alibaba/canal · error · RuntimeException

requestPost remote error, request

Error message

requestPost remote error, request : {}

What it means

Outer catch in HttpHelper.post0() (HttpHelper.java:150-151): catches any Throwable from the POST flow and rethrows it as a new RuntimeException 'requestPost remote error, request : <url>' with the original as the cause. This is the exception callers see. It covers the inner non-200 throw (error 358, preserved as cause), connect/socket timeouts (all three RequestConfig timeouts set to `timeout`), unknown host/connection refused, URIBuilder failures, JSON serialization errors from post() (JSON.toJSONString on the requestBody), and NullPointerException when httpclient is null because the constructor's SSLContext builder failed silently.

Solutions

1. Classify via getCause(): the inner 'requestPost remote error, request : ..., statusCode=...' → handle per error 358; SocketTimeoutException → raise timeout or reduce manager load; ConnectException/UnknownHostException → network/DNS; NullPointerException → httpclient not built (constructor SSL init failed), restart and verify crypto deps; JSONException → fix the requestBody shape.
2. Confirm manager reachability: curl -X POST -v <manager-url> from the canal host.
3. Increase the timeout passed to post() if manager responses are slow.
4. Validate that the payload passed to post() is POJO-serializable by fastjson2 (avoid cycles, opaque types).
5. Monitor this RuntimeException as the signal for manager connectivity/health problems.

// Pre-flight: confirm manager reachable and payload serializable
try {
    JSON.toJSONString(requestBody); // throws inside HttpHelper if this fails
} catch (Exception e) {
    throw new IllegalArgumentException("payload not serializable", e);
}
try (java.net.Socket s = new java.net.Socket()) {
    s.connect(managerInetSocketAddress, 3000);
} catch (IOException e) {
    throw new IllegalStateException("manager unreachable", e);
}

try {
    String body = helper.post(url, heads, payload, timeout);
} catch (RuntimeException e) {
    Throwable c = e.getCause();
    if (c instanceof java.net.SocketTimeoutException) {
        log.warn("manager POST timeout to {} (timeout={}ms)", url, timeout);
    } else if (c != null && c.getMessage() != null && c.getMessage().contains("statusCode=")) {
        log.error("manager POST non-200: {}", c.getMessage()); // see error 358
    } else if (c instanceof NullPointerException) {
        log.error("httpclient null — HttpHelper constructor SSL init failed; restart and verify crypto deps");
    } else {
        log.error("manager POST failed to {}", url, e);
    }
    throw e;
}

When it happens

Trigger: Any failure during HttpHelper.post()/post0() — non-200 manager response, network/DNS failure, timeout, malformed URL/URI, requestBody not serializable to JSON, or httpclient null due to constructor SSL init failure. All are uniformly wrapped by the outer catch.

Common situations: canal-manager unreachable or down; POST timeout configured too low for manager response; requestBody contains a non-serializable field (fastjson2 throws inside the try); httpclient left null because SSLContextBuilder threw in the constructor (then httpclient.execute NPEs); firewall dropping the manager connection; manager overloaded returning slowly.

Related errors

• requestGet remote error, request
• requestPost remote error, request
• requestGet remote error, url=
• requestPost remote error, request
• requestGet remote error, request

AI-assisted analysis of alibaba/canal@87be50e876 (2026-08-14). Data as JSON: /api/errors/46dfc888fd0199d2. Report an issue: GitHub.

Appendix: source

Thrown at instance/manager/src/main/java/com/alibaba/otter/canal/instance/manager/plain/HttpHelper.java:151

            if (heads != null) {
                for (Map.Entry<String, String> entry : heads.entrySet()) {
                    httpPost.setHeader(entry.getKey(), entry.getValue());
                }
            }

            HttpClientContext context = HttpClientContext.create();
            context.setRequestConfig(config);

            response = httpclient.execute(httpPost, context);
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode == HttpStatus.SC_OK) {
                return EntityUtils.toString(response.getEntity());
            } else {
                throw new RuntimeException("requestPost remote error, request : " + url + ", statusCode=" + statusCode
                                           + ";" + EntityUtils.toString(response.getEntity()));
            }
        } catch (Throwable t) {
            throw new RuntimeException("requestPost remote error, request : " + url, t);
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    // ignore
                }
            }
            if (httpPost != null) {
                httpPost.releaseConnection();
            }
        }
    }

    public void close() {
        if (httpclient != null) {
            try {
                httpclient.close();

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