influxdata/influxdb · error · Error::NoHandler

not found

Error message

not found: {0}

What it means

`Error::NoHandler(String)` from `iox_v1_query_api` indicates the HTTP request path has no registered handler. The API router throws it when a request arrives for a route that was never registered, and includes the offending path in the message.

Solutions

1. Check the request URL path against the documented v1 API endpoints (`/query`, `/write`, etc.).
2. Verify HTTP method matches the route — some handlers register per-method only.
3. Confirm the server binary actually registers the handler for that path (feature flags may omit routes).

Example fix

// before
GET http://host:8086/query2?db=db0&q=...
// after
GET http://host:8086/query?db=db0&q=...

const KNOWN_PATHS: &[&str] = &["/query", "/write", "/health"];
fn path_is_supported(path: &str) -> bool {
    KNOWN_PATHS.iter().any(|p| path.starts_with(p))
}

fn as_no_handler(e: &iox_v1_query_api::Error) -> Option<&str> {
    match e { iox_v1_query_api::Error::NoHandler(p) => Some(p), _ => None }
}

match client.get(url).send().await {
    Ok(r) if r.status().as_u16() == 404 => eprintln!("check URL: path not registered"),
    Ok(r) => handle(r).await,
    Err(e) => return Err(e.into()),
}

When it happens

Trigger: Sending an HTTP request to a path that is not one of the registered v1 query API endpoints (e.g. GET /query2, typos like /querie, or disabled features whose routes were never mounted).

Common situations: Client pointed at the wrong server type (query API instead of write API), API version changes renaming routes, or a proxy stripping/adding path prefixes.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• authorization failure
• error decoding multipart file upload
• error decoding params from url
• error decoding query body
• invalid mime type ( )

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/cae7bddfbc1788de. Report an issue: GitHub.

Appendix: source

Thrown at core/iox_v1_query_api/src/error.rs:19

use std::fmt::Debug;

use datafusion::error::DataFusionError;
use iox_query_influxql_rewrite as rewrite;
use thiserror::Error;

/// Error type for the v1 API
///
/// This is used to catch errors that occur during the streaming process.
/// [`anyhow::Error`] is used as a catch-all because if anything fails during
/// that process it will result in a 500 INTERNAL ERROR.
#[derive(Debug, thiserror::Error)]
#[error("unexpected query error: {0}")]
pub struct QueryError(#[from] pub anyhow::Error);

#[derive(Debug, Error)]
pub enum Error {
    /// The requested path has no registered handler.
    #[error("not found: {0}")]
    NoHandler(String),

    #[error("authorization failure: {0}")]
    AuthorizationFailure(String),

    #[error("invalid mime type ({0})")]
    InvalidMimeType(String),

    /// Missing parameters for query
    #[error("missing query parameters 'db' and 'q'")]
    MissingQueryParams,

    #[error("error decoding multipart file upload: {0}")]
    MultipartFile(String),

    #[error("Invalid UTF8: {message} {error}")]
    Utf8 {
        message: &'static str,

View on GitHub (pinned to 06200ef96b)