What causes "VRL is not enabled: please recompile with the `vrl` feature" in quickwit-oss/quickwit?

Rebuild/reinstall Quickwit with the `vrl` feature enabled (e.g. `cargo build --features vrl`).

VRL is not enabled: please recompile with the `vrl` feature

Error message

VRL is not enabled: please recompile with the `vrl` feature

What it means

`DocProcessor::try_new` checks at construction time whether a VRL transform was configured. The binary was compiled without the `vrl` feature flag, so any non-None `TransformConfig` is rejected with this message, since VRL transforms cannot run in that build.

Solutions

Rebuild/reinstall Quickwit with the `vrl` feature enabled (e.g. `cargo build --features vrl`).
Remove the `transform.vrl` section from the index config if VRL processing is not needed.
Switch to an official release binary that includes the `vrl` feature.

Example fix

// before (Cargo/build)
cargo build --release
// after
cargo build --release --features vrl

Defensive patterns

Strategy: fallback

Validate before calling

// check feature support before deploying a config with a transform
// (outside the binary: verify your build's feature set)
// cargo metadata / build script: ensure --features vrl when transforms are used
let uses_vrl = index_config.doc_mapping.transform.as_ref().is_some();
if uses_vrl && !build_has_vrl_feature() {
    plan_err("this build lacks the vrl feature; rebuild or drop the transform");
}

Try / catch

match DocProcessor::try_new(...) {
    Ok(dp) => dp,
    Err(e) if e.to_string().contains("VRL is not enabled") => {
        // fall back to a build with the vrl feature or strip the transform config
        ...
    }
    Err(e) => return Err(e.into()),
}

Prevention

Use release binaries built with the vrl feature when index configs use VRL transforms.
Gate configs containing transform.vrl to builds that support it via deployment checks.
Document feature flags alongside index config schema so operators know the requirements.

When it happens

Trigger: Starting an indexer with an index config containing a `transform.vrl` section while running a Quickwit build compiled without the `vrl` cargo feature.

Common situations: Using a minimal/distro binary or a build with default features stripped, then deploying an index config authored against a full build with VRL support.

Related errors

AI-assisted analysis of quickwit-oss/quickwit@a39730c5cd (2026-09-08). Data as JSON: /api/errors/7ff4296a9add5ff5. Report an issue: GitHub.

Appendix: source

Thrown at quickwit/quickwit-indexing/src/actors/doc_processor.rs:430

    publish_lock: PublishLock,
    #[cfg(feature = "vrl")]
    transform_opt: Option<VrlProgram>,
    input_format: SourceInputFormat,
}

impl DocProcessor {
    pub fn try_new(
        index_id: IndexId,
        source_id: SourceId,
        doc_mapper: Arc<DocMapper>,
        indexer_mailbox: Mailbox<Indexer>,
        transform_config_opt: Option<TransformConfig>,
        input_format: SourceInputFormat,
        fingerprinter_opt: Option<Fingerprinter>,
    ) -> anyhow::Result<Self> {
        let timestamp_field_opt = extract_timestamp_field(&doc_mapper)?;
        if cfg!(not(feature = "vrl")) && transform_config_opt.is_some() {
            bail!("VRL is not enabled: please recompile with the `vrl` feature")
        }
        Ok(DocProcessor {
            doc_mapper,
            indexer_mailbox,
            timestamp_field_opt,
            fingerprinter_opt,
            counters: Arc::new(DocProcessorCounters::new(index_id, source_id)),
            publish_lock: PublishLock::default(),
            #[cfg(feature = "vrl")]
            transform_opt: transform_config_opt
                .map(VrlProgram::try_from_transform_config)
                .transpose()?,
            input_format,
        })
    }

    // Extract a timestamp from a tantivy document.
    //

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