hasura/graphql-engine · error · Error

Error while making the HTTP request to the pre-parse plugin

Error message

Error while making the HTTP request to the pre-parse plugin {0} - {1}

What it means

The pre-response plugin executor failed to make the HTTP request to its hook endpoint at the transport level (connect error, timeout, DNS). Note the message text says 'pre-parse plugin' but the variant lives in the pre-response plugin's error enum — the wording is copy-pasted between crates. Fields are the hook URL and the underlying reqwest::Error.

Source

Thrown at v3/crates/plugins/pre-response-plugin/src/execute/common.rs:17

use std::{collections::BTreeMap, str::FromStr};

use axum::{
    http::{HeaderMap, HeaderName, StatusCode},
    response::IntoResponse,
};

use hasura_authn_core::Session;
use lang_graphql::{ast::common as ast, http::RawRequest};
use open_dds::plugins::{LifecyclePluginUrl, LifecyclePreResponsePluginHookConfigRequest};
use reqwest::header::HeaderValue;
use serde::Serialize;
use tracing_util::{ErrorVisibility, TraceableError};

#[derive(Debug, thiserror::Error)]
pub enum Error {
    #[error("Error while making the HTTP request to the pre-parse plugin {0} - {1}")]
    ErrorWhileMakingHTTPRequestToTheHook(String, reqwest::Error),
    #[error("Error while building the request for the pre-parse plugin {0} - {1}")]
    BuildRequestError(String, String),
    #[error("Reqwest error: {0}")]
    ReqwestError(reqwest::Error),
    #[error("Error parsing the request: {0}")]
    PluginRequestParseError(serde_json::Error),
    #[error("Error parsing the engine response: {0}")]
    EngineResponseParseError(serde_json::Error),
    #[error("Unexpected status code: {0}")]
    UnexpectedStatusCode(u16),
    #[error("Error serializing the modified response: {0}")]
    ResponseSerializationError(serde_json::Error),
    #[error("Error while preparing the response: {0}")]
    ResponsePreparationError(axum::http::Error),
}

impl TraceableError for Error {

View on GitHub (pinned to 724551b9ae)

Solutions

Confirm the pre-response hook service is up and reachable from the engine pod/host.
Fix the hook URL in plugin configuration.
Check DNS/firewall/service-mesh rules for the plugin route.
Raise the hook timeout if the plugin legitimately needs longer.

Defensive patterns

Strategy: retry

Validate before calling

async fn hook_up(url: &str) -> bool {
    reqwest::Client::new().get(url).send().await.is_ok()
}

Try / catch

Err(Error::ErrorWhileMakingHTTPRequestToTheHook(_, ref re)) if re.is_connect() => {
    // hook down: log, retry with backoff, or fail open
}

Prevention

Health-check the pre-response hook before traffic.
Deploy hook and engine together; use service readiness gates.
Set sane timeouts so a hung hook doesn't stall responses.

When it happens

Trigger: A pre-response plugin is configured and the engine, after producing a response, tries to call the hook and the connection fails (service down, wrong port, timeout).

Common situations: Pre-response hook service scaled to zero or crashed; wrong service name in config; network policy blocking engine→plugin traffic only for that endpoint.

Understand the failure class

Background: 'Something went wrong' / 'Request failed (500)' / 'HTTP error! status: 404' — what failed HTTP requests actually mean and how to find the real cause — this error's family across 28 libraries.

Related errors

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/a4abc27fb8d9ae05. Report an issue: GitHub.