{"record":{"id":"eb568c289dae36d2","repo":"vectordotdev/vector","slug":"failed-to-bind-to-listen-address","errorCode":null,"errorMessage":"Failed to bind to listen address.","messagePattern":"Failed to bind to listen address\\.","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"src/components/validation/resources/http.rs","lineNumber":486,"sourceCode":" let request_method = config.method.clone().unwrap_or(Method::POST);\n\n // Create our synchronization primitives that are shared between the HTTP server and the\n // resource's core logic loop.\n //\n // This will let the resource be able to trigger the HTTP server to gracefully shutdown, as well\n // as be notified when the HTTP server has served a request, so that it can check if all input\n // events have been sent yet.\n let (http_server_shutdown_tx, http_server_shutdown_rx) = oneshot::channel();\n let resource_notifier = Arc::new(Notify::new());\n let server_notifier = Arc::clone(&resource_notifier);\n\n let output_runner_metrics = Arc::clone(runner_metrics);\n\n tokio::spawn(async move {\n // Create our HTTP server by binding as early as possible to return an error if we can't\n // actually bind.\n let server_builder =\n Server::try_bind(&listen_addr).expect(\"Failed to bind to listen address.\");\n\n // Create our router, which is a bit boilerplate-y because we take the HTTP method\n // parametrically. We generate a handler that calls the given `handler` and then triggers\n // the notifier shared by the HTTP server and the resource's core logic loop.\n //\n // Every time a request is processed, we notify the core logic loop so it can continue\n // checking to see if it's time to fully close once all input events have been consumed and\n // the input receiver is closed.\n let method_filter = MethodFilter::try_from(request_method)\n .expect(\"should not fail to convert method to method filter\");\n let method_router = MethodRouter::new()\n .fallback(|req: Request| async move {\n error!(\n path = req.uri().path(),\n method = req.method().as_str(),\n \"Component sent request to a different path/method than expected.\"\n );\n","sourceCodeStart":468,"sourceCodeEnd":504,"githubUrl":"https://github.com/vectordotdev/vector/blob/bdb87aeaa4c4ff27c0ba643c1c77b21bf2ef4013/src/components/validation/resources/http.rs#L468-L504","documentation":"The validation HTTP test server binds its listener early so bind failures surface immediately; if `Server::try_bind(&listen_addr)` fails (address in use, permission denied, invalid address) the process panics with 'Failed to bind to listen address.' This is an environment/configuration problem, not a code invariant.","triggerScenarios":"`spawn_http_server` (used by input/output HTTP validation resources) called with a `listen_addr` that is already bound by another process, is privileged (<1024 without CAP_NET_BIND_SERVICE), or is unparseable on the platform.","commonSituations":"Another Vector validation run or other service already using the port; running in a container/sandbox that blocks binding; IPv6 address configured where only IPv4 is available; ephemeral port exhaustion.","solutions":["Free the port: find and stop the process using it (`ss -ltnp` / `lsof -i :`)","Use a different port or `0.0.0.0`/127.0.0.1 address in the test-case config","Avoid privileged ports (<1024) unless you have bind permissions","Check the address syntax matches your platform's supported families (IPv4 vs IPv6)"],"exampleFix":"// before\nlisten_address = \"0.0.0.0:80\" # privileged port\n// after\nlisten_address = \"127.0.0.1:8125\"","handlingStrategy":"validation","validationCode":"// Check the port is free before starting validation:\n// bash\ntimeout 1 bash -c \"/dev/null && echo \"port in use\" || echo \"port free\"","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Pick unprivileged, uncommon ports for validation servers","Kill leftover processes from prior runs before rerunning","Verify container/sandbox networking policies allow binding","Use explicit 127.0.0.1 instead of hostnames when unsure"],"tags":["rust","http","bind","port","validation"],"backgroundTag":"address-already-in-use","analyzedSha":"bdb87aeaa4c4ff27c0ba643c1c77b21bf2ef4013","analyzedAt":"2026-09-16T02:53:35.741Z","contentChangedAt":"2026-09-16T02:53:35.741Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}