vectordotdev/vector · error

could not parse path

Error message

could not parse path

What it means

This panic occurs in the CEF serializer's `Default`/default-config constructor when `ConfigTargetPath::try_from("cef.severity")` fails to parse. Target paths must be valid event path expressions; the library hardcodes these literals so failure is treated as an impossible internal invariant break.

Solutions

1. Confirm you are on an unmodified build; this literal is hardcoded and should always parse
2. Check for a recent Vector/codecs version change to path parsing rules and downgrade or upgrade accordingly
3. Open an issue with the version and stack trace if it reproduces

When it happens

Trigger: Constructing the default CEF serializer config (e.g. `CefFields::default()` or the public `Self` constructor) when the path parser rejects the literal `"cef.severity"` — only possible if the path grammar or parser changed.

Common situations: Essentially unreachable for library users; could surface after a Vector version change that alters the accepted path syntax (e.g. stricter parsing rules for key names).

Related errors

• can't run runner twice
• enums must always have a tagging mode
• named struct fields must always have an ident
• static regex always compiles
• This can't fail because the inner writer is a Vec

AI-assisted analysis of vectordotdev/vector@bdb87aeaa4 (2026-09-16). Data as JSON: /api/errors/35cc5c65d56981c7. Report an issue: GitHub.

Appendix: source

Thrown at lib/codecs/src/encoding/format/cef.rs:253

        docs::additional_props_description = "This is a path that points to the extension value of a log event.",
        docs::required = true,
    ))]
    pub extensions: HashMap<String, ConfigTargetPath>,
    // TODO: use Template instead of ConfigTargetPath.
    //   Templates are in the src/ package, and codes are in the lib/codecs.
    //   Moving the Template to the lib/ package in order to prevent the circular dependency.
}

impl Default for CefSerializerOptions {
    fn default() -> Self {
        Self {
            version: Version::default(),
            device_vendor: String::from(DEFAULT_DEVICE_VENDOR),
            device_product: String::from(DEFAULT_DEVICE_PRODUCT),
            device_version: String::from(DEFAULT_DEVICE_VERSION),
            device_event_class_id: String::from(DEFAULT_EVENT_CLASS_ID),
            severity: ConfigTargetPath::try_from("cef.severity".to_string())
                .expect("could not parse path"),
            name: ConfigTargetPath::try_from("cef.name".to_string()).expect("could not parse path"),
            extensions: HashMap::new(),
        }
    }
}

/// Serializer that converts an `Event` to the bytes using the CEF format.
/// CEF:{version}|{device_vendor}|{device_product}|{device_version>|{device_event_class}|{name}|{severity}|{encoded_fields}
#[derive(Debug, Clone)]
pub struct CefSerializer {
    version: Version,
    device: DeviceSettings,
    severity: ConfigTargetPath,
    name: ConfigTargetPath,
    extensions: HashMap<String, ConfigTargetPath>,
}

impl CefSerializer {

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