extensions/kafka-factories/src/main/java/org/apache/beam/sdk/extensions/kafka/factories/KerberosConsumerFactoryFn.java#L123-L151","documentation":"While rewriting keytab secret references in sasl.jaas.config, processSecret() matches each secret reference and requires a non-empty captured secret ID. If the regex matched but group(1) is null or empty, it throws this RuntimeException, since it cannot resolve a secret for an empty identifier.","triggerScenarios":"sasl.jaas.config contains a keytab secret reference whose captured group is empty — e.g. a dangling prefix like \"gs://\" or an empty ${...}/secret placeholder produced by templating.","commonSituations":"Config templating left an empty variable; hand-edited sasl.jaas.config with a truncated secret URL; regex-matching a prefix pattern in a value that was never fully substituted.","solutions":["Inspect the sasl.jaas.config value and fix the incomplete secret reference so the captured secret ID is non-empty","Ensure template substitution ran before the pipeline consumed the config","Validate the secret reference format (prefix + non-empty ID) in a pre-launch config check","Escape/avoid literal occurrences of the secret prefix pattern in unrelated values"],"exampleFix":"// before\nkeyTab=\"${KEYTAB_SECRET}\"   // substituted to empty\n// after\nkeyTab=\"gs://my-bucket/secrets/krb5.keytab\"  // non-empty secret reference","handlingStrategy":"try-catch","validationCode":"java\nPath dir = Paths.get(localKeytabDir);\nif (!Files.isDirectory(dir) || !Files.isWritable(dir)) {\n  throw new IllegalStateException(\"Keytab directory missing or not writable: \" + dir);\n}","typeGuard":null,"tryCatchPattern":"java\ntry {\n  factoryFn.processSecret(config);\n} catch (RuntimeException ex) {\n  if (ex.getMessage().startsWith(\"Unable to create the keytab file\")) {\n    log.severe(\"Keytab write failed — check worker FS permissions/disk (cause not chained)\");\n  }\n}","preventionTips":["Pre-create a writable staging directory in the worker image","Ensure containers run with a writable /tmp or designated keytab dir","Monitor disk space on workers","Instrument Files.write with your own try/catch to capture the real IOException"],"tags":["java","kafka","kerberos","configuration"],"backgroundTag":"empty-required-field","analyzedSha":"12126d8942aaf848030c478b4c6a28c6af861c66","analyzedAt":"2026-09-13T01:50:10.254Z","contentChangedAt":"2026-09-13T01:50:10.254Z","schemaVersion":2},"datasetVersion":"2026-09-14T16:17:12.679Z"}