EpicGames/lore · error · anyhow::Error

Missing composite store settings

Error message

Missing composite store settings

What it means

Thrown by configure_immutable_store_via_plugin when mode is "composite" but settings.immutable_store.composite is None. Composite stores need the list/description of backing stores in their settings; without it configuration cannot proceed.

Solutions

1. Add an [immutable_store.composite] section describing the backing stores.
2. Verify the subsection key matches the Settings schema field name.
3. Select a mode whose settings block is actually present.

Example fix

# before
[immutable_store]
mode = "composite"

# after
[immutable_store]
mode = "composite"
[immutable_store.composite]
stores = ["local", "remote"]

if settings.immutable_store.mode == "composite" && settings.immutable_store.composite.is_none() {
    return Err(anyhow!("mode=composite requires [immutable_store.composite] settings"));
}

fn composite_store_configured(s: &ImmutableStoreSettings) -> bool {
    s.mode != "composite" || s.composite.is_some()
}

When it happens

Trigger: immutable_store.mode = "composite" in config while settings.immutable_store.composite is None (missing [immutable_store.composite] subsection).

Common situations: Switching mode to composite without adding the composite subsection defining the member stores; copy/paste from a local-mode config; key typo after editing.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Missing local immutable store settings
• Missing replicated store settings
• Missing remote immutable store settings
• Failed to create immutable store plugin
• [environment.endpoint] auth_url is set but [server.auth] is…

AI-assisted analysis of EpicGames/lore@074eb0b0d1 (2026-09-13). Data as JSON: /api/errors/4e73f3804b975925. Report an issue: GitHub.

Appendix: source

Thrown at lore-server/src/server.rs:896

) -> Result<Arc<dyn ImmutableStore>> {
    let mode = &settings.immutable_store.mode;

    match mode.as_str() {
        store_mode::LOCAL => {
            let local_settings = settings
                .immutable_store
                .local
                .as_ref()
                .ok_or(anyhow!("Missing local immutable store settings"))?;

            configure_local_immutable_store(local_settings).await
        }
        store_mode::COMPOSITE => {
            let composite_settings = settings
                .immutable_store
                .composite
                .as_ref()
                .ok_or(anyhow!("Missing composite store settings"))?;

            configure_composite_store(registry, composite_settings, settings, topology).await
        }
        store_mode::REPLICATED => {
            let replicated_settings = settings
                .immutable_store
                .replicated
                .as_ref()
                .ok_or(anyhow!("Missing replicated store settings"))?;

            configure_replicated_immutable_store(replicated_settings).await
        }
        store_mode::REMOTE => {
            let remote_settings = settings
                .immutable_store
                .remote
                .as_ref()
                .ok_or(anyhow!("Missing remote immutable store settings"))?;

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