{"record":{"id":"3c1bc47818c6b806","repo":"gofr-dev/gofr","slug":"failed-to-read-random-bytes-w","errorCode":null,"errorMessage":"failed to read random bytes: %w","messagePattern":"failed to read random bytes: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/gofr/service/mock_oauth_server.go","lineNumber":164,"sourceCode":"\tfor key, value := range r.Form {\n\t\tif key == \"client_id\" || key == \"client_secret\" || key == \"grant_type\" {\n\t\t\tcontinue\n\t\t}\n\n\t\tclaims[key] = value\n\t}\n\n\treturn claims\n}\n\n// Helper function to generate a random string.\nfunc generateRandomString(length int) (token string, err error) {\n\t// Generate random bytes\n\tb := make([]byte, length)\n\n\t_, err = rand.Read(b) // Use crypto/rand.Read\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"failed to read random bytes: %w\", err)\n\t}\n\n\t// Encode to base64 to make it URL-safe and human-readable (for tokens)\n\treturn base64.URLEncoding.EncodeToString(b), nil\n}\n","sourceCodeStart":146,"sourceCodeEnd":170,"githubUrl":"https://github.com/gofr-dev/gofr/blob/187eb24962502e91f1fee856230670958b66e89c/pkg/gofr/service/mock_oauth_server.go#L146-L170","documentation":"generateRandomString (mock_oauth_server.go:164) reads random bytes via crypto/rand.Read to build random client credentials/tokens, and wraps any failure as \"failed to read random bytes: %w\". crypto/rand only fails when the OS entropy source is unavailable, which is effectively fatal for the process.","triggerScenarios":"Calling generateRandomString (via oAuthConfigForTests during mock server setup) when rand.Read fails — e.g. /dev/urandom unavailable in a stripped-down container or sandbox, or fd exhaustion preventing opening the entropy source.","commonSituations":"Running tests in minimal Docker images/chroots without /dev/urandom; seccomp policies blocking getrandom(2); resource-limit exhaustion under heavy parallel test runs.","solutions":["Fix the environment so crypto/rand works: ensure /dev/urandom exists or the getrandom syscall is permitted by the container/seccomp profile.","Read the wrapped %w cause to distinguish ENOENT on /dev/urandom from fd exhaustion (raise ulimit -n).","Run tests on a host/container with a working entropy source instead of a hardened sandbox.","If reproducible only in CI, compare the CI image with the working local image."],"exampleFix":"// before (docker run)\nFROM scratch  // no /dev, rand.Read fails\n// after\nFROM golang:1.22  // standard /dev/urandom present","handlingStrategy":"try-catch","validationCode":"if _, err := rand.Read(make([]byte, 1)); err != nil {\n\treturn fmt.Errorf(\"crypto/rand unavailable in this environment: %w\", err)\n}","typeGuard":null,"tryCatchPattern":"token, err := generateRandomString(32)\nif err != nil {\n\tvar pe *os.PathError\n\tif errors.As(err, &pe) { /* entropy source missing — fix container image */ }\n\treturn fmt.Errorf(\"cannot create mock credentials: %w\", err)\n}","preventionTips":["Use standard base images that ship /dev/urandom.","Do not apply seccomp/AppArmor profiles that block getrandom(2) in test containers.","Raise open-file limits if tests run with high parallelism.","Fail fast in TestMain with a clear message when rand.Read fails."],"tags":["crypto","entropy","testing","environment"],"backgroundTag":"entropy-source-unavailable","analyzedSha":"187eb24962502e91f1fee856230670958b66e89c","analyzedAt":"2026-09-01T20:34:54.554Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}