Skip to content

Error Types

Hornet defines its error types in hornet::error.

Error

The main error type returned by all parse and IO functions.

pub enum Error {
    /// A syntax error encountered while parsing.
    Parse {
        file: String,
        message: String,
        src: miette::NamedSource<String>,
        span: miette::SourceSpan,
    },

    /// One or more semantic validation errors.
    Validation(Vec<ValidationError>),

    /// An IO error reading a file.
    Io(std::io::Error),

    /// An error serialising the AST to text.
    Write(String),
}

Error::Parse

Returned by parse_named_conf, parse_named_conf_file, parse_zone_file, and parse_zone_file_from_path when the input text does not conform to the BIND9 grammar.

Fields:

Field Type Description
file String Source file path, or <input> for string input
message String Human-readable description of the parse failure
src miette::NamedSource<String> Source text for pretty-printing
span miette::SourceSpan Byte range of the offending token

Error::Io

Wraps std::io::Error. Returned by parse_named_conf_file and parse_zone_file_from_path when the file cannot be read (not found, permission denied, etc.).

Result

Type alias for std::result::Result<T, Error>:

pub type Result<T> = std::result::Result<T, Error>;

ValidationError

Returned (in a Vec) by validate_named_conf and validate_zone_file.

pub struct ValidationError {
    pub severity: Severity,
    pub message: String,
    pub location: Option<ErrorLocation>,
}
Field Type Description
severity Severity Diagnostic severity level
message String Human-readable description
location Option<ErrorLocation> Source location (line/column), if available

Severity

#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub enum Severity {
    Info,
    Warning,
    Error,
}

Severity implements PartialOrd: Info < Warning < Error.

Variant Meaning
Info Informational; best-practice reminder
Warning Suspicious configuration; BIND9 will load but may behave unexpectedly
Error Definite misconfiguration; BIND9 will likely refuse to start

ErrorLocation

Optional source location attached to a ValidationError.

pub struct ErrorLocation {
    pub line: usize,
    pub column: usize,
}

Note

Most validation diagnostics currently have location: None. Source location tracking is planned for a future release.

Working with miette

Error::Parse implements miette::Diagnostic, enabling pretty-printed error output with syntax highlighting when using miette::IntoDiagnostic:

use miette::IntoDiagnostic;

fn main() -> miette::Result<()> {
    let conf = hornet::parse_named_conf_file(path).into_diagnostic()?;
    Ok(())
}

Sample output:

Error:   × expected ';' after statement
   ╭─[/etc/bind/named.conf:7:5]
 7 │     recursion yes
   ·                  ^ expected ';'
   ╰────

Next Steps